New Keel Bolts

[Ian McColgin]

A friend's 50 year old sloop needs new keel bolts. Since it's an iron keel, I plan to to the job the same way it had been done on Goblin many moons back.

Getting iron bolts out of an iron keel is futile. We'll sister.

Like with Goblin, I'll be sistering in new floors for the new bolts.

Plan is really to bore down to the iron and then bore enough into the iron that we can thread the keel, put in the threaded rod, and torque it with a nut on the top.

Plan is to thread each rod individually so that we have as much solid, unthreaded rod, as possible.

It's been a good while since I tackled a job like this. Any thoughts on good jigs to set up a boring machine inside the boat? Other thoughts?

I'll likely be renting all the major tools so it really comes down to what are the best portable, not lathe mounted, threading and taping tools, especially for the deep tap into the top of an iron keel at the bottom of a couple of feet of wood?

[Art Read]

Ouch! You did this before!?! My first thought is that it would be easier to haul out, drop the keel and maybe even re-use the old holes?

[Ian McColgin]

With a lead keel, that would be the ticket, though even at that extracting the old bolts can be entertaining.

In an iron keel, the bolts do not go all the way through anyway. The originals are threaded in the top inch or two of the keel. After all, the keel itself if just an eight ton nut.

There's not way those old bolts are going to back out of those holes. I am going to test that there's no rot or such around the bolts in the keel. If there is, then we're looking at dropping the iron to work on the wood. But preliminary poking and sniffing it seems ok.

After Hurricane Bob, which seperated Goblin from her keel a bit, I got a good look at the waste in the old fastenings. After sixty years they were indeed gone. The new bolts were fine and it was not the fault of those bolts that the keel was seperated a bit. Turned out the keel timbers were also in good shape, though the hood ends of most of the frames showed rot.

Anyway, we can get at this in a lot of ways. If need be, I'll yank the garboards to get some leverage when we go to tighten the upper nuts.

[Ken Hutchins]

Ian, what size thread? My first thought is make sure you bore the clearance hole through the hard skin surface of the iron. A tap will not cut through it. I would get all the holes drilled and tapped, then measure the lengths and cut the threads on a lathe to fit rather than trying to do it in the boat. Predrill the floor timbers to use as a guide with bushings for the drill shank when drilling the iron.

[Art Read]

I hear you about the iron, but still... that makes my head hurt! You're a better man than me, Gunga din!

[Ian McColgin]

Bushings in the wood. Like a pillow bearing on a long shaft - super idea. Thanks.

I think you're right about doing the rod threads on a lathe.

Is there a brand of tap for threading into iron like this that will likely work? God help us if we have to create a welded extension for the taps. Grahhhghgh.

[Ken Hutchins]

Are you sure the existing bolts don't go through? Depends on the boats builder. As for taps a good quality US made HSS plug tap would be my preference, don't use any foreign junk, might be able to get a pulley tap depending on the size you need, this would eliminate the extension but would be sort of expensive, pay em now or pay em later! Less chance of breakage with the pulley tap.

[Ed Harrow]

Well, um, Gezuz, I hope I never meet you in a back ally... You gotta be one tough SOB to do this sort of thing.

Are you certain the keel is threaded??? I'm not suggesting it's never been done, but it's outside of my limited knowledge. The bolts on Phoenix went into pockets (four I think, done in pairs) and another four or so that go all the way through. Dick, her previous owner, replaced the originals a few years ago. I'm not certain how he removed them, however.

Seems to me you might:
1. Cut off the nuts (not the bolts) inside
2. Jack her up so the ballast is hanging a very wee little bit
3. Sawzall the bolts between the ballast and keel.
4. Toast the bolts within the ballast, wherein they will probably be more inclined to come out
5. Use a hole saw to core the bolts out of the keel/floors.

Now, if they really are threaded into the keel, they likely could be "burned" out, and then the threads cleaned up with a tap.

Good luck!

[Gary E]

Ian,
This sounds like a really big job. First of many questions is how do you know they need to be replaced?

