1978 with a serious Porpoising problem

[kyfooter]

What are the chances the previous owner hung the boat for long periods of time from the lift rings? I had a friend who did that to his boats years ago, and after a while, both of his boats porpoised. I was somewhat common to hang boats from the lift rings in boat houses in the 70s and 80s. End result...stringers/hull lose their original shape and the boat does things it shouldn't.

That being said, you could try and add hook to the rear of the hull to keep the nose down. Shouldn't take much to make a difference.

[snork]

isn't one of the causes of porpoising too much weight in the aft

[ricford]

I would bet my bottom dollar on rotten stringers. I had a J craft, which doesn't use stringer, but the plywood floor acts as the stiffener, and when the floor rotted out it porpoised really bad. Once that was fixed the problem went away.

[ctjahn]

Originally Posted by thatsmrmastercraft

Would like to see that. My '77 will porpoise a little when not loaded enough. Never an issue with a slalom skier or a footer behind the boat.

I will see if I can snap a pic this weekend... (and btw: My description may be wrong... but I dont know how to best describe it. - The photo should tell)

[thatsmrmastercraft]

Originally Posted by ctjahn

I will see if I can snap a pic this weekend... (and btw: My description may be wrong... but I dont know how to best describe it. - The photo should tell)

I know what you are talking about. No worries.

[ahhudgins]

My neighbor had the same problem with is late 70s S&S. It only takes a very small amount of hull distortion or bad stringers to cause this to happen. He had the hook added to his hull and it's been fine for many years now.

[ctjahn]

Originally Posted by thatsmrmastercraft

I know what you are talking about. No worries.

Not sure if this is a "hook" or just a lip but this is what I have.... (Sorry - bad pics via Iphone and yes its dirty.... too busy USING it)

Cj

[psychobilly]

There's things you can do to the wheel that will solve the "porpoising" issue. I don't know the voodoo but I'm sure that Eric would know what to do. The wedge will work if you don't mind attaching it to your hull. It actually don't have to run the while width of the transom. It's also best to do with wood so that you can tweak it. Too much will shove your bow down. I hand out in a wood boat forum and this has been a topic of discussion over there. I looked last night for the post but couldn't find it. Look up Chelsea coach works on the net and email Mr Hot Rod. I'm sure he will tell you about the wheel voodoo as he has tweaked that hot rod that he built. You gotta see it, it's a work of art in the making and he's a real nice guy.

If you're just wanting to go the wedge route, go to the glen l forum and search out Dave lott's post othe Midnight Cry build. He added wedges to it as it was porpoising BAD as he LOTS of power in her. As you will read it was trial and error or tweaking to get her just right before he sealed the wedges.

IMHO on a MC like you have, tweak the wheel.

[SkiDog]

My 03-X30 did the same thing. Thats one reason I sold the damn thing.

[barefoot]

My guess is rotten stringers or hanging from lift rings. Both would probably create a slight U shape to the hull causing it to porpoise.

Another thought would be to add some weight to the bow. Throw some sandbags up front and see if it solves the problem. might be a quick and inexpensive fix for the time being...