Stanchon mounting screws have pulled out of the fiberglass and will no longer will hold it.

[smoothsailing]

One of my Hunter 340 lifeline stanchon mounting screws have pulled out of the fiberglass and will no longer will hold it.

What is the best way to repair/fill the holes?

Some suggest enlarging the holes and filling them up with:
MARINE TEX
WEST SYSTEM
FIBERGLASS CLOTH SOAKED W/EPOXY

How have any of you done this?

TIA

Bill

 

[Bill Roosa]

Drill out the hole. Fill with epoxy, redrill the hole and through bolt it.

 

[Don S/V ILLusion]

Drill out the hole. Fill with epoxy, redrill the hole and through bolt it.

With a large washer or backing plate. Using screws there is just stupid.

 

[fred1diver]

drill the hole slightly bigger and fill with west system, when cured drill your hole and screw it back in

 

[mitiempo]

Stanchions should be through bolted with backing plates - lives often depend on these.

If screws were used by Hunter it says a lot about their quality.

 

[Benny17441]

For life lines to be able to perform their intended task, as Don indicates, the stanchions need to be through bolted. Drill the holes and use epoxy to protect the wood core and apply sealant to the stanchion base and the bolts.

 

[fred1diver]

mitiempo you are correct it should be through bolted

 

[Maine Sail]

Stanchions should be through bolted with backing plates - lives often depend on these.

Absolutely! The only exception or caveat would be embedded metal backing plates.

Remember they are called LIFElines...

 

[Ted]

I have heard that some boat manufacturers embed an aluminum plate in the fiberglass. The plate is tapped to accept the bolts. The bolt or plate may have corroded or stripped the threads. You might be able to go up one fastener size and re-tap the plate if there is one or add a heli-coil insert. If Hunter just screwed the stanchion bases to the fiberglass it's a very poor way to make that connection. If you have access below the deck, install through bolts with backing plates.

 

[kito]

Lifeline stanchions not bolted through from the factory? Oh my!

 

[sailfree20770]

Lifeline stanchions should not be just screwed on, unless tapped into a backing plate of some sort.
Sometimes there will be an aluminum plate embedded in the laminate. Maybe that's stripped and you could tap it the next size. It's a bad design (if that was a factory install) to just screw into the fiberglass deck!

West System Six10 is the easiest epoxy to use for something like this. TotalBoat Thixo is probably very similar, though I haven't tried it yet.
Through bolting is preferred, however it is entirely possible to develop the full strength of a bolt or screw just by embedding the threads in epoxy.
IF (big if) done right, the screw would break before the threads stripped. The length of thread embedded varies of course depending on the diameter of the bolt.

The book "The Gougeon Brothers on Boat Construction" has a section on bonding bolts to wood which will give some guidance on how much thread needs to be embedded. There may be something on their web site about this too. It seems to be down at the moment, so I couldn't look it up.

If impossible or impractical to through bolt, then the repair is more dependent on the structure of the deck in that area.
Does it have a core? Is there a gap below the fiberglass where the screw has pulled out? If there's a core then it would need to be dug out to create a pocket for the epoxy to fill. If there's a big gap, it may need some foam injected in there first, otherwise it could take up a lot of epoxy to fill the void or it may run away completely and drip out someplace below.

Generally the screw should be coated with wax before embedding it in epoxy.

 

[Ken13559]

Mine has a backing plate. Hunter uses machine screw. When thread is striped, you can retap one size up or if its assessible use bolts and nuts.

 

[JamesG161]

One of my Hunter 340 lifeline stanchon mounting

I am curious which stanchion?
My Hunter 430 is same production year as your 1998. I have found mine to be through bolted and have access to tighten the nut. I haven't looked at all of them, only the ones that seem to be my docking helpers " hand grip" pull poles.
Jim...

 

[BigEasy]

My Hunter 33.5 (predecessor to the 340) had thru bolted stanchions. Puzzling that the 340 wasn't thru bolted also.

 

[Ken Cross]

Ours have 3 fasteners. The largest is a bolt that goes up from under the toerail. The other 2 are threaded into the aluminum piece molded into the fiberglass. The biggest issue I've seen is the stainless screws seizing in the aluminum. That's why I recommend using anitseize compound. and that's why you need the impact screwdriver. First clean up the threads with a tap. It sounds like the fastener has stripped out. If that's the case drill up one size and re-tap. Then be sure to use the anitseize to keep the problem from coming back.

I also see that you think it's 3M 5200 sealed. That stuff never gets brittle so you won't fracture it with a hammer. It may however be difficult to clean off to prep for your new sealant.

If it's just tapped into fiberglass I'd look for another method of repair. Threads in glass or even in epoxy aren't suitable for a lifeline sanction, but I'd be willing to bet there is aluminum buried in there.

Ours is a 1989 H 30 I found a pick online that looks like ours:
Ken

 

[Phil Herring]

If there's no thru-bolt you can access from the bottom, there is capsulated aircraft aluminum in the deck and the bolt taps into that. Bill and Ken have it right. Hunter has done this with deck hardware for about 30 years, as have other builders.

 

[JamesG161]

The biggest issue I've seen is the stainless screws seizing in the aluminum. That's why I recommend using anitseize compound. and that's why you need the impact screwdriver.

Good Idea! The best is Teflon® impregnated. The reason Stainless is notorious for seizing is HEAT builds up as the friction tensioning and metal stretch energy, expands the thread. In absence of anti seize, turn the bolt VERY VERY slowly to allow cooling.
Jim...

PS: A 1/2" bolt uses ≈5.4 Tons of force to tighten to spec.