To examine them without removal can be done with portable Xray equipment, For a start I would look here http://www.asnt.org/ to find someone with equipment. If this inspection shows replacement is required, then Ed's ideas seem good, although I dont know where you will find a hole saw to go 2 ft deep, spose you could make one. Maybe just drive them out or drill and tap them and then use a portapower to pull them up and out. How many? what diameter?

Good luck
G

Edit...
Here is a company that does this...
http://www.rndt.net/ and a brief description of what and how from their site..

Radiography involves the use of penetrating X- or gamma radiation to examine parts and products for flaws that could be detrimental to their intended use. An X-ray machine or radioactive isotope is used as a source of radiation. Radiation is directed through a part onto a film or an electronic device (plate). When the film or plate is processed, a negative-like picture is obtained that shows the internal characteristics of a part. Possible imperfections show up as density changes in the film, in much the same way an x-ray can show broken bones.

RNDT provides radiographic services in both our laboratory and in the field at customer locations.

[ 01-03-2004, 01:45 PM: Message edited by: Gary E ]

[Andrew Craig-Bennett]

Ian - I am very surprised!

For myself, I have never seen an iron ballast keel where the bolts do not go all the way through. Certainly I have never seen one where the bolts are tapped into the cast iron. It was so much easier for the builder to ask the foundry to cast full depth cores in the iron, than to try boring it!

I have seen a few lead keels where the bronze bolts have nuts on both ends - the lower nuts are in pockets, and the pockets are filled with putty after the bolts are set up. The putty is easy to remove when renewing the bolts.

This was done because forming upset heads in bronze bar was considered a bit "iffy". No such worries exist with wrought iron or mild steel, which are excellent forging materials.

Every cast iron ballast keel whose bolts I have looked at has through bolts, with flush upset heads on the underside of the keel. It can indeed be very hard to find the remains of the upset head after half a century or so.

Three years ago we removed Mirelle's old mast step (oak, iron bolts, wet, split, hence locally rotted. Replaced with teak.)

The mast step, according to the drawings, extended over three iron keel bolts, two of which went through the step. Where was the third? There was no evidence of an upset head on the underside of the keel, but when the old step was finally pried out (by the yard, not by me) there was the nut on the inside end, under the mast step, which had been hollowed out round it (someone in the builder's yard ordered one bolt too short, methinks!)

After cutting the nut off with a cold chisel, the 63-year old wrought iron bolt was "persuaded" out with a 14lb sledge.

The reason for telling this story is that nobody suspected the bolt was there, for six decades. Yet it went all through, and out it came.

Provided that the bolts are not unduly "necked" due to wastage in the wood keel, I have always found that they will come out of the iron keel if walloped hard enough. Almost no wastage or corrosion occurs where the bolt passes through the iron keel.

I frankly don't understand why any builder would choose to do it the hard way, by boring and tapping cast iron.

[ChuckG]

Where angels fear to tread ... I know nothin' from nothin' about this, BUT ...

The front cover photo on the Sept/Oct 2003 issue of Boatbuilder has a pix of a guy doing something like what you describe. Garboards off, right angle 3/4 drill going down thru thru about 8" of wood keel. But you'll have iron below that, right? So when the Grizzly catalog came in the mail today, I flipped to the tap and die section and found maybe what you were asking about: an extra long tap handle, and tap extentions. They have a chuck on the end of the extention which would need clearance thru the wood.

Another idea might be to drop the cast iron onto the ground, wrestle with it there installing new keel bolts, and then with some judicious measuring, fit the keel back onto the bottom of the boat?

Like I said, nothin' from nothin' ... <shrug>
cg

[Ed Harrow]

Originally posted by Gary E:
...although I dont know where you will find a hole saw to go 2 ft deep, spose you could make one. ... http://home.fiam.net/eeharrow/WayneEddie.JPG

Here's just the ticket, if 1.25" dia is what you want. ;)

[Hughman]

Welding the preferred size hole saw to a peice of auto exhaust pipe (or such) is done for large shaft holes through deadwood. less torque distortion/deflection, too. ought to work here, too.

