Proper Prop??
06-25-2008, 10:19 PM
#1
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Proper Prop??
I'm looking for some ideas on which direction to head in propping my boat....
It's a 1993 Checkmate 230 Enforcer.
21' of hull 24° deadrise 7' beam...
ACTUAL weight is 3900 lbs "wet"
The propshaft is 6 inches below the keel...
The boat always seems to like a LOT of trim to reach top speed..
It has a 516 cu in big block which put out 592 hp at 5700 rpm at the flywheel dyno'd AS INSTALLED in the boat..
I had a Bblades labbed 28 Bravo on it for a short time and it ran 85.4 mph GPS before I wrecked the prop on some rocks.
unfortunately I wasn't able to get accurate rpm readings on this run but I think it was around 5600-5700...
Right now I'm running a stock 28 Bravo and did get some accurate rpm readings........
3000 rpm at 47 mph
3500 rpm at 55 mph
4000 rpm at 63 mph
5250 rpm at 81 mph
I couldn't get any more that 81mph out of it with the stock prop..
I also just added a Stern Jack which didn't gain me any speed but DEFINATELY helped the handling..
My chine walking is all but gone and the trim has WAY more effect on the boat....
...the only downside is most likely my propshaft is even deeper yet....
Sooooo my question is, would a 3 blade possibly work better for me at this point ?something like a 27 or 29 Mirage plus?
..........or should I get a labbed 28 again and maybe put a "shorty" on it??
Thanks,
Doug
It's a 1993 Checkmate 230 Enforcer.
21' of hull 24° deadrise 7' beam...
ACTUAL weight is 3900 lbs "wet"
The propshaft is 6 inches below the keel...
The boat always seems to like a LOT of trim to reach top speed..
It has a 516 cu in big block which put out 592 hp at 5700 rpm at the flywheel dyno'd AS INSTALLED in the boat..
I had a Bblades labbed 28 Bravo on it for a short time and it ran 85.4 mph GPS before I wrecked the prop on some rocks.
unfortunately I wasn't able to get accurate rpm readings on this run but I think it was around 5600-5700...Right now I'm running a stock 28 Bravo and did get some accurate rpm readings........
3000 rpm at 47 mph
3500 rpm at 55 mph
4000 rpm at 63 mph
5250 rpm at 81 mph
I couldn't get any more that 81mph out of it with the stock prop..
I also just added a Stern Jack which didn't gain me any speed but DEFINATELY helped the handling..
My chine walking is all but gone and the trim has WAY more effect on the boat....
...the only downside is most likely my propshaft is even deeper yet....
Sooooo my question is, would a 3 blade possibly work better for me at this point ?something like a 27 or 29 Mirage plus?
..........or should I get a labbed 28 again and maybe put a "shorty" on it??
Thanks,
Doug
Last edited by Boatally Insane; 06-26-2008 at 06:19 AM.
06-26-2008, 09:07 AM
#2
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If you could find a shorty to try out, it may work good for you, it looks like a labbed 28 is the better choice, I hac a similar boat, and it didn't like 3 blade props, it would cavitate with a small amount of trim, but the sternjack may help that. is this a land&sea stern jack, If you are not running hydraulic steering, it is a absolute must with that set-up, moving the drive back 8" puts a tremendous amount of stress on the steering arm and could lead to a steering failure at high speeds, and you don't want that.
06-26-2008, 09:36 AM
#3
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Thread Starter
If you could find a shorty to try out, it may work good for you, it looks like a labbed 28 is the better choice, I hac a similar boat, and it didn't like 3 blade props, it would cavitate with a small amount of trim, but the sternjack may help that. is this a land&sea stern jack, If you are not running hydraulic steering, it is a absolute must with that set-up, moving the drive back 8" puts a tremendous amount of stress on the steering arm and could lead to a steering failure at high speeds, and you don't want that.
... and I DO have FULL hydraulic steering....
Doug
Last edited by Boatally Insane; 06-26-2008 at 12:23 PM.
06-27-2008, 10:44 PM
#6
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Thread Starter
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