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Discussion Starter #1 (Edited)
One of my winter projects is to fix a problem at my stem piece (where the forestay attaches). I noticed in the fall that one of the 4 bolts at the bow has a rusty head. The other three heads are very shiny but when I looked from inside, there seems to be also some rusting going on some of the nuts or washers. Since this is a safety issue, time to act!

[As an aside, I am a bit confused by the markings. These are 3/8" stainless bolts with two marks on the heads. But I thought that grade 1 has no marks, grade 5 has 3 marks, and grade 8 has 6 marks. What is two marks? I understand that stainless may use a different system but I am a bit confused what I should replace them with.]

The logical way would be to just turn the nuts from the inside and replace the nuts and bolts, one at a time since I don't want to take down the mast. The problem is that this is, by the nature of a stem piece, at the very tippy end of the boat and, furthermore, at the very end of the anchor locker. I have to creep through a hatch that _barely_ admits my ample girth and even then it is a real stretch to even reach those nuts. I want to spend as little time in the locker as necessary so what I decided to do is to cut off the bolt head with a dremel, push the remaining bolt through, and replace the whole thing. Rinse and repeat with the other bolts.

Well, the cutting off part went reasonably well. Of course I have to hang upside-down over the bow but I got the sucker off alright. To my surprise, I could not push the bolt into the boat. In fact, even when I hammered on it (with a hammer and center punch) it did not move! I did not break out a sledge but I hit it pretty well with the hammer I had at hand (maybe a pound or a bit less?).

What is going on? I would not expect galling of the bolt in the hole since I always thought that pressure between stainless steel pieces is needed to cause galling. Is it possible that corrosion in the space between the stem piece and bolt has become so hard that I cannot push it in even with a hammer? Or, and I think this is extremely unlikely, was the bolt threaded into the stem piece?

The attached pictures show the bolt seen from forward of the bow (you see my mug peeking down from the deck while I am taking the bolt-selfie). The arrow points towards the cut-off head. There is a nice brown ring all the way around the bolt so it is not that I missed to cut off a part of the head. The brown scribbles on the cut bolt is rust; I did the Dremel deed a week ago and some rust developed on the surface.

The next image shows the same but, in addition, the next (shiny) bolt head which is not cut (yet).

Finally, the third picture shows the situation from the inside. We are looking at the very tip of the boat inside the anchor locker, where the deck (top) meets the most forward part of the hull. You see why it is hard to get there. Arrow 2 points to the bolt whose head I cut off (the top one in the hull). Above it you can see another bolt with nut which goes through the deck. The aluminum plate under the deck is a backing plate for a cleat. Arrow 1 points to the lowest stem piece bolt (which has less rust than the others), incidentally you can see the cable for electric bonding on this one.

Any idea what is going on?
 

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One of my winter projects is to fix a problem at my stem piece (where the forestay attaches). I noticed in the fall that one of the 4 bolts at the bow has a rusty head. The other three heads are very shiny but when I looked from inside, there seems to be also some rusting going on some of the nuts or washers. Since this is a safety issue, time to act!

[As an aside, I am a bit confused by the markings. These are 3/8" stainless bolts with two marks on the heads. But I thought that grade 1 has no marks, grade 5 has 3 marks, and grade 8 has 6 marks. What is two marks? I understand that stainless may use a different system but I am a bit confused what I should replace them with.]

The logical way would be to just turn the nuts from the inside and replace the nuts and bolts, one at a time since I don't want to take down the mast. The problem is that this is, by the nature of a stem piece, at the very tippy end of the boat and, furthermore, at the very end of the anchor locker. I have to creep through a hatch that _barely_ admits my ample girth and even then it is a real stretch to even reach those nuts. I want to spend as little time in the locker as necessary so what I decided to do is to cut off the bolt head with a dremel, push the remaining bolt through, and replace the whole thing. Rinse and repeat with the other bolts.