[Ian McColgin]

I had only the experience of Goblin with a cast iron keel. I may have made an incorrect assumption about the length of the keel bolts from that and will take a really good look - with grinder - at the bottom before anything else.

The owner's insurance surveyor called for replacement. If the bolts don't look too bad on my own closer inspection, it may well be worth the expense of an Xray.

Thanks all.

[RGM]

Keel bolts, one of my favorites. I would be suprised if they don't go all the way thru your ballast keel. I've removed wrought iron keel bolts from the cast iron keel of one of the old schooners that's here in Puget Sound before. They were pocketed. It wasn't easy, but they came. I've long been a proponent of using X-ray anywhere "X-ray Vision" is called or begged for. The knowledge gained is well worth the expense. In my experience the expense wasn't that bad anyway. One thing to consider if you have to change keel bolts, you will probably be better off by removing and replacing the floor timbers that you may be fastening thru. Getting the floor timbers out of the way will make things easier when it comes to removing old bolts, whether you are driving down or jacking up. Drop a sawzall blade down both sides of the keel bolt to free the floor timber from the bolt. This leaves you with full length keel bolts which potentially gives you more options for removal methods. Much better that weed-whacking them off flush with the top of the keel immediately and then wishing you had left some length to them. Some times you can use the cropped out sections of floor timber to develope patterns for new ones, but that is rarily worth the trouble. Hopefully the bolts aren't drilled and tapped into the ballast as you suspect. Saw that once done with lead ballast and stainless keel bolts. You can imagine the results. Going back the same way (drilled and tapped) will certainly be labor intensive. Good luck with the grinder.

[ 01-04-2004, 01:38 PM: Message edited by: RGM ]

[cbob]

All, Went through this a year ago, 45 year old,1/2 inch, 4.5 ft. long glv. steel deadwood bolts, in pairs aft of lead. After a preliminary check of portable X raying costs, made an assumption these could be weak or discontinuous and sistered with centerline 5/8 in. bronze through a floor sister. What would have been the cost for a portable Xray job to say, take a shot of 4 of these Galv. Seems like the major cost was the setup? How about an experiental estimate, anyone??

On the same subject, in a recent WB article there was an article using two jacks and a pipewrench and etc. I have used and seen advertised in Boats and Harbors, hollow hydraulic jacks, instead of this (read dangerous after the pipewrench explodes) method.

If this method fits the application, prior to chopping the floors as suggested, screw/bolt sandwhich style plywood to the floors, marked up as necessary for later, so after the two old floor sides are out, the shape can be recreated, as a pattern for the new floors, recreating the bolt hole alignment in the new floor is another matter. Seems like the boat was supported, so the iron keel could be dropped slightly, the inside nuts removed , and the iron encouraged downwards for sawzalling off the bolts flush or better above the iron, and the bolts drawn upwards, for which the hollow jack would be just the ticket, either with the floors removed, by jacking up bolts from below, or attaching threaded extenders for jack strongback purchase. The advantage of drawing upwards was the bolt in tension decreased slightly in I.D. Now how to do all this won't work if the mid length corrosion has weakened the bolt, ie. only part of the bolt coming up, or when driving down from inside the keel/lower part of the bolt doesn't come down. cbob

[Ian McColgin]

Now I have an idea of how to do it right.

Finastkind and thank you.

[Ed Harrow]

Brian, sorry for your loss. Your Dad sounded like a clever guy.

Re big motha drills: As Brian points out, they don't stop for nothing. Big Bertha will continue to whirl for at least 30 seconds after being shut off (with no load, of course). If the bit ain't turning it is Big Bertha, and whom ever is attached to her, that's going to whirl for those 30 seconds!! Careful, careful is the word.

There may, however, be a better way, tho I have no personal experience drilling with an impact wrench (electric or pneumatic). It was suggested to me that using said wrench eliminated the risk of going for a ride, or of getting one's body parts smashed.

