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porpoising-prop, ballast, or ???

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Old 07-08-2011, 11:08 PM
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I don't think Baja made a boat without some hook in it. My 280 is much better with 4 blades.
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Old 07-08-2011, 11:17 PM
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Right. To me Baja's are a bit on the low end of the cig boat spectrum, but then again Sunsation actually molded this hull, so who the hell do ya blame. There's no physically noticeable hook, but I guess if I took mic measurements, it wouldn't be perfect.

To four blade land I go, where it ends up, nobody knows.


Last edited by bigbang; 07-08-2011 at 11:27 PM.
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Old 07-08-2011, 11:35 PM
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Originally Posted by bigbang View Post
There's no physically noticeable hook, but I guess if I took mic measurements, it wouldn't be perfect.

"you'll have to clarify that a bit"

physically noticeable as in with a long straight-edge? or just to your eye?
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Old 07-08-2011, 11:41 PM
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If you take a 4 foot long straight edge, I bet that you will find a hook. You might be able to overcome the bottom with a 4 or even a 5 blade prop, but if you do have a hook, the boat will be faster, more fuel efficient, and much easier to drive if your bottom is straight. It is much easier to fix a handling problem if your bottom is true and sharp.
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Old 07-09-2011, 08:12 AM
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Thanks for all the input. I'll try and prop my way out and see where it goes, I'm thinking a bit more stern lift via propping will help some. Thanks again.
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Old 07-09-2011, 08:37 AM
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DIAMETER? I think the mirage 23 plus is 14 5/8, so if I go down an inch in pitch, where should I go with my diameter? I've found 14, 14 5/8, 15 1/4 and others.

Thanks.
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Old 07-09-2011, 03:30 PM
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Originally Posted by bigbang View Post
You'll need to clarify that a bit. that is "bottom of the boat" or "bottom number on props". It's not impossible to drive, it's just a game of chance whether or not she'll porpoise, and the research shows all of these hulls had the same issue. I can get her beyond 60, but not without dragging some tab, and in a windless and waveless condition, I shouldn't have to do that. But everyone's input here is going to finally resolve the issue, and maybe I'll sink her, maybe I won't.
Bottom of boat. You may find the issue in the hull. props can make it worse too.
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Old 07-09-2011, 05:36 PM
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Originally Posted by bigbang View Post
You'll need to clarify that a bit. that is "bottom of the boat" or "bottom number on props". It's not impossible to drive, it's just a game of chance whether or not she'll porpoise, and the research shows all of these hulls had the same issue. I can get her beyond 60, but not without dragging some tab, and in a windless and waveless condition, I shouldn't have to do that. But everyone's input here is going to finally resolve the issue, and maybe I'll sink her, maybe I won't.
+1 on the bottom. If Sunsation built the hull, maybe they can help you. I think your speed is out running the hull. How does the boat ride at 50-55 MPH? If the answer is "good", get someone to help you with changes to the bottom.

Last edited by BenPerfected; 07-09-2011 at 05:37 PM. Reason: clarity
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Old 07-09-2011, 06:41 PM
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Two suggestions based my experience with a similar boat.

First, find a boat shop at a marina that will let you water test props. The one I found required a credit card deposit and then let me test as many props as I wanted. So, I took a Tuesday off work and headed early to the lake so it was empty. I took the boat in and out of the water to change props. Take with you a stopwatch, gps and a notebook. Nothing better than simply trying different options. I also bought a prop from them. It was maybe $100 more expensive than I could have got it elsewhere, but being able to test 5 props in 1 day was well worth the premium.

Second, going from a 3b Mirage Plus to a 4b Revolution in the same pitch did wonders to tame down my boats porpoising. Whomever said a 4b Bravo 22 will run near same rpm as 3b Mirage is right. I found the 4b Bravo's diameter to be a bit overkill for a smaller boat. The 4b Revolution was spot on - improved holeshot, better cruising speed, much less porpoising and only a tiny reduction in top end vs the Mirage Plus.

So, test some options if you can. If that's not possible, go with a 4b Revolution 23p.
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Old 07-09-2011, 09:39 PM
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I would try a Rev4 as well. Lots of lift and bite. Propgods.com has a prop testing program that might work for you.
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