5 July ’17
Within a week, we’re leaving for Monte Carlo for the Monaco Solar & Electric Boat Challenge. This week we are mainly testing, with succes! Since the beginning of this week, the boat can finally fly above the water on the hydrofoils. The boat cannot fly long distances yet, but it starts looking like this is going to happen soon. Now we must fine-tune the stabilization system, so the flight can last longer. This week we’ll try anything to get this done before the race in Monaco. The race itself is the 13th till 15th of July, we will leave the Netherlands the 10th of July. Still want to receive our postcard from Monaco? Then this week is your last chance to support our crowdfunding! The program for the coming week is as follows:
We’ve already done an endurance race and a sprint in Friesland, but the slalom is a new part for us. Several buoys are placed over a 400m course, all boats must sail between them. Each team gets two attempts, the fastest counts. If you miss a buoy then you get DSQ (disqualified) and 0 points, so it’s important to complete the course successfully at least once.
Another important difference compared to Friesland is that the race is at sea while the rest of the team is in the harbour. This causes a much larger distance between boat and team, which is more difficult in communication with the pilot. If a technical problem occurs during the race, you cannot simply go to the shore. It is therefore well thought out what needs to be done in certain situations.
Another difference is obviously the weather in Monaco. There will probably be a higher temperature and solar radiation. The irradiation is certainly positive, but the temperature can be a risk. The solar panels are becoming less efficient as they become hotter, so they should be kept as cool as possible. The engine temperature is crucial too, we have previously had problems that it got too hot. If it gets considerably warmer than here, a proper cooling is really necessary.
Finally, the sea causes some more challenges: the water is salty and there are high waves. When salt water touches the electronics, you almost immediately get short circuit. If salt touches metal, it will corrode very quickly. All parts are protected, but you can never guarantee it won’t happen of course. So, we need to clean the boat well and take some spare parts with us.
The waves at sea are particularly affecting the stabilization system. This system should keep the boat stable even on larger waves, but of course it has mostly been tested on the channel where there is hardly any wave at all. So we must still wait longer to see how it will behave on the higher and longer waves at sea.
28 June ’17
Because many of our followers have a technical background and aren’t afraid of some numbers, this week we summarize Solar Boat Twente in numbers.
The Conrad Solar Boat Twente is 7.5m long and 1.6m wide, which is 2 times our Renault Twingo in a row. In terms of weight, the 120kg boat is however 16 times as light as those cars. This allows us to reach speeds up to 50 km/h, 35 km/h over long distances (cruise speed). That is as fast as Usain Bolt ran during his world record at the 100m, but then we can keep this speed until the sun goes down.
The deck is covered with 11 m2 of solar panels, with which we can fill more than 1/3 of our office. With an irradiation of 1000 W/m2, perpendicular to the sun deck, we have 1750 W of solar energy available to drive the boat. This energy is temporarily stored in the 1500 Wh battery. On a full battery, we can make coffee for the team for 2 days. Instead, we prefer to drive the engine with it. The engine has a power of 6 kW, but at cruising speed only a quarter of that is required, about the same as the kettle. When the engine is working, it turns around the 5 blades of the propeller, one 3-blade and one 2-blade propeller. At cruise speed, both propellers turn around over a 30 times per second, each in a different direction.
Since the boat is propelled by solar energy, we save a lot of money in our wallet and CO2 in the air: it kills 2 birds with 1 stone! If you look at a speedboat, one of the few boats that reaches speeds like ours, it’s emission is 0.5 kg of CO2 per km. Take for example the 55-km endurance race in Akkrum. On that day we saved 27 kg CO2 and 11.3 L of gasoline, which would have cost us €18.29. Imagine that every test would cost so much …
With 15 people, we have been working since the 5th of September to start the World Cup in Monaco in only 15 days. Due to a great collaboration of 8 different studies and 50 external companies and organizations, it has been possible to present the design of the boat after 12 weeks. After another 19 weeks of construction, the boat could be presented to all 225 attendants!
In 12 days, we’ll leave with 3 cars towards Monaco: 1300 km one way through 5 different countries. After 8 weeks of testing time since the unveiling event, the first of 3 racing days is on July 13th. The race consists of 3 parts:
1) the endurance race: get as far as possible in 2 hours
2) a slalom
3) the 200-metre sprint.
Now there’s another 2 weeks of hard work left to make sure we’ll get back with that top 3 classification from Monaco!
21 June ’17
After a long, exhausting but also enjoyable and educational nine months, we finally have a presentable and (also important) floating boat! Ever since the NK in Akkrum we have showed our boat multiple times at fairs, open doors days and company visits.
For a boat with a length of 7.5 meter and a width of 1.60 we need a very special trailer of course. Many of our faithful followers will know that we are hosting a crowdfunding right now based on our trailer. This colossal trailer is 10.5 meters long, 2.5 meters wide and 2.25 meters high and has been in our workshop for a few weeks now. This trailer was custom made by Cobra Trailer in Germany. When it’s opened, it has a striking resemblance with a stapler by the way 🙂 We have received this trailer on loan until the crowdfund expires at the end of July.
Driving with this giant object is not an easy task. In the past few weeks we’ve hit a handful of curbs and even destroyed a piece of green, but it’s getting better! We even spent an afternoon learning how to reverse with it.
In less than three weeks, this trailer, along with the boat, will have to travel 850 miles to Monaco. Until that time we are still busy with a small optimizations and a handful of practical things on the boat. I think I can speak on behalf of the whole team when I say we are looking forward to the next couple of weeks!
Would you like to help us with paying the trailer? Then check out the crowdfunding.
Would you also like to have the boat at your event or a business visit from Solar Boat Twente? Then contact email@example.com!
One and a half week ago we participated in our first race, the Eneco Solar Boat Race in Akkrum. Only one person is steering the boat. Also, the race doesn’t cover the complete weekend. So what is the rest of the team actually doing during the whole race? We’ll explain it to you now in ‘Racing behind the scenes’.
It all started on Thursday, we’re heading towards Friesland. Everyone has packed his camping gear. Our clumsy coffee machine has also been brought. The boat is in the trailer, tools and spare parts are ready and around 12am we are on our way towards Akkrum. Upon arrival, we get to a grass field next to a small harbor: our campsite for the next few days, together with about 35 other teams. Our tents are pitched next to our boat and it starts to look like a cozy camp. Meanwhile some team members are still working on the boat, since it’s never finished. At night we are really curious for checking out the competitor’s boats at the campsite.