[whb]

RE big drills.

I had a lucky accident once that kind of taught me a survival method for these drills.

The drill took off in a relatively cramped space and could have beat me up real good.

But the cord snagged and as soon as enough was wound up (I think about two turns) it pulled out of the wall. Sort off like an automatic shut off.

Since then I tend to use this type of with only enough cord slack to work. That way I know it will unplug itself.

Howard

[Gary E]

Brian,
Your Dad was a very smart guy, he knew exactly how to do it.

I can only offer a couple more points..

Dont use motor oil, it's intended to make things slipery. Drop by a machine shop or a pipe fabricator and ask them for some cutting oil for the drilling and tapping. In the real world Cast Iron is machined dry, but as you say, this stuff could have hard spots.

Wrap a bit of masking tape around the extensions and mark with a pen, this will tell you exactly how deep you have drilled.

Dont use cheap import taps. the first one your calling it "starter" I rember is called a "taper" , it's used for starting the taping operation, next use a "plug" tap.. no need for a bottoming tap. If you feel any torsional spring in the tapping, make the extensions as large a diameter as posible.

And last, give your Dad a hello from a fellow machinist, not many remain in the trade. He must have been a very good guy.

Best of luck to you,
G

[Noah]

Just a few quick notes here:

Ian, make sure to check for bolt pockets on both the bottom, and the sides of the ballast. My Folkboat had the 2" X 3" holes cast through the side of the ballast about half way up it. This was just large enough to get a nut on the bottom of the "bolt" which is actually a rod with threads on both ends.

I chipped the concrete out of the pockets, cut off the nut with a sawzall, and pulled the bolt up from the top. I think if you do a search in here you will see my technique. It worked pretty well, didn't take any hard labor (though getting the concrete out sucked...) and let me not drill more holes in the keel timber or have to build new floors.

I am kinda looking at doing this job at some point again on my Hinckley. Except they are Monel bolts, and I have no idea if they are cast into the keel or not...

Brain, great writeup on making the tools and drilling. This is good information that we need more of on here.

Noah

[cbob]

Noah and Bryan, Now that youve brought up pockets, My experience has been with long (4.5 ft. bolts, removed originals were, lab tested and, yes brass, some screw up, presume ok'd by builders as a time expedient, or an error in translations to and from the Hispanic? Foumd two of the ten broken clean off at the floor to keel juncture, not necked in, just broken. Got ready to replace eight of these, cleaning cement from counterbores on the flat underside of the lead ballast and jacking up from below. Two of these turned out to be monel, both on one side, so replaced six with 5/8 bronze and put the monelback in a side by side, rather than one behind the other on one side, as found. The monel bolts were like new. I would expect on a Hinkley monel, into I expect Lead, but maybe not, the bolt lower ends would be in counterbores or pockets. Cannot imagine casting non ferrous into lead or iron.

The next suggestion, if you can use it, involves the two forward most brass bolts, singles in pockets, at different levels, opposite sides, nuts in pockets under cement, took a while to find the cement, anyway rather than trying to pull the bolts up, which would only been possible, as one was broken clean at the same place as the previous ones found years earlier, friends loaned a sawzall and whacked off the lower ends in 2 inch stubs as the bolt was driven downwards with a 30# buttonset. The pockets didn' go clear through, so the sawzall had very little travel, as you might guess. cbob

[Stephen Smith]

I am in the process of removing a keel bolt to check its soundness after sitting undisturbed for about 35 years. This is fitted to an East German carvel hulled (mahogany on oak) Folkboat and is I think galvanised steel. I have been following the threads posted on how to remove keel bolts but my problem is that the steel stud (rod with threads on each end) fitted seems to be screwed in from the inside of the hull. I have taken a grinder to the bottom of the cast iron keel and can see no evidence of either a counterbored pocket for a nut or outline of a cored hole. I have also ground away at the sides of the keel to see if there was a cast in pocket to take a nut and washer but no luck there either.
I have cut away the floor to expose more of the stud but the problem I now have is that the top of the stud is only about 12" up from the underside of the keel and there is no room to attach a wrench due to the shape of the hull; I only have about 6-8" clearance either side. I was thinking of cutting the handle off of a wrench and welding on a thick bar at right angles to the wrench to allow it to be turned where I have room to swing a wrench ( a bit like the type of wrench a plumber uses to reach inacessable nuts).
Has anyone got any other ideas?
Thanks
Steve

