I am working on my first ROV. I would like to have your advice about the design that I intend to build, because I am not sure that this is a good or feasible idea.
The ROV main body will be a traditional tube, and it will have 4 thrusters:
- 2 thrusters oriented vertically, in order to provide vertical motion and roll control (with differential thrust). They will be placed around the center of gravity of the ROV, on both side of the main body.
- 2 thrusters oriented horizontally, to provide back and forth propulsion and yaw control (with differential thrust). They will be placed at the stern of the ROV, on each side of the main body.
In order to have some pitch control over my ROV, I would like to be able to orient the back thrusters around the pitch axis. To do so, I think of two solutions:
- Link the motors to a servo inside the main body of the ROV, using a shaft that would cross the body of the ROV, perpendicularly to the main back/forth direction of the ROV.
- Put one or two servos outside the main body of the ROV, linked to the motors to orient them.
Solution 1 tempts me, but I think it is a challenge to make the shaft crossing the hull of the ROV and preserve the watertight of the main body, while allowing it to rotate around its axe. I could not find any solution for this on the forum I visited. Does anyone has an idea on how to achieve that? What depth could be reached with such a system? Do you think that it is too difficult to have a watertight connection between the motor and the inside servo?
Solution 2 is much simpler, but the downside would be the price. I found some watertight servos on the internet that rated around $100! It is too much for my budget, so I was wondering if there would be some simple way to make a standard servo watertight? Compare to solution 1, this solution seems to me safer because if the watertight servo fails, I only lose a servo, and not the full electronic onboard the main body of the ROV!
So I would appreciate to have your opinion about this design, and the best solution to make it real!