Deck attachment ideas needed

KeyWest · 10-26-2006, 07:03 AM

I'm looking for ideas on how to better attach something to the deck. The current method being used is as follows:

I was hoping to do something a bit better than that. I don't have access to under the deck and certainly don't want to cut a hole in the deck to attempt a backing plate. Not only that, the space around the stringer is foam filled so I would have to remove floatation foam to get to it. I have looked at toggle bolts, and have used them successfully in the past, but it would be pretty tough to get them to rotate once inserted into the foam filled stringer.

Anything out there that is stainless, and can somehow attach under the deck once inserted through the hole - but NOT a toggle bolt?

Metal Manipulator · 10-26-2006, 07:25 AM

If you can't manage to use the toggle bole then another way is to drill out a slightly bigger hole dig out some extra foam core space and back fill with fiberglass resin and choped fiber glass material. This will give you a backing plate made out of resin with which to ancor your lag bolt to.

Hope this idea helps.

Robin

trollking · 10-26-2006, 07:41 AM

Robin,
that's a great idea, although I'm not sure why a lagbolt wouldn't work. Don't quite understand the need to 'rotate' once it is inserted.

Anyway, drill a hole for your fasterner, then mount a L-shaped allen wrench in your drill chuck....long end in the chuck. Maybe even fabricate something, so you can start with a small bend, and then work up. Feed the short end of the wrench into the hole, allign your drill vertically, and slowly power up. Using a shop vac hose to remove bits and pieces, you should be able to easily clear away the foam, and have a nice space for the epoxy/micro-balloon filler. Then fasten away.

I haven't done this, I used the stainless lagbolt, and it seemed to work ok, but I think I like this approach better.

Mark Mc · 10-26-2006, 07:58 AM

Being the owner of a foam-cored boat.....that was molested by previous owners......

I would think long & hard about putting ANY hole / penetration into the deck of a boat with a foam core nearby.

I think the first question is....how strong does it need to be? Unless it is a davit for a crab block or crane, I would look at doing it this way:

Create a base (for whatever you want to attach) that is glassed to the deck. For example if it is a 2 x 4 frame, you would make about a 6 inch wide strip of glass mat & roving, built up in a few layers, then the 2 x 4, then more glass on top. Same way you do an engine mount. Now you put your bolts / screws into the wood / glass assembly, but NOT into the deck.

You can always grind the whole mess off later and re-paint / coat the deck. But once you put a hole in the deck, it is "forever".

Something Good · 10-26-2006, 10:03 AM

What Mark said, unless it needs to be flush with the deck. I had a friend that did boat repairs and when I asked him to help me install a crab davit in a previous boat he glassed a 2X6 to the deck and installed the base to it.

Chrome Bumper · 10-26-2006, 10:14 AM

http://www.bertram31.com/proj/tips/sleeving.htm

http://www.bertram31.com/proj/tips/pedistal.htm

THis guy has a nice page

Nordic Sun · 10-26-2006, 10:35 AM

Dean

Prior to drilling any holes,

1. take a 3'x5' piece of white sign board

2. Using a large tipped black magic marker

3. Write in Large letters " FOR SALE"

4. Tape it firmly to the side of the boat.

5. Purchase a quality Aluminium boat.

6. Drill hole and use appropriat lag bolt, or weld item in place.

Simple isn't it. Pluse, you now have room to mount all the new electronics.

Bob

KeyWest · 10-26-2006, 11:40 AM

Some great ideas - thanks and keep them coming! (well, almost all were good - Bob). The EXACT application is to better hold my T-Top to the deck. I now have 16 lags (4 per leg) - 3/8" - holding it down along with copious amounts of 5200 under each pad. Its also attached to the center console in three spots. Its a high vibration / shock application and the lags seem to work loose or wallow out over time. The current method of continuing to upsize the lag won't be feasible above 1/2" so I'm looking for alternatives.Again - thanks!

Onokai · 10-26-2006, 12:14 PM

Dean
Was your t-top a later add on or come with the boat??. I'd go with the epoxy suggestions. Mark

Miss B Haven · 10-26-2006, 12:20 PM

Use Shad Scales- those things are better than Superglue or Epoxy.....they never come off!

Miss B Haven · 10-26-2006, 12:27 PM

Okay- want a real answer?