[Ed Harrow]

Originally posted by Ed Harrow:
...
Are you certain the keel is threaded??? I'm not suggesting it's never been done, but it's outside of my limited knowledge. The bolts on Phoenix went into pockets (four I think, done in pairs) and another four or so that go all the way through. ...(Just setting the record straight ;) )

Maybe a pocket sniffing dog is required. I'm sure Finbar would love to take up the task if you offered him sufficient inducement. He's pretty good.

http://home.fiam.net/eeharrow/3.24.02.JPG

Steve, if I understand you correctly you are looking at a nut in the bilge. Using a suitable socket and extension should get you up out of the bilge so that you could swing a breaker bar. I also gather that you've cleaned up the sides (both) of the ballast and found no signs of pockets. Based upon limited past experience (DAMHIKT) I would double and triple check the area directly below the floor(s) with the bolt(s). Don't forget to look on both sides. You might well want to check with a magnet, in case the pocket has been filled with a non-ferrous metal filler. (More typically, in my experience, they are filled with wood or, for newer stuff, bondo or some other polyester-based filler.)

If the bolts really are threaded into the ballast, and are fitted with nuts on the top, then you will (I think) have to either:

1. Break out the floors to gain access to the length of bolt so that you can attack it with something on the idea of a pipe wrench. (Given limited swing room, this doesn't seem promising to me.)

2. Weld something suitable to the top of the bolt (leaving the floor in place) and see if you can get sufficient purchase to turn the bolt. (Or, if there is sufficient thread exposed, clamp something between two nuts, but I suspect welding would be more likely to work.)

3. Raise the boat, and attempt to lower the ballast, exposing the bolts between the keel and ballast, and then attack them with whatever falls to hand and makes sense.

Others, of course, may have different (and better) ideas. Good luck!

[whb]

Stephen

8" might be enough to fit a small impact gun and socket if you have access to one.

Otherwise what about one of those socket type wrenches with the universal joint for going into strange locations.

Howard

[Stephen Smith]

Thanks for the replies gents. No work done last night due to driving rain and gale fore winds although it is nice and mild for this time of year only going down to 41F.
I had no difficuilty removing the nut from the top of the stud but of course this has left me with nothing to grip. I could however clean up the top of the stud with a grinder and weld the nut back on to allow the socket wrench to be used to remove the offending item. (New idea only formulated as I am typing this!!) I have already cut away the floor to allow better access and I have been pouring release oil round the base of the stud, anything to make life easier.
I did go right round the keel in the area of the keel bolt with an angle grinder and now have a nicely polished cast iron area on both side and underneath. Still no sign of a pocket.
I will be attacking it this weekend so will post a note giving the outcome in a couple of days.
Thanks for all the help, it is much appreciated.
Steve

[Stephen Smith]

Latest in the Folkboat keel bolt saga is that the first of the offending items now lies proudly on the work bench. The bolt was screwed into the keel from inside and was removed by pouring release oil down the bolt for a week before welding on the nut and using a 3/4" drive socket, 2ft of extension bar and me wedged beteween the hull and the tommy bar, pushing with my feet.
The exercise was worth while as the bolt had wasted away to about half of its diameter just above the lower threaded portion. Enough strength left in the bolt to allow me to extract it, but not if I had left it much longer. I plan on making up new bolts from some high tensile steel bar I have lying around. I might even galvanise them!!
Only another 5 to go.
Steve

[cbob]

Ian, A small magnet, mightly secured to a stick, so it positivly won't come off, no matter what, will clean up the magnetic junk down in the hole after the bottom tapping. Anti -seize, some times called lead paste, seems like a very good idea. Persevere. cbob

[Alan D. Hyde]

When I was a boy, my father used kerosene when drilling metal.

