Black Pearl II Hydro - 2020
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Than you kindly sir! The pictures help a lot.
Including the one you are working on right now, how many have you built?Nortavlag Bulc
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HA! I made a spread sheet for this.
Number of factors to consider. Speed, weight of boat, then diameter of the turn. With that you can come up with G force. That math assumes a perfect world though. There were too many missing pieces in my formula. You enter at say 70 mph. Apex at 45? Not sure. Then......how much actual slide happens with the fin. Sorta like prop efficiency. Props don't give us 100% grip on the water they pass through. Same with a fin. You may do a 40' radius turn but the speed changes through the whole thing.
If you turned a perfect 40' radius at 60 mph..............you end up at 2.81G. That weight is hanging/sliding on the fin and the rudder......sorta? There's also the angle of the fin. The shape of the hook. Is the hook lifting in the turn or pressing into the ride pads? Are the sponson edges doing anything? Depends on that lift again.
Clear as mud.
There's likely a way to figure it out but I quit farting with it. Figured I'd burned enough brain cells on it.Noisy personComment
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Jeese... ask a simple question.... lol...
I'm just going to copy this. https://www.mojoracingproducts.com/c...rt-hydroplanes I don't want to bother with an adjusting rod like Larry and some others use... I have some 1/4" material but the buggers cut it 1-1/4" high so I have some material to remove the hard way...Nortavlag Bulc
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You can use a version of the pictured system to hold the turn fin straight. That's what I'm using on my Black Pearl.
Lohring Miller
Anderson Sp 40 rt side 2003.jpgComment
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Past NAMBA- P Mono -1 Mile Race Record holder
Past NAMBA- P Sport -1 Mile Race Record holder
Bump & Grind Racing Props -We Like Em Smooth & WetComment
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Larry does it in a similar way. I'm not sure I'm into breaching the hull there. What if the rod starts turning instead of adjusting? I need a diagram or something to understand how that rod stays put when you try to adjust it.Nortavlag Bulc
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The picture is of an experimental Mark Anderson sport 40. I don't have a picture of my Black Pearl but this is a similar size boat. I anchored the hull end that goes into a blind nut with a lock nut that keeps the threaded rod from turning. Two nuts on either side of the turn fin end allow adjustment and can be locked against each other. You can see the hull side lock nut and the outside adjusting nut in the picture.
Lohring MillerComment
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Thank you. Last question. Is the blink nut and a lock nut on the inside of the hull ?Nortavlag Bulc
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Lohring Miller
P1010006.jpgComment
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O.k. thanks I got it now. I was also talking to Larry yesterday and he explained a lot.Nortavlag Bulc
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I haven't bothered with trailing edge fin support on a P boat. I did do it on my Q whip though. The one with no transom has a support at the end of the turn fin. I put a piece of aluminum backing inside. Drilled and tapped the aluminum through the hull. Bullet proof......until the deck rips off of course.Noisy personComment
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