RBeyer

Hi all,
I've change drive ratios from 1.36 to 1.5 and have developed a porpoising issues, I can throttle out of it play with trim, tabs, etc. but it is irritating at slow speeds. My props are spinning outward, will spinning them in help. Looking for your thoughts and how you run with a 28 Cyclone with twins.

hotjava66

Mine would porpoise under 40 or so if you ran any trim at all. I would just keep drives down all the way until 45 and that pretty much eliminated it. Not worth trimming up for an extra mph or 2 at that speed anyway. 3 blade props were better with porpoise also, and faster if you dont mind having to ease on plane. Had my props labbed with more cup helped a little also.

hotjava66

Duplicate

RBeyer

Thanks for the response, usually trimming up for ride at lower speed in rough water, I guess I could try a 3 blade just wonder about acceleration response, I am boating on inland lakes and are typically short. Quick is better than fast. Do you spin your props in or out?

Sydwayz

iTrader: (1)

Did you change props when you changed the drive ratios?

hotjava66

If you are looking for soft ride when slow drag about 3/4 tab, a 28 will plow through just about anything with tabs down. Thata what I did when my kids were small and riding along

RBeyer

I did not, it is borderline of labbing the 30's a bit more or trying 32's I don't know if it will spin the 32's. It was over propped for the 1.36 struggled to get 4800, light it will press 5400 now. Running 86 GPS though with 4 adults and full of fuel.

FunHome

Keep the drives tucked in and the hop will usually go away. Then once you get up and running above 45mph. Drag a little tab, and trim the drives out a little bit at a time. I run 30p Labbed Bravo 4 blades, but I'd love to upgrade to new five blades and have Casey and Jesse at FJ Propeller Midwest customize them to my needs! If you did this, I think your hop would go away and it would plane better and run faster!

Bring your Boat down to Lake of the Ozarks for the Shootout and I'll show you around!!

RBeyer

So I may have made too many changes and am working backwards to figure out where we went wrong. So I ran best with 32s with -2 but the stern lift was crazy. It ran fastest 95 normally with both tanks full and 5 adults.
We thought let's get rid of some of the stern lift and that should help. BBLADES added rake and cup and removed the diffusion ring thinking the flare on the ring was contributing to the lift. I could not get on plane at all. We put 1" spacers in and got on plane with some cavitation until it came over, acceleration was amazing and it had great bow lift but topped out at 90 MPH and too much RPM 5700 to 5800 slip was 20%. We sent props back put the diffusion rings back on went to 17% slip still running 90 mph at 5500. After talking to Brett today we are gonna try spinning the props in. I know I've seen a bit of talk about it but little in the way of a definitive answer. Trying to get some speed back by reducing slip and keeping RPM. Thoughts?