Hi.
I have a boomaroo 22 (Catalina ) in need of serious repair of the pivot hole.
There are several ways to fix it but all require major engineering or welding skills.
My idea is to manufacture a metal sleeve that fits over the hole and attached to the side of keel flush with it with screws.see diag.its like a U bracket that would be 250mm deep and wide with the pivot pin welded to this bracket. Would stainless steel be compatible with the cast iron keel.
Would need to drill and tap new screw threads into cast keel...
Any thoughts ??.
If you haven't already, you may want to check out www.catalinadirect.com/keel-and-pivot-pin-wear/
They recommend boring out the pivot hole and re-sleeving with 1.25 inch outside diameter stainless steel bush (which they stock see www.catalinadirect.com/shop-by-boat/catalina-22/hull-deck/keel/pivot-assy/c-22-keel-pivot-pin-bushing/?SearchResults=1) or bigger (custom made) if necessary.
"Take the keel to a machine shop and have the hole bored out. Some shops have a machine commonly referred to as a "mag drill" or portable magnetic drilling machine. These machines have a powerful electromagnet which clamps the machine directly to the keel when energized. There is no need to hoist your keel onto the table of the milling machine.
"If there is plenty of material left for adequate strength, we have a stainless steel bushing available. It is 1.250" outside diameter (#D1908). I like the idea of having the machine shop prepare the hole so they can press the bushing into place. Epoxying the bushing in place may also be an option. The factory simply installs the bushing with a slip fit into the hole. Any of the three are probably fine."
Given how elongated your pivot hole is, you may want to epoxy the new bushing in rather than boring it out to the max and using a much fatter custom made bushing, Not sure how well epoxy would hold up given weight on the bushing and possible residual movement.
Another approach would be to take the keel to someone with the equipment (a preheat oven) and the expertise to add weld metal to partly fill the elongated hole before re-boring and sleeving.
I presume you're going to replace the pin?
Interesting to note the article suggests keel pivot wear in Catalinas is mostly due to movement while moored, rather than from lowering and raising, and suggests that re-fitting the keel so as to eliminate side to side movement is important to reducing wear.
What about non metal? Finot Conq use an ertalyte? bush for the swing keel on the 12.50 despite it weighing nearly 3,000 kgs. Admittedly, the keel head to keel box tolerance was so tight you couldn't even antifoul the keel head so I don't know how ertalyte goes with a sloppy fit.
Thierry, the main problem is see with your "cover plate" option is that it will be screwed and tapped onto the cast iron keel, which raises the issue of galvanic action between dissimilar metals (presumably, the thought behind your comment about compatibility). Although you are going to get galvanic action with whatever solution you adopt, the contact area between the screws and keel will be small, which makes them vulnerable to corrosion. Murphy's law will dictate that one side will give way before the other, giving you a stuck keel, or that the whole thing will fall off in rough weather in mid-passage. A better solution could be through-bolts. However, the time and effort to drill the through-bolts could be better spent reaming the old hole and fitting a bushing.
I went through a similar experience in July 2017 and kept a blog, theboattinkerer.blogspot.com/2017/07/episode-8-that-blasted-keel.html. The solution was reaming out the old hole and fitting a bronze bushing. It was a ship-wright's job, but the ship-wright did a good job of it and made it much easier than I expected. My biggest problem was getting the keel out of the boat, and getting it back in again.
I would employ a welder to do the job, but if I had to diy it, I would grind it back to shiny and epoxy a bush in with milled glass. The bush & the new pin should be of the same material. I'd go stainless and incorporate a grease nipple but that's just me being Asperger
Select to expand quotewoko said..
I would employ a welder to do the job, but if I had to diy it, I would grind it back to shiny and epoxy a bush in with milled glass. The bush & the new pin should be of the same material. I'd go stainless and incorporate a grease nipple but that's just me being Asperger
Agree about the using same material for the bush and pin. I should have put a bronze bolt into the bronze bush, but I was trying to be cheap. The shipwright filled in the holes around the bush nicely (see photos on my blog). I didn't find any problems, but sold the boat not long after. Like my Austral 20, the Boomaroo is a trailer sailer, so it should not be sitting in the water all the time.
