Shimming a strut?

[kfxguy]

So I thought I was slick. Made a nice little brass shim of .015 thick to start off with. Then I realized because the bracket is two piece (two 90 degree angles with the strut blade inbetween) as soon as I loosen the strut screw, it's just going to misalign and no longer be cocked one way. So....would it hurt to just bend the strut over just a little at a time until it goes straight? (Single powered 32" cat, agressive prop).

[modvp55]

Travis how about machining a one piece mount bracket, then you could add or remove shims. I know not what you asked just a thought.

[longballlumber]

I am guessing that your trying to counter act some behavior that you don't like...

Have you thinned out your prop? Many times boat's that won't go straight can be cured (or greatly reduced) by simply thinning the prop.

Later,

[kfxguy]

Travis how about machining a one piece mount bracket, then you could add or remove shims. I know not what you asked just a thought.

Trying to get away from machining anything....if I do it will be an all out custom made adjustable unit like I had on the one that sank. Bending is quite a bit easier unless there's some ill effects.....



My props are already as thin as I can get without sacrificing strength. They have slit of pitch for this size hull, and the boat is fairly light and narrow. That's a lot of the reason it walks.

[Darin Jordan]

If you aren't going to machine the struts, then I'd make some small shims that go under the strut. More precise and will maintain the relationship between the strut mount halves.

STRUT_ANGLE.jpg
(Angle MUCH exaggerated for illustration)

Once you figure out what angle you need (guessing 2-3-degrees), I'd machine the strut mounts and be done with it.

However, if you are doing this on a Mono, I think you may end up compounding the problem.

Walking is usually prop-torque related, or hull lift related, and can usually be tamed using proper Trim-Tab setup, or by properly blue-printing the hull. A "hook" on or a raised area on one side or the other can cause the hull to have different lift points side-to-side, inducing chine-walk. Rounded trailing edges, inconsistent Surface textures, etc., similarly can cause issues as well.

[kfxguy]

If you aren't going to machine the struts, then I'd make some small shims that go under the strut. More precise and will maintain the relationship between the strut mount halves.

[ATTACH=CONFIG]140278[/ATTACH]
(Angle MUCH exaggerated for illustration)

Once you figure out what angle you need (guessing 2-3-degrees), I'd machine the strut mounts and be done with it.

However, if you are doing this on a Mono, I think you may end up compounding the problem.

Walking is usually prop-torque related, or hull lift related, and can usually be tamed using proper Trim-Tab setup, or by properly blue-printing the hull. A "hook" on or a raised area on one side or the other can cause the hull to have different lift points side-to-side, inducing chine-walk. Rounded trailing edges, inconsistent Surface textures, etc., similarly can cause issues as well.

Good info, but to keep from machining anything (don't really have time right now) is there a down side to lightly bending (twisting) the strut a couple degrees?

[ray schrauwen]

We used to bend struts a bit in the Nimh days when things weren't as rigid as today. More so on Hydros...

[Darin Jordan]

... is there a down side to lightly bending (twisting) the strut a couple degrees?

You can try it. I know that's how a lot of guys used to tweak their stuff.