Where can I get a long core drill to drill around a steel spike in a floor timber?

In my old timber framed boat, the oak floors that sit on top the keel are pinned with long steel spikes to the keel. Those spikes are causing problems as boat is 52 years old. The spikes are rusting away and also causing parts of the oak to rot with perhaps iron sickness. I have so far repaired 2 badly rotten floor timbers due to the bottom part of the floors turning into black mud. It was a pain but I did a good repair and now those floor timbers are very solid. I cut off the bottom part of the bad wood into the solid oak all along the floor and at the good top part of the floor glued and screwed oak boards on each side of the floor timber leaving the nasty iron spike idea out of the repair. And I replaced the lower part of the floor with glued in pieces of PT SYP with a tight grain patter. IMO, the 2 floors are actually much stronger than new as they are no longer pierced all the way down the middle with a badly rusted oak sickness inducing steel spike. I would really like to yank out a bunch more of these steel spikes as I know they are causing future issues with rot on several other floor timbers. My idea was to drill down the steel spike with a long core drill and then would be able to simply pull out the spike.

It will take about 9 or 10 inch long core drill to do that, preferably a foot long for some possible other floors are deeper. So anyone have an idea of how to remove those steel spikes? They are like very large timber nails and are 1/2" in diameter.

I have thought about cutting a core drill in half and welding in a steel tube to make a longer core drill. Course that is a lot of effort. A core drill will follow down the straight steel spike, loosen it from the wood and make it easy to remove.

I donit believe those steel spikes do anything after the boat is constructed, they aided in the original assembly of the boat to keep things aligned. The floors are screwed into the frames and planking, and some are bolted to the stringers that sit on them.

 

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Maybe something like this. Could cut teeth into the end of the tube to drill through the oak, or weld on a bimetal hole saw. It could be driven at the tip using another bimetal core drill thru bolted into the pipe.

 

Those spikes (called drifts) are what keep the planking attached to the keel, remove them and all that is holding the keel (and ballast if it exists) to the rest of the boat are the screws into the rabbets. They are critical and need to be replaced, either by other drifts, or by bolts or rivets. If you want them not to rust, use bronze or copper.

For removal, buy a piece of steel tube, cut teeth in the end and harden them in a small gas forge.

 

Maybe on some boats. On mine, the frame ends are pocketed into the keel.
There is no ballast. It is a powerboat 37 foot Egg Harbor 1970. It has a 4" width skeg 1/2" bronze bolted to the keel, and it has a pretty good depth to it as it moves aft.
Frames are 1.125" tall and 2.25" wide.
And the garboard plank edge is fastened all along its length to a rabbit on the keel.
Wood floors (joists) are 1.75" width and bottom edge follows the hull, so as to form a triangular structure. The floors sit on top of the frames, and are of a pretty long length.
It just seems superfluous considering how my boat was made those steel spikes.
Keel is 8" wide and 4" depth white oak. Surprisingly, the 2 floors I fixed, the spike hole the steel spikes had been fit into had completely rusted away to nothing, as in gone, but the oak was not damaged. I plugged them with glued in Poplar dowels. I cleaned out the keel spike hole using my home made drill bit from a steel rod, with one end smashed and shaped into a spade bit shape. Flushed and sucked it all out with a wet vac and a garden hose.

Making my own tube drill might be what I have to do. I see plenty of diamond cutting long core drills, but wonder dimensionally about them, and also do they cut wood.

Where I am working on rotten floors, is the forward end of the boat before the engines, and where the skeg is only about 6 inches in height. The design of the hull forces all the bilge water to this spot so it is a continually wet area.

 

Here is a pic of a completed repaired floor. The wood under the oak added on boards on each side of the floor is the new wood, coated with PL so it is rough, but solid. Hit with a hammer it rings nicely.
Also there are 2 hull drains, plan to get rid of them eventually. On one, the the bronze corroded too much to hold the plug, so I cut a wood taper cone and glued it in and slammed it down with a hammer. Basically, cut off floor bottom with jig saw. Cut wood multiple pieces to fill in the floor bottom again, all glued together, it takes 4 pieces of wood to do that, and of course have to match the angle of the frame too. The last piece to fit in has to be the exact height to fit.

 

I would also advise a steel tube with teeth cut in the end.My somewhat limited experience of diamond cutting edges in wood is that the grit is too fine to really cut and just abrades the wood into fine dust which then clogs the grit and impairs cutting.The larger teeth that can be formed on a piece of tube will have a better chance of remaining clear to cut.If you do use a piece of tube it is well worth trying to give any teeth a little set and it helps to choose an even number of teeth if you don't want the last tooth and the first to be set in the same direction.In practice it doesn't make a huge difference.

