The Dis-Pro Boat Company located in Canada produced an inboard style wooden boat between 1914 and 1926 (and some were built up into the 1950’s) known as the “Dippy” that you could raise the drive shaft and boat propeller up into the bottom of the boat using a manual hand lever while under way so you could avoid hitting stuff like rocks and stumps and saving you from boat prop damage. Pretty clever idea for that era.
The boat looked like a big canoe that was steered with a rudder on the transom connected to a rope and pulley system. The small inboard single cylinder engine was located under a bench seat with the drive shaft extending out from the motor almost a foot that connected to a little gear box that was the pivot point with the propeller shaft coming out the box on the other side and out through the bottom of the boat. The propeller shaft and boat propeller were inside a waterproof case so the boat was water tight.
With the hand lever you could raise and lower the propeller shaft to any angle you wanted and the boat even had a skeg located in front of the boat propeller that if you hit anything with the skeg it would automatically raise the prop shaft up so it would stop the boat props from being damaged. Seems like a good idea for today’s inboard boats.
The “Dippy” was not fast so it was used for just leisurely cruising around lakes. Restored they are a popular and prized boat these days that is worth a considerable amount of money. A very interesting, rare and unique boat.
Boat propellers for these boats are no longer available but we can save boaters a lot of money on all modern boat props.
question, you are using the hose to generate prssruee / water flow past the prop in an attempt to force the prop to spin and generate electricty?if that is the case, i would think that you want the prop actually positioned just inside the end of the hose, or apiece of tubing the proper size for a tight fit but not contacting the prop used. that should help avoid caviation and allow the water prssruee / flow to really push directly on the prop blades.which prop is better, given the same total surface area and the same pitch, they are the same. with what you are attempting, i would think more surface area would be better then more pitch, but more pitch may spin faster and generate more power.i suspect the only way to find out which is truly better is to get both and actually try them out.