bonding underside wood deck to fiberglass hull

[builderbob1]

I'm restoring a 26' yukon delta (trailerable houseboat). I've replaced the stringers and am ready for the deck. It is a trihull with one stringer down the center hull and two short 5 footers in the front of the side hulls. The deck is 3\4 ply that when pulled down to the center stringer spans over to the top of the tunnels and rides there for about 12" before it cantilevers over the outer hulls for about 6" where it gets fiberglassed to the sides . The top of the tunnels are only about 1/8" fiberglass and have a lot of flex. I assume the 12" of contact for the rear 20' with the deck was designed to give the hull strength. My question is whether I should bond that entire area together or just a part of it. As near as I can tell they originally tried for more of a bonding area than they actually got.Sorry for such a long post I hope I've succeeded in explaining my question. Any thoughts would be appreciated. Bob

 

[evildocrsx]

Re: bonding underside wood deck to fiberglass hull

Any pictures?

 

[builderbob1]

Re: bonding underside wood deck to fiberglass hull

I'll try to get pictures up tomorrow. I thought a thousand words would be worth a picture. Bob

 

[drewpster]

Re: bonding underside wood deck to fiberglass hull

If the "bonding area" is there to give the thin part of the glass strength I would recommend you bond the whole area. I would use epoxy for this because it has much better bonding capabilities than Polyester resin. Since the area is so thin it may be a good idea to temporarily screw the wood down to the hull until the epoxy cures from outside the hull. Then repair the holes from the outside after the epoxy cures. This will guarantee a good bond and keep the hull from cracking.
Assuming of course I am following your question correctly.

 

[Mark42]

Re: bonding underside wood deck to fiberglass hull

If the "bonding area" is there to give the thin part of the glass strength I would recommend you bond the whole area. I would use epoxy for this because it has much better bonding capabilities than Polyester resin. Since the area is so thin it may be a good idea to temporarily screw the wood down to the hull until the epoxy cures from outside the hull. Then repair the holes from the outside after the epoxy cures. This will guarantee a good bond and keep the hull from cracking.
Assuming of course I am following your question correctly.

Drewpster has given the same advice I was going to give. The more contact the better, and this is a good application for epoxy in those stressed areas.

If you use screws, be aware that they may not come out again due to the epoxy, so consider using stainless steel screws to avoid rust stains, etc. or coat the screws with Vaseline or grease to prevent the epoxy from taking hold.

Might be too late for this advice, but I would use pressure treated plywood for the decking in that boat. Just let it dry a bit and it will last as long as the rest of the boat.

 

[builderbob1]

Re: bonding underside wood deck to fiberglass hull

http://lh5.ggpht.com/_9g4w3dfNMZ0/StgA8bZjDbI/AAAAAAAAADA/lXudT2WZB2I/s640/img_1850.jpg

 

[builderbob1]

Re: bonding underside wood deck to fiberglass hull

Thanks for the replies. It is to late for pt ply I have already cut the pieces. I am using epoxy for the hole job and I have put 7 oz. glass on the bottom side of the ac ply that I am using. I tried to post pics but they didn't transfer very well to this forum. probably need advice on that as well. To bond that large area should I use a colloidal silica thickened epoxy, a wet layer of glass, both? When the ply gets pulled down to the center stringer it pulls the deck down firm on the hull and so far I've left most of the 14'x8' cabin on the boat to stay out of the sun and rain and I can also use sticks from the ceiling to help hold down the deck as well. I hope I won't be the one to pull the deck up next time after gluing that large of an area to the hull. (about 40 square feet) Bob

 

[lowkee]

Re: bonding underside wood deck to fiberglass hull

EDIT: If you upload pics to flickr or google picasa (preferred), you can simply view them on that site and right-click on them and select "copy image location", then use the 'insert image' button in the WYSIWYG here on the board. When the URL box pops up, just paste the copied link into it. Boom, perfectly posted image.

 

[drewpster]

Re: bonding underside wood deck to fiberglass hull

After looking at your pics I recommend you bond maybe a 5 or 6 inch band down the center of each tunnel. Thicken the epoxy just enough so that it wont run. Make sure both surfaces are scuffed and clean. An equal width band down each tunnel should be plenty to hold it together.
Of course a wider patch down them wont hurt, but 6 inches or so should be plenty. Use a high quality marine epoxy. Do not use the stuff they sell at the home centers, you never know how long it has been on the shelf. (it has a shelf life) US Composites, Mas epoxy and West system all make good epoxies. I dont think you need any cloth unless you are concerned that you cannot get firm contact all the way down the deck where it meets the inner hull. The trick is going to be getting good contact all the way down the deck. Once the glue cures, it will be there from now on. You might want to consider installing some access hatches in the deck so you can inspect the bilge.

 

[StampCreekHustler]

In the center scupper it appears that builder bob is using 2x10's.....My question is what about using 2 1x10's bonded together but instead of wood, what about pvc trim? I ask because pvc trim is water and rot resistant.

Here is an example of it:

http://www.homedepot.com/p/Veranda-...-ft-White-PVC-Trim-3-Pack-IN5416445/203640258


by the way I have the exact same boat/trihull


and if you do think its a good idea, what adhesive would you use to mount to the fiberglass hull?

 

[GA_Boater]

In the center scupper it appears that builder bob is using 2x10's.....My question is what about using 2 1x10's bonded together but instead of wood, what about pvc trim? I ask because pvc trim is water and rot resistant.

Here is an example of it:

http://www.homedepot.com/p/Veranda-...-ft-White-PVC-Trim-3-Pack-IN5416445/203640258


by the way I have the exact same boat/trihull


and if you do think its a good idea, what adhesive would you use to mount to the fiberglass hull?

StampCreekHustler

Please start a new topic. Bob has not visited in 7 years, which is how old this thread is.

Closed.