Day #1: Endurance
On the first day, the boat has to cover 53km, not quite interesting for spectators. So it’s still quiet ashore. Captain Ids de Vos is in the boat, but the strategy team is keeping busy too. Part of the team races along with a car, in order to stay within the range of the portable phones. All data from the boat is received on the ground station. The racing strategy is adjusted to produce an optimal cruising speed, this is then communicated to the pilot. The technical team must be ready to leave at all times: when something happens, it must be fixed quickly. That’s why another car with tools and technical knowledge on board keeps within close proximity of the boat too. As long as no problems occur, this car can just watch and cheer. Fortunately, this was the case.
In the meantime we are keeping everyone up to date: we keep in touch with partners, send pictures to family and friends and post updates on social media.
Day #2: Laps Akkrum & sprint
The second day, we all stay in Akkrum. No need for cars means less of a hassle. Lots of visitors have decided to see the solar boats in Akkrum: the town is extra full because of the yearly ‘ReuzeDei’. Team strategy is collecting data again and communicating this with the boat, this time from one spot. The technical team can watch the race and meanwhile be ready in case technical help is necessary. Today this turned out to be necessary: our propeller got a bit loose, so we had to get the boat out of the water to fix it. We all run back towards the harbor through the crowded streets. There we had our first pit stop, not entirely flawless, but for a first time it went reasonably well. Now we can finish the race, so the team heads back towards the finish line.
Until the sprint the boat has to leave the water again. This is to make way for the 20 Young Solar boats. They have their sprint first, it’s a busy day for the men in charge! After an hour we can get back to prepare for the sprint. It’s not far, so no strategy or reparations will be necessary. That’s why we are all present at the finish to cheer our boat across the finishing line. After crossing the finish line, we show the boat to the public and celebrate the successful finish. We were all really relieved and happy: All team members end up in the water.
The award ceremony is later that day. Rumors are that we finished third in our class. It turns out that this is correct, but since 2 classes were combined, we end up at the overall 4th place, but we are still happy with the result. Time for some celebrations! A BBQ makes a great conclusion of this successful weekend.
28 April ’17
The past weeks we travelled a lot to Eindhoven for testing and producing our solar deck. The thin-film technique we’re using is very innovative, which also means some basic things must still be tested and discovered. We’ll take you with us on our route towards a complete solar deck!
After putting together a timeframe with Solliance Solar Research the next stage started, looking for an appropriate laminate to protect the solar cells from the elements. We had to consider both the longevity, the weight of the materials and of course availability. Luckily the opportunity arose to use an experimental boundary layer for the front of the laminate. This foil is made from PET material coated with a chemical layer which makes the film 100% watertight. As strange as it might sound, ordinarily PET is not 100% watertight, which is not quite favourable with solar cells which dissolve in water. Several different samples were made with different barrier foils and back sheets which were thereafter tested under different conditions to see how they degraded. These tests existed from laying some samples on a roof, in sea-water, fresh water, in the lab and in the damp heat chamber. We were especially interested in the results of the damp-heat experiments, since this is a common test used in the solar industry which simulates 30 years of normal use in 1000 hours. We will probably not race our boat for 30 years, but it does give a good estimation of how our “homemade” laminate compares to commercial pv-systems. When comparing the results of the degradation test you could clearly see difference between the samples with the experimental barrier and without it. As expected the laminate with the experimental barrier performed better.
While the tests were running we certainly didn’t sit down. Apart from the fact that we need the solar panels, they must also be connected in a smart manner. When one cell is shaded and thus produces less power, all other cells connected to this cell in series generate the power of the weakest link. This loss cannot be completely ruled out, but by cleverly dividing the cells among different arrays and using so-called smart bypass diodes, we can minimize this loss.
Immediately after the test phase we started production. With the help of Monique and Dorrit of Solliance we spent a couple of weeks cutting, pasting and laminating the cells in the laboratories and cleanroom of Solliance, where we frequently could be found until late hours. Something you might have picked up during a radio broadcast from 3fm last week.
Now that all the panels have been made, tested and photographed for defects we have started with placing the panels on our boat. Bringing us a little bit closer to the end of the production phase!
29 March ’17
This year we are working towards several solar boat races. A race consists of different events and sets many rules for our boat and the team. With less than 2 months to go until our first race, it’s time to explain you anything about it!
The first race is the Dutch Championship in Akkrum, Friesland. This year it will take place at the 26th and 27th of May. This is the fifth anniversary of the race, so therewith it’s a special one for the organization too. We’ll be fighting for a top-3 ranking versus about 10 other teams in our class. Besides, there will be 10 teams in other classes and on top of that 20 teams in the Young Solar Challenge. For us, this first race consists of three events: the endurance race (May 26th), short laps around Akkrum and the sprint (both May 27th).
The first day we have to cover a distance of more than 50km. This is a scenic route through the beautiful ditches and lakes of Friesland. Goal is to finish first, obviously. The biggest challenge in this part of the race is to spread the energy over the whole distance. What speed can you go without running out of energy? What do you do when the sun isn’t shining? Wait until the battery is full (or at least fuller)? Or go along at snail’s pace? Another thing to keep in mind: in some ditches you can’t overtake other teams due to the narrow passage. So do you overtake and consume lots of energy, or do you wait? As you can see, this race is mainly about racing strategy.
On the second day, there are 2 events: the short laps in Akkrum and the sprint. The short lap is a route of just over 2 km, straight through the town of Akkrum. The teams get 1 hour to race as many laps as possible. For spectators I would recommend this event, you’ll see all boats several times without having to move in the meanwhile! This part of the race is preceded by a running race. The boats can start when the runners tip the boat after 1.7 km of running through Akkrum. I still don’t know exactly why this running is, but it’s a funny addition!
Then it’s time for the final event, the sprint. With a distance of about 400m, this is by far the shortest one, which means it’s the fastest and most spectacular one too! All teams push their boats to the limit to be the quickest boat of the day.
Afterwards we can add points to find out who won: on both days, you can get a maximum of 45 points, based on ranking. The first day’s endurance is therefore most important. The team with the most points wins the race and can call itself Dutch Champion for the next year.
For more information, you can always take a look at the website of the race.