Well, the cutting off part went reasonably well. Of course I have to hang upside-down over the bow but I got the sucker off alright. To my surprise, I could not push the bolt into the boat. In fact, even when I hammered on it (with a hammer and center punch) it did not move! I did not break out a sledge but I hit it pretty well with the hammer I had at hand (maybe a pound or a bit less?).

What is going on? I would not expect galling of the bolt in the hole since I always thought that pressure between stainless steel pieces is needed to cause galling. Is it possible that corrosion in the space between the stem piece and bolt has become so hard that I cannot push it in even with a hammer? Or, and I think this is extremely unlikely, was the bolt threaded into the stem piece?

The attached pictures show the bolt seen from forward of the bow (you see my mug peeking down from the deck while I am taking the bolt-selfie). The arrow points towards the cut-off head. There is a nice brown ring all the way around the bolt so it is not that I missed to cut off a part of the head. The brown scribbles on the cut bolt is rust; I did the Dremel deed a week ago and some rust developed on the surface.

The next image shows the same but, in addition, the next (shiny) bolt head which is not cut (yet).

Finally, the third picture shows the situation from the inside. We are looking at the very tip of the boat inside the anchor locker, where the deck (top) meets the most forward part of the hull. You see why it is hard to get there. Arrow 2 points to the bolt whose head I cut off (the top one in the hull). Above it you can see another bolt with nut which goes through the deck. The aluminum plate under the deck is a backing plate for a cleat. Arrow 1 points to the lowest stem piece bolt (which has less rust than the others), incidentally you can see the cable for electric bonding on this one.

Any idea what is going on?
Perhaps the bolt's were bedded in epoxy? Try putting a wrench and cheater bar on the nuts, give em a turn or two, maybe break them loose, if the nut's are corroded to the bolt's badly enough to turn before breaking loose from the bolt's. Good luck, hope everything works out for you.
 

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I am not sure about your boat, but a number of builders are using metal core sections instead of core at chainplate and mounting locations. If so, that plate may be threaded onto the bolt you just cut the head off of.

Alternatively if the plate was installed with 5200 the bolt may just be glued to the hull. In which case 5200 remover and or heat may be in order.


My advice is find someone willing to come give you a hand for 30 minutes, and never ever cut the head off of a bolt unless you have no other option.
 

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My primary tools for a job like this would be
Deep socket and extension, would try to get the nut off.
If necessary a helper on the outside to lock the head.

Since the head is already off you must start with the nut on the inside.
If the nut spins you could try using double nuts on the inside to rotate the bolt.
 

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From the pic of the inside, it appears as though the bolts are covered in 5200. It's possible that 5200 was used as a caulk, but it's adhesive properties are now your problem.
Don't we all LOVE just folks who misuse 5200?
 
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Discussion Starter #10
Perhaps the bolt's were bedded in epoxy? Try putting a wrench and cheater bar on the nuts, give em a turn or two, maybe break them loose, if the nut's are corroded to the bolt's badly enough to turn before breaking loose from the bolt's. Good luck, hope everything works out for you.
I doubt very much they were bedded in epoxy (the boat is from the seventies) but yes, from what I see from the inside, they may well have sprayed gelcoat over the nuts. And they do seem corroded.

I was trying to avoid having to fight the nuts from the inside (it will be tough to turn a breaker bar in the space, in particular if _I_ will be occupying some of the space) but I guess I have no choice.
 

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Discussion Starter #11
I am not sure about your boat, but a number of builders are using metal core sections instead of core at chainplate and mounting locations. If so, that plate may be threaded onto the bolt you just cut the head off of.

Alternatively if the plate was installed with 5200 the bolt may just be glued to the hull. In which case 5200 remover and or heat may be in order.


