Replacing Keel Bolts, One at a Time

[OrangeCrush]

Hello,

I'm looking to begin replacing the keel bolts on my 1978 Pearson 26. They are showing signs of corrosion, mostly around the nut and washer. The bolts themselves still look pretty solid, at least where I can see them. I scoured them down to bare metal and painted them with POR-15 a few years ago, but the corrosion is now back (Please refer to the attached pics). I do a good deal of coastal cruising in my boat, along with some offshore passages, and as you can imagine I would rather be safe than sorry with this sort of thing.

My plan is to replace the bolts one at a time so that the keel will never actually need to be dropped. The boat is out of the water until April. I figure I will start with one bolt and see how it goes before taking the rest out. The bolts on the P26 go straight up from the bottom through the flanged part of the iron keel, through the hull and the large fiberglass/plywood keel plate, and the nuts and washers are screwed on the top. (Please refer to the attached diagram)

I'm writing this post, then, to check to see if my approach will work, or if there are any major issues that I'm not thinking of. I will probably need to drill and break off the nuts. Then I will use a punch tool to push the bolt down from the top. When I see a bulge in the faring compound over the keel flange, I will open it up and pull out the bolt. I plan on getting the new bolts from McMaster Carr. I will need to use some sort of sealant/filler around the bolts to prevent water from seeping into the plywood core. It's possible that it already has gotten in, of course, but the keel shows no sign of movement at the keel/hull joint so I'm hoping it's still pretty solid. Then I will put a large washer on and tighten up the bolt, then cover up the head of the bolt (on the bottom) with new faring compound or west systems epoxy.

So, here are some of my many questions...

Does this plan sound ok in it's basic approach?

Will I be able to punch out the old bolts through the faring compound as I described, or will I need to find and expose the bolt heads first?

What is the best type of caulk or sealant to use around the keel bolt? (5200? Lifecaulk?) It seems like it should be permanent and very strong yet slightly flexible.

If I find signs of rotten plywood core inside the keel plate, will it be possible to dry and drill it out and fill it with epoxy resin around the bolt holes? I'm not really sure what the 'Resin Insert' on the keel diagram will look like when I get the bolt out.

It seems like the existing washers are a bit undersized for the job that they are doing. Would it make sense to get larger ones, or even steel plates that span multiple bolts for greater backing strength?

How tight should I tighten the nuts? Will it present any issues in tightening them evenly if I am replacing one at a time?

If the first bolt(s) I replace take much more time and effort than anticipated, is there much danger in waiting to replace the rest until next season?

As you can imagine, I am anxious to do this job right. Just because I can visualize how to do it, doesn't mean I have the right plan. I know this is a lot. but I would really appreciate any experiences or advice you can share. I want to make sure my boat is safe and sound when the job is done.

Many thanks in advance!

Jack

[RabidRabbit]

To do it right you need to lift the boat off the keel. Then replace all he bolts. Cleaning, fairing, sealing the keel joint should all be done at the same time. Tighten all the bolts slowly in a circular pattern, headgasket style.

[Tar34]

I imagine increased torsion trying to manipulate the bolt from one extreme end. The end result a greater danger of broken bolt. You can try it but I think in the end you will be dropping the keel.

[OrangeCrush]

I know that would be ideal, but I don't think I have the means or machinery to do it that way. How would I lift the boat off the keel, and how would I support the keel or move it around when it is off?

The only way I see that happening is if I took the boat out of the water for the entire season and worked out some system of jacks and braces. Not desirable or even possible for me right now.

Is replacing them one at a time out of the question? i thought this was a viable (if not perfect) alternative.

[sailvayu]

I am wondering why you are doing this in the first place? A bit of surface rust does not mean the bolts need replacing. Admittedly the boat is older and this could be a concern but if you are not seeing other signs of problems I wonder if maybe you can do more harm than good. I am thinking of the ol If it aint broke don't fix it. You could try tightening one of the bolts some if the nut tightens about a 1/4 turn and feels solid leave well enough alone, if you apply pressure and it feels like it is getting looser the bolt has broken and you should replace all. If you just have to replace them to sleep well at night then I would think you can do them one at a time.

