Finally, as the ship was design only within an hour, I changed a bit my mind concerning the technical data:
As this ship is supposed to be built very simply and as, according to the challenge rules, able to go deep is not required, it is now working only on diesel engine ( a 1200hsp salvaged from old mining truck) with a schnorchel.
It remain a twin hull even if I thought about making it a single one (keeping simplicity in mind).
The hull is black because of a thick rubber painting to increase waterproofing.
For the schnorchel i was thinking of a flexible on, who would be connected with a floater enabling it to be quite longer than a standard one.
Do you think it’s a completely silly idea?
I will develop the story of this ship in a AU thread.