Hey Jerry how long is your ride plate ?
B


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I really didn't see anything on the bottom that stood out as a problem but there is a little 5200 sealant on the bottom I should sand off.

With the shim installed the porpoise was even worse.

Do you have any nozzle wedges?  I would put about 6° of up wedge in, not necessarily get more up trim, but raise the thrust line. See what it does, good or bad. I hate that intake install. .

Thinking it might be worthwhile to reset it. Yuck.



GT

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I hear ya on the intake. I think I might have 6* of wedges at home. I am running 2* now.

What is your shutdown like?  Crazy?

Not crazy but Not good. It's better without the shim but still worse than the old shoe.

I have turnbuckles on my plate and mis adjusted them at one point and it porpoises like no ones business. Made a couple of turns to the buckles and all fixed. Maybe think about changing to an adjustable component instead of the fixed.


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The plate is set at 2* and I have shims to change it.

Got it.


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My buddy had 78 Southwind miniday
He got it home we took it out that damn thing would porpoise like a mofo. 
Got it home 180 the wedge - didn't do anything
He replaced the chevy window motor (the berk e trim motor)
Then went from jetovator to PD nozzle and tried different trim tabs
long story short never fixed the issue had kids sold the boat would have been nice to have cured it.  At one point he sucked a valve into the original block and the piston chewed it up.  Built a 498 had a screaming motor in a lake boat that couldn't ride right.  Oh well cant wait to read how you cure yours. 

TrollerDave

Yeah, I remember the post back on Hot Boat in fact I was the one that gave Squirtcha? the picture of Flyin Brian Neal's (*BN*) cavitation plates so he could copy them. However, he ended up getting some for free off of a buddy's boat. I just can't find the pictures I had of them since the old Hot Boat meltdown so I put up Dan's set up (they both had Southwind type bottoms). Dan put the plate down by 1/8" and Brian 1/16".

I talked to Chris about it when I picked up the shoe to see if he worked with Jack back when *BN* was trying to figure out his porpoise. He said he did and remembered Brian's boat and he said they must of tried 7 or 8 different combinations of things and could never get it to settle down until they used the cavitation plates. I think Brian gained about 6 MPH (went from 88 MPH to 94 MPH) after installing the plates. Here's a picture of his boat at Ming before the plates.

I am no expert but I didn't notice anything that looked bigger than a 1/16" and I don't think that would cause the dreaded Southwind porpoise.

A

A thought:  If it's possibly just a question of moving the CG a bit, why not throw some weights in the bow to see what it does?  If it responds favorably, you could look at relocating the battery to the bow.  A lot easier than moving the engine...

Chris and Joe built me some cavitation plates for the Southwind. The Southwind now rides like a Cadillac and I am extremely happy about it. However, I lost 5 MPH on the top end.



I am not sure what happened maybe I explained it wrong but when Chris and I talked I told him that I wanted the plate to be somewhere between 1/16" to an 1/8" down. I was pretty surprised that I had lost so much MPH (I thought I might lose a couple or break even) so I measured the hook created by the plate and it's between 3/16" and a 1/4". Not much of a big deal since I wanted to get the pieces powder coated anyways. So Chris said he would be happy to make it to my specs with no additional charge.