[RabidRabbit]

The marina travel lift would lift you off the keel and set the hull on stands or keep it in slings while you changed all the bolts. Have them lift the hull friday afternoon and set you back on the keel 1st thing monday morning. The super right way to do this actually needs 3 lifts not 2, a middle step involves covering the keel top in epoxy and setting the boat back on to fit the bottom of the hull exactly, then pull and seal with 5200.

[Wotname]

OC,

The answer to the basic question of "can you do it one at a time" is probably "yes". As you state, not the best option but doable!

Next you need some hard data to work with. As others have posted "do you need to replace them". Only real way to know is to take them all out but just taking one out would be a good indication. That is what I would do, take one out and inspect carefully. Choose either one that appears to be worst case or one that has the best access. Now you will some idea of what is necessary and how to do the rest if needed.

My experience tells me it won't be easy but it will be possible.

I don't like the idea driving the bolt out without removing the filler around the head but again, this might work and might be the only easy way to locate the head.

If the nut won't turn using conventional methods (correct sized socket and breaker bar etc), then maybe the bolt is also suspect. If you have to destroy the nut to remove it, then driving the bolt out with a punch may not be possible - at least not possible without causing too much colaterial damage.

Normally I would use heat to help release the bolt but not in this case - too risky; especially as it may cause damage to the "resin core". Maybe drill a small hole (say 1/8" or 3/16") first (after removing the nut) down through the centre of the bolt. Drill it all the way through. At least this will tell you where the bolt head is under the fairing compound!

Spend some effort to keep this pilot hole very well centred but rather than drill the bolt out with bigger drills and thus destroying any evidence on the outer surface of the bolt, you could make up a custom "bolt pulling jig". Use the centre hole to pass through a long bolt from the inside and tightening its
's nut from the outside against a custom made spacer (or very large socket).

Of course if you can't remove the bolt reasonably intact then perhaps that is a sign that it should be removed.

Good luck with this project and please keep us updated with your progress / results

[Wotname]

I agree with you general concept that you rather know the actual status of the bolts after 25 years of service than just hope that they are OK!!!!!

[OrangeCrush]

Thanks all for the feedback so far.

You said it, sailvayu, it's about sleeping well at night. I've had the boat for 5 years and the 'if it aint broke' approach is definitely my preference, but I worry about the age and condition of the bolts. One of the bolts oozes a bit of rusty water out of bottom, through the filler over the bolt head. Who knows how much of the bolt heads are intact at this point. The washers are pretty badly corroded, which I'm thinking could lead to more focused stress on the keel plate. Also, my keel regrettably took a moderate impact with a rock four years ago, and it's possible the bolts suffered some damage from that.

Even so, the hull/keel joint stays dry and does not wiggle. That's why I was thinking I could avoid the trouble of dropping the keel and instead just replace the bolts. I doubt I could tighten the nuts at this point without a lot of banging, and that still wouldn't address the issue of the weakened washers. I don't really understand the torsion concern, since the other six bolts would still be tight while I replaced a pair of them, say. If necessary, I could do them all at once and tighten them as you described.

Rabidrabbit, I see what you're saying but I am envisioning that removing and rebedding the keel is where I would get in over my head and do more harm than good. If the keel is snugly attached to the hull now, do I really need to mess with that? I would hate to have my boat sitting in slings and not be ready/able to put it back together in time.

[donradcliffe]

I think your plan will work, except I see no way to capture the bolts from turning. My guess is that if you try to back off the nuts, the bolt may spin inside the fairing, but that's OK. You can use a nut cracker or a cutoff wheel to remove the nuts, but you will need a big hammer and a good drift to drive the bolts out. A dremel tool with a thin grinding bit will work well on the fairing to create a hole big just enough to get a socket on the bolt heads. Once you locate the first bolt on each side you can measure to the next, and remove the fairing with the dremel first.

My guess is the first bolt will take 10 time as long as the last.