22 March ’17
In this blog, the hull itself tells his story:
“In the beginning of this week, I was finally ready to be moved to the Solar Boat Twente workshop in Hengelo. I am born in Emmeloord and have never been somewhere else, so I was quite nervous. My main ingredients? Many square metres of carbon fibre, honeycomb, adhesive film and above all 8 weeks full of long days and hard work. After the complete process of making a mould, putting all different materials in the mould one by one, baking and finishing off the details, I’m finally finished. That was the trigger to move on to a new phase of assembling all separate parts and finishing the complete solar boat.
As the team doesn’t own a trailer yet and I haven’t learned to float, they had to outsource the transport. Fortunately, the transport company Heisterkamp agreed to help us. A large truck came and I was placed into the truck. They said that I suddenly looked small for the first time in my life, although I am 7 metres long. I’m not sure whether that was a compliment or not…
Then the doors closed and we went on our way to Hengelo. I was joined by the bikes that the team members used to travel between house and workshop, so don’t worry that I was lonely. About 2 hours later we arrived at the Thales terrain, I was eager to see my new home! But then the bad news came: the people to open the gate had already left so we couldn’t enter the terrain. One of Thales’ major clients is defence, so the terrain is not simply accessible for anyone. That means we have to spend the night in the dark truck.
After a long time of waiting during the night, the next morning we can enter the new workshop in the old radar tower and I can finally see where I’m going to live for the coming period. It’s great! Lots of place for me to stand and for the team to work on their boat. On top of that it’s close to the water, the Twente Channel. When it’s time for testing, I can nearly jump into the water myself. It was an exciting journey, but I’m so happy to be at my beautiful new home now!”
15 March ’17
Another update from our composite boat builders in Emmeloord. This will be the last blog from here, as we are almost finished after 8 weeks of hard work! The releasing of the boat (getting the hull out of the mould) was quite thrilling: as a result of a little shrinkage of the mould whilst cooling it down, the product can get stuck. By releasing the boat already before the mould had cooled down, the hull was released without any damage, fortunately.
After getting the boat out of the oven for the last time, we glued the ribs into the hull. These are made in order to prevent the boat from bending and twisting during the race. The aluminium inserts are placed in the boat too: the struts (vertical parts on which the hydrofoils will be attached) can be attached to these inserts. The most important is that the inserts are placed in exactly the right angle. With a tiny deviation, the propulsion and hydrofoils are placed in a wrong angle as well. Lastly we cut the top deck to size, so that it can be connected to the hull seamlessly.
Another great detail is that, during the past three weeks, we’ve been building next to Solar Team Eindhoven! The team from Eindhoven started building their car at VABO Composites in Emmeloord, it’s really interesting to share experience and knowledge in such comparable projects in the same phase. It’s always great for us to know why they have made certain choices, same the other way around of course.
This week we’ll dot the i’s and cross the t’s, before moving the boat and all materials to Hengelo. Those eight busy, but at the same time really instructive weeks have passed incredibly fast. In fact we are also looking forward to continue building in Hengelo together with the rest of the team, as we have barely seen them in the past period.
9 March ’17
At 5.30 (!) in the morning my alarm goes off. After some snoozing, it really is time to get out of my bed. At 6.30 we leave Enschede. With a car fully packed with stuff for our booth, we’re heading towards Amsterdam. You cross the ‘Randstad’ during rush hour, so we encounter the unavoidable traffic jams too. With about an hour delay, we enter the Amsterdam RAI about 9 o’clock.
The HISWA Boat Show is one of the greatest aquatics tradeshows in the Netherlands. Lots of boats of all kinds are shown, the newest products and anything in the field of surfing and other aquatic sports. This afternoon, there will be different activities on the water and, for the younger visitors, at the ChildrensLAB. But first all exhibitors are coming in one by one. Fortunately, the organization put coffee ready for us!
Then it’s time to get our own exhibition stand ready. As we can’t take our boat already with us, we’ve taken many pictures and videos of what we’ve been doing the past weeks. Besides, we brought with us some boat components and materials, some finished, some just the bare material. Our flag is positioned right at the end of the longest aisle of the whole tradeshow, can’t be missed 🙂 Then it’s 11 o’clock and the show is finally opened.
During the day, much people come by. It’s great to show all those enthusiastic people what we are currently busy with, the visitors love examining the parts and materials. Everyone wants to weigh and bend our solar cells for example. At the quiet moments, it’s nice talking to our neighbours: our competitors of the Delft Solar Boat Team.
In the course of the afternoon, you start noticing that days like these are gruelling. A whole day of actively starting conversations with people and enthusiastically telling you story is quiet demanding. We alternately make a tour around the show, as we don’t want to miss all other cool stuff that is shown. But when it’s 6 pm, closing time, we are actually relieved. Exhausted, but after a great day with lots of nice conversations, seriously interested people and much inspiration, we leave Amsterdam satisfied. Tomorrow there will be a new day at the HISWA!
1 March ’17
It’s official! From now on our boat goes by the name of the Conrad Solar Boat Twente. We are very pleased with this partnership and we are looking forward to a great time. In addition to the name, Conrad will also supply parts and equipment for the construction of the boat.
In addition, our cozy office has become even cozier. A new team member has joined us to secure a spot in the top three in Monaco. Mark Bruijn is a master’s student in electrical engineering and is working on the boat’s telemetry system. The telemetry system is important in determining the racing strategy. To determine this racing strategy, the team on shore remotely needs to know how the boat is performing (battery and motor temperature for example). Will you risk an overheated motor when positioned second in the race? And if you’re positioned 5th? Will the boat make it to the finish? The team on shore will determine the racing strategy by analyzing the information provided by the boat. This information is sent real-time through a direct connection or a connection through the mobile network (GPRS).
Mark is also going to work on the dashboard and steering wheel. These are of great importance for the driver of the boat. Control of the boat should be simple and clear. We also want the controls to be waterproof, after all, we are on the water. Currently, the design of the steering wheel and the dashboard is finished and testing the electronics can begin.
One of our partners is Benchmark Electronics in Almelo, they focus on test equipment, medical systems and telecommunications. Benchmark provides us with expertise in the field of battery packs, motors and telemetry systems. They can do extensive battery pack testing with our battery packs by charging and discharging our battery packs at different temperatures. The more we know about the performance of the batteries, the better. Definitely since there are substantial time penalties to a battery with too much capacity.
Of course not everything goes without problems. Last week our motor controller suffered a short circuit due to a mistake in the test setup. Too bad, but we learn from mistakes, so let’s call it a good thing.
