11.1_Optimist
Dimensions:
- Total : 960 * 190 * 1310
Weight:
- Total: 3kg
- Ballast: 1kg
What is really changing is that we are now using a rotating mast. In french we call these "mat a balestron" in which one long boom supports both the main sail and the jib. Other autonomous sailing robots use this system such as Vaimos on ENSTA France. The advantages :
- better performance with a self tacking jib
- no attachment to the hull bow. And that is very important since we are building a shape shifting hull.
- balancing the load on the mast. The push on the main sail and on the jib on different sides minimize the power required to trim the sheet. less "mess" on the deck. We no longer use ropes but a mechanical arm straight from the motor to the boom arm.
disadvantages :
- it is a little less intuitive and tolerant to sail than a regular bermuda rig that we've used so far
- the adjustment of the sail is super sensitive and fast - almost too sensitive and too fast
- the direct mechanical connection could be worrisome for the servomotor in case of extreme wind conditions
We investigate a new mechanism to rotate the mast more effectively. The stainless stain join to link up the mast and Acrylic arm. Acrylic arm is connected to a servo motor. When we control the servo motor, the arm drive the mast and rotate in same direction. the output amplitude unchanged with 90 degree.
In the old system, we used water tubes for the cable guide held by PC sheet. We need to tray the shape of hull, cut the water tube pieces and PC sheet and finally fasten them together with hot glue and zip tie. This is very time consuming and materials consuming, but the performance is not really good. Not only spending lots of time in manufacturing, but also when we rig the cable. We need to point at small hole of the tube and cross it carefully. Therefore, we redesign the system in order to increase the manufacturing efficiency and reduce the rigging time.
Folding the PC sheet and make it because the support and cable guide at the same time is happened in this version of Protei. We fold the PC sheet with triangular shape which allows more tolerance during rigging the cable. Also, in the manufacturing process, the new design save the materials which mean the cost would be lower as well.
In the last version of Protei, we used two servo motor to control the hull and sail, in that design, we need a bigger disk to ensure there is enough amplitude for shifting hull. To reduce the size of disk, we hack the servo motor and change it to a winch which can rotate 360 degree freely and keep tension of cable. Now, the area of the disk reduce 48% and it becomes more stable. Pic(1) show how it works .
The disadvantage of new system is that it become more complicated and we need to adjust the tension of winch before rig to the boat.
Other changes
- add a Acrylic layer between screw and cabin
- Wider hull
- less hole on the PC sheet
- thinner gap in bow and stern
In this part, we explain you how to launch protei 11.1 by setting up electronic, the system direction which controls the shifting hull and finally the rigging.
First, remove the dry box and open it to switch on the batteries.
Then, put the dry box in the boat and screw it with the 4 ear nuts.
Remove the wheel by unscrewing the small screw. Attach the two ropes on the wheel with the two pins : one rope on the first level and the other on the second level.
Make two turns with the line of the upper level in clockwise and two turns with the bottom line in the opposite way (counterclockwise) that the upper line. Then, thread the line in the small plastic tubes. Ropes of each level is for on side of the boat.
Now, thread all the ropes in the loops on the deck. And attach the ropes on the bow and on the stern. Make sure that there is enough tension on the lines to prevent them from tangling at the level of the wheel. Even, when you attach one rope, you can (as in the bottom right picture) curve a tiny bit the hull of on side. The other line will make up for this curve.
Now, you have just to set up the rigging and your boat will be ready to go sailing! Start by putting the mast in the foot mast and finish by connecting the mast at the servomotor arm.
And your boat is ready to go in the water!
See Protei-11.2