Bent skegs and cavitation plates

[wiscoboater]

Whats the best way to straighten out bent skegs and cavitation plates. The seem very brittle and hammering on them usually causes more harm then it fixes. Does applying heat make the cast aluminum more pliable for bending, or is there another method ? Is hammering to form the correct procedure or trying to bend it with a clamp?

[beerman57]

Heat definitely helps

[david-bartlett]

I have had great success using some heat first, then cautious use of a hammer.

[chris-p]

I use heat, and a home made jig for cav plates. The jig can be anything straight, old angle iron even, with c clamps to hold it.

[green-thumbs]

Mercury KD4 skeg (actually same as other early K Model skegs) bent sideways about 1/4"
Gave it a great deal of thought before setting up press to straighten. In a series of gentle
applications the bend was bumped back to eyeball straight. No point in pushing my luck
as that was good enough. It may be that preheating would be a good idea, but, I got away
without it this time.
On the other hand I once tried to press a bent aluminum connecting rod…lucky I had my face out ot the way when rod snapped and both parts flew out of press.
As for broken skegs. I have had several welded at $40 each! Good workmanship but
not cheap. I now tend to look for replacements rather than repair.
Louis

[Mumbles]

The plates are soft can be dollied out using a heavy piece of steel or a big hammer to back them up. Skegs are a different story as they like to break off. A press might be your best friend for straightening skegs but if they aren’t too bad, I leave them alone.

[garry-in-michigan]

I have seen some damaged by backing over rocks while launching the boat with the motor down. This sometimes bends the driveshaft/exhaust housing. This in turn can cause the drive shaft to break at the water pump drive pin hole. When you do your repair, be sure EVERYTHING is properly aligned. Use caution, too much concentrated heat can warp the gear case

[wiscoboater]

So would a small propane torch be the tool for the job? I can pick up a MAPP gas canister if needed. I don’t have a big oxyacetylene set up or anything like that. I would have to stop by Mumbles place if I need the big guns. What I am trying to straighten out is the cav plate on my 1975 135 Johnson. It took a good hit by the last owner and if I’m going all out with new paint and decals I want the plate fixed.

[chris-p]

You don’t need a lot of heat for this, a propane torch will do it. The plate is not that thick. Can you post a pic of damage?

[Tubs]

Your better off bending them back in place than
trying to beat them back into place if possible.
Having the part clamped in some way and then
applying pressure and then releasing, going a
little at a time, while applying heat gives you
the best chance of straighten a part without
breaking it.

A "Boathouse Repair" is one that done without having tools or the skills to do it properly.

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