Hi! I want to make a Hybrid Aerial Aquatic Vehicle. The question that I have will sound preposterous, is it possible to combine a T series Thruster and Plane Motors and Propellers and do a sailable UAV configuration. As aerial propellers are inefficient in water, I wanted to explore this possibility.
Hi @Arkhan007 -
That’s a cool idea! Unfortunately, Blue Robotics motors don’t hold up for more than a few seconds when running under load in air - the bearings are oil-impregnated plastic, and need water for lubrication…
Generally large quadcopter propellers can be quite efficient at low RPM underwater!
You can use regular brushless DC motors, and expect to get a few uses of them in saltwater if they are rinsed well, before the standard bearings corrode and seize…
Hi @tony-white -
Makes a lot of sense. Thank you for your input!
Hi @Arkhan007, welcome to the forum! 
Given you’ve mentioned sailing, rather than going below the surface, could you consider having thrusters underneath the vehicle (perhaps with a float to keep the rest of the vehicle suspended), and aerial motors that remain above the water level?
That is understandably more weight than just one set of motors (which could be challenging for the aerial part), but at least in terms of power usage you could switch between the motors when you switch domains, so it may still be reasonably bounded?
Hi @EliotBR! Thank you for the welcome!
I believe the idea you suggested is feasible. Just read an article on NASA - AUAV, which did get the job done in they way you mentioned.
May I ask, if there is a Plane - Surface Vessel vehicle type available similar to Quad - Plane vehicle type to do the switching correctly? Kindly correct me if I’m wrong.
Have a good day, Cheers!
I’m not aware of an ArduPilot seaplane or flying boat type, but that’s also very much in the weeds of ArduPilot, in a section I’m not familiar with. @rmackay9 may have some idea, but otherwise you may get more responses and thoughts in the ArduPilot forum.
If a custom implementation is required, I imagine it would be most straightforward to use Lua scripting to add special functionality to a plane firmware for how it should operate when on the water surface, but that’s very much a guess - as mentioned I’m not well-versed in that aspect of the codebase (and it could depend on what kind of boat and plane setup(s) you’re interested in).