Replacing keel bolts: Which metal is best?

[Scout 30]

Originally Posted by reed1v

Depends on how long you want the bolts to last. Silicone bronze absolutely the best for any keel. Galvanized steel or monel with cast iron. Never use stainless steel with any keel if you want longevity. Stainless subject to stress corrosion and rots when no oxygen available. Not sure why folks use stainless anyways other than pure looks. Most grades of stainless have no use in stress situations.

But for disposable plastic boats that are not used too much, then go with whatever is cheapest.

Best advice so far.

[jeepbluetj]

Chris95040 has a good idea. Call up Catalina and ask em. They will answer your question.

Catalina Direct says 316 stainless:https://www.catalinadirect.com/index...-c-25-c-27.cfm

For a C-22 I would likely drill/tap and use galv bolts or allthread

[Jim Cate]

Originally Posted by reed1v

But for disposable plastic boats that are not used too much, then go with whatever is cheapest.

Offensive and unnecessary comment. Shame on you.

Jim

[capt jolly]

Whatever bolts u use try a product called "rescue steel" on the threads and all over the shafts as well. In 20 yrs if your still around to pull them again you'll be thankful.

[Curious Sailor]

Originally Posted by capt jolly

Whatever bolts u use try a product called "rescue steel" on the threads and all over the shafts as well. In 20 yrs if your still around to pull them again you'll be thankful.

I tend to agree with all of the responses. This is one of those " many ways to skin a cat" questions...

It really all depends on how often you do routine maintenance on that area of the boat. If diligent, the manufacturer recommends a periodic inspection and turning of the bolt to ensure its integrity. If you don't think you are going to follow through with that, you can oversize the hole and use a bronze sleeve with 304 ss or better for the best corrosion resistance or any of the other fine solutions offered up in this thread... Really, I think they would all serve the purpose.

Be careful putting that thing back..

[Lokiyawl]

Monel is the best material lead keels but not for iron. Stainless could work ok but if you are willing to replace the bolts every 15 years or so, galvanized would actually be your best choice. You can coat the heads with a sealant or epoxy to help seal them up. With steel, no worries of crevice corrosion with can be a problem with stainless so if the bolts still look ok, they should still be safe. The fresh galvanizing will also help to protect the iron threads. You could also use a non copper anti seize compound on the threads to make future removal a bit easier. It's rare that the cheapest is the best way to go, but this is one of those times.

James

Originally Posted by partingclouds

The boat is a Catalina 22, without the smile... yet. The existing bolts are pure rust and should be easy to drill out to a larger size and tap. What's the most appropriate metal for new studs/bolts to mate with the cast iron of the keel?

[UNCIVILIZED]

I'd PASS on any regular alloy of Stainless, as there are far better materials (many of them cheaper) which don't suffer from crevice corrosion; Stainless's nemesis. As previously mentioned - better metals for the job I mean.

You can sometimes find old propellor shafts, made of Bronze, or Aquamet (Nitronic 50), which you can have cut to length, & turned (threaded) into bolts.
Both of which will likely outlast the boat, & only cost you the price of the machining.

Or if you've got a lot of excess coin, you can go & scare up some Monel K-500, or a few of the other exotics mentioned. And if you want to look up some of the physical properties of a material/metal in question, try www.Matweb.com

Also, I'd suggest going to Loctite's website (& that of any other bolt coating compound) to see what specific formulation, or product that they recommend for application X, or Y. That, & contatcing them directly, if there's any question as to what's wise to use, is a smart idea as well.

PS: On some keel bolt applications, molten lead is used as the thread locker & isolater.

[GrahamHO]

Originally Posted by reed1v

Depends on how long you want the bolts to last. Silicone bronze absolutely the best for any keel. Galvanized steel or monel with cast iron. Never use stainless steel with any keel if you want longevity. Stainless subject to stress corrosion and rots when no oxygen available. Not sure why folks use stainless anyways other than pure looks. Most grades of stainless have no use in stress situations.

But for disposable plastic boats that are not used too much, then go with whatever is cheapest.

I would debate your generalisation if 2205 grade SS is used. Monel is also very good. I used Monel on my previous keel, and 2205 SS on my present one.
I agree with your comments but in regard to 316 SS and lesser grades of SS such as 304.

[GrahamHO]

Originally Posted by partingclouds

The boat is a Catalina 22, without the smile... yet. The existing bolts are pure rust and should be easy to drill out to a larger size and tap. What's the most appropriate metal for new studs/bolts to mate with the cast iron of the keel?

I didn't have time earlier to go into detail. The first thing I would like to know is if you are intending to or already have removed the keel. Personally I would remove the keel before undertaking any work on the bolts. (I have had experience doing that on a few occasions.)

But I doubt that is necessary!!