22 February ’17
As you might have noticed, we are building a racing boat. But when you want to take part in a race, you need a driver of course. Not just one, but a team of three drivers in case something happens, whatever that may be. It turned out however, that it’s not an easy job to choose the right person. The whole story starts at least two months ago:
Time had come to choose someone, but what do you base such a decision on? First we made a list of preferred competences, like experience on the water, technical knowledge about the boat and whether we expect that he/she can follow orders from the shore. One of the most important requirements is about weight: according to the race regulations, the minimum weight is 70 or 80 kg (in Akkrum and Monaco respectively). ‘Minimum weight’ means you have to take extra weight with you up to that minimum, but each extra pound is unnecessary. So we decided the driver’s weight should not be more than those 80kg.
We then constituted a committee out of team members that didn’t want/ couldn’t be our driver. During the team weekend, they finally told us who they had chosen. But the next week we discovered something whilst building the hull: the gap in the solar deck quite narrow. Would our drivers fit in the boat? As this is quite essential, they must be measured again. Two of our three drivers were in Enschede, the boat in Emmeloord, so simply trying out wasn’t an option. The measuring showed that it would either just fit, or they just needed an extra inch. So this wasn’t really helpful…
Then we received the new regulations for the world championship last week. What do they say? The minimum weight was changed to 70kg, just like in Akkrum! Do we want to change drivers again? Easy question, yes! We are racing, so minimizing weight is essential. Less and less people are now possible, so in only one day the committee chooses the final drivers. After some months of measuring, considering, changing, considering and making decisions, we now have made our final decision. And the names of our driving-team are… … *drums*… … … Martijn Wilpshaar, Ids de Vos en Jeroen te Braake! In the coming months, they’ll first get their sailing licence and then gain lots of experience on the water to finish top-3 during the race!
16 February ’17
Last weeks the main focus of the blogs was on high-tech developments, but this not the only aspect of Solar Boat Twente. As a matter of fact, this project would be completely impossible without partners.
This sounds like a cliché, but the support of organizations isn’t a matter of course. At the moment that I’m writing this, already 26 companies and organizations have joined us and there are at least 15 companies we are finishing a collaboration with. This may sound like a lot, but, looking at the statistics, we have contacted a whopping number of 473 companies and spoken to 650 people during more than 1500 conversations.
In the ‘External Affairs’ subteam, 4 team members are daily working on making and maintaining contacts with current and future partners. But how do we do that? Well, you might have noticed that it can be quite busy in our small office. This is usually sociable, but not quite nice for calling a partner. That’s why we use a separate room for our phone calls almost every day.
During the last period, you can obviously see an evolution in the types of companies we are contacting. First there wasn’t much to show them (and we didn’t even know what the boat would look like ourselves), but now it’s possible to talk about specific products and parts. For example, the design of the hydrofoils is nearly done now, so we can show the design to milling-companies and they can immediately see whether they can make it or not. Another benefit is that the whole subteam consists of technical students: we all have a good understanding of what the technical teams have designed and therefore we can easily communicate this with all different companies.
“Why do you still have an extra person in between the technical subteam and the (mainly) technical company?”, you might wonder. Well, the ‘External Affairs’ Subteam is the first to get in touch with the companies. This is primarily not about technical specifications, but in most cases a general explanation about the whole project and what we can do for our partners. Then we can connect the right person in the company with the right person in our team and efficiently communicate about the right things. Most meetings we send two team members: one external affairs and one technical member. By doing this, the technical sub-teams can focus on what’s important for the boat design and not waste time on collaborating with partners. This is better both for us and for the companies: a great collaboration is only possible by connecting the right people.
All collaborations are not just great for Solar Boat Twente as a team, but personally we all learn a lot of it too. When do you ever get to a company that can turn metal up to a height of 5 meter? Or when do you get the chance to laminate solar-cells in a semi-clean room?
1 February ’17
Only 16 weeks to go until the solar boat race in Akkrum, the national championship. We are currently busy realizing everything we have designed since the beginning of this year. During this designing phase, everyone was always present at our narrow office, but now we suddenly have to get used to empty space. A part of the team is in Emmeloord now, parts are being fabricated in the university workshop, in Eindhoven some people are busy making our solar deck and there are company appointments every week again. Fortunately, our electrical engineer provided us a qualitative sound installation for our nice tunes.
After fulltime looking at your laptop screen for a half year, it is great to be actually building the boat now. Sometimes you get some astonished reactions: ‘Is this part really this small?’ or ‘Is the boat seriously this big?’, but most time the real parts look way better than the designed drawings. Sometimes it turns out that a certain part cannot be made in the way you designed it, only thing left is improvising. For example, we wanted to make a hole in an aluminium sheet, which wasn’t possible with the used moulder. Only option was to pierce a circle of a hundred small holes, which together form the large hole. Unfortunately, there are parts too that need to be redesigned: a learning moment and meanwhile a new challenge.
At the office there is an unexpected visitor in between the nice tunes: it is the parcel deliverer with new parts for the boat, again. This is the moment that everyone becomes a child again and starts ‘playing’ with the new parts. As said by one of our team members: ‘men remain kids, only their toys change’. Gradually, all cabinets start getting overloaded by parts and parcels so that we can’t even see the entire office anymore.
Not for long though. Soon, we’ll move to our own workshop at the ‘High Tech Systems Park’ in Hengelo, at Thales. It is the intention to assemble all parts we got and made over there, to finally construct a complete boat. This means that the team is even more distributed throughout our small country. And sadly, less and less enthusiastic team members to receive all parcels from the beloved parcel deliverer.
26 January ’17
This weekend we had our team weekend with 13 men and a woman. We went to Germany, near Bad Ems. These days were full of relaxing and team building in a great atmosphere. It started with the travel towards Germany, where we could finally share everything that happened in Emmeloord and Enschede. Some of us hadn’t seen each other for 3 weeks!
The house was huge! We had a sauna, wood stove, industrial kitchen and enough rooms to get lost in the house. On top of that, there was a great amount of snow which improved the atmosphere even more.
At night, we had dinner and after that just a relax-evening. One of the team members had taken his Wii, so there was a serious Solar Boat Mario Kart Contest. An important thing was at stake, the winner will sail our boat during the race. (Maybe there are some other factors of interest as well…)
Next day, we decided to drive to Koblenz, a town on a 40-minute drive distance. After an endless search for a parking area, we finally found something on a distance of about 3 km from the city centre. When we arrived there, we found out why everything was occupied: there was a populist meeting in town! This led to several demonstrations and a massive police force was present too.
