17 P Saltwater series gain of only 5mph?

[magnoman]

I tried a demo Saltwater series II 17P prop this weekend on my 03 Yamaha F225.
I had on a 17P Alum and the dealer gave me a 17P SS top try. I gained 5 mph and 200 rpm and seem to get on plane faster and not cavitate as much.... the WOT was 5800 , perfect for a F225. where the ALum 17p was
5500 WOT.

Not much of a difference and I thought the SS would bite more with the cupped blades and bring down the RPM?

$100 per MPH not sure if its worth that???

 

[QC]

Re: 17 P Saltwater series gain of only 5mph?

5 MPH with better low end performance is huge. Sounds like a much more efficient prop and maybe you could swing a 19. That might even be faster on the top end. When you get above 60 people talk $1K per 1 MPH . . .

 

[Fireman431]

Re: 17 P Saltwater series gain of only 5mph?

That's pretty good performance improvements. An additional 5 mph and 200 rpm? And your perfect in the WOT range? Great! Don't forget, that SS prop is twice as heavy as the aluminum prop, so that more mass your engine has to spin. Also, the cupping increases frictional drag on the prop that the engine is overcoming. You might get some other improvements with trimming or a set of trim tabs if you don't have them already. I'd be pretty happy with what you have.

 

[Irv964]

Re: 17 P Saltwater series gain of only 5mph?

I tried a demo Saltwater series II 17P prop this weekend on my 03 Yamaha F225.
I had on a 17P Alum and the dealer gave me a 17P SS top try. I gained 5 mph and 200 rpm and seem to get on plane faster and not cavitate as much.... the WOT was 5800 , perfect for a F225. where the ALum 17p was
5500 WOT.

Not much of a difference and I thought the SS would bite more with the cupped blades and bring down the RPM?

$100 per MPH not sure if its worth that???

Get on plane faster, not cavitate as much plus an extra 5mph in the "perfect" rpm range?? What more do you want? If the Stiletto I plan on purchasing soon gives me half of what you gained, I will be totally happy!

 

[QC]

Re: 17 P Saltwater series gain of only 5mph?

Just for clarification, the revolving mass of the SS prop is inconsequential as compared to the load from the pitch itself. Prop weight is just not an issue.

 

[Fireman431]

Re: 17 P Saltwater series gain of only 5mph?

Just for clarification, the revolving mass of the SS prop is inconsequential as compared to the load from the pitch itself. Prop weight is just not an issue.

I've read (I'll have to find it) that the greater diameter of the prop means increased rotational drag, as does the overall weight of the prop being spun. They specifically mentioned that the weight of the SS prop may have a direct impact on the total attainable RPM's due to the mass being moved, combined with the drag (albeit minor) of the cupping. However, I don't remember the test engines used, so his engine may not have an issue.

Nontheless, I think he has a great set up the way it is and shouldn't look to gain too much more.

 

[steelespike]

Re: 17 P Saltwater series gain of only 5mph?

I would say a 5mph increase at the speed you were allready traveling is close to spectacular especially with the other improvements.
I'm thinking it would take a pretty big bunch of hp to gain 5 at that speed.

 

[magnoman]

Re: 17 P Saltwater series gain of only 5mph?

It is pretty good.and I found out today when i returned the demo prop that it was a SWS I older version and that the SWS II will give me even better performance? so I guess I should go for the SWS II

 

[QC]

Re: 17 P Saltwater series gain of only 5mph?

Only thing to remember is that propeller selection is a combination of some Voodoo, mixed with some Physics, mixed with a little luck, and then some more Voodoo . . . It is possible that the SWS II could perform worse as some props just work well with a certain engine/hull combo and your initial results with the SWS I are fantastic. Of course you could've had an especially bad Aluminum prop that made the SWS I look even better. Good luck.

 

[magnoman]

Re: 17 P Saltwater series gain of only 5mph?

Well I guess I will find out just bought a 17P saltwater II . I had a friend with the same F225 that was having performance issues and the Yamaha factory rep
came down and put on a SWS II he said it was a world of difference and the rep
gave him the prop for free !!!!! wish I was so lucky

I asked if I could buy the demo Prop I tried but the Tech siad it was his personal one not for sale........

 

[Fireman431]

Re: 17 P Saltwater series gain of only 5mph?

Also, there is only so fast a boat will go. The hull design limits the top speed. And figure the fuel use at 5500 RPM's is almost twice that of 4000 RPM's.