First deck replacement, I have questions

[Bluemelj]

I have a 1996 Glastron for about a year. Noticed that the deck was soft in a couple of spots from the ski locker back. I pulled all of the carpet out and removed the wood deck from behind the ski locker back. Under the deck that I removed everything looks like its in good shape the 2 stringers are completely covered in fiberglass and the is in good shape just had one small area in very back that was slightly wet.

Kickoff questions:

1. I have the 1/2 plywood cut out and ready to go, glastron stapled down the plywood I took out what is the best way to attach to the stringers?
2. The hull comes up to a V as you reach the sides of the boat and it appears that the plywood should just lay on the side, the way I cut out the boards the new ones lie on the hull and match up with the old fiberglass with a small amount of foam on top, followed by carpet glue that has been sanded but not completely removed. Should I just tab in the new floor at that point with 1708 and will the 1708 stick to the sanded down carpet glue.
3. I noticed that the new 1/2 plywood moves some on the piece over the gas tank, will fiber glassing the plywood make it stronger? Should I only use 1708 or 1/4 chop strand on my new deck as well as the old section that I did not replace? How do I treat the bottom of the new plywood deck before attaching it?

That should get me started, thanks in advance for any input.

 

[Bluemelj]

I have a 1996 Glastron for about a year. Noticed that the deck was soft in a couple of spots from the ski locker back. I pulled all of the carpet out and removed the wood deck from behind the ski locker back. Under the deck that I removed everything looks like its in good shape the 2 stringers are completely covered in fiberglass and the is in good shape just had one small area in very back that was slightly wet.

Kickoff questions:

1. I have the 1/2 plywood cut out and ready to go, glastron stapled down the plywood I took out what is the best way to attach to the stringers?
2. The hull comes up to a V as you reach the sides of the boat and it appears that the plywood should just lay on the side, the way I cut out the boards the new ones lie on the hull and match up with the old fiberglass with a small amount of foam on top, followed by carpet glue that has been sanded but not completely removed. Should I just tab in the new floor at that point with 1708 and will the 1708 stick to the sanded down carpet glue.
3. I noticed that the new 1/2 plywood moves some on the piece over the gas tank, will fiber glassing the plywood make it stronger? Should I only use 1708 or 1/4 chop strand on my new deck as well as the old section that I did not replace? How do I treat the bottom of the new plywood deck before attaching it?

That should get me started, thanks in advance for any input.

Attached is a picture of the wood deck that has been cut out, if you zoom in you should be able to see how the wood deck is connected to the section still attached to the boat hull. I do not understand why there is foam built up on top of the fiberglass. Can I tab in to the hull of the boat with the way I have this setup. I basically removed all of the plywood and stopped leaving the fiberglass, covered in foam with carpet glue on top.

 

[todhunter]

The best way I came up with to attach deck to stringers was to make cleats that bolted to the sides of the stringers and screw the deck down into those. The cleats are attached with SS hardware coated in 5200. I resin coated the cleats and also put PB between them and the stringers. I used SS screws to attach the deck to the cleats, with a bead of PB along the tops of the stringers/cleats before screwing the deck down.

I would remove all the carpet glue you can from the area you plan on glassing by grinding or chemical stripping. Not sure about the foam...if it were me I'd probably consider removing it where you're going to tab, but you may be OK to tab right over the foam.

For treating the back side of the plywood, I did 1-2 coats of resin to seal the wood then a layer of CSM for waterproofing.

 

[Scott Danforth]

before you screwed the deck down, I do not see any mention of new stringers or transom or foam. the deck always rots after the stringers and transom.

so, did you pull the motor, replace the stringers and replace the transom?

 

[PC on the Bayou]

I would do a thorough check of those stringers. You mentioned a wet spot. If it's wet, it's bad and needs to be replaced. I would also check that foam and make sure it's not saturated with water. If so, it needs to be removed and replaced as well.

I agree with TodHunter with regard to fastening the deck to the stringers. Install a cleat alongside them to screw the deck to. Make sure you seal those screw holes between the cleats and stringers. I glued the cleats to the stringers with Peanut Butter as well as some screws then wrapped over my cleats and stringers with a layer of 1708. I also glued my deck down with peanut butter (thickened resin with 1/4 chop strand.

As for removing the carpet glue, it definitely needs to be removed along with as much of the gelcoat that appears to be in those areas as possible. I found that a wire brush on an angle grinder did a fantastic job of removing the glue and gelcoat.

On your new deck, paint the back side with a coat of resin and then once that soaks in and hardens, go over it with a layer of CSM. It'll help stiffen up the deck boards as well as protect them from water. Over your fuel tank, if there's room, I would put in a couple of stiffeners on the back side of the deck board. Just a couple of strips of wood as thick as you have room for encapsulated with CSM to the bottom of the wood. The little extra thickness will stiffen it up well.

Also be sure to paint the edges of each board with some resin to seal the grain.

Once the deck is tabbed in with 1708 along the edges, go over the entire deck with at least 1 layer of CSM (preferrably 2).

 

[Bluemelj]

I appreciate all of the input, as far as stringers and foam it was all dry underneath except a small spot way in the back, the deck softness appeared to be all from above. Stringers are in good shape, the glass over them look good I cannot put a screw driver threw them, is there something I am missing?

Really starting to wonder how to handle the foam on the sides. The wood I have in is as wide as the original, but the manufacturer put in foam on top of the fiberglass to soften up the slope between the floor and the hull. The problem is that my new floor is even with the foam. Could I take the foam out, replace it with peanut butter and tab over the peanut butter?

thoughts?

 

[Scott Danforth]

Did you make test drills into the stringers and take foam samples?