 

Hey Rumars, I did have a thread from several years ago about this same area that I am now forced to fix.
replacing steel drifts in floors of Egg Harbor 37 | Boat Design Net

Also shows the floors under the engines, which are in much better shape. The damage is all in the forward bow area where the water tends to collect.
I think steel set in wood creates a battery with the bronze, and salty water is the electrolyte. I think it actually eats up oak and is called iron sickness.

 

So if they rot the surrounding wood, why don't they just pull out ? Or do they break when you try ? Adapting an existing hole saw seems appropriate, trying to make one with a steel tube does not sound easy.

 

Even if the frame heels are screwed to the keel, wich is by no way guaranteed since this depends on local tradition, the screw there is a single small screw intended to keep the heel in place while building. Similarly, the garboard screws are dimensioned to keep the garboard to the keel, not to have the keel hang from the garboard.

Iron reacts with the tannin in the oak. It eats the iron and can decompose the lignin in the wood. This happens regardless if the wood is wet or not, it's just faster with wet wood. Longevity is beside the point, boats buildt this way were designed for 20-30 years lifetime. Many survive longer, but there comes a time when the drifts are gone and often part of the surrounding wood. This kind of drift also holds your stem and sternpost to the keel, as well as the deadwood. The only way to properly repair such damage is to replace the affected structures. There is no way around this, this are primary fasteners and when they are gone they need replacement (usually together with the wood).

Iron and steel can coexist in wet wood just fine for a while. You have a big bronze skeg plate and various other bronze fittings all in the same wet wood, and the boat is still floating.

 

I have a friendly observer question. Rumars seems to know this business well.

Is there enough space to just add new fastenings less prone to decay and let the others rot away or is the wood too compromised then? Or already? Or is drilling out a bit of the wood enough?

 

They cant pull out or pry out as the wood is mostly still sound. For the 2 really bad floor I fixed, top upper parts of the floor is still perfect such as the top 6 inches in these 2 floors, the damaged wood is in the lower part of the floor close to the keel. The wood drift holes in the keel are not holding the drifts any longer with any friction, since they are gone, all the friction is in the floor wood where it did not get wet. But the keel and lower floor rusted these drifts in the 2 floor to nothing. Other drifts I dont know, but if they are not completely wasted at their bottom ends, they are still holding the keel. On those 2 bad floors, I removed the bottom floor wood to create a window to expose the spike and used a 3 foot Pry bar to pop the remaining spike from the hole out the floor top. Some of the top of the floor had also rotted around the drift-spike, so it came out leaving a pretty large hole. So sandwiching the floor with oak on each side gave it back the strength it needs. I also thought of welding a heavy ring to the drift top, use a heavy round bar and 2 hydraulic jacks to pull the drift out.

 

yes screwed frame ends which are socketed into the keel. The OEM builders actually cut using a hole saw, a rounded end into the keel rabbit running at the same angle as the frames, so it is a little thinner on keel edge, but very thick at its end into the keel, like 2" thick pocket at the pockets edge. That is a lot of wood locking the keel to the boat since keel also sits on top of the garboard planking, it is well locked together. Planking Bronze Screws are #12 by 1 3/4 long. That is what I put in when I rebuilt the hull back in 2005. I may have a picture I can show of the disassembled boat.

 

ok, here is showing how the socketed frames are fit into the keel and lock structure together. When I rescrewed with 4000 new bronze screws, I also replaced a ton of the framing. You can see how thick the parts are and how they fit together. The wood skeg is bronze bolted to the keel. It is very dried out here and you can see the gap between keel and skeg

 

Further out view. This is the aft port side. Also shows where oak skeg rises back up where the props are

 

This pic shows more of the hull, the area I am working on is forward of the depth sounder sticking down. And is right at the hull drain area, which is forward of the head water through hull pickup. right near the depth sounder. The only way for the keel to separate from the planking is a total destruction of the hull. The bronze bolted skeg could fall off and I doubt boat would sink.

I know at the wooden boat forum, many of those guys hate socketed or pocketed keels for frame ends, but they do have their uses. Some boats also have no ledge or rabbit for the planking to sit under the keel, some guy had constant leaks along garboard seem from that. Hard to imagine the bad things people do when making these old wood boats. I also have issues with mine against how they did some things.