View Full Version : Floor to keelson drift pins

07-20-2014, 09:18 PM
I know mine are rusting away and wonder if they should be replaced.
Do they serve a purpose after the hull is built? They certainly helped locate everything when the hull was laid out.
My frame ends are socketed into the keelson and large oak floors sit on top of the framing, the whole assembly is strong enough without these drifts, I think. But they are there so wondering about them.

When the oak floors dry out and the pin tops are more exposed they are easier to pull when the boat is out of the water. Last time I was out years ago, I did not drive them back down on purpose to aid in pulling them at a future time.

The pins I was thinking maybe the cheapest way to replace them would be using 1/2 inch diameter 8 foot copper coated ground rods cut to length, the copper will help keep the rust down. Epoxy coat the free ends. The rove washers can be reused.
Cut the rod, chamfer the tip, drive the drift and its done.

The drifts I wonder if they would pull out intact. I think pulling using twin hydraulic jacks on either side of the floor timber with a bar locked into the top of the drift might work ok.
Or start with a crow bar.
So anyone done this?

07-21-2014, 06:04 AM
For example this
about dollar per foot.
The few I have removed from the boat look like plain mild steel rod, these will be an improvement.


wizbang 13
07-21-2014, 09:05 AM
keelson? keelson is a timber that sits on top of the floors... sure you have your nomenclature correct?
Anyway , I assume we are speaking of your Egg Harbor , The floor to keel fastenings are less important than on a ballasted sailboat, but they still hold the frames to the keel . The notches in the keel do not do much other than make a place for rot to start.
By changing from steel to copper you may be changing the whole galvanic balance of your boat .
I might consider using bonded drifts.
That is , boring oversise holes through the floors into the keel , at an angle, pouring resin in the hole and simply dropping in an old galv bolt, that sinks to the bottom , then locks up when the resin kicks.
Strong and corrosion free.

07-21-2014, 11:01 AM
I dont want to increase the hole size in the oak floors.
I had to fix one of the shorter floors that cracked in the front area, could have been a blocking issue from years ago. If that pin was not there never would have cracked.
I am able to put a jack under the keel in the mid section and almost lift the entire boat and those floors must bear a lot of weight holding up 2000 lbs of engines and boat too. Did that too pull off the old worm shoe. It all stayed relatively straight while jacking so the timber seems to me in excellent shape. Jacking under the center of the boat actually lifted the rearmost part of the keel up off the blocks.

No doubt that I dont know for sure the name of all the parts exactly.

The keel then has the notched pockets for the frames. The floors sit on top. There are also keel pieces under the notched top keel and that is bronze bolted with 5/8 bronze bolts, some are very long.

EggHarbor cheaped out on these steel pin drifts. Likely cause they knew were going to last a long time.

No doubt also some of these drifts are rusting badly. I will post a picture later when I get out there.
The copper clad ground rod interests me because it would be more protected from corrosion than plain steel and it is cheap.

Oak and steel I read have issues years down the road, which maybe I am affected, I do not know for sure.

Gib Etheridge
07-21-2014, 11:40 AM
Increasing the hole sizes enough to insert hot galvy allthread in epoxy will work very well so long as the wood is dry enough for the epoxy to bond. Not only that, the epoxy bonded to the sides of the holes in the floor timbers will actually help prevent them from splitting.

Otherwise (too wet) you might try twisting in some big long carriage bolts once you've drilled out the damaged wood. I would put epoxy in the hole and grind a slot up one side of the bolt to relieve hydraulic pressure as it's screwed in.

Either way I would let the epoxy sit in the hole for a while so some can soak into any damaged oak before you add the metal.

07-21-2014, 09:52 PM
showing the drifts, floors, keel and the rust between floor and keel from the drifts. The drifts some are popped up which will make it easier to pull them out,


These timbers are in the boats center, these drifts did not get wet over the decades as the ones closer to the bow, so are in much better condition I think.