If I really wanted this to hold and not leak- grind the deck down (enough to get raw glass to bond to), lay an inbed plate with predrilled holes (or welded SS nuts on the back side with an offset inbed plate, ot you could drill and blind tap after glassing) and then glass the whole thing down to the deck. This is how they do engine beds in stringers (on real boats anyway). Lotsa work and a little engineering but its the only way I know to make it last. The bolts may vibrate loose eventually but at least you can just tighten them back up (a little

black magic · 10-26-2006, 01:09 PM

Dean,
I have mounted three pedestal seats as well as a stand-alone radar mast on the flybridge deck of my boat without thru-holes. The deck is 1 inch thick with balsa core between the laminates. This arrangement has survived 2 years of moderate service with no problems. I bored oversize holes at the mounting points. Cleared away the balsa core with a hex key or a bent nail in a drill as previously described. I cast these pockets full of Devcon plastic steel epoxy. I then drilled short of going thru with a drill of the proper size for a ss helicoil thread insert (coarse thread). The various items were then mounted to these after installing the helicoil inserts. Sealing was done with 5200. Even if water does get in it is not likely to penetrate the epoxy if it has not been drilled through. I have included a modified version of your picture insert. It came out very small so I included the file attachment.

KeyWest · 10-26-2006, 07:47 PM

Quote:

Originally Posted by Onokai

Dean
Was your t-top a later add on or come with the boat??. I'd go with the epoxy suggestions. Mark

Mark - came with the boat.

Something Good · 10-27-2006, 10:21 AM

Ever thought about doing a little less extreme fishing? Is it really that important to be the first one at the tuna grounds every time?

Onokai · 10-27-2006, 11:08 AM

Dean -I'm wondering what Key west would say about this issue?? Maybe they have a solution for this as it's most likely not just your vessel. Give them a call???Mark

KeyWest · 10-27-2006, 06:33 PM

Mark - as a matter of fact.... I was at the factory and at the boat dealership last weekend (Charleston, SC). The have "never heard of this before and its not covered under the hull warrantee". So... but there are a lot of good ideas posted here - I don't mind working on it myself. A good winter time project!

jocose · 10-27-2006, 07:20 PM

i replaced my wooden/fiberglass deck with 3/4 inch thick high density poly ethylene plastic, (marine board). i fastened the seat pedestals to the floor by drilling and inserting stainless steel thread inserts. the ones i used had external threads that were sharpened, you drilled a undersize hole then screwed in the inserts which i smeared contractors adhesive on first. they sit flush to the deck i then sealed my pedestals prior to fastening them into the inserts. so far its been a year of fishing and rough play on the water and none have worked free or loosened up.
http://www.mcmaster.com/
(go to the fastening and sealing section then to threaded inserts sub group)

KeyWest · 10-27-2006, 07:39 PM

Quote:

Originally Posted by Something Good

Ever thought about doing a little less extreme fishing? Is it really that important to be the first one at the tuna grounds every time?

No, and yes

KeyWest · 10-27-2006, 07:40 PM

Quote:

Originally Posted by jocose

i replaced my wooden/fiberglass deck with 3/4 inch thick high density poly ethylene plastic, (marine board). i fastened the seat pedestals to the floor by drilling and inserting stainless steel thread inserts. the ones i used had external threads that were sharpened, you drilled a undersize hole then screwed in the inserts which i smeared contractors adhesive on first. they sit flush to the deck i then sealed my pedestals prior to fastening them into the inserts. so far its been a year of fishing and rough play on the water and none have worked free or loosened up.
http://www.mcmaster.com/
(go to the fastening and sealing section then to threaded inserts sub group)

That's what I was looking for - thanks!

Onokai · 10-27-2006, 07:53 PM

Dean
west marine has that Marine board in many thickness and sizes (mail Order). I have made many things from it -mostly dash and radio and holders. Get the thickest size you can use as its soft and has some flex in thin sizes. Comes black or white. I can mail you a small sample if that would help. Mark

KeyWest · 10-27-2006, 08:14 PM

Quote:

Originally Posted by halibutsteve

Robin,
that's a great idea, although I'm not sure why a lagbolt wouldn't work. Don't quite understand the need to 'rotate' once it is inserted.

Here is a link to the stainless toggle bolts I've used in the past:

http://fastenmsc.stores.yahoo.net/togglebolt.html