Question about sealing bow rail stanchions

The survey last September indicated minor moisture readings at certain spots along the gunwale where the fuel cap and stanchions are fastened. Last weekend I took a look and found that the stanchions are fastened down with pan-head stainless wood screws, not bolts with backer plates or washers. While I can't be sure, it feels like the screws are going into wood, which I assume was glassed in or glued under the gunwale before they assembled the top half to the hull.

Assuming that is the case, and even if not, what should I do to seal the screw holes to prevent further water intrusion. I am thinking maybe inject some thin epoxy resin into the holes so that it absorbs into the wood and then screw back down before epoxy hardens. Maybe I should put butyl tape under the stanchion foot for good measure?

Any other thoughts or suggestions?

Thanks.

If you can't get to the back side and need to use screws again, you could enlarge the screw holes and then fill with epoxy, and then re-drill for the same size screws.

Here is a web site with lots of good info.



Link wont work. Go to marinehowto.com

I love butyl for bedding through bolted items, but sometimes with screws you may not be able to compress the butyl properly. How many stanchions do you have to bed? Maybe you could install a couple of access panels to get to the bottom of the deck to through bolt them.

Greetings,
Mr. 55. IF the current screws are holding tight but simply leaking (deterioration or lack of original bedding), you might do just what you suggest: "... inject some thin epoxy resin into the holes so that it absorbs into the wood and then screw back down before epoxy hardens." OR as Mr. RC suggests (post #2).


I would probably use Dolphinite as bedding material rather than butyl tape for the reasons of potential lack of compressible tension provided by screws alone. (post #3). I would be very hesitant to go to the extent of access panels for through bolting.


Some "Rocket Scientist" DPO of our boat had the bright idea of using a marine caulking to fill loose woodscrew holes. Not much bite at all and as a result we have several screws loose in some of our stanchions.


My approach has and will be to remove the stanchion, and insert these things: https://www.grainger.com/category/fasteners/thread-insert/knife-thread-inserts
Then use dome head machine screws to tighten down. I'm going into the teak cap rail. 4 per stanchion base. 5/16-18 I think in brass. Brass were about $2 per. SS were about $6 per. IF I do all my stanchions, I'll need about 130 pieces so going with brass "saves" me about $500. I will use butyl tape because the machine thread enables a good tightening AND the brass insert should be sealed from water.

I would say there are 14 stanchions, 7 each side. I can't get to the underside, they are way up in the gunwale. I was familiar with the process on Marine How To but it seemed to apply to the installation with through bolts, backers and nuts and I just have screws. But now that I look at it again, I think if I put a countersink under the stanchion and apply a cone of butyl, once I screw it back down it will have the same effect. Butyl tape on order!

If it were me, I'd repair the wood by allowing to to dry and then using epoxy first. I'd probably end up filling the screw holes, by original intention, or otherwise, and then drill new pilot holes through the old holes. Then, from there, I'd use 4200 to bed the new screws.

This way, the wood is repaired and sealed up, the screw-wood interface is sealed up, and if there is ever reason to remove those screws all that'll be needed is a screwdriver or bit and drill.

When I've run into screws epoxied into wood and had to take them out, it has been bad. Either the wood gets damaged a lot or the screw head gets broken off -- and then the wood gets damaged a lot before it can be reassembled.

RT Firefly said:

My approach has and will be to remove the stanchion, and insert these things: https://www.grainger.com/category/fasteners/thread-insert/knife-thread-inserts
Then use dome head machine screws to tighten down. I'm going into the teak cap rail. 4 per stanchion base. 5/16-18 I think in brass. Brass were about $2 per. SS were about $6 per. IF I do all my stanchions, I'll need about 130 pieces so going with brass "saves" me about $500. I will use butyl tape because the machine thread enables a good tightening AND the brass insert should be sealed from water.

Click to expand...

Nice RT! I like when someone does the thinking for me.