In order to escape from the fuss, we went to a café to enjoy a cup of coffee/hot chocolate/beer. After becoming warm again, time had come for our way back to the cars. This time we took the Koblenz Cable Car to cross the river.
Once home, we wanted to have a winter barbecue. But because of a lack of fire, we soon moved back into the kitchen to ‘barbecue’ the meat there. The rest of the evening was more relaxing, games and Mario Kart.
Sunday, the last day, we slept until late and then started tidying and cleaning up the house. We got back to Enschede not too late, as we had to be back at work Monday morning. Some of us back in Emmeloord, the rest back in Enschede. We’re now actually manufacturing things, so it is all becoming very very real now!
18 January ’17
In this blog we will show you what a normal working-day looks like when you are a composite boat builder for team Solar Boat Twente. At the moment of writing this blog, 7 days have been completed at ‘’VABO’’ composites and we are steadily getting into the flow. The first few days you waste quite a lot of time just looking for the equipment you need but by now our efficiency is pretty good.
At 5:30 our alarm goes off and we have to resist the urge to snooze and just get up to have breakfast. We are on the clock because our bus to Emmeloord leaves at 6:05. We sleep at a farm about 30 minutes away from Emmeloord right in the middle of the fields.
We start our working day with a discussion about our plans and we get some final remarks from the workshop manager. Typical activities are sanding, cleaning, glueing, cleaning, cutting, cleaning, applying mould release and last but not least cleaning.
The mould for our hull has been milled out of a foamy paste and is delivered in two halves. These two halves will need to be sealed so that we can apply a vacuum to our carbon fiber later on, but first we need to apply a lot of chemicals to our mould. The first step is to clean our mould with water and after that mould cleaner. Mould cleaner is a chemical substance that can dissolve most resins, plastics and grease. After cleaning, several layers of mould sealer will need to be applied. This is done to ensure that the mould will become airtight (the foam by itself has very large pores and leaks air when put under vacuum). After applying mould sealer on our mould the next layer is the mould release agent. This layer will ensure that our carbon product can be removed from the mould without too much sticking. It is said that if the mould release is applied perfectly, that you can take a piece of tape, stick it to the mould and then just simply blow it off. A total of 12 layers of chemicals have been applied to our mould and now we have reached the point where we will need to combine the two mould halves in an airtight manner.
We work from about 6:30 to 16:30 after which we go home and charge up for our next day. We hope to finish all of our carbon parts within 8 weeks so there will probably be another blog from the Emmeloord-team within the next few weeks 🙂
21 December ’16
Only 4 nights left and Christmas has come, 7 days later and it’s already 2017! The year that the boat will be made in. The year of the first races of Solar Boat Twente. Immediately in January, we’ll start making the carbon hull. In the meanwhile, we are still working on optimizing all other parts and actually making them. Afterwards all parts will be assembled to end up with a floating boat by the end of April.
This building period is of course perfect for making good photos/videos, so we’ll definitely do that and share them with anyone. That’s already a good prospect for 2017!
But first, the Christmas holiday is coming again. We notice that all team members really need vacation, so no one is allowed to do anything for the boat for at least a week. To ease this a bit, we’ve made some Christmas holiday tips, so we still cannot forget the boat. We’ll share these tips with you now!
- There is no good Christmas without Christmas cookies! The perfect recipe is that of delicious boat cookies. The dough can easily be made of flower, sugar, butter and egg. Then you make a filling, in this recipe a coconut filling, but you can make anything you like.
- The best Christmas song is: “I saw three ships (come sailing in)”
- Celebrate new year’s eve at a special location: on a boat. There are several possibilities like Rotterdam and Amsterdam/Ijmuiden.
- Instead of starting the new year with champagne, take a “Duikboot” (submarine) this year. This is a glass of beer with a small glass of gin inside, upside down. We can’t promise anything about a good taste…
- The 1st of January is the day for New Year’s Dive. It would of course be a lot more pleasant to stay in the boat, but this really is the only moment we all have to get out and plunge into the cold water.
- After New Year, there is still a week left until the start of the new academic year, time for a trip! Enjoy a few days in sunny Monaco, before we all have to get back to work.
We wish everyone a very pleasant Christmas holiday with these holiday tips!
Merry Christmas and a sunny 2017 on behalf of Solar Boat Twente.
15 December ’16
Solar Boat Twente will challenge the waters of Friesland and Monaco with the help of the energy of the sun. However, before this energy can be used it needs to be converted into electrical power of course. We will do this, as you might have guessed, trough means of solar panels and not just any ordinary solar cells. As a unicum in the solar-race world we’ll be using thin-film solar cells.
But how do these solar cells actually work in general? Well, solar cells are made of semiconducting material; these are materials which do not conduct electricity under some conditions but under other conditions they do. Simply put out, a solar cell exists of a sandwich of two different so-called ‘doped’ semiconductors of the same material. One of these has been doped so it has too little electrons and therefore carries a positive load, this is the p-type semiconductor. The other one has been doped so it has too much electrons, therefore carries a negative load and is called the n-type semiconductor. When these two types come in contact with one another the positive holes and the negative electrons will attract each other and form bonds on both the p-type side and the n-type side. Under normal conditions nothing else will happen, however, with a small push in the back electrons can be excited out of the holes. This push in the back comes from energy carried within light. Simply put: the light that surrounds exists of infinitely small energy carrying particles called photons. When these photons hit the p-type side of the material it will free an electron from an electron hole pair. This electron will move to the n-type side of the material and with that create a certain voltage difference between both sides of the material. When both sides are connected trough means of a wire with a lamp connected to it the electron will be able to flow back to the p-types side and light up the lamp along with it.
So now that we’ve got the basics we’ll continue with the materials which you can use to produce solar cells. Typically you would use silicon as a semiconductor for your solar cells. Now these cells are well developed and have a relatively high efficiency, the production process is expensive and complicated. Before the cells can actually be made a silicon crystal has to be grown. Hereinafter the now up to two meter long crystal will be cut in slices of about 0.5 mm, after which some additional layers need to be added to protect the cell and actually let the cell produce electricity. Another technique is the so-called thin film technique. This is a technique which makes it possible to make flexible solar cells with a semiconductor layer of around 0.002mm. Compared to a silicon which would break if you just bend it slightly you can actually wrap this film around your coffee mug. Another nice feature is that you can produce these thin film solar cells through a roll to roll fabrication process like newspapers. Of course it is not as easy as just said but it is not far off. The fact that you need less material in combination with that the production is less labor intensive, makes these cells among the cheapest on the market.
