Pat Ousborne

My Fountain 38 Sport Cruiser [loaded down with generator,AC fuel and etc] turns 23 Hydro Quad 4s 4950-5000 RPMs and 64-65 on GPS. Would lab finishing be worthwhile in this speed range? What would you expect for an SC?

737jetmech

iTrader: (1)

My boat responds well to stock merc props. I've tried labbed props with little to no speed increase although my rpm has increased (higher slip #). I would try some 24 bravo1's before labbing your hydro's.

Bob

Pat Ousborne

I just bought these Hydro props to provide more sternlift as needed for twin step hull design I believe these are the right props based on Fountain info and personal research and Merc props would also work. Really, I don't want to switch props again. Also 23 Hydros are equivalent in pitch to 24s in Bravo specs and rpms are where they should be. I picked up 3mph already and am very pleased with Hydromotive but just wondered if others had seen increases with similiar boats and similiar speeds -mid 60s when lab finishing. Its not worth it to me to get half a mph but 2 would be good enough .

Griff

What engines???? Do you want more rpms????

Pat Ousborne

I'm running 502 MPIs @4950-5000. I could pick up a little rpm maybe up to 5100? but already am near the top of recommended rpm band. If lab finishing would get me 100-150 rpms that would probably be ok and under the rev limiter.I wonder if it would?

Griff

You could have them labbed with added cup and increased pitch to keep the rpms about the same, and you would still pick a few mph.

bbladesprops

You can Lab the propellers and gain some top rpm and top speed (.5-2 mph, smoothness and throttle response). It is a balancing act with those props as far as losing mid range also. Make sure the it is done correctly.

You picked up 3 mph already from what propellers before?

Hydros can give better top speeds on Fountains out of the box only, compared to B1's, but rarely improve and often decrease midrange speeds. Especially on SC editions.

Pat Ousborne

The props on the boat were 23 Mirage plus put on by the prev. owner for no good reason I can come up with. They slipped lacked top end and felt very unresponsive in acceleration. With the 23 Hydro Quad 4s much better all around.The difference made me think that props must be about the best way to increase in efficiency. It sounds like you prefer the Bravo 1s if I lab them on this twin step 38 SC.

bbladesprops

I do like the B1's better especially on the SC's. It's not that the Hydros aren't good, they are. It's just that the B1's have better mid range where you spend most time running.

It's no doubt you picked up performance over the Mirage + props on that boat. What you really did was harness the slip issue.

You already own the Q4 props and they are running in the 10.71% slip range. Having them Labbed to gain 100+ rpm is a fine idea. You will see some acceleration and smoothness gains.

B

Pat Ousborne

Thanks Brett for your input. Sounds like a winter job when the boat is put away this fall. Would the reliability of the props be a concern with this work? Also if you don't mind, what would be fees are we talking here to do the job right?