If you do not intend to remove the keel I would let it be. If the bolts are rusty, they are presumably mild steel and likely they are still sound under the rust. Assuming the keel is still in place, the rust you can see must be on the nuts as there won't be very much of the bolts visible. You could wire brush them using a suitable brush in an electric drill. A battery drill won't go as fast. Wear eye protection and use a safety earth leak cutout or isolation transformer. You will likely make them fairly clean again. Then buy some Res-Q-Steel ( I think that's how it's spelt. I have some but not right here.) it's messy and dark red in color and will prevent more rust if you coat it all over the nuts and visible bolts.

If your boat is out of the water check the hull to keel join for signs of cracking. If there is cracking get a boat builders opinion as it's likely surface cracking and easily repaired. If the boat builder says that it's terrible and he needs to fix it at great expense get another boatbuilders opinion.

I would not try removing the keel bolts without removing the keel from the boat which is not very difficult with the boat hauled out and a travel lift available. Basically you remove the keel nuts with the boat resting it's weight on the keel supported by the travel lift. Then lift the boat a couple of inches and wack the keel with a sledge hammer. The keel should drop down and be supported be a cradle for it to rest in. Then the boat is lifted away to another cradle.
As you are in a yard with a travel lift the yard will probably want that work supervised by an approved person. Again I doubt that work will be necessary.

To remove the nuts in the first place use engineering grade penetrating oil for a few days and then a 1/2" drive impact wrench with a socket and a big hammer.

I would definitely not drill out the old keel bolts to a larger size. You may think they will be stronger but it will be weaker because bigger bolts need bigger holes.

Likewise I would not as someone suggested drill "sister holes" as your hull would need more holes ie perforations. Also they won't be in the correct places in the keel.

I don't think it will come to that as I'm sure your old bolts will clean up fine whether or not you need to remove the keel. You would only need to remove the keel (in my opinion from thousands of miles away) if the keel / hull join looks really dodgy.

If it is a total disaster of rust, which is highly unlikely!!! I would use the cast iron keel as a pattern for casting a new keel in lead with new 3' long keel bolts cast in
to exactly the same spacing as the old bolts. That is another story again. I'm not recommending you do that but it might be what I'd do if necessary as I have the facilities with skilled help available. It would be a heavier keel. Out of my head, cast iron is 450 lb cu' and lead is 700 lb cu' or similar ratio.

I am though fairly sure your problem is surface rust, however unsightly it may appear to be.

[Emmalina]

Originally Posted by Curious Sailor

I agree... Just removed my stainless steel bolt and had to cut it out with a sawzall and then drill it out with a carbide bit .. The dissimilar corrosion pretty much welded the bolt to the keel... I'm still going to replace it with a 316 stainless for strength and corrosion resistance, but I will make sure that I either insert a sleeve that won't react, or epoxy the bore so there won't be metal to metal contact.

Duralac ...

[reed1v]

Originally Posted by Jim Cate

Offensive and unnecessary comment. Shame on you.

Jim

Like there are not disposable plastic boats out there? There are bunches of beat up plastic boats in the back of most boatyards up here that simply wore out with use or neglect. Thin gelcoats, thinner hulls, horrible pot metal fittings, wood screws used to match hull to deck, and so on. Worst one was a Hudson 51 which had regular small plywood pieces used to fill the deck's core, pine boards to fill the hull/deck seam, and several different metals used in the keel.

[Curious Sailor]

I'm curious, if you are experiencing corroded bolts? What is the condition of the keel? Mine looked like it came off the bottom of the sea floor when I got the boat but it's cleaning up nicely. It's out of the boat, sanded, treated and painted. The keel is about 450lbs + and the job of removing and repairing the keel was a lot scarier than it actually looked.. Wish I would have been on this site when I started the job! A lot of friendly helpful sailors out there! Happy Thanksgiving!




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[Scout 30]

Regarding "disposable boats" this is actually a valid point even if it sounds harsh. The question is whether the cost to cure exceeds not just the contributory value of the repair but possibly the value of the whole boat after repair. This is an issue everyone with an older boat has to grapple with.

[Curious Sailor]

Originally Posted by Scout 30

Regarding "disposable boats" this is actually a valid point even if it sounds harsh. The question is whether the cost to cure exceeds not just the contributory value of the repair but possibly the value of the whole boat after repair. This is an issue everyone with an older boat has to grapple with.

Scout couldn't have said it any better! One issue I'm grappling with right now lol. I picked up a 1973 venture 22 with trailer and outboard for $475. I figured this is my entry ticket to the world of sailing. I planned to fix the boat (which is in horrible shape)and learn to sail with it. Like any other project the initial excitement causes us to visualize a shiny new vessel once the repair is completed but you quickly realize that comes with the price tag of a shiny new vessel if not careful... The hardest part of this project for me is having to remind my self every time I'm working on it to stick to the original plan. Fix it and learn to sail!

[sunbear1]

The hot dipped galvanized bolts will be slighty larger due to the coating of zinc so you will need a slightly larger tap--ask. To isolate the threads i have had really good results with some polysulfide caulking from Home Depot--but this probably 10 plus years ago--cheap. Go with the galvanized or whatever is the cheapest that is supposed to be used--titanium is gilding the Lily.