We are two students from the Technical University of Eindhoven and we are currently working on Protei, an open-source initiative to develop sailing drones to clean the oceans.
We designed and built a sailboat that could be easily adapted to different designs, we also took into account to built it using accessible materials and tools.
We hope that we can contribute to the Protei project by designing a platform that enables people to explore different sailboat designs and sailing principles.
We think that one of the major advantages of open-source is the ability of having a large audience during the development of the project. This is the reason why we are making an Instructable, we are hoping that you will help us in developing an autonomous oil-collecting sailing drone by contributing in one way or another.
Check out the Protei group here: https://www.instructables.com/group/protei/
We made a short video of the sailboat in action:
And the Protei video:
We hope that you will have as much joy reading this Instructable as we had building our Protei boats.
Step 1: Constructing the hull
PVC tube (540 mm in length, 70 mm diameter)
We use PVC piping since it is a very common material at most of the hardware shops in the world. The kind of PVC pipe that we are using is the kind that is used to collect rainwater. Another reason to use PVC has to do with the big collection of different couplings available. Using PVC glue it is very easy to experiment with different shapes and sizes.
To transform the PVC tube into a sleek and hydrodynamic sailboat hull we deform the tube by using a heating-gun (used to burn of paint and to isolate electric connections).
Apply the heat evenly on the tube and use some scrap wood to squeeze the soft PVC into such a shape so that the hull cuts through the water. Make sure that the hull is more or less symetrical to make sure that the ship goes in a straight line.
Watch out, the PVC it hot! Don't burn you're hands!
When the sides of tube are more or less touching use a hand-saw to make a diagonal cut (see pictures) to get a nice shape.
Use hot glue or even better; PVC-cement to fill any holes that the bow might have. Fill the other side of the tube with water to check for any leaks. We used hot-glue and got a small leak ;(. To finish the bow, sand any imperfections.
Use a PVC end cap for the stern (back of the boat), don't glue it yet!
Alternative: If you do not have a heat-gun just get a 45 degree coupling and an extra end-cap to make the bow of your sailing boat!
Step 2: Making the keel
Plywood / MDF
PVC tube (100 mm in length, 32 mm diameter)
We designed the keel in such a way that it could be moved along the hull instead of having a fixed location. This creates the oppurtunity to experiment with creating sailing vessels, changing the keel, it’s position, it’s all possible.
Get a piece of wood and sand down the keel to make it more hydrodynamic (it will make your boat faster). Drill two holes at the top and bottom of the keel, use a drill bit that will fit a tie wrap. Using tie wraps, attach the keel to the hull and attach a smaller piece of PVC tube to the bottom of the keel (see pictures).
Use the smaller piece of PVC as a container for the balast, experiment with the amount of weight and glue the cap ends with PVC cement. We used a sheet of lead of about 350 gram and rolled it up (see pictures).
We also experimented with using a PVC clamp to fit the keel, our experience is that it might be sturdier but also induces more friction in the water.
Step 3: Rudder
Scrap MDF pieces
One of the things we can experiment with is the placement of the rudder. Having a long oil absorbing tail makes it difficult to steer with a rudder placed at the back of the boat. To get going we will give some instruction on how to make the rudder, you can place the rudder anywhere along the PVC hull.
Cut down a piece of the hollow aluminum tube, sand the edges. Mark the PVC hull where you would like the rudder to go. Drill in the hull with a slightly smaller drill bit and force fit the aluminum tube in with a hammer. Use PVC glue to completely water proof the hull.
The rudder is made out of MDF wood, sand the edges down, drill a hole from above to glue a wooden rod in it that fits the previous aluminum tube.
We attached another piece of MDF at the other end of the rudder, this wind vane will act as the automatic auto-pilot. The boat will react if the wind direction changes. This means that we don't need any electronics for now, but are limited to the control we have.
