fiberglass void

[strike26]

hello all
I am looking to mount brackets on my transom for a swim platform.
there is a void about 1.5" between the outside fiberglass and the inner fiberglass
any suggestions as to fill this void for structural purposes as i will be bolting the brackets thru both sides .
thanks

 

[briangcc]

On a typical fiberglass boat, there isn't a void at the transom between the inner and outer fiberglass. What's between those two, on a typical boat, is your wood transom. Newer boats may be some sort of composite material that doesn't/resists rot.

So if you have a void up high, chances are very, very good that whatever was there beforehand rotted away and you have more concerns beyond how to mount a swim platform.

What boat are we talking about here?

 

[strike26]

the boat is a strike made in florida
the void is because of the outer fiberglass transom and the inner finished fiberglass
there is a live well at the stern above

 

[Scott Danforth]

strike boats were made in the hayday of wood core boats

 

[strike26]

this is not a wood boat, I can see thru the battery hatch to the transom,, no wood
This boat was built to be the tender / fishing boat for a yacht called life of riley.
the inside floor fiberglass wraps up to form part finished of the interior side of the transom+*

 

[Scott Danforth]

your tender is a fiberglass over wood structure. It was built in 1988 or 1989. Life of Riley was splashed at Delta Marine in 1989. has a nautical structures davit on the upper deck.

Photo courtesy of Delta Marine

 

[strike26]

it is a 2002
the fellow i bought if from bought it from his friend owner of life of reily
and brought it to vancouver in 2010
meanwhile back to the origional inquirey
how to fill the void

 

[briangcc]

As Scott mentioned, the way the boat is layed up is gelcoat/fiberglass outer shell, laminated to a wooden transom, which is then covered by more fiberglass and possibly gel on the inside. So a Fiberglass-Wood-Fiberglass sandwich if you will at the transom.

Given you have a void, the wood core may very well be gone which now raises the question of the structural integrity of your stringers. More investigation is in order as the swim platform is the least of your concerns.

It wasn't until a few/several years later that most manufacturers switched from wood to composite materials. Sorry to be the bearer of bad news.



You can call the manufacturer of the boat to confirm all this - provided they are still in business as many have come & gone since 2002.

 

[Scott Danforth]

you could bee seeing the void between the cap well and the transom.

if that is the case, drill a clearance hole in the cap well (non-structural) to the transom. the hole will need to be big enough to get backing plates on the inside of the transom . you will not want to try to sandwich the cap liner to the transom as they move a bit with respect to each other.

 

[strike26]

update
On my quest to show you there is no wood I contorted myself to get a pick of the void. looking upward
looks like they have put spray foam between the 2 layers. I don't think it is low enough as to were the upper bolts will go thru, and not sure of structural integrity of spray foam.
the transom pic of swim ladder mount is above water line but below where my upper bolting would be
the pic of the aluminum plate is where it is bolted from the inside.
the 4th pic is the material i drilled thru mounting a windlass on the bow
I don't think the outer transom material would be like this?

 

[Scott Danforth]

The deck coring is different than transom coring.

However Nida core on the deck is a good thing. For decades it was balsa or foam core, because that is all that is needed

2-part foam between the cap liner and transom would be flotation foam if 2# or structural if 4# or heavier

The transom itself will be 2" thick. That is 1-1/2" of core and 2 layers of structural FRP, on being the outside hull layer, one being the inside bilge layer

If you can measure the total thickness from outside of the transom to inside the cap liner, you can determine how thick the 2-part foam is

 

[strike26]

heres life of riley ; with my strike on top