It seemed to work well.

Alan

[Stephen Smith]

Thanks for the encouragement gents. The floor and keel timbers are both white oak and are in remarkably good condition given the neglect they have suffered over the years. So much for these boats being cheap, poorly built, batch built boats. The keel bolts show signs of having been galvanised; I could smell the zinc when I was cleaning up the top of the bolt proir to welding on the nut. Likely that the galvanising was much thicker than that applied at present. I had planned on brazing a tap to a steel bar to allow me to clean up the existing thread in the cast iron keel. I was going to carry this out without using any tapping compound as I want a dry waste product. The theory is that I will be able to attach a length of copper plumbing pipe to the shop vacuum cleaner and be able to clean out the bolt hole. The new studs will be sprayed with "cold galvanising" spray (a very zinc rich paint)and liberaly coated in a lead free copper paste (coppaslip). I will be planning on removing and replacing the studs on a regular maintenance schedule.
Last night I had a go at removing the next stud but this time without removing the floor as this is still in good order although needing re-fastened. I have managed to unscrew it from the keel but will need to devise a method for pulling the stud through the floor although that is the easy part.
Here's to good sailing weather.
Steve

[keithw]

Dear All - great set of posts with excellent info. My issue is how can I get a really tight fit on my replacement keelbolts. To explain: my keel stub is mostly mahogany, the floors and skins(s) kauri (good pine): there is a layer of teak below the mahogany, on top of the lead keel. The keelbolts are bronze and show just the beginning of corrosion in the area which was in the mahogany - but I have been advised to change them as (the argument goes) once corrosion has started it will continue. The boat was built (launched 1983) with epoxy glues and was covered with glass down past the top of the lead - in theory water-proof but the wood was indeed damp (I drilled down outside the keelbolts with an extended holesaw and therefore was able to smell and taste the sawdust). Now, when I find good stock for my new bolts (and am being told Stainless 2205 is the stuff to go for as no current bronzes contain enough nickel - at least whats available here in New Zealand) I want to seal them so that water will not pass up from the pockets (which I am not confident can be made waterproof except by somehow filling them with molten lead).

My original bolts were 19 mm or 7/8ths...what about buying 20mm stock and hammering that stock thru the lead, making a good "interference" fit (is that possible?) -or should I ream out to 20mm and use some goop along the bolts? The easiest way to fill the pockets is to use some epoxy and filler powder - any comments on the best?
One bolt was tilted somewhat so that the washer and the nut had to be ground down to make them flush to the lead - again I want to make it truly waterproof - -any comments>

By the way, I personally know of some hundreds of UK_built boats which had cast iron keels held on by stainless steel bolts tapped into the keel and topped by nuts inside the bilge ( a method i understood the previous conversations to say was pretty-much unknown). I assume these have to be replaced every few years. And a source of my concern about now being advised to use 2205.

Comments please!!

[keithw]

This is to add to my original post....
I have drilled down thru the keel stub with an extended holesaw, which cut timber about 3/8ths wider then the keel bolts. Quite a bit of the timber I cut thru was damp (I think from timber leaking up the keel bolts but I don't know for sure), but apparently not yet in a state of decay.

Before I refit new keel bolts, I want to dry out the timber. When I pour epoxy down around the new keel bolts (using a so-called penetrating epoxy), I want to be sure I am sealing timber but not sealing in rot and even sealing in solvents etc.
So - I think I need to remove salt, as if there is any there it will stop wood drying out at all and will sit there waiting to suck in and hold water molecules (even if they are just from water vapour). I intend to wash the holes (by filling them with fresh water for say 30 minutes - by plugging the bottom of the keel bolt hole)....then?? what about filling the hole with meths to somehow extract the water which will have soaked into the wood ??? or using acetone?? I don't want to lock in such solvents (which I guess I will do when I pour in epoxy unless I have waited for days or weeks) unless I can be sure the stuff left in is benign as far as both the wood and the metal of the keel bolts are concerned.