My advice is find someone willing to come give you a hand for 30 minutes, and never ever cut the head off of a bolt unless you have no other option.
You may well be right, it may have been a mistake to cut the head off. I just did not imagine that there would be a problem pushing a bolt that is held with a nut through its hole after the head is off. Live and learn :(

I still consider it unlikely that there are actually threads involved anywhere but at the inside of the nut. If they put in a threaded metal plate, why would they have the nuts? That seems way too complicated.

I sure hope I don't have to apply heat in that space. Man, what a mess!
 

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Discussion Starter #13
My primary tools for a job like this would be
Deep socket and extension, would try to get the nut off.
If necessary a helper on the outside to lock the head.

Since the head is already off you must start with the nut on the inside.
If the nut spins you could try using double nuts on the inside to rotate the bolt.

Yep, I have to get myself into there and try to turn the d*mned corroded nuts. If they turn, I _really_ should be able to push them through, right?

I had thought that I just would slide a new bolt in their from the outside and tighten them nicely from the inside.

Incidentally, I think I will put a bit of butyl tape under the new bolt heads. When I saw the corrosion at the nuts and washers, I wondered where it comes from. It must be from (salt-)water getting under the bolt heads and then sitting in the relatively airless space around the bolts and under the washers. Better to avoid getting water in there in the first place.

It is true that it has held up for 40 years (in two months) but putting a little butyl under there should avoid this problem once and for all.
 

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Discussion Starter #14
From the pic of the inside, it appears as though the bolts are covered in 5200. It's possible that 5200 was used as a caulk, but it's adhesive properties are now your problem.
Don't we all LOVE just folks who misuse 5200?
Maybe 5200. Or, what I consider more likely (and probably better for me) is that it is gelcoat that they sprayed in after the stainless steel parts were in place.

I will definitely keep you posted what I find out.
 

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The gel coat is applied when the hull or deck is in the mold before the glass is layed up. Unless there was a botched repair job gel coat is very unlikely to have been used later on.

My guess is 5200, since you already have the bolt heads off you can try to get ANTI BOND Anti-Bond 2015 | West Marine into the hole. It takes time to work but it will eventually help break it down. The other suggestion is to get a hot knife or soldering iron and try and heat the bolt.

Combine these while having someone trying to turn the nut/bolt. Hopefully you can break it free.
 

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Discussion Starter #17
The gel coat is applied when the hull or deck is in the mold before the glass is layed up. Unless there was a botched repair job gel coat is very unlikely to have been used later on.
What you say makes sense. But there is some white stuff on the bolts and it sure looks like the same color as the gelcoat. Could they have sprayed some in there to 'finish' the anchor locker?

There is absolutely no evidence for a repair, botched or not, so I think I can exclude that.

My guess is 5200, since you already have the bolt heads off you can try to get ANTI BOND Anti-Bond 2015 | West Marine into the hole. It takes time to work but it will eventually help break it down. The other suggestion is to get a hot knife or soldering iron and try and heat the bolt.

Combine these while having someone trying to turn the nut/bolt. Hopefully you can break it free.
I don't think the chemical will have much of a chance. There is a TINY distance between the bolt and the surround. It would take ages to creep into there. Oh, and it does not help that gravity would work against it, letting the stuff drip out.
 

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Discussion Starter #18
Socket extensions are a must for any boat owner and considering you need to work in a restricted area you might want to try an electric impact wrench.
Excellent idea! I had not thought of that.

I only have a rather puny electric impact wrench but this might be a case where my pneumatic one earns its keep. A bit of a bother to schlep the compressor to the boat but if that solves the problem, it is surely worth it.

Thanks!
 

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Working with the bolts still intact I would hold the bolt from the outside and drive a socket on from the inside and get as much leverage as you can and turn it until it breaks if that's what it takes. It will be broken under the nut then the bolt will come out from the outside. If there's a plate in there like Catalina did some anchoring points on their 27 jib tracks then it will either back out or strip. Don't expect all the bolts to come out the same either. In any event the inside comes off first.
 
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