stiletto prop question

[red10]

i don't know if any of you prop gurus know if adding cup to a stiletto 21 pitch prop would make a difference in prop efficiency when mounted high on the transom. I have a johnson 150 on a fish and ski thats mounted to the transom in the 3rd out of 4 holes from the top, my rpms are good but i want to know if i can get more speed and handling having the motor mounted at the highest setting and it does have a stepped hull(transom). thanks guys

 

[jimmbo]

Re: stiletto prop question

Any time drag, either lower unit or boat hull, is reduced speed should increase. As you raise the engine out of the water you reduce the engines' leverage to hold the bow/boat high. Stilettos have a blade shape that responds well to high transom heights and provides a good deal of bow lift. The only way to know what happens is to try running the engine at higher heights. Adding cup on the stiletto can be done by adding it to the trailing edge of the blade, adding pitch. Another way would be to add the cup to the tips of the blades, this would be like adding more rake to the prop.

 

[red10]

Re: stiletto prop question

thanks jimmbo, i think i need more rake so the bow will ride higher because i tried a raker and the bow rides pretty good compared to the stiletto. The raker likes to blowout on take off and in corners it won't hold on real well even trimmed down, the stiletto holds real well, anymore input is appreciated. thanks again

 

[jimmbo]

Re: stiletto prop question

I run a Raker and am very pleased with it. It was the prop I had on my 150 outboard. I never had it blow and it held very well in turns, unless the motor was overtrimmed. I also used a Stiletto on the outboard and found it had almost as much bow lift as the Raker. The raker is a 20 yr old design but it was a good desihn and still holds its own against newer props. When I switched to my I/O I had it rehubed. Bombardier has or is about to reveal a newer Raker 2

 

[red10]

Re: stiletto prop question

thanks jimmbo for the help, i think i'll get my raker worked a little because its the old style and a few nicks in it, i also need to take an inch of pitch out of it.