RT Firefly,

I don't know the history...my boat is still new to me. But, at some point a previous owner used those thread inserts on my boat. And, many, many of them have been failing. I don't know why. It might well be an installation problem, or failure to prepare the wood before putting them in problem, or the wrong type of metal, or not enough depth of thread problem, or asking too much of them problem (the boat was caught in a major storm/"hurricane" at one point).

The failure is that they stay attached to the bolt, but disattach from the wood. They are a pain to fix, since I need to take everything apart and back off to get to them, and they leave bigger holes. So, when I've pulled them out, I haven't put them back. I've mostly gone with the rebedding I described above. As long as the wood is dry before repairing, I've had great luck with epoxy.

In once case, I drilled holes into the gunwale in order to secure a cleat with washers and nuts from underneath. But, in that case, the problem was clearly an "asking too much" issue.

But, again, I don't know the history here. And, there might well be an installation problem, or preparation problem, or asking too much problem, etc.

gkesden said:

RT Firefly,

I don't know the history...my boat is still new to me. But, at some point a previous owner used those thread inserts on my boat. And, many, many of them have been failing. I don't know why. It might well be an installation problem, or failure to prepare the wood before putting them in problem, or the wrong type of metal, or not enough depth of thread problem, or asking too much of them problem (the boat was caught in a major storm/"hurricane" at one point).

The failure is that they stay attached to the bolt, but disattach from the wood. They are a pain to fix, since I need to take everything apart and back off to get to them, and they leave bigger holes. So, when I've pulled them out, I haven't put them back. I've mostly gone with the rebedding I described above. As long as the wood is dry before repairing, I've had great luck with epoxy.

In once case, I drilled holes into the gunwale in order to secure a cleat with washers and nuts from underneath. But, in that case, the problem was clearly an "asking too much" issue.

But, again, I don't know the history here. And, there might well be an installation problem, or preparation problem, or asking too much problem, etc.

Click to expand...

I wouldn’t consider putting them directly into the wood without a little (or maybe a lot) of epoxy depending on the application.

Greetings,
Mr. gk. I can appreciate that potential problem and in case of failure I will probably go the larger epoxy filled hole, drill the epoxy and put the insert into the epoxy route.
I tried to second guess just such a scenario. I really only need the machine screws to be about 3/4" long but I've chosen to use 1 3/4" machine screws hoping the extra length will absorb some of the lateral force that may be applied to the inserts in the future. I've replaced a few but may have to rethink my installation engineering due to the ideas posted above. Still going with the inserts though.


I do have the room to install access panels but not for 35+ stanchions and brackets. Plus something doesn't seem right to me to cut into perfectly good gunwales...

Rather than use epoxy to replace wood, you could drill out the existing screwholes and epoxy a piece of dowel matching the drill hole. Drill a pilot hole into the plug and with a suitable bedding seal between stanchion and boat, re-attach the fitting.
The drilling out process should enable you to see how much water damage has been done, you may need wider repair.

Greetings,
Mr. BK. To whom is your post (#11) directed?

BruceK said:

Rather than use epoxy to replace wood, you could drill out the existing screwholes and epoxy a piece of dowel matching the drill hole. Drill a pilot hole into the plug and with a suitable bedding seal between stanchion and boat, re-attach the fitting.
The drilling out process should enable you to see how much water damage has been done, you may need wider repair.

Click to expand...

All good ideas. Each application will be a little different but it gets you thinking.

Cigatoo,

The inserts used on my boat definitely did /not/ have epoxy holding them. They were screwed right into the wood.

BruceK,

I put dowels in any time an epoxy fix fails. The advantage to using epoxy-alone is that I can normally inject it from a syringe into the hole and get it soaked into any nearby wood without needing to fully disassemble things.

When I've had failures, it has been because more was going on underneath than I had estimated. I haven't had luck with super-thin dowels. But, 3/8" in diameter or more seem to solve most screw/bolt related problems nicely.

