wow.. neat.. you need more nozzles.. 2 for the bow for reverse thrust .. 2 for the transom for forward thrust. then and adjustable volume output.. find an electric start diesel outboard power head for power. but create one with a water tight housing and a air inlet that can be routed in from the upper cabin. so it will work partially with the power head submerged just in case. the power head will fit a multi impeller section pump body this will have inflow blocking valves to the different impeller sections. flow control will also be at the impeller section for each of the 6 hose outlets.... six.. bow and transom are shared .. then you just have singles for the 4 sides for steering.. this would give all kinds of small to 50' boats all kind of handling abilities . and also. the ability to run around the harbor on the diesel outboard with the main engines off. imagine sail boats.. with this system. nozzles don't really need to be below the water line.. but if they are.. sea cocks like you have installed. but i would prefer a flow opened check valve at each nozzle. could it be a tapered plug spring loaded... could it have be a pull in type of unit. that the water pressure in the hose pulls the tapered plug back like a diesel fuel injector. so the thru hull fitting is always plugged and streamlined.. could the thru hull fittings pop out nozzles like a pop up sprinkler head.. just think.. something like this could even be used in tiny boats like oregon dorys.. i would love to build one of these using a PWC jet pump and engine if it could be a diesel.. so vapors are not an issue in the bilge/engine room. there would need to be piston and springs as bypass valves on the impeller sections.. so any trapped water is recirculated back into the pump inlet instead of building too much pressure.

Great