Now you will probably think: “Well, it’s flexible and cheaper, why isn’t everybody using it?” Of course it is not all roses and sunshine with these cells. They are at the moment less efficient that ordinary silicon solar cells. By contrast, it is a highly promising technique which is also much more versatile to include curved surfaces such as roof tiles and transparent variants for windows. The last couple of years there has been a lot of research with as focus to improve and diversities this technique and make solar energy cheaper and therefore more accessible!
We as Solar Boat Twente have, besides setting the goal of a podium finish, set the goal to be an inspirator of the use of green energy by use of innovative techniques. With this attitude we came in contact with Solliance, a leading research institute with a focus to make thin film flexible and tailor made deployable in both large and small scale. Together with the expertise of Solliance we will put together our own protective laminate to be able to make our solar deck as efficient and light as possible!
7 December ’16
Thank you for the presents and ‘pepernoten’ this year! The crafts Piet did a good job in making boat ”surprises” too! I know you have already left the Netherlands, but I would like to give you some advice to make next year’s December a lot easier for you.
Why do you still use a steamboat to sail all the way from Spain to the Netherlands? The steamboat was invented a stunning 233 years ago and since then a lot of progress has been made in maritime industry. That’s why we think it’s time for something new, dear Sinterklaas! Solar Boat Twente recommends using a solar boat for next year, and this is why:
- It’s way faster. You can travel from Spain to the Netherlands within 3 days!
- This boat can reach more people. It’s smaller and has a lower draft. Therefore, the boat won’t hit the seabed, like this year. It can go through narrow canals too, so you can reach small villages without having to ride your horse.
- It is environmental friendly. You have to burn lots of coal to make your steamboat move. The whole journey from Spain, the boat causes enormous damage to the environment. By using a solar boat, you can prevent this and help saving our climate.
- Last but not least, a solar boat looks way better than the old-fashioned steamboat. With a modern and high-tech boat, you immediately get the attention of all those modern Dutch people.
We are currently still building the boat. Past week, we ordered the mould for our boat! Constructing a boat is actually comparable to making chocolate letters: you have a shape, put chocolate in it and then you’ll get chocolate in exactly the right shape. We have a mould, put carbon in it (a thinner layer than the chocolate though) and then get our carbon hull out. The mould is currently being made for us in exactly the right shape! In January, we’ll start putting carbon in the mould. After working about 2 months, we can bring the brand new hull to our workshop, in order to put all parts together.
This summer we will come to Monaco with our boat, which is quite close to Spain. So we want to invite you and the ‘pieten’ to come over and support us during the race. Take a look if this boat is useable for you. Naturally, you may test our new boat too.
So, dear Sinterklaas, we recommend you to move with the times and get a solar boat. Maybe, we’ll see you arriving in the Netherlands in a new boat next year.
See you again in Monaco!
Solar Boat Twente
30 November ’16
Past week, we presented the design of the very first Solar Boat Twente! It was quite an exciting moment for the team, but the design has been received very well. Some regional, even national media noticed this special moment, on which we got lots of positive reactions as well.
On Thursday the 24th of November we had our ‘Day of inspiration’, an afternoon organized especially for our partners and some other involved people. We started the afternoon with a presentation of the boat design. After that, we had some short cases for all participants to think about improvements of our design and other aspects in the whole process. These cases were performed in mixed groups, so communication experts worked on a technical problem while the real technicians thought about PR. In the beginning, some people thought they couldn’t really be helpful therefore, but this turned out not to be the case. This didn’t happen by accident though, we actually hoped to get original ideas with this combination of fresh ideas and knowledge.
We’ll share the 3 most original tips with you:
- Fill the boat with helium, that will decrease its weight
- Watch out for a rebellious driver during the race
- Write a book: ‘Solar Boats for dummies’
Apart from this, we got many critical questions too, on which even we didn’t always have the answer. Luckily there were some very experienced people, who could help us in these situations. These questions however make us think if something’s worth a research and if we have sufficiently taken it into account.
From now on it’s all about optimizing every single detail, evaluating the input of the ‘Day of Inspiration’. In January, we’ll start the actual building of the boat. It might be the case that you’re reading this and thinking: ‘I’ve seen your design and … can be improved a lot!’ or you have another great tip, please let us know!
17 November ’16
With the help of some daylight and great solar panels, also known as photo-voltaic cells, our Twente Solar Boat is going to sail. Through a variety of electrical systems, the solar energy will be guided towards the propellers, where it will meet the water. With about five horsepower aboard, the energy can easily cause a severe damage to our boat. We’ll need to keep an eye on the internal network by measuring the ingoing and outgoing currents. This has to be done continuously, even when the boat is sailing at high speeds.
The ‘Hall Effect Sensor’ is frequently used for measuring those currents. When you place a ferromagnetic ring with a Hall Effect Sensor inside around the wire, you can measure the magnetic field that has been generated. Any blog would get a lot more interesting when the Hall Effect Sensor is mentioned, but this is not the case for us. The following is the problem: it’s a precise and cheap sensor that perfectly uses the Lorentz Force. It is however strongly reacting on other magnetic fields. A large running electrical engine near the sensor will result in worthless outcomes, and probably a disappointed team with a boat on fire.
So to prevent this situation, we chose to use shunt resistors. Those can give us good measurements, despite the magnetic fields in our boat, as shunt resistors work according to the well known Ohm’s law. The shunt is a resistor with a value that is determined very very accurately. This results in a tiny loss of a few millivolt. This difference will be used to calculate the current, through the following formula:
Current = Voltage / Shunt Resistance
A great amount of different shunts exist, all based on this simple principle. In our boat there will be some high currents, so we will need large shunts. Such a shunt is shown in the image. The black strip is the accurately determined resistance. These strips are mostly made of manganin, a metal alloy which is stable even with lots of temperature changes.
The two bolts are the connectors for the wires; the two smaller screws are used to connect the signal cables for measuring the difference in voltage.
