Prop frustration

[JasonB]

I have a 19' deep V bowrider with a Mercruiser #1 (888) and about 215 hp 302, recommended wot rpm is 4200. I have two props.

1. 14.25 x 21 cup Michigan wheel aluminum. Runs well, carries load ok, somewhat responsive to trim, minimal-moderate bow lift. Won't back for anything. Hard to control around the dock.Top speed: 48.8 @ ~4050 Engine accelerates well with this prop to midrange.

2. 14.25 x 17 Hustler aluminum, heavy cup. Handles great. Load carrying so-so, pulls hard at mid range thru wot, very responsive to trim, good bow lift. Backs great. easy to control around the dock. Top speed: 46.x @ ~4050

Any suggestions of a prop that combines the best of both? I generally run the Hustler, but would really like the load handling of the MI Wheel. If the MI would back worth a dang, I would run it more.....

 

[Tail_Gunner]

Re: Prop frustration

I have a 19' deep V bowrider with a Mercruiser #1 (888) and about 215 hp 302, recommended wot rpm is 4200. I have two props.

1. 14.25 x 21 cup Michigan wheel aluminum. Runs well, carries load ok, somewhat responsive to trim, minimal-moderate bow lift. Won't back for anything. Hard to control around the dock.Top speed: 48.8 @ ~4050 Engine accelerates well with this prop to midrange.

2. 14.25 x 17 Hustler aluminum, heavy cup. Handles great. Load carrying so-so, pulls hard at mid range thru wot, very responsive to trim, good bow lift. Backs great. easy to control around the dock. Top speed: 46.x @ ~4050

Any suggestions of a prop that combines the best of both? I generally run the Hustler, but would really like the load handling of the MI Wheel. If the MI would back worth a dang, I would run it more.....

Someting's amiss here gary, 21p alum doing 4050@49 or a 17p doing 4050@46. Using standard number's heavy cupping should account for 1 maybe 2 inche's of pitch id stick with 1, making that Hustler act like a 18p.

So if both props are in good condition the huslter should run at a much slower speed. Id check your tach first since that is the only thing that is a constant, and secondly is your speed gps? These kind of question's are annoying but prop's are expensive and getting good result's is a kick in the pant's and bad results...... well a kick in the other side.......

If you could post your gear ratio we could play with some slip calc's

http://www.go-fast.com/Prop_Slip_Calculator.htm

 

[JasonB]

Re: Prop frustration

speed is GPS and the ratio is 1.5:1.

The tach is a bit in question.

 

[Silvertip]

Re: Prop frustration

Then perhaps you should be looking at tach replacement or at least verifying that it is accurate. You can't get reasonable figures with an inaccurate instrument. Use any of the on-line prop calculators to run the numbers you are seeing. The calculator will tell you if you have unreasonable slippage or the numbers simply don't compute. GPS is apparently providing accurate speed. That leaves the tach, gear ratio, or prop as the point of error.

 

[Tail_Gunner]

Re: Prop frustration

I have a 19' deep V bowrider with a Mercruiser #1 (888) and about 215 hp 302, recommended wot rpm is 4200. I have two props.

1. 14.25 x 21 cup Michigan wheel aluminum. Runs well, carries load ok, somewhat responsive to trim, minimal-moderate bow lift. Won't back for anything. Hard to control around the dock.Top speed: 48.8 @ ~4050 Engine accelerates well with this prop to midrange.

2. 14.25 x 17 Hustler aluminum, heavy cup. Handles great. Load carrying so-so, pulls hard at mid range thru wot, very responsive to trim, good bow lift. Backs great. easy to control around the dock. Top speed: 46.x @ ~4050

Any suggestions of a prop that combines the best of both? I generally run the Hustler, but would really like the load handling of the MI Wheel. If the MI would back worth a dang, I would run it more.....

Reading a bit closer, a good deep v wander's worse the a gypsy at low speed's, mine is useless at 2-5 mph. However trim tab's have been said to greatly reduce the issue and benefit's your hole shot quite a bit, I'd take a close look at them if that's what your looking for......low speed stability if not tach's can easly be adjusted it's just a matter of getting them on a machince and the calibrate them accordingly..

 

[Tail_Gunner]

Re: Prop frustration

Using your number's the 21 pitch is showing good slip number's of 8%, as to the Hustler it's running beyond it's theoretiical speed which is 43, your tach is Hoodwinking you......

Iv'e used a stilletto 3 blade on my I/O and it had just as much bite as the 4 blade i have now in turn's and i could not percieve any better holeshot, but i dunno if they make a prop for that leg,which to say is probably a good thing........dont want to give BoomYal any type of hope for that old barge of his........