Prop Rotation on a 27 footer
 

I have a 98 27 footer with a single step. I currently run a 502 EFI with a Whipple (3 to 4 pounds of boost) and HP 500 cam and valve train. I had a Bravo 1 and I ran a 28 pitch non labbed bravo prop. With that set up I would run right around 82 to 84 MPH at 5100 RPM. I might add that the motor wanted to spin faster but I would always back out of the throttle and stayed right at 5100 RPM because the rev limiter would scare the crap out of me every time. I blew the drive and replaced it with an IMCO SC with a 2 in shorty. My question is I reversed the rotation of the prop and have lost close to 8 MPH. I ran a labbed 28 pitch and lost about 8 MPH at 5100 RPM and had a considerable amount of slip in the lower midrange rpms. Should I try a larger prop or should I lower the lower an inch or so. Any help would be great as I want to get this thing dialed before spring. Does any one know what the optimum X Dimension is on this hull? How much does the rotation of the drive affect the performance of this hull?

Thanks in advance

Re: Prop Rotation on a 27 footer
 

I cant believe that with all of the knowledge here that know one has any suggestions or ideas on these questions. Come on now help a brother out. :drink:

Re: Prop Rotation on a 27 footer
 

Well, I would think that you lost speed because you changed lower units, Just a thought but most Founains run an aggressive X dimension already and then you raised it 2", my guess is that you prop is not getting clean water, (its sucking air causing slip) my x is 17 1/2" 2001 27 w/ 500efi

The reason I have been told about different rotation is that the LH rotation levels 27's better at slow speed 25-45mph. I find this to be true I had a 1998 set up LH, and it was level, My current 2001 27 is set up RH and lists heavy to left in mid range.

WILL :D

Re: Prop Rotation on a 27 footer
 

I would say drive height. a single engine hull does not know which way the prop is spinning. but Your wallet will when the drive come apart. max rpm dyno the motor and turn it where the power is. Remember a boat is a hole in the water surrounded by fiberglass that one pours money into, or break out another thousand. Happy boating.

Re: Prop Rotation on a 27 footer
 

Deltarat,
Do a seach on my posts here in the Fountain section, I have a 27' that that started with a ProCharger M3 on a 502 EFI back in 2000 and have tried over a dozen props, LH & RH, Imco 2" shorty (which didnt work out) headwork a few years ago to my current setup with roller cam & lifters. Best speed to date is 89 with a stock Bravo 34p rh, also have a stock Hydro 31p rh that has run 88.2 but bounces of the the rev limiter at 5400+. I plan on playing with props more and also have a set of CMI E-tops to install so 90+ is well within reach.