What is the shallowest pitched aluminum prop you can find at a marine dealer that has been in business for decades and has a wall full of used props and a box full of thrust washers. How about a 4 blade aluminum of shallow pitch and you cut 2 opposing blades off at the root? Or more difficult, find a used 3 bade alum. and cut off the blades half way or so.....just make it a point to get the modification as even as possible.......one way of doing that would be to cut one blade in half and use it as a pattern for cutting the other two.
I would suggest you go to a boat dealer's service area and ask the manager for what you seek, or likewise at a repair shop. Faztbullet who posts on here regularly, is a shop owner and certified mechanic. Might "ping" him.
That certainly would be a more accurate method of determining the operation of an engine.
