New Method for Bolting Stanchions to Deck?

[maccauley123]

I had to do some repairs to the deck where my lifeline stanchions are mounted, balsa core got wet, and will be remounting the stanchions. I have already removed all the wet balsa and filled with epoxy so the bases are stronger and there is no way for water to get to core any more.

The stanchions have always been a source of leaks into the cabin which I want to eliminate. I know about using a good bedding compound when bolting them on again but am considering another method. I am thinking of putting the mounting bolts in from the bottom so the threads come out above deck and epoxying the bolts into the deck. This would make a water tight seal around the bolts making it impossible for water to get below. I could then just mount the stanchions with nuts above deck.

I have seen traffic poles and other street sign hardware mounted like this with the bolts cemented right into the base with threads sticking up. If it works in this application exposed to all kinds of weather at all times why not on the boat?

[lshick]

I'm no marine architect, so all of the following may be wrong. As I see it, the problem (or one of the problems) is that stanchions get a lot of lateral loading. If the bolts are rigidly mounted, the lateral loading will crack the bond between the bolt and the whatever (epoxy). So you'll get a leak again. Traffic poles don't worry about leaks--the water can just flow down to the dirt, and as long as the pole stands up, nobody cares.

[davidpm]

What lshick said makes sense to me.

The accepted way to do the fix is to do the following:
Lets say you have a 1/4" bolt.

• You drill a 1/2" hole through the top layer of glass only.
• Put a 3" nail in your drill motor and bend the end of it about an inch, 90 degrees so you have a hook. Use this contraption or whatever other method you can think of to hook out the core between the two skins.
• Tape the bottom
• Fill the hole to slightly above level with epoxy thickened with high density filler.
• Sand
• Drill to 1/4 inch. Bed the deck fitting with boat-life 4200 not 5200.

Now you have a solid plug of epoxy with a hole in it. No water can get into the core. The re-bedding may have to be redone every 10 years or so but at least their will be no core problems.

Things will move no matter what you do. The goal is to control what happens. Your idea of trying to prevent things from moving will eventually fail anyway.

[mitiempo]

I agree with lshick and david. The key to sealing the bolt holes will be a good seal with the bedding compound of choice. I would recommend butyl for this as it has the most elongation of any bedding and with the leverage of stanchions this is an issue. A small leak every 5 - 10 years isn't that big a deal as long as the balsa doesn't get wet. It sounds like you've beat that problem with epoxy filling in its place. When you drill the bolt holes countersink the top of the holes a bit. What this does is create a "o-ring" around the top of the bolt hole.
As far as street poles - they do it the way they do so the pole can be easily replaced in later years without access to the bolts - not really applicable to stanchions. Here's a link to Maine Sail's excellent tutoria; on the best way to do this. Re-Bedding Hardware Photo Gallery by Compass Marine at pbase.com
Brian

[Capnblu]

Don't forget to chamfer any hole you drill before assembly, this will allow your sealant to form an O ring around the bolt and threads.

[tommays]

On my J24 the PO had really nice 3/8 thick plastic plates CNC routed for ON THE DECK and good size plates for below deck.

You can pretty much do pull ups on them now as before even when NEW the skin is a bit thin to take any real abuse

[chef2sail]

Our 84 C&C has the stantions bases attached to the toe rail so there is no stress on the gelcoat at top deck. The other advantage is that they are a few inches ouward of most designs so the gunwhales are a small amount wider.

They are also easy to work on and repair as when you bend one you dont fracture the gelcoat.

Dave