This floor I repaired by screwing and gluing two one inch thick pieces of red oak on each side. I like the repair and think it is stronger than new, or even so strong enough. I discovered the crack when boat was in the slip so repaired it in the water. There are 2 pieces on each side of the floor.
Edited because I had wrong picture! This does show the repair.


07-21-2014, 09:59 PM
Another floor up near the bow.

Another floor in the center area with it's head popped up. This and the few more forward sit under the battery box.
PRIOR owners let battery acid leak onto the tops of these floors slightly eroding the wood. I created a sealed battery box which can not leak. theses floor are very tall, so a lot of oak. I dont think the strength was hurt.
My foot is placed on a 2x4 which I screwed on top of the floor to raise the box a little so the cables fit better. I suppose the 2 x 4 could be sacrificial if acid started soaking into them.

And here she is sitting there in nice shape, straight and all looking in good condition. Minus the worm shoe.

07-25-2014, 07:15 AM
I have an idea on how to pull these out.
Use a come along ratcheting hoist, I have one rated 4000 lbs.

Take two 2 by 6 by 4 foot boards
Cut a central slot in bottom of each board say 5 inches deep by the width of the floor.
Place them over the floor interlock notch and floor.
Put 4x4 on top of 2x6 boards. Could screw this together
Connect hoist to the 4x4 with chain.
Take a 1/8 flat bar, bend into a U type shape
Cut side slot into u bar
Drill holes thru U bar at top for a bolt.
the bolt will be hooked by the hoist.

Take U bar and slip below the washer of the drift.
Then hoist the drift up and out of the floor.

For buried-flush drifts, the floor will have to be cut down a little in the center to slip the U bar under the drift washer.

The shortest distance is straight line, so hoist pressure will keep this lined up straight, it wont go wonky sideways since the distance is then longer .

Doing it this way, there is no force generated between floor and keel, all the force is kept within the floor and the drift which is a good thing.

Doug Schultz
07-25-2014, 07:49 AM
Seems there is lots of room around those floors. Widening the holes for new galv. threaded rod seems a good idea.
How about laminating a strip on each side of the floor. Sand it clean and epoxy a nice piece of the same wood on either side of the drift. It wouldnt have to be that big of a piece. say 1/2" thick, the full height and maybe 6 or 8 inches long.
No chance the bolt would split out then. And it would give you a bit more support at the floor to keel joint.

07-25-2014, 09:19 AM
There is sufficient support already at floor to keel interface. Although running oak planks on each side of the floor higher up will strengthen the entire frame of the boat.
Forces pushing up on keel, strengthening top of floors will help bear the load. That is the only force that could bear on these floors since this is no cargo ship.

From past decades of grease and dirt on those old oak floors, likely lower down no glue would stick to the wood. But higher up where bilge water never went, the wood is clean enough to glue.

Also it does not need larger diameter metal drifts. I think these are 1/2 inch steel rods. They dont do a lot after the hull is finished although they likely do something.

I mean the entire hull is a structure joined together and where is the load on these drifts?

Up, no, frames are screwed to floors, planks are screwed to frames, keel just pushes up on floors.

Down? no, frames just lay on top keel. Where is the force generated?

Sideways? Well better not be much or the entire hull is about to fail.|:)

Hull twisting forces in heavy seas, that is more likely that the drifts would be more useful.

I have read some wood hulls flex under power and waves. But I deliberately measured mine at sea in waves and it does not move at all. No keel flexing, no changes in height from keel to the sole.
Maybe it would move in huge slamming hull waves.

Doug Schultz
07-25-2014, 03:41 PM
And make yourself completely crazy if you do everything you can think of "while you are in there"
I was just speculating that if you wanted to. It might not be that big of a job. I figured it would be tough to get glue to stick but I was thinking about getting that 7" sander out with a 16grit disc on it and cleaning up the wood til epoxy would stick.
Just to ease the thought that the floor might split if you bored a bigger hole to replace the drifts with epoxy glued galv. threaded rod.