 

[TankerDan]

I'm far from an expert but removing foam and filling the void with pb I would think would add a lot of weight to the boat. Also if you haven't yet drill some inspection holes into the transom and stringer to check for wet wood. Also all my foam was wet on the underside where I couldn't see it untill it was removed

 

[Bluemelj]

Did you make test drills into the stringers and take foam samples?

Scott thanks for your questions about the integrity of the stringers and transom. I did not pull the motor or replace the transom plus I have not attached the deck yet. Attached are a couple of pictures. The softest spot I had in the floor that was honestly just driving me nuts was over the gas tank. It was basically a cover that any water could flow between it and the decking around it and the other small soft spot was right up against the gas tank panel that again was not water proofed from the top. Although dirty the pictures show the tank area where the second soft spot was. The exposed foam is not wet or rotted.

I have not drilled any test holes in the stringers, this boat has 2 on either side of the tank, the fiberglass is intact, do you recommend some further exploration before attaching the deck?

 

[88 Capri (2022 SOTY)]

Scott thanks for your questions about the integrity of the stringers and transom. I did not pull the motor or replace the transom plus I have not attached the deck yet. Attached are a couple of pictures. The softest spot I had in the floor that was honestly just driving me nuts was over the gas tank. It was basically a cover that any water could flow between it and the decking around it and the other small soft spot was right up against the gas tank panel that again was not water proofed from the top. Although dirty the pictures show the tank area where the second soft spot was. The exposed foam is not wet or rotted.

I have not drilled any test holes in the stringers, this boat has 2 on either side of the tank, the fiberglass is intact, do you recommend some further exploration before attaching the deck?

Now is the time to check for other possible issues with the old deck being removed. Why do all the work of putting the new deck on when there could be other hidden problems making you remove the new deck to fix them.
These guys are a wealth of knowledge and wouldn't steer you wrong.....I wouldn't be where i am at with my build if it wasn't for them

 

[todhunter]

Yeah, you're only deceiving yourself if you don't drill holes and inspect the wood shavings that come out. The fiberglass can be thick enough to not poke a screwdriver through, and the wood behind it can be black mush, and you wouldn't know it. Knocking on it tells you absolutely nothing. The wood rots...not the fiberglass. There really is no other way to tell other than a core sample. See the pictures in this post for an example of good and bad. You're likely to find something you don't want to find, so prepare yourself.

 

[KJM]

As already stated, be sure to test the transom as well. A soft floor is annoying, a soft transom is dangerous. As for the foam, if the wood above it was rotten, then its likely wet at least on the bottom. The choice is to do a easy and quick cover up job that you will be doing again in a few years or a more complete job that will last years. With a 1/2 inch plywood deck, I put 1708 underneath and CSM and then 6oz cloth on top. That seemed to work out well.

 

[Bluemelj]

Where do you guys suggest testing the transom, in the link that @todhunter provided there were small holes drilled along the bottom of the transom. Honestly not crazy about drilling those holes when I have no evidence that its soft, there are no outwardly visible cracks and there is no play in the transom when wiggling the outboard. I realize that those tests do not guarantee anything...

 

[Scott Danforth]

never ever seen a floor that rotted prior to the transom or stringers. and that includes looking at thousands of restorations here in iBoats.

your transom will be wet and rotting 10 years before you see cracks and play.

start on the inside the hull, about 2" above the fiberglass hull, starting at the drain plug, drill a series of holes starting 2-3" from the drain plug and move along the hull.

if the shavings are dry, light colored and smell like fresh cut lumber, just mix up some epoxy putty and carry on.

if the shavings are wet, dark colored and smell like rotten mulch...... fire up the sawzall

 

[JASinIL2006]

My outdrive had no play and it ”sounded” solid when knocked on. And it was rotten to the point that I could grab handfuls of it when exposed.

Drill some holes, and if all is well, fill them thoroughly with 3M 5200 and no harm done.

 

[76SeaRay]

Granted my boat is a 1976 but something that was weird is the inside stringers near the bottom of the V hull were actually in better shape than the outside stringers on each side and higher up on the V hull. I would have thought the water would accumulate near the bottom and rot out those stringers first. My center stringers sounded good and some test holes showed reasonably good wood, BUT, they have to be replaced as they are really bad in some spots and good in others. My opinion is that it is best to replace them if they show rot anywhere. My water intrusion was from the floor through the foam fill holes. It appears those were drilled through the glass on the floor instead of drilling the plywood only and filling before covering the floor with glass.

My transom showed rotted wood up about 6 inches from the bottom of the hull and the rest was good solid wood. But, I had to change all the wood since it was OMC and I changed to an Alpha One. When I changed the transom wood I found a lot of voids in the plywood and some rot around the outdrive opening.

 

[88 Capri (2022 SOTY)]

That is the right way to do it. I found the same issue with my transom. How hard was it to change to an Alpha 1?

 

[Bluemelj]

everyone really appreciate your input the 2 exposed stringers checked out. Honestly I have not had the guys yet to drill into my transom.

another question my plan is to cover my floor and sides with durable, would take other suggestions. But glastron put foam in the area between the hull and the floor along the sides, they also ran foam up the sides with what looks like a thin layer of fiberglass over top.

I really do not want to remove the thin layer of fiberglass and foam or completely exposed foam on the corners.

can I fiberglass over the foam? Thought I saw somewhere where polyresin breaks down foam, if so can I seal somehow?
Many thanks!!!

 

[Bluemelj]

Typing to fast on my phone I plan to use durabek and haven’t had the guts yet to drill into the transom!

 

[JASinIL2006]

I would strongly suggest you reconsider your choice of Durabak. I used that stuff and it sucks. It is a relatively soft rubberized coating. It is not durable, it wears thru and/or peels in spots, and it will be a major pain in the neck to remove when I need to refinish the deck. It's horrible stuff. I wish I had never heard of it.