Grab rail and Cam Cleat Mounting Cabin Roof

[Squidd]

Now I've seen the many options and your specific epoxy filled plug method, but they assume there is a core to drill, fill and protect...

On my boat there is a 1" hollow space between cabin roof and inner liner...

I understand "thru bolting" is the prefered method of attachment, but with the hollow core, I'm worried the inner and outer liners will compress and I won't be able to get a good seal, not to mention, even with washer or backing plate, I'm really only held on by one 1/4" layer of fiberglass...?

Whats a fellow to do...? Drill a 1" hole from the bottom up, fill gap by adding a wood plug, drill thru and then use an even larger backing plate on the interior...then I'm still only being held by the 5/16" outer liner...?? If that's the case I think I may just drill the 1" holes on the inner liner, thru bolt and washer to the outer liner and put the plastic plugs on the interior...

Thing is, I have 14 attachments on the grab rails, the 4 on the cam cleats I want to add and another 4 on the deck organizer/blocks I want to install...That's a lot of bolt heads in the cabin ceiling...

 

[Squidd]

Seems different sections of the cabin top have different compositions...

Here you can see the Single Block I want to replace with a double...and just below it (to starboard) the "patched" holes where the old grab rail was...



What threw me is from below, the four bolt holes for the block show a "hollow" space between inner and outer layers...



But I did drill a test hole 6"-8" over where the Grab Rail goes, and it "IS" core filled and able to be drilled and filled per MS...

I'll just have to do the washer and Plugs on the block mounts...

And wait and see what I have where the Cam Cleats are going to go...??

 

[py26129]

Squid

Washers and plugs worked like a charm on my PY26. I only used the washers and plugs in the ares you show in your pic when I mounted the 4 sheave line organizer. I mounted 4 cam cleats on the aft end of the cabin top and foudn solid glass there. I drilled & tapped the glass andmounted the cleats with machine screws. for 10 years this was fine and weas used for the spinnaker halyard and the vang, among others.

Matt

 

[Squidd]

Squid

Washers and plugs worked like a charm on my PY26. I only used the washers and plugs in the ares you show in your pic when I mounted the 4 sheave line organizer. I mounted 4 cam cleats on the aft end of the cabin top and foudn solid glass there. I drilled & tapped the glass andmounted the cleats with machine screws. for 10 years this was fine and weas used for the spinnaker halyard and the vang, among others.

Matt

Going to drill into that area today and see what I find...looks like I may have three different mounting stratigies for the three different areas...

 

[Squidd]

Of the 20 some holes I drilled today, only two or three were actually "cored" with wood...

The rest went thru a 3/8" to 1/2" thick fiberglass outer layer then a 3/4" to 1" air space and then the 1/4" inner liner...Inner liner is intregal part and not removeable...

Here' is a shot of a different area, but shows the thickness of the glass build up...



Looks nothing like MS's photo of a deck section, with 1/8" glass, 3/4" wood and 1/8" glass...



Where the wood is supposed to be, I have air space...so drilled a 3/8" hole on outerlayer, and filled the gap with expanding foam...



Then hollowed the foam out to fill with epoxy...



Once this hardens up I can drill it and thru bolt it to the rail with just a pan head showing on the inside.

 

[GorillaToast]

This may be too late, but on the boat I just sold I had the same problem. What I did was drilled 1/4" holes for the bolts from the top, thru the roof and liner, then used a hole saw to drill 1" holes in the liner. Using bolts that were short enough to not reach the liner, I installed 1"fender washers, lock washers, and nuts and snugged them up to the solid coach roof. Then I got white plastic snap-in plugs from the hardware store to cover the holes. (Well, actually I was going to, but I sold the boat first.)

 

[Squidd]

Yeah, now you tell me...

Actually the nut/bolt/washer/plug is what someone did on the halyard block shown in the first post...

Considering the thickness of the outer layer, it's not bad for a "shear load" like the block, and "maybe" oK for a pull load like the rails...

I was a little leary of the pull load on the rails but I think the epoxy plug and thru bolting should give me a big enough chunk of material grabbing that the wood rail will probably break first...

The original rails were just screwed in from the top in to the outer layer and held up well for some time...

 

[GorillaToast]

Yeah, now you tell me...

Actually the nut/bolt/washer/plug is what someone did on the halyard block shown in the first post...

Considering the thickness of the outer layer, it's not bad for a "shear load" like the block, and "maybe" oK for a pull load like the rails...

I was a little leary of the pull load on the rails but I think the epoxy plug and thru bolting should give me a big enough chunk of material grabbing that the wood rail will probably break first...

The original rails were just screwed in from the top in to the outer layer and held up well for some time...

Sometimes I have to remind myself that many of the repair procedures talked about on these forums are meant for much bigger boats that sail in much bigger seas that inflict much bigger loads on the mountings. Although its fun to do the repairs the proper way, and is a great skill-building experience, I occasionally think, "the manufacturer didn't think it was necessary to put 1/8" thick stainless backing plates under this grab rail, so why do I think I need to?"

 

[mitiempo]

On the other hand the force on a grab rail when it is needed is the same inshore as when crossing an ocean.