A post popped into my email about the West Systems manual that describes how to do handle this situations. But, somehow when I got back to the forum, it seemed to be missing :-(

I think the original poster (Won't name names in case it was intentionally deleted) was pointing folks to Chapter 6 of this manual:
-- https://www.westsystem.com/wp-content/uploads/Wooden-Boat-Restoration-and-Repair.pdf

...it is good stuff!

Screws into wood or wood cores always eventually leak. The water goes down the threads long before you notice the stanchion wobble. It doesn't matter what bedding compound is used, the threads will still leak. The only permanent fix is to inject epoxy into dry wood of the screw hole. So dry the wood first. If you drill a new hole and use a dowel or epoxy fill, make the hole deeper than the screw length. The end result is a screw surrounded by epoxy. Epoxy holds better to wood or fiberglass than the screw alone. I've been doing it this way since the 1960s, as a yard worker, yard owner, boat builder and my own vessels.

While it takes some time but no big boat bucks one solution is to purchase a GRP sheet 1/2 inch thick trim it to the stanchion base and deck fill sizes and epoxy it to the deck .

This will raise the source of a potential leak so minor rain or deck washing wont be a hassle if the sealant fails..

Repair the screw holes before fitting it and screw thru it back into the deck.

Inserts with machine screws would be grand just be sure to use a bedding compound that is easy to R&R as rebedding every few years should be on the PM list.

All excellent suggestions. Thus far I don't think I have any loose stanchions, I just want to stop the water intrusion into the wood and prevent a future problem. I think I will try injecting thin epoxy and see if it absorbs like I hope it will. I will look into Dolphinite instead of Butyl, but the screws are not loose so I think there will be enough tension to hold if I went with Butyl tape.

Real men use 5200 and only need to do the job once. You are all a bunch of sissies! Butyl and Dolphinite pitiful. ��

The backing wood is probably plywood. If it is then the thin epoxy will not work well in absorbing into plywood. It does work very well absorbing into real wood because of capillary action. Plywood doesn’t work the same way due to the plys running in different directions.

HopCar said:

Real men use 5200 and only need to do the job once. You are all a bunch of sissies! Butyl and Dolphinite pitiful. ��

Click to expand...

Please tell me you are kidding Spent the last few days replacing sink faucets in our boat - 4 of them including the wet bar. Only way to get to the bottom of two of them was to remove the stainless sink - PO, or someone, had sealed the basins in with 5200 (I found a small plastic tub with several half used tubes of 5200) Just lots of fun

You only do the job once with 5200 because it is almost impossible to get off...

Actually I was just kidding a little. In this application where you are mounting metal to fiberglass I would use 5200. It is very easy to break the bond between metal and 5300 by warming the metal. You are then dealing with the exposed 5200 which can be attacked with a razor blade and a solvent like DeBond.

All of my deck hardware and thru-hulls were bedded with 5200 and never leaked in almost thirty years.

You make me laugh! And I love 5200.

HopCar said:

Actually I was just kidding a little. In this application where you are mounting metal to fiberglass I would use 5200. It is very easy to break the bond between metal and 5300 by warming the metal. You are then dealing with the exposed 5200 which can be attacked with a razor blade and a solvent like DeBond.

All of my deck hardware and thru-hulls were bedded with 5200 and never leaked in almost thirty years.

Click to expand...

I inject epoxy into holes and it works pretty good.

I use 5200 for things I don't want to take apart - thruhulls, stanchion bases, cleats, winch bases and all sorts of stuff. BUT, I'm really careful about how to do it.

I dry fit what i am mounting / installing. I tape off around what I'm putting in, lets say a stanchion base. Usually I also tape off the edges of the base. Then I remove the base and drill a small countersink for each mounting hole then squirt some epoxy in the holes. The last prep step is to put down a layer of 5200 over all of it.