It’s great to see how simple components like the shunt are still adding value to a high-tech boat, because of the great reliability and applicability. Getting the right information from the shunt and processing data will however get a lot more complex. Perhaps something for a future blog.
11 November ’16
Our boat will get hydrofoils that lift the hull out of the water. Because boats on hydrofoils have very little water resistance, they can go incredibly fast. This design however poses many challenges. The first requirement is that the hydrofoils should stay at a constant height. Besides, the boat must be stable in 2 directions (roll and pitch). The hydrofoils will be actively controlled to make our boat completely stable. Height and speed will be measured and with that the angle of the hydrofoils can be determined. But how do we actually do that?
First of all the height: we want to keep the hydrofoils at a constant height of 20 cm below the water surface, in order to achieve the optimal efficiency. In control engineering you want to predict the system’s behaviour. Therefore, we model the dynamic behaviour and then look at the 2nd order behaviour of our boat including the controller. The system including hydrofoils is simplified to a so-called ‘mass spring damper system’. Our boat without hydrofoils behaves like a damped mass, so we just have to add a spring to finish the system. That can easily be done by linearly connecting the hydrofoil angles to the measured height. This gives us a first equation.
Secondly, it’s important that the boat is roll stable. This is however much more difficult in control engineering. When the boat starts losing its stability, gravity causes a further rolling of the boat. It’s like when you try to put a pen upright on a table. To get our boat back in balance you need a resisting moment. This is accomplished by increasing the lift on the left or right side. Like that we can prevent the boat to roll over.
Third is the pitch stability. The pitch exhibits the same behaviour as the roll stability, so it’s possible to use the same equation for the pitch. But when the height is regulated, the pitch is already stable. The back hydrofoil automatically gets a higher angle when the boat starts tilting. As a result of this, this hydrofoil creates more lift and the whole boat is straight again. So for pitch stability, the back hydrofoil doesn’t have to be regulated separately, which gives us our last equation.
We get 3 equations resulting from all 3 appointed factors. When the height and roll stability of the boat are measured, we can solve all equations and determine the necessary lift for each hydrofoil. This is how our boat will remain stable on hydrofoils!
2 November ’16
Designing a boat is great and all, but if you’re not moving forward it’s all for naught. That’s why it’s essential to design an efficient and powerful propeller. In order to differentiate ourselves from the other teams we chose to design a counter-rotating propeller set; that is to say, two propellers mounted on the same axis, but rotating in opposite directions.
Why? As it turns out, counter-rotating propellers are more efficient that single propellers. The fundamental principle of the propeller is that it accelerates the water passing through its plane, which transfers momentum from the water to the ship. Only speed parallel to the axis of rotation is useful here. Unfortunately, the propeller also induces rotational motion in the water passing it. This energy is not useful, so normally it is lost. By placing a second, counter-rotating propeller behind the first, part of this lost energy can be regained, increasing efficiency by up to 16%!
This sounds fantastic, but how does one go about actually designing such a set of propellers? This turns out to be quite complicated. A propeller is really a set of wings; the thrust it produces is actually a lifting force, the same force that enables planes to fly. Since the ‘wings’ rotate and the boat itself also moves forward, the velocity of the fluid flow that causes the lifting force is not the same across the propeller blade. Instead, it varies across the radius, both in magnitude and in direction. Besides that, the propellers also influence the flow near themselves and each other, which in turn influences the lifting force and the drag on the blades.
In order to account for as many of these effects as possible, we would ideally use Computational Fluid Dynamics, which is a term for various numerical methods that can be used to numerically determine the behaviour of fluid flows. Unfortunately, we have neither the expertise or the computational resources required. Instead, we can make use of certain approximations that are very useful in propeller design. Chief among these is Lifting Line theory, which approximates each propeller blade as a single line of bound vortices, which ‘shed’ (helical) vortices into the flow field.
According to the Kutta-Joukowski theorem, these vortices are responsible for the lifting force. Besides, they also induce velocities into the flow field that can be predicted with mathematical methods. This way, an optimal distribution of these vortices can be determined, which is the basis for selecting a wing profile for the propeller blades.
Aside from all this, one should also account for the possibility of cavitation. This is a phenomenon where pockets of air form on the propeller blades, which then violently implode. This reduces the available thrust and can damage the blade. At the speed with which our propeller rotates cavitation can be a real problem. Then there are also surface effects, which occur because the propeller is situated a short distance below the water surface, flow aspects caused by the hull and the hydrofoils… These are all factors that influence how well the propeller functions.
All in all, designing the propeller has turned out to be quite a challenge. It is a test of all skills a technical student attains during their studies. But above all, it has been an incredible learning experience to apply all these theoretical methods in a real situation, and the rewarding feeling when you finally attain results knows no equal!
26 October ’16
This week we will, as promised, talk about the developments within one of the sub-teams. Team ”hull” will explain some of the basic concepts when designing a carbon fiber body and ribs.
As stated the hull will be made out of composite material e.g. carbon fiber with epoxy resin. Carbon fiber possesses some properties that make it very nice to work with (strength) but also difficult (an-isotropic). An-isotropic means that the mechanical properties of carbon are not the same in every direction. This can also be seen in the image below: carbon fiber is exceptionally strong when loaded in the fiber direction but a lot weaker and less stiff when loaded perpendicular to the fiber direction. There are several ways to deal with this effect and to maximize the usable strength of the material.
The first action to reduce the an-isotropic properties is to create a weave out of the fibers. Weaves are used a lot more frequently than unidirectional fibers due to the easier handling and increased performance after being damaged. A woven fabric will behave the same way when bent over the Z-axis or the Y-axis. A second possibility to increase performance of the material is to make use of a so called sandwich material: When creating a sandwich plate two outer ”skins” of carbon are placed onto a super light, thicker and structurally weaker core material (often honeycomb or foam). When the sandwich plate is loaded perpendicular to the surface the upper skin will be loaded on compression and the lower skin on tension which will greatly increase the stiffness of the plate. The third and final necessity is to design and place every component in such a way that the forces are loaded in the correct direction as much as possible.
In practice every team participating in races will build their vehicle out of carbon fiber. Other options such as fiberglass combined with balsa wood are certainly possible but also much heavier.