Or should I just leave the holes as they are - -freshly-drilled - -and trust the epoxy to penetrate and to prevent future rotting and decay?

[pukka]

This is to add to my original post....
I have drilled down thru the keel stub with an extended holesaw, which cut timber about 3/8ths wider then the keel bolts. Quite a bit of the timber I cut thru was damp (I think from timber leaking up the keel bolts but I don't know for sure), but apparently not yet in a state of decay.

Before I refit new keel bolts, I want to dry out the timber. When I pour epoxy down around the new keel bolts (using a so-called penetrating epoxy), I want to be sure I am sealing timber but not sealing in rot and even sealing in solvents etc.
So - I think I need to remove salt, as if there is any there it will stop wood drying out at all and will sit there waiting to suck in and hold water molecules (even if they are just from water vapour). I intend to wash the holes (by filling them with fresh water for say 30 minutes - by plugging the bottom of the keel bolt hole)....then?? what about filling the hole with meths to somehow extract the water which will have soaked into the wood ??? or using acetone?? I don't want to lock in such solvents (which I guess I will do when I pour in epoxy unless I have waited for days or weeks) unless I can be sure the stuff left in is benign as far as both the wood and the metal of the keel bolts are concerned.

Or should I just leave the holes as they are - -freshly-drilled - -and trust the epoxy to penetrate and to prevent future rotting and decay?

I am interested in what you did in the end? Was it successful?

[MN Dave]

This is to add to my original post....
I ...not yet in a state of decay.............Before I refit new keel bolts, I want to dry out the timber.... - I think I need to remove salt, ...by filling them with fresh water for say 30 minutes -.......then?? .... extract the water which will have soaked into the wood ??? or using acetone??............Or should I just leave the holes as they are - -freshly-drilled - -and trust the epoxy to penetrate and to prevent future rotting and decay?

Ventilation comes to mind, lots of ventilation. The fumes are explosive, so keep the air moving. I think that lots of warm, dry air will be good enough, but the solvent idea has some merit, and making sure the solvent is dry to begin with will help. A loose fitting pipe or dowel in the hole will allow you to fill the hole using a lot less solvent. . If the humidity is high, heating the damp air lowers the relative humidity, which makes the air effectively dryer, if not cheaper. Water comes out slowly no matter what you do.

The fresh water idea to remove salt is not bad, but diffusion is a slow process, so I would try several changes of water for longer times. While you are soaking with water, some borax in the water might not be a bad idea. It is not so hygroscopic, very toxic to fungus, and safe to handle. The borax will not affect the salt removal.

Now wasn't this Ian's thread? In the wild sounding "don't try this at home' idea department, I was cutting the head off of a frozen 3/4" steel bolt in an old, 10-12" gate valve with an oxyacetylene cutting torch in a sewage plant one sunny afternoon down in Florida, when I got the idea to just follow the bolt down the hole with the torch as long as the valve seemed to be a goner anyway. The bolt burned away cleanly, leaving a nice dirty, as in rusty, but otherwise unharmed, cast iron hole. I think that the rust was just enough of a thermal break and the casting was enough of a heat sink that it worked. I could see well enough that the molten metal wasn't wetting the casting and that it didn't even start to glow, so I kept going. If the keel looks like it is starting to burn, you can stop before doing any real damage and go back to drilling, pounding, swearing, drinking... well either way, you don't have to stop drinking.

One last FWIW, iron is a good anode for protecting stainless underwater. It won't do anything at the far end of the bolt, so the head might fall off, but the part in the keel should be OK. 2205 or Monel are good, but galvanized steel, what'shisname's Devcon zinc rich primer and some nice tarry mess to keep the water out might be cheaper and last longer. I would also like to see how well pultruded fiberglass (http://www.creativepultrusions.com/LitLibrary/general/superstuddata.pdf) bolts would last.