Speed

[Russell1]

I have a 1991 20' Capri Bayliner with a Force 125. No matter what I do I cannot go faster that 37mph. Seems like everyone can go 40 or better. Hull is clean, engine runs excellent. Any thoughts or helpful hints?. Timing is good and plugs are good.

 

[Frank Acampora]

Re: Speed

21 foot Manatee cuddy with 1988 Force 125. Speed 37 mph. That's pretty much what you will get. Playing around with the tilt/trim, props, and engine height on the transom may yeild another 2 mph but that's probably it.

Take the pitch of your prop in inches. divide by 12 to get feet. Gear ratio is 1.78 to 1 so for 1.78 turns on the flywheel, the prop turns 1 revolution. use this to figure out how far through the water the prop will move at the engine rpm. divide by 60 to get feet per second. 88 feet per second is 60 mph and 44 feet per second is 30 so now you can figure out your theoretical MPH. I think you will find that at 5500 rpm with a 19 inch pitch prop it comes out to around 48 MPH. multiply by about .85 (this assumes 15% slip) and now you are down to 44. Most of those 125s will not push a 19 pitch prop at 5,500 rpm. At about 5,000rpm with a 19 pitch prop I think it works out to about 40 MPH. so: You aint gunna get too much more than 38.

 

[QuadManiac]

Re: Speed

'91 Capri 18' with Force 90... 38MPH (GPS) Me and 5 gals of gas.

 

[Bigprairie1]

Re: Speed

.....I'm pretty much bang on with Quad (boat/speed wise) and I agree with the Frankster...ya' ain't gonna see too much more than 37-38mph.
How much do you want or do you need?

 

[yfz450guy]

Re: Speed

are there any other manufactures that will interchange between ther're props and the force props?

 

[MikDee]

Re: Speed

If you look at my boat here in my signature, it is a 19' Bayliner Capri Ski boat, it is smaller, lower, (squat city!) & a few hundred pounds lighter then a regular Capri, similar to a Cobra, and approx. the same weight, and the best I can do is 38 right now, but 40 if I trim it up to the max at WOT. It appears to be a 13X19" prop right now, and I just put a new tach in so I don't know top rpm till next time out, But I'd say your doing pretty good!

 

[Russell1]

Re: Speed

Thanks for all the input. It helped.

 

[mighty_bd]

Re: Speed

Ironically I was going to make a thread about this similar topic. I have an 88 procraft 17ft bass boat. I run about 40 max. as well.
Seems right on, I just wanted to add my notes since you asked about speed.
(which I was going to do the same thing)

 

[lakelover68]

Re: Speed

If you look at my boat here in my signature, it is a 19' Bayliner Capri Ski boat, it is smaller, lower, (squat city!) & a few hundred pounds lighter then a regular Capri, similar to a Cobra, and approx. the same weight, and the best I can do is 38 right now, but 40 if I trim it up to the max at WOT. It appears to be a 13X19" prop right now, and I just put a new tach in so I don't know top rpm till next time out, But I'd say your doing pretty good!

I have the identical boat.....but trying to get pic's of others.........I cannot find another boat with the same seating arrangement as mine......It says capri but looks more like the arriva or cobra......with a 19 aluminum prop I was getting 48...bouncing to 50 at 52-5300 rpm..............now bubbling water out of top of block................GREAT !!!!!!

 

[newbie4life]

Re: Speed

I have the identical boat.....but trying to get pic's of others.........I cannot find another boat with the same seating arrangement as mine......It says capri but looks more like the arriva or cobra......with a 19 aluminum prop I was getting 48...bouncing to 50 at 52-5300 rpm..............now bubbling water out of top of block................GREAT !!!!!!

Is this GPS verified? Realizing, of course that the speedometer on the boat is +/- 30 mph.

 

[Shifflett115]

Re: Speed

i have a 1985 19ft bayliner cuddy with an 85 125 force outboard and getting between 37-40 mph