A difficulty concerning design and simulation of composites is the difficulty of predicting the failure modes and the difference between the digital failure modes and the failure modes in reality. Compared to steel composites fail in a sudden and explosive manner. It is also troublesome to model all of the interfaces between different parts such as bolts, glue and other ribs. Something else to consider is the possibility of imperfections in the hull after baking of the material (air bubbles or shrinkage) which can lead to a reduced local strength or the weakening of a glue bond due to deviating gap size. This results in the inevitability of making a lot of assumptions, especially when working within a limited time frame.
The use of composites in structural applications has greatly increased over the past decade, this has resulted in the improved performance of the software dedicated to these materials. Provided that the assumptions are correct and some of the interfaces have been simplified it is now possible to gather usable information about for instance the number and placement of ribs within a limited time frame. So that is exactly what we are doing. The image at the bottom represents our boat with carbon fiber sheets draped in it. The arrows (although somewhat chaotic) show the fiber directions within the hull. It is important to check these fiber directions to ensure that the software has draped your sheets successfully.
This concludes the small update on the design and related topics of the hull. We hope to see you again next week!
19 October ’16
As a new student team at our university, we would like to increase the cooperation with the other teams here in order to help each other. In this context, we had a ‘coffee date’ with both the Green Team and the RoboTeam this week. We obviously didn’t forget Solar Team Twente, as a meeting is already planned with all four teams. I can say though that those gatherings actually led to some really awesome ideas! Naturally, we have to compromise between the different timings and ambitions, but we came up with some seriously good ideas. More about this later on…
Before the end of the week we have a deadline again, this time a very different kind of deadline from the last time though. The goal is to arrange at least 50% of the total budget this Friday. If the sponsoring would fail completely, we will decide to design and build a cheaper boat as we don’t have any spare money yet. So team external affairs continues calling and e-mailing people, but they are (at least still) confident to get everything done.
From a designing perspective everything seems to come along nicely. All sub-teams are making steady progress with no large failures or problems so far, although we do expect to make some errors/flaws in our design that will only surface later on (pun intended). Goal right now is to try and think of every possible risk and error and to adjust the design for these errors. This also means that sometimes the options that are theoretically the strongest/lightest are not the best choice. The reason for this is that we must also account for the producibility of our boat and sometimes look for more practical solutions for problems. Next week our blog will be dedicated to a single sub-team to further clarify this and to give a more in-depth look into our design decisions!
We also felt a bit like photo-models these days, with 2 photo shoots in only 2 days. The first one was at our own office, to show what we do on a regular basis. It does feel a bit forced though when you’re told to discuss spontaneously. Fortunately, you can’t hear our very interesting discussions in a picture. The second shoot was at a more photogenic place, more meant as a team picture. If you happen to be curious about the results, so are we. We haven’t seen any results yet, so the only thing we can do is just being curious too.
12 October ’16
You are probably interested in what happened with the first deadline for our technical team of last Friday. Well, not everything went entirely smooth. We discovered that we wouldn’t get everything ready on time during work hours, so the only option was to keep working in the evening. It was however a very useful evening and we finished all of our tasks. So at the end there was time for some beer too. Although we’re working really hard, we are still students you know.
Then there was some news from the university: plans are being made for a common workshop for all student teams at the campus. Naturally, we will be one of them, together with Solar Team, Green Team and RoboTeam. The UT News and UT Magazine (for alumni) are writing articles about such a place and we got interviewed by both. Keep an eye on them and you’ll see those articles appear in the near future!
This week still has a great experience in store for us. Tomorrow (Thursday), a group of students of the secondary school Waerdenborch are going to visit us. They are working on a solar boat too, so we will give them some kind of a ‘behind the scenes tour’ in our project. We hope to provide them a helpful and most of all a fun afternoon. Looking forward to it!
6 October ’16
In the end of last week, two of us went to the ‘Day of the Innovation’ at Twente Airport. We were present in order to get in touch with other innovative companies from the neighbourhood. Everyone we talked to was very enthusiastic about our project and some even wanted to get involved! We found out that team shirts work too: people really look at your shirt and then start a conversation. That was a great thing to see.
Then this Monday our “Meet the Team” film was ready and shown to the world. We found out that lots of friends see it and start commenting on you. You suddenly get comments on what you do in the film or even strange screenshots of your own face… But on the other hand, this also means that lots of people receive our messages. So let’s stick to that conclusion! (Secretly we like it to get strange screenshots and laugh about ourselves too)
Back to business now. At the end of this week we set ourselves a deadline to have the conceptual design of the boat ready. So this includes major design choices, approximate dimensions and all parts that will be needed. As soon as we have that, we can start trying to find all parts we need and meanwhile improve the design with new conclusions made. Enough to do this week!
28 september ’16
Despite the official start of the fall last Thursday, we enjoyed the nice summer weather at the barbecue by Maxon Motor. A lot of other teams from the entire country were present: solar cars and boats, hydrogen cars and soccer robots. We got in touch with many other teams, and our co-boat builders from Delft and Leeuwarden even took their boats with them! Of course we studied every single detail of them. After all, it was a helpful (and delicious) barbecue.
Furthermore, we visited some companies with a few team members. Last week we got some great tips about hull design from the company Van Oossanen in Wageningen, they’ve got a lot of experience in designing boats. This week we went to Friesland to see whether there is space and tools for us to build our hull over there. Our plan is getting real now.
The highlight was nevertheless this morning, we gained our first experience in film industry. We are currently making an introduction film in which our team will be introduced, with the help of Addictive. This morning we made the records of all team members. It feels quite strange when the camera is filming you at a distance of just a few centimeters 🙂 At the moment they are working hard for us to put everything together. You will see the results soon!
21 Septemer ’16
So this is it: the very first blog post by Solar Boat Twente! We started already two and a half weeks ago, so it’s time to set up our blog. Through this blog, we will take you with us on our path towards the Monaco Solar Boat Challenge 2017. In this weekly update you will get to know what keeps our team busy, all about our latest progress and whether all team members can still stand each other.
In the last weeks, we started expeditiously: Our new office was furnished, the first appointments with companies are arranged and even the first concept designs of our boat started taking shape. Moreover, some magazine articles about our team are published. Despite the tight schedule, we still trust that we’ll finish our boat on time for the first race in May in Friesland.
Hilarious was last Friday afternoon: the first screening for the pilot of our boat. How much space do you actually need to sit and steer the boat? Well, you can measure with a high-tech tapeline. And as the pilot in Friesland can have a maximum weight of 70kg, everyone’s weight has been noted too. We prefer to keep exact results for ourselves…