aquaforce

If I run a prop slip calculator I have about 10% slip. My boat is a triple and I'm sure the center drive does not slip at the same rate as the outters so what is the difference between them? Is there a rule of thumb to apply here? Does the center drive down deep on a Bravo 1 slip less than the outters by a typical amount?

Just trying to figure out this phenomenon so I can set up my prop labbing project correctly and so all the engines are loaded the same.
What about 26P on the outters and 24P in the center? Good combo? Would the slip difference work well with this setup when labbed?

Ok so learn me.....lol.
Thanks

Griff

If the center engine is turning the same rpm, then the slip should be pretty much the same as the outers.

ben

iTrader: (1)

If your running the same pitch prop on all 3 drives and running the same RPM your slip will be the same for all 3.
Not sure how you would calculate slip on each prop if running a different pitch on the center motor?

aquaforce

Then why is the center drive called the work horse if all the slip is the same?
The center drive is buried deeper and is said to work harder? Why is that?
Some Fountains have different pitch on triples so how does this work?
Is surface props different from Bravo 1 props when it comes to slippage on triples?
For all the claims I've heard and differences out there how can all three slip the same on my B1 setup?
Are triples so rare these days that nobody remembers how they work?

Unlimited jd

iTrader: (5)

The drive is deeper on the boat, but not necessarily deeper under the hull. I'm not sure why it's called the workhorse, but if you have the same prop, the same ratio and the same rpm you have the same slip. It's just math. Now if you have a different pitch to achieve the same rpm the slip will be different

GLENAMY 242SS

iTrader: (1)

I think I see what you are saying, if the center is getting better slip #'s than the outers you would never see it by WOT RPM as the center has no where enough difference to pull RPM independently of the others. More thought required.

rak rua

If revs and ratios are the same then all three props are doing the same number of rotations per minute.

Only variation could be if one engine was fresher (or tired) and could be working easier/harder to maintain the revs. If you put an engine in neutral and drive on two engines, the neutral engine prop will still spin freely by the force of the water rushing past so it is possible a tired engine could be 'helped' to maintain the revs slightly but it would need to be very tired to make a significant difference.

My 2 cents

RR

kr1276

I run the same props on all three. I have heard the same thing about the center being the workhorse but it is always the port that has had a drive failure. The port is RH rotation and center
and starboard drives are left hand rotation. I can get on plane with any combination of two engines.

Friend's 47 Fountain had four blades on port/starboard with a 3 blade and less pitch in the center. He wound up switching his to the same props on all three.

airjunky

iTrader: (2)

420 es the starboard and center are righthand and the port drive swings the goofball prop. The passenger side drive has been ok so far using reverse as fwd. Prob optimal for reliability and such, this boat had had extension boxes installed by the p.o. so some more dialing in is needed. Curious how your testing workss out

kr1276

So do you still have the extension boxes and if so how does it perform with them? If not, then why were they taken off? Just curious. Always thought that extension boxes would really help with
these big boats.