Keelbolt Arrangement

[slug]

Originally Posted by Muaddib1116

I've gotten a brief response from the original builders in Finland. He says that the reason they did this was to increase the draft and secondarily to move the keel back a little bit to balance the boat because of heavy equipment in the bow. The way he said it makes me think the secondary reason was more of a rationalized additional "benefit" after they decided to do this to increase the draft. I have asked whether this was done sometime during the original build process or sometime afterwards as a modification, but I haven't heard back yet.

I'm not overly concerned with the structural strength of the steel frame as designed, but I am very concerned about a drastic increase of crevice corrosion that is not able to be inspected on a regular basis. Primarily, the fact that there are a lot of welds, and my basic understanding of crevice corrosion makes those welds prime targets.

Keel wings cause the boat to “ trip “ on the wing

To overcome this tripping you need more ballast in the keel or a deeper keel

Wing keels are bad news

They were fashionable 20 years ago , not now

[Muaddib1116]

Originally Posted by slug

Keel wings cause the boat to “ trip “ on the wing

To overcome this tripping you need more ballast in the keel or a deeper keel

Wing keels are bad news

They were fashionable 20 years ago , not now

I'm not sure what that has to do with this thread, but I've never heard that before. Can you explain what you mean by "trip"?

[slug]

The wing provides lateral resistance

Unless the wing is ballasted it will trip the boat

Whoever built your keel must have got this wrong

This is why they tried to increase draft

[Muaddib1116]

I'm not sure that's what's going on here. The wing is solid lead. I've never heard of an unballasted wing keel.

[boatpoker]

If I'm understanding what I'm seeing .... One would have to cut through the side of the stub to access those lower bolts.

Also one one woould have to cut off the sides of the stub to inspect the welds for corrosion.

No thanks.

[Muaddib1116]

Originally Posted by boatpoker

If I'm understanding what I'm seeing .... One would have to cut through the side of the stub to access those lower bolts.

Also one one woould have to cut off the sides of the stub to inspect the welds for corrosion.

No thanks.

I think the thing to do would be to drop the keel, rather than cut in from the side. It's not great. I am trying to gather more information, but I believe that this was done at some point during the build process, after the keel was already made and fitted. So I think that the bolt pattern for the steel frame extension is the same as the original keelbolts. I am trying to price out what it would cost to drop the keel and remove the extension frame and reattach the keel how it was originally intended.

[Adelie]

Crevice corrosion is localized attack on a metal surface at, or immediately adjacent to, the gap or crevice between two joining surfaces. The gap or crevice can be formed between two metals or a metal and non-metallic material.

Welding creates the conditions for other types of corrosion. The heat affected zone around a weld has modified metal structure relative to the weld metal and the bulk of the base metal so corrosion can occur between the now dissimilar metals. Modified crystal structure may also lead to increased corrosion. All this depends on the base material, the weld metal, the welding process used, conditions during welding and post weld processes used.

[Muaddib1116]

Originally Posted by Adelie

Crevice corrosion is localized attack on a metal surface at, or immediately adjacent to, the gap or crevice between two joining surfaces. The gap or crevice can be formed between two metals or a metal and non-metallic material.

Welding creates the conditions for other types of corrosion. The heat affected zone around a weld has modified metal structure relative to the weld metal and the bulk of the base metal so corrosion can occur between the now dissimilar metals. Modified crystal structure may also lead to increased corrosion. All this depends on the base material, the weld metal, the welding process used, conditions during welding and post weld processes used.

I see, thanks. That's even more of a reason to have some concern about this arrangement. My thoughts were that it's a relatively tight frame with tight internal corners, and it's likely that the welds were not perfect, and have some pits, fold, or tight voids that could be prone to crevice corrosion.

[boatpoker]

Originally Posted by Muaddib1116

I think the thing to do would be to drop the keel, rather than cut in from the side. It's not great. I am trying to gather more information, but I believe that this was done at some point during the build process, after the keel was already made and fitted. So I think that the bolt pattern for the steel frame extension is the same as the original keelbolts. I am trying to price out what it would cost to drop the keel and remove the extension frame and reattach the keel how it was originally intended.

Don't see how you could drop the keel without accessing the lower bolts. ie. cutting through stub.

[Sailmonkey]

Originally Posted by boatpoker

Don't see how you could drop the keel without accessing the lower bolts. ie. cutting through stub.

Dropping that keel would be straight forward IMHO. But tearing apart whatever was placed over the frame to inspect it would be destructive, then the whole mess would need to be rebuilt if the frame was intact to assemble the keel.

[Muaddib1116]

Originally Posted by boatpoker

Don't see how you could drop the keel without accessing the lower bolts. ie. cutting through stub.

You would just undo the nuts in the bilge and drop it like a normal keel.

Originally Posted by Sailmonkey

Dropping that keel would be straight forward IMHO. But tearing apart whatever was placed over the frame to inspect it would be destructive, then the whole mess would need to be rebuilt if the frame was intact to assemble the keel.

It is likely that as you drop it that you'll need to trim some glass that was fairing that whole area. It is possible that they created a pocket for the frame that would remain intact. I don't think that you risk the structure though, at most it would require some glasswork to smooth the connection point, I think.

[robwilk37]

assuming the boat is priced to sell, and thats why youre even considering this? looks to me like a poor bandaid fix of a poor design. no piece of mind below the waterline...

[Muaddib1116]

I'm already under contract to purchase the boat, and this arrangement was revealed to me in response to a question about the keel bolts. So I already have a deposit on the line for this boat, and I am trying to determine how big a deal this is and what my options are.

[robwilk37]

what are the terms for the deposit? escrow acct or holding a check? you can stop pay a cashiers check (learned that the hard way), is a broker involved? what country are you/boat in and where is it flagged? different if you plan to cruise or be a marina-queen i guess.

these are all good questions, but the bigger question for me is peace of mind. id always worry about it...

[Muaddib1116]

It's in the broker's escrow acct in Sweden. I'm in the US. I am quite concerned about it. In my mind, it is a flaw in the boat's construction, but obviously the owner and I'm sure the builder do not think so. If I were to walk away, I would have to make that decision with the assumption that I would lose my deposit. I could always try to recover it, but as far as my decision making, I think that's how I have to think of it.

That's why I am trying to get an idea of the costs involved with dropping the keel and removing that steel frame and then reattaching the keel normally without it. If those costs are acceptable to me, then I have that plan of action as a backup if there are problems with the keel or I simply decide to get rid of that thing sometime down the road.