Da Vinci Submarine DIY Kit
A boat with sails has a part that is submerged in the water and invisible to enemies. The pilot used a passage to get into the lower part undercover: the Mechanical Submarine. A pulley and rope system lowers the submarine, which can unhook itself underwater and proceed invisibly towards the enemy. The submarine has two air chambers, which can be used for steering and for air needed by the pilot, who has a mouthpiece.