Twisted

[johnsonm50]

In the last few days of warmer temps I got out one of my hydros & turned it bottom up to put a finish on. I checked it by putting a level on various places & found about a 3/8" twist from across the aft of sponsons to the transom between traps. Its twisted in the direction that would press the port sponson deeper, guessing that to be worse than the other way?
Ive got it weighted to counter the twist & when I turn it over will be sure its on a flat level plane. Has anyone had luck straightening one out like this? Its an old hydro that is otherwise in very good shape. At CSH speed would it matter much in terms of performance?

[Skoontz]

It is my understanding that some boats have been built with that "twist" you describe to make them corner better. My daughters boat has about a full inch of twist, the right sponson is about a full inch higher than the left so when it goes into a turn, it glides across the water rather than have the right sponson push into the water and further slow the boat.

[johnsonm50]

It is my understanding that some boats have been built with that "twist" you describe to make them corner better. My daughters boat has about a full inch of twist, the right sponson is about a full inch higher than the left so when it goes into a turn, it glides across the water rather than have the right sponson push into the water and further slow the boat.

Thanks Bill, food for thought.. That would set the starbord aft trap deeper too, why I thought it the worse of the possible way to go..?

[Skoontz]

Thanks Bill, food for thought.. That would set the starbord aft trap deeper too, why I thought it the worse of the possible way to go..?

I think I wrote that backwards...I was referencing right/left from behind the wheel.....

[johnsonm50]

I think I wrote that backwards...I was referencing right/left from behind the wheel.....

Easy to do, lol. Ive seem a few hydros padded on the starboard sponson about 1/2 its width on the inner aft part. Why I thought mine to be wrong. Weighting has worked a little, from my old autobody experience Id say to go a little past then release & check to be what might work.

[Bill Huson]

Not uncommon. I think it is called "warp plane" - whatever - I built twist into several of my boats, not much, usualy about 5mm.

[johnsonm50]

Not uncommon. I think it is called "warp plane" - whatever - I built twist into several of my boats, not much, usualy about 5mm.

Thanks Bill, When you did that was the plane warped to set the starboard sponson & port transom deeper ?

[johnsonm50]

This for me is hard to guess at. If the twist has the port sponson & skeg deeper at the same time as the aft starboard corner was deeper in a turn would this cause the boat to dig in, hop & drag the speed down or go around smooth & easy. Often I find things to be kind of opposite of what would seem right. On this because of what Ive seen I think if a twist is good mines the wrong way.

[csh2z]

Starboard sponson -up. Port sponson -down. When the boat is right side up.
I suggest that it is intended that way. Leave it alone and no need to compensate. It improves turning.

[Bill Huson]

not sure . . .

Thanks Bill, When you did that was the plane warped to set the starboard sponson & port transom deeper ?

about the sponsons. I had a pair of L frames set at bottom width that I built the boat on. The long L frames were jointed flat and squared up. Boat was built off "sponson girders" - 5mm foil shaped pieces that served as the air trap and even deck fins. Yeah, weird way but I liked it. Anyhoo, after I flipped the right-side-up frame build over and sheeted the bottom the boat would be flipped again and clamped down to the L frames with a 5mm shim at each corner. Then I would lossen clamp under starboard (right) transom corner, yank that shim, and clamp it down tight, making the right corner of the transom lower.

Then came time to deck the boat and install the cockpit sides. Said I was weird, cockpit sides going in near the end of the build. Sides were rarely straight. I usually pinched them closer at the engine board and often tilted the aft part of the cockpit side even closer at the top of the engine board.

Since the frame was clamped to the dead straight L jig I think the sponsons stayed where they were when I imparted the twist AKA warp plane. Of course when someone eyeballed it they might say one sponson was lower if they choose the aft bottom edge as a reference.

[johnsonm50]

Starboard sponson -up. Port sponson -down. When the boat is right side up.
I suggest that it is intended that way. Leave it alone and no need to compensate. It improves turning.

Thanks John & Bill. The twist is like you wrote John or- Right side-Up, facing forward.. the Left sponson & the Right rear corner would be lower. I dont have much weight on & am removing it. [when the wind dies] I hope to run it at spring Millville so will find out then if any good.

[blueskyracer]

I would like to add that if you decide you don't like the twist the only way to get ride of all of it is to make a good flat and level jig and remove all of the decking. Let it lay flat and then put the new deck on.

[L. Allen]

Some people like a bit of a twist.

[csh2z]

Laurie,
I know I prefer a little twist every now & then.

[johnsonm50]

Me too, 'vodka & orange' just don't wanna drive a right hand screw into a left hand thread. Thanks much, Mike