My skeg repair

[erikgreen]

Hello all -

I have an old pre-alpha drive on my boat that has seen better days. It holds pressure well, and the water pump works, and I take care of it as best I can, but it had a major problem I had to deal with this spring. When I had an accident with the boat before my rebuild, one of the things that got goofed up was the skeg on the drive unit. It got mostly snapped off.

It snapped off so close to the gear case that a skeg guard was out of the question... most of the commercial ones require a certain amount of remaining skeg.

Now that the boat is rebuilt (only things left original are the drive, which except for the skeg was in ok shape) and the hull fiberglass, I'm using it on lake superior.

I use the boat mostly to run a side scan sonar unit, and I need to be able to drive very slowly, usually idle only (and I got into the wind to go slower) so I have to be able to steer in a straight line. With this boat, which is a 21 foot 2.5 ton lady, I had a heck of a time steering at low speed without a skeg.

I tried having the skeg welded last year, and it lasted about two months. One windy day I came into the ramp and the boat blew sideways into the concrete and stuck. No problem except the wind and some small waves pushed the skeg exactly where it was weakest, and it snapped off.

This actually left slightly less skeg to work with since the welding took some more metal off (grinding to get to good metal) and there wasn't enough uncontaminated aluminum left after it broke again to do the job cheaply... it would require a complete disassembly of the lower unit, shimming with a throw-away set of internals so it wouldn't warp, then re-welding after cutting off more dirty metal with a chance of breaching the gear case, requiring more work. If anything unusual happened during the welding, it was sure to cost more than just buying an SEI SE-106 lower.

But with all the stuff I've been doing I'm short on cash. So, I decided to give repairs a shot myself. Here's the before pic:

My plan was to cross drill holes for small bolts across the remaining skeg bits, then construct the skin of a skeg from two pieces of heavy gauge aluminum sheet cut to shape. Then I'd weld the aluminum together with one end open and shimmed to the right width.

Once the aluminum was welded I'd put it on the drive, clamp in place, and drill the through holes.

Then I'd bolt it on, using stainless bolts, and trim the bolts to size. I'd use lock-tite to hold the nuts on.

Following that I'd fair it with a mix of epoxy and chopped fibers, and a final top layer of glass microbubbles in epoxy, and sand.

Finally I'd coat it with aluminum primer and spray paint it black.

So, how well did it work? I'll show you when I get home tonight... I could have sworn when I started typing this I had both before and after pics, but I guess not :\

I took it out this last weekend for a test... it worked flawlessly, turns were fast and responsive at high speed, and the boat was easily controllable at low speed.

Erik

 

[Ritchie555]

Re: My skeg repair

Is it possible to encase the whole "torpedo" part of the gear case in an aluminum jacket with enough length to come down and form the skeg? That might be better than trying to tie onto the tiny fragments left at the bottom.

 

[WAVENBYE2]

Re: My skeg repair

Aguy here who fixed my lower unit welds on new skegs for $150.00, he's good at it too, can't tell after painted. Check around in your area and see if some one does that kind of work.

 

[erikgreen]

Re: My skeg repair

Ritchie, that was one thing I considered. I was worried about making it look good though, that's a lot of fairing work. But it was a backup plan.

I actually did have the skeg welded before. The problem with getting it done again wasn't so much the cost of welding as the cost of preventing the gear case getting destroyed in the process... there wasn't enough metal left to avoid warping by overheating, plus the little bits of metal remaining were "contaminated" aluminum, IE would have to be ground back a bit and cleaned with acid or acetone to ensure a good aluminum weld. Anyone doing the weld would have to do that work, and if they didn't they're probably not skilled enough to do it well.

Anyway, what I did seems to have worked pretty well:

The oversize skeg really helps me steer at low speeds, and gives me great turning capability at high speed. I don't think it drags much extra either.

I already forgot to raise it when bringing the boat out of the water too... it cleared that ramp by about 1/8 of an inch Just lucky there.

I'll post back on how it worked out later... basically the stainless bolts, fasteel putty, and epoxy filled with fiberglass seem to be holding up well.

Erik

PS: That's my "junk" prop... it's really old. I need to get a decent 19p.

 

[erikgreen]

Re: My skeg repair

Just thought I'd post a further note here. I elaborated on this in another thread, but since I posted my nice skeg pics here I thought I'd add to the story a bit.

Looks like I don't get to keep my nice big skeg.... last weekend I was cruising at 20mph on lake superior... I heard a loud bang, then a high pitched whine, and then it sounded like my drive was beating eggs inside its casing.

I got a tow back in (which bummed me out... my boat was the only one in our group of 6-ish friends with 10 or so boats that hadn't ever needed a tow... I really need a kicker) and put her on the trailer to go home.

The next day I pulled the drive off. U joints were ok, still perfect. Upper half was in fact ok completely. I drained the lube, finding a christmas tree of shavings on the magnet from the lower hole.

I separated the drive halves, and checked the water pump just for completeness. Generally ok, with the impeller looking pretty new. But the lower base of the pump had some melting of the plastic at the shaft... not sure if that's old or a new problem.

I haven't been able to pull out the gears in the lower half yet, I don't have a wrench for the retaining nut, but it looks like at least one lower gear or possibly the clutch lost some metal and ground until it broke.

I maintained the drive well, changing the lube annually, but three years ago I had the boat in an accident on its trailer. I rebuilt the boat nearly completely since then (although I'm redoing parts now for looks) but I chose to use this old sterndrive because I already had it, and buying an aftermarket new model was a $1400 or so I didn't want to spend unless I had to do so.

That's why I repaired the skeg as shown above (after I tried to have it professionally repaired) and that's why I was still using it two years later.

Last night I went and bought a used but cleaned and painted lower from a local guy who does boat salvage for $300. It's in great shape, and when mated with my old upper and a new pump installed should get me back on the water.

I'm going to blast it with walnut shells and repaint it with the midnight black quicksilver paint most likely, and then I'll have a normal, if slightly worn skeg on my boat.

I did pick up some sheet stainless steel at my favorite junk dealer today, so I'll probably fold/weld up a basic skeg guard for it.. I hate not having a skeg, so I think I'll protect this one better than the last

Erik

 

[45Auto]

Re: My skeg repair

Make SURE you clean out and flush that upper real well. It's garunteed to have some of the metal shavings from the old lower in the bearings. Hopefully it won't self-destruct and take out your new lower with it ......

 

[erikgreen]

Re: My skeg repair

Thanks for the advice... I tried sandblasting the halves last night, I'm going to repaint both... but the darn sandblaster wouldn't work right. It's a cheap model.

So today I'm going to finish chemically stripping the halves, then the upper (the only half partially blasted) is going to get a thorough soap and water rinse followed by alcohol, then an acetone wipe down to get rid of the blast grit and any remaining shavings.

Then comes the water pump service, assembly, and painting, followed by the pressure test and lube fill.

Erik