Step 4: Mast
Aluminium or steel hollow tube (700 mm in length, we used 8 mm diameter) (mast)
Aluminium or steel hollow tube (230 mm in length, we used 8 mm diameter) (boom)
Aluminium or steel hollow tube (210 mm in length, we used 6 mm diameter) (jib boom)
PVC tube clamp
Use the PVC clamp to fasten the mast to the hull (see pictures). Drill holes in the top of the mast and approx 40 mm above the hull. Use rope to fasten the mast to the bow and to the stern.
Put a bolt (about 5 centimeters in length) through the hole at the top of the mast.
Step 5: Hosting the sails
We used (colored) transparent sheet used in flower shops as the material for the sails. Besides it's cool appearance it is also widely available.
First print out the attached pdf file of the sail template. If you have a bigger sailboat, scale it in the printer menu. Use some tape to stick the template to a surface in which you can cut. (we just use our table ;P ) Then cut the sail sheet approx the size of the template and make sure to tape it to the table.
Start cutting a small piece with a sharp knife and use the tape to fix it again (see pictures). Repeat this process, cut a small bit and tape it back together. This will make sure that the sheet doesn't get pulled while you are cutting. When you cut out the the two sails (jib and mainsail) it's time to make some reinforcements in the sail that is needed in the corners of the sail (the place where it is attached to the ship.
We used duct tape since any prototype is not complete without a touch of duct tape! The duct tape is very sturdy and will make our sails a bit stronger and, of course, it will make it look cooler too, giving it a nice carbon-edition feeling! Just tape the end of the sail with duct tape and then use a sharp knife to cut away the edges (see pictures). Do this also on the other side of the sail, and use your knife to make small holes to fit the rope that will hold the sail in place.
We also put some reinforcement at the front side of the jib because there is a lot of tension there. The mainsail is also reinforced (see pictures) we used the knife to cut small slots to fit tie wraps in that go around the mast.
To make your sail even cooler then it already is with it's sleek design and carbon race edition transparent look, get a sharpie and trace the 'Protei' logo on the sail, note that since it's a transparent sail, any text will get mirrored on the other side!
Next step: rigging!
[need to add the file]
Step 6: Rigging
Solder iron or lighter
Coffee stirring sticks
Aluminium hollow tube (210 mm)
Get yourself a nice cup of coffee and make sure to bring more than one wooden stirring stick with you to make the line tensioners. At least that is what we did. You can also use other kind of flat material as long as it is strong and light.
Cover about two centimeters of from the top of the stick with tape (prevents splitting the wood. Drill three holes on the taped area. Put two holes close to each other and one further away (see the pictures for the position of the holes). Now cut away the taped area and remove the tape. Sand the corners round and you've got yourself an old fashion wooden line tensioner. We use it to tension the mainsail, jib, hale-bas, etc...
You have made two holes in the bottom corners of the foresail(the smaller sail). Tie these holes to the jib boom(210mm aluminum tube) using ropes.
Connect the front hole of the jib boom to the bow using the line tensioners. Now tie the upper corner of the foresail to the screw on the top of the mast, also using line tensioners.
Play with the line tensioners to tighten the foresail about 5 centimeter higher than the bottom of the Mast.
Connect the middel hole of the jib boom to the bottom of the mast with line tensioners. Adjust the length of the connection rope to give the foresail about 60 degrees of freedom.
Tie the mainsail boom to the sail and using a line tensioner mount the sail to the mast. We use tie-wraps to hold the mainsail close to the mast.
Step 7: Testing
We had a lot of fun testing the boats! Here are some reflections:
At the more windy location we could see balanced sailing properties, it was nice to see the boats cut through the water.
We think that the shape of the bow cuts neatly in the water, we couldn't see any major turbelence.
The buoyancy of the hulls are fine, we did not have any water leakage.
One of the masts came loose from it's fitting, by drilling a hole at the bottom of the mast and securing the clamp's bolt through might prove to be a more solid construction.
We had some control over the sailboat by pulling on the safety / retrieval line, it might be cool to have a kite-like control over the sailboat by having the lines attached at the rudder.
The line we used to retrieve the boat more or less acted as the oil-absorbing tail, we could see that our sailboat had lot's of pulling power.
Here is the video again: