Deck Plate repair over forward gas tank -24' Explorer

[wrg49]

I have a 24" Explorer (1994) with a 24"x52" deck plate over the forward fuel tank in the area of the helm. When you'd walk on the plate, it would sag a little, so I took it off for inspection. I found that the cross braces had let go from the plywood core. (Actually I don't know if they were ever epoxied to the core, or just held in place by the overlaid fiberglass fabric.) It also appeared that the fiberglass cloth was not very well saturated with resin. I also noticed that the plywood core was of different thicknesses (thinner at the edges) and not one solid piece, but made up of numerous sections. Does anyone have experience with repairing these deck plates ? Is the built up construction I've found normal ? I'm not the original owner, so I don't know if this is a standard design or someone's previous attempt to repair the plate. Any info would be helpful.

 

[Grog]

Very common problem. The deck was cored with roughly 4"x4" plywood peices. When water gets in there it wrecks havoc and you see the result. If you do a search there are pictures of someone doing that project. Basically remove ALL the old wood and cut a new piece of marine grade plywood to fit the inside. Epoxy the wood to the deck then seal with resin and fiberglass cloth. It's not a hard job just take your time.

 

[1st grady]

I had water intrusion just around the forward inspection plate, about 1' X 2'. I just replaced that section as the rest really was dry and sound. Maybe I caught it early.

 

[cdwood]

If you DIY, remember to cut around all the screw holes and fill with thickened epoxy so even if they leak the wood won't be exposed.

 

[bhemi]

Doing same repair right now

I had the support between the two deck plates pretty rotten. I just cut of the top layer of glass and am replacing the patchwork with one piece of 1/4" plywood well soaked in epoxy. I have noticed that anywhere out of sight Grady did an awful job of finishing. Lots of glass with limited epoxy, unfinished edges etc.. I cut my hands to shreds cleaning my forward bilge with all the glass strands. The boat is solid as a rock but back in '92 they didn't worry about what you couldn't see. The funny thing is it probably wouldn't have added $1,000 to the final cost of the boat to clean up these areas.

 

[wrg49]

Hey Guys !
Thanks for all the helpful info.. I'll let y'all know how my repair works out.

PS: This is a great forum !!!

 

[BobP]

Bhemi - so true: out of sight, out of mind.

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Keep the same thickness wood as before when renewing, add plenty of glass to face to make it rigid, even more so than original.

Angle grinder with 36 grit paper rubber adapter, a must tool, belt sander handy also.

Wood was damaged by water going down screw holes improperly sealed, even worse, same screws continue into stringers and bulkheads. The glass would not have delaminated if the wood stayed dry.

2 or more layers of 1708 or equal.

 

[wrg49]

The wood in the center of the plate is thicker than that along the sides..so are you saying I should do the same ? ...use multiple pieces rather than one solid piece of plywood ?

 

[BobP]

I think you will find the wood is thicker around the deck plates. True?

I built a stronger deck with more glass both sides, and glassed well into the deck plate areas and added plenty of cabosil resin to make the transition where the wood ends. Grady had a sharp edge and one layer of 1.5 oz mat, as I recall.

My finished tank covers were obviously heavier than the orginals.

You can increase the wood thickness, just be aware, aound the perimeter must remain 0.5 inch so tank/bilge cover aligns with fixed floor height.
I had to do this myself with a router when I used a piece of depot project plywood untreated when I ran out of marine grade. Routered down bilge cover along perimeter to match original 1/2 in.

Also be carefull of any supports underneath across beam, the extra quater inch will cause height problems.

I like to use 1708 as my all purpose cloth, very easy to work with, doesn't unravel or stretch out of shaps, but very strong comparable to woven material of same weight, creatin a greater fiber to resin ratio.

I prefer least amount of differnet materials to get eveything done.
Raka has the material good price, ships out right away, ask him to ship in roll not folded, his 127 epoxy resin is economically priced. Ask for Larry for advise.

 

[wrg49]

Thanks for the great advice !.. one other thing with regard to the cross member supports.. it appears that they are hardly (if at all ) secured to the plywood core.. just laid in place and covered with the cloth... in fact, in the area of the thinner plywood (around the edges of the plate) there is a visable gap between the cross member and the plywood. I assume it would be better that the cross member be securely epoxied to the plywood and all gaps filled. Thanks again for all your advice !!

 

[bhemi]

I had the same experience

There are major problems in the quality of the glass around the crossmembers. There are gaps, voids and places where the glass was not properly wetted out. They built the cross bulkheads very strongly and it seems they believed the mass was so substantial they didn't need good finishing. The problem is they didn't anticipate years of the deck plates coming on and off and water penetration around the screw holes. It would have been better to put hatches in like on the new '33 Express.

 

[BobP]

When you say cross members, are you talking about bulkheads ? Stringers are running lengthwise, bulkheads run across beam, it all makes for an egg-crate grid structure.

Or are you talking about the 2x4s that partially support the gas tank cover, that are layed flat and toe-screwed into stringers? These serve to hold the gas tank down, as well as a mid span support for tank cover.

 

[wrg49]

no.. I'm talking about on the underside of the deck plate itself. There are two pieces of plywood laid on edge across (ie: from starboard to port) the bottom side of the deckplate intended to strengthen the plate. The plywood core of the plate is thicker in the center than along the edges. The cross brace is epoxied (barely) to the center but not to the thinner edges. I've started to dis-assemble the fiberglass and plywood core (yes they are 4x4 pieces of plywood laid grain perpendicular to each other). Based on the info I've leaarned from forum members, I intend to replace the whole plywood core with one piece of wolmanized plywood (at least 1/2 " thick), installl new cross braces, route the edges of the plywood to appropriate thickness, clear drill and epoxy fill around the fastening screw holes and apply fiberglass cloth to the underside.

 

[BobP]

I'm not familiar with your gas tank/bilge covers, mine have no stiffeners, as they are called.

The term deck plate if for the pop out or screw out handway fittings, the floor coers are called the gas tank cover and bilge cover (or hatches).

Gets confusing with the terminology.

Wolmanised (treated plywood) has not been recommended due to bond strength and specail preparations thereof, with resin, vs. marine plywood (untreated). Besides marine plywood, "project plywood" is untreated also, like the Depot has in the 2x4 pre-cut size. Epoxy resin is recommended when bonding to existing glass, over polyester and whatever else - ester.
May not matter with covers at all, but if you got the advise over at ClassicMako. com, then ignore what I wrote.

 

[bhemi]

Terminology

Bob is right. There is a "Bulkhead" between the aft compartment and where the first gas tank is. Grady laid what I call a "cross member" over the top the bulk head creating a "T" structure. The Aft bilge cover and the gas tank cover meet in the middle of the "T". It is made of a sandwhich of a little glass (very little in my boat) then 4" square pieces plywood, then more glass, then gelcoat. Over half the pieces of plywood in my '92 Marlin were rotten and no longer holding the screws.

I'm almost done fixing it. I ground out all the plywood and laid down a first layer of epoxy today. Tomorrow I'll add a proper layer of glass, then plywood and then epoxy back the top piece I saved. A little gelcoat to finish and it will look good.

My lumber guy is recommending "Baltic" plywood. Many more layers of wood than regular plywood and made with water proof glue. You don't have to buy full sheets and he says he left a piece in a bucket of water for three months and it was fine. No swelling or delamination.

 

[stmry]

deck plate

I had the same problem on my 1997 226. I stripped all the old fiberglas and little square pieces of plywood off of the cover. I replaced the wood backing with 5/8" thick marine grade or equivalent. epoxied it, used stainless nuts and bolts through the access panel mounts and fiberglassed the entire underneath. It is strong as the "rock of gibralta". Cost about 100 bucks.

 

[wrg49]

OK here's an update on my deck plate repair. I removed the deck plate from over the forward gas tank. The plywood that was laminated to the underside was all random sized pieces with two cross braces of plywood strips laid on end. The whole underside was covered with a loosely laid fiberglass cloth (random fiber type) that was poorly wetted with fiberglass resin (many voids and dry areas). I removed all of the fiberglass, cross braced stiffeners, and laminated plywood pieces (wasn't an easy job) and cleaned it down to the underside of the deck plate. I cut and fitted a full piece of 1/2 " marine ply to the underside of the plate. I routed a 1" wide strip completely around the edge of the plywood to 1/4" depth. In the area of each of the mounting screws, I drilled out the plywood completely. I then epoxied the plywood to the undersideof the deckplate, clamped and weighted the entire section to provide good adhesion and let it cure overnight. Next I filled all the areas around each of the screw holes (and any voids around the edge of the plywood core) with epoxy. This would help prevent any water leakage from penetrating the edge of the plywood. I next wetted the plywood and laid the fiberglass cloth. Once that was set, I applied a final coat of resin and let it set up.
There was also some wear and cracks on the non-skid sufface of the plate. I colormatched a batch of gelcoat, applied it to plate and rolled it out with a foam roller. When I re-installed the deck plate on the boat, I used some quick set epoxy and filled all the holes in the boat deck. I pre -drilled and countersunk all the holes in the deck plate prior to installation. The plate was laid on 1" wide rubber strip gasketing and screwed in place (I temporarily used strips of the gasket material to maintain equal spacing around the plate while I secured it in place.) I then removed the spacers and caulked the plate in place with the almond colored, 35 year, exterior GE silicon caulk ( it's a lot cheaper than West Marine's silicon caulk).
The repair looks great and the plate is a whole lot stronger than when I removed it. Hopefully it will last for years.
Thanks to everyone in the forum for all the advice !

 

[wrg49]

Just one correction on my previous post.. it was 5/8" marine ply.. not 1/2".

 

[BobP]

For years? It will last forever.

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It is not unusual to find voids and resin starved glass in the Gradys, takes skill working those resin guns to get it right while not overdoing it on the heavy roven and mat they use.

Not saying this as an excuse.

 

[striped bass]

"Next I filled all the areas around each of the screw holes (and any voids around the edge of the plywood core) with epoxy. This would help prevent any water leakage from penetrating the edge of the plywood."

wrg49
You got that right!! To avoid a recurrence of this problem you did the right thing to make sure the new screws are properly embedded with the right material in the fiberglass panels when you re-installed them. This is the origin of your problem in the first place. Grady White manufacturing in Greenville simply puts the screws directly into the fiberglass deck panels without any attempt to embed the screws with the proper material to keep out the water. Over time water enters through the fiberglass cracks around the screw heads and presto change-o the underside of the deck panels rot with fungi and you get a soft deck. Same goes for the screws holding down the round inspection ports. I hesitate to suggest additional work but perhaps the other deck panel also needs attention while you are at it. Seems unlikely that one panel would be affected by the sloppy Grady workmanship and the other would escape the problem.

I would be interested to hear from Bob if epoxy is the best material to embed around the screw holes to keep out water from re-entering the the area around the screw heads. Also what, if any, boat manufacturer that you know of uses the proper manufacturing process with screws in the deck and topsides to avoid this problem?