After all this I install the stanchion base. I tighten the screws as much as I safely can and most of the 5200 gets squeezed out. When tightening the screws in I add a little 5200 just under the head of the screw. Once it is all tightened down I wipe off everything as much as I can. Once it is all clean the last thing I do is pull up the tape while everything is still wet.

All of that leaves a nice, tight, usually waterproof install. The countersink in effect makes a small washer / gasket of 5200 under the stanchion base.

I forgot a step! I clean everything with acetone before the epoxy and 5200.



... you only wanted to know how to stop the leaks and all the screws still feel tight...

Back out the screws 1/3 to 1/2 way. Force 5200 around the the screws and fill the threads. Tighten it in back in and make sure there is enough 5200 to squeeze out around the top of the screw head. Then wipe it all off and forget it till the next rainy season.

I also use new driver bits and sockets / extensions and either a ratchet or a shoulder brace to drive in big screws.

As I've gone this far on my rant I'll add that I have a handheld impact driver and a propane torch to get tough ones loose.

But yeah, 'to do the job right' you should put in a backing plate and use bolts and still tape it all off etc. But if everything still feels tight just back out those screws and screw them back in with the 5200.

RT Firefly said:

Greetings,
Mr. 55. IF the current screws are holding tight but simply leaking (deterioration or lack of original bedding), you might do just what you suggest: "... inject some thin epoxy resin into the holes so that it absorbs into the wood and then screw back down before epoxy hardens." OR as Mr. RC suggests (post #2).


I would probably use Dolphinite as bedding material rather than butyl tape for the reasons of potential lack of compressible tension provided by screws alone. (post #3). I would be very hesitant to go to the extent of access panels for through bolting.


Some "Rocket Scientist" DPO of our boat had the bright idea of using a marine caulking to fill loose woodscrew holes. Not much bite at all and as a result we have several screws loose in some of our stanchions.


My approach has and will be to remove the stanchion, and insert these things: https://www.grainger.com/category/fasteners/thread-insert/knife-thread-inserts
Then use dome head machine screws to tighten down. I'm going into the teak cap rail. 4 per stanchion base. 5/16-18 I think in brass. Brass were about $2 per. SS were about $6 per. IF I do all my stanchions, I'll need about 130 pieces so going with brass "saves" me about $500. I will use butyl tape because the machine thread enables a good tightening AND the brass insert should be sealed from water.

Click to expand...

RT....are you sure brass will be strong enough for that application ?

Okay I for one thought the 5200 thing was pretty fun. On a more serious note, this forum has helped me to reduce my disdain for 5200 and I use it more again than I used to. Specifically the whole softening with heat trick.

I still prefer a simple sealant over adhesive where a mechanical clamping is reliable.

I’ve been reading those that use inserts. Maybe I should rethink that. I’ve just considered inserts to simply be the next size up screw that will pull out for the same reason the original screw did, just slightly later. I do whatever I can to get a nut on the backside.

Anyway, I appreciate everyone here making us all think objectively.

One of the first jobs I had in a yard was fixing stanchions in wood and cored boats. Any repairs done at that yard were designed to last the life of the boat. The wood/core was dried, the screw holes were drilled oversize/over depth, and filled with epoxy of that time - 1960s. Later a pilot hole gets drilled in the epoxy, additional epoxy is put down the hole when the screw is driven so the screw sits in epoxy. There is no break in the resin, the screw sits in epoxy, so the bedding compound used on a cored boat isn't important. Later, if the screw needed to be removed, a small impact wrench was needed. Otherwise the repair lasted the life of the boat and never leaked again.
Using an insert only works if the insert is enclosed in epoxy.

Greetings,
Mr. A. "...are you sure brass will be strong enough..." I hope so. I suspect any failure would be at the insert/wood interface (coarse thread) rather than the insert/ bolt interface (fine thread). The only scenario might be the insert tearing out of the wood and both the brass and the SS inserts have the same exterior profile (coarse thread).

At this point I'm willing to bet the $500 saved.