[Sam Plan B]

I live on my Columbia 41. Soon after buying the boat I decided to change the keel bolts. They were threaded into the cast iron keel. I found the imbeded end of the anchor bolts to be in good shape. Only the exposed ends of the bolts and the nuts and washers were corroding. It looks from your photos that mild steel bolts, nuts and washers were used. Next time you haul the boat back off the nuts one at a time. Check if the bolts are okay before you do major surgery like lifting the boat off the keel, etc. If the bolts are found to be in good shape, replace the nuts and washers one at a time with stainless steel and paint.

[casual]

Please do not punch the bolt's out.They have to be secured so as not to turn when tightening.I,removed the keel on my C&C 36 20 plus years ago for inspection of bolt's.Building braces to steady the keel was not a big job. How about a pipe wrench on the bolt's from the inside?I,bet they are threaded into solid glass not just pushed in.You have a seeping problem now you may have a distroted hole.Just some ideas.Perhaps some other pearson owner's have done this is there a owner's site?
Good Luck

[minaret]

There are numerous methods for inspecting keel bolts without removing them. Do a search here, I've made a number of posts on the subject. Often keel bolts are J bolts and cannot be removed. The usual quick and dirty method in a small boat like this is to install new lag bolts in between the original keel bolts. It's easy, requires no lift, and often works quite well. Not all keels are a candidate for that method though. I believe Mars Metals has numbers on what size lag bolts with how much "bury" are needed for various materials and weights.

[Jim Cate]

Well OC, here's another unsupported opinion:

First, the bolts are quite short for keel bolts. This alone should make getting them out easier than on many keels. Unless, of course, they put them in with 5200 which will be a bugger!

Second, since your keel is cast iron, they may well have cast it with hex sockets to match the heads of the bolts as a means of keeping them from turning whilst tightening. That's how I would have done it... Thus, attempting to loosen one of the nuts might be quite informative to you. If the bolt doesn't turn, all maybe good! If it does turn you will have to find the recess where the head lies and remove the filler so that a wrench may be applied. Finding that will be easy if you use a small magnet... less attraction in the filler area. And the good news is that if it turns it should be fairly easy to drive out!

Third, I don't see any big drawbacks to punching them out. I think that you will be able to tell from the feel of the rebound if the bolt is hung up with sealant or with corrosion. If corrosion, a soaking with penetrating oil may well help free it up. Heating from the bottom, with caution, should also help loosen the bolt from whatever holds it.

Fourth, your idea of using larger plates instead of washers is fine, but after all, the small washers have worked for a long time, and you may be overdoing things.

All in all, this shouldn't be too big a job, and doing it one bolt at a time is a reasonable way to approach it.

Cheers,

Jim

[OrangeCrush]

Hello all,

Thanks again for all the advice; it was very helpful and I'm proceeding forward with the plan.

I have a question about the actual hardware I'll be using. On Dan Pfeiffer's P26 page, which is pretty much the authority on all things Pearson, they recommend some specific bolts for my the P26.

Keel and Keel Bolt Servicing
91253A808 5/8-11 3-1/2" flat head bolts
95479A125 or 93827A253 5/8-11 nuts
98099A035 or 98025A035 washers (thick and large)
McMaster-Carr
Plug these part numbers into the search window.

Before I order them, I just wanted to make sure this looks right to everyone. I was a bit surprised as I was expecting to be using stainless, but after some research I learned this is pretty common and it has its advantages with an iron keel. Even so, the bolts indicate what seem like very high strength ratings but also say they are not recommended for 'high strength' applications.

There are two sets of nuts recommended, though, Grade 5 and Grade 8. It seems like Grade 8 is stronger, but I'm not sure which is better for corrosion. It also seems like these should match the grade of the bolts, but the bolts don't indicate a grade other than "Black Oxide Alloy Steel".

And what arrangement of washers seems the best?

If anyone is able to quickly look at the parts for me and make sure everything looks ok before I order, it would be greatly appreciated!

Thanks,

Jack