Propulsion by glider -second way-

[Externet]

Another contraption accepting opinions:

A  submarine glider towing a boat.  
Linked by a hose doing the pull.  
Solar panel+battery on the boat compresses air.  Flow of compressed air towards a bellows/bladder in  submarine bow makes it buoyant with rising bow or sink with dipping bow when venting.
Glider fins on submarine and cyclic compressing/venting should propel the contraption forward.

Would the 'dorsal fin' or the 'tail fin' , or where be a better point to attach the hose for the glider to tow the boat ?

This is a variation from an older thread ----> https://www.scienceforums.net/topic/72310-pour-your-brains-here-on-how-to-build-this-contraption/?page=2&tab=comments#comment-1102215

 

[Ghideon]

1 minute ago, Externet said:

Solar panel+battery on the boat

Interesting idea! But what is the purpose? What would happen if battery just powers a propeller on the boat? And the solar panel+battery could also power a propeller on the submarine, if the submarine is required for other purposes than generating propulsion since boat and submarine is attached through the cable.