1985 SPORT 15 Deck Repair: Best Adhesive; Best Sealant

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
Florida15Sport
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1985 SPORT 15 Deck Repair: Best Adhesive; Best Sealant

Postby Florida15Sport » Tue Apr 06, 2021 9:29 am

[In regard to 1985 SPORT 15 whose deck was soft and was repaired as described below;]

Q1: what is the best product and best method to stick down or adhere or glue the replacement plywood reinforcement pieces to the foam before putting back in place the fiberglass deck?

Q2: what is the best product and the best method for sealing holes in the fiberglass cockpit deck sheet?

Q3: what is the best product and best method to re-install the fiberglass deck that was cut out for repair of the underlying wood?

Q4; what is the best product and best method to seal [the joint lines between the original deck and the fiberglass deck section that was cut out]?

BACK STORY--THE SHORT VERSION
I originally wrote a much too long description of how I’ve used and kept my 1985 SPORT 15. The above is a seriously edited version.

[Moderator's note, I deleted even more information not cogent to the repair topic from the short version.]

In 2004 I bought [a 1985 SPORT 15 boat] in in South Florida with no trailer. The hull was in good and usable shape.

[The SPORT 15 boat] has been generally cared for but poorly stored both in the water and on trailer.
In mid-summer 2020 I was finally able to get the boat under a roof so it could dry out. A one-foot-square of the fiberglass floor was cut out to allow drying. The plywood in that area was mush.

After hatch cover, console, seats, and side support wood were removed, a continued inspection revealed much more softness and several areas where brown water would push out of holes in deck.

I decided take up the complete non-skid floor area. I used a Roto-zip tool and straightedge guides to take up the fiberglass. Much of [the wood under the deck] had rotted plywood and was easy to remove; some needed real encouragement to come loose using various thin blades to affect release.

After the fiberglass was up I preceded to remove all the bad plywood. Most was easily done with a wide putty knife with other requiring more encouragement. Finally, again using the Rotozip bit set at 1/2-inch, I cut out rectangular sections of the plywood until I got to good areas.

As I took up the bad plywood I realized the foam was dry and firm and in good shape. I purchased marine grade AB plywood and have cut and fit replacement pieces for the damaged areas.

jimh
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Re: 1985 SPORT 15 Deck Repair: Best Adhesive; Best Sealant

Postby jimh » Tue Apr 06, 2021 9:48 am

Florida15Sport wrote:Q4; what is the best product and best method to seal [the joint lines between the original deck and the fiberglass deck section that was cut out]?

In the original construction of Boston Whaler boats where a removable deck center deck section was used, the joint line between the fixed deck and the removable deck was sealed with a marine caulk whose color was a close latch to the gel coat colors. Many people have used a silicone caulk with a white or off-white hue.

The caulk is applied according to the instructions provided by the manufacturer.

jimh
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Re: 1985 SPORT 15 Deck Repair: Best Adhesive; Best Sealant

Postby jimh » Tue Apr 06, 2021 9:53 am

Florida15Sport wrote: Q1: what is the best product and best method to stick down or adhere or glue the replacement plywood reinforcement pieces to the foam before putting the fiberglass floor surface back in?


Note that originally the wood reinforcement was not bonded to the foam, it was bonded to the deck section. Apparently in your repair the bond between the laminate and the wood was broken while the bond between the wood and the foam remained. This is an unusual situation. Generally the wood reinforcement panel remains bonded to the deck laminate and pulls away from the foam with ease.

The best product to use as a means to stick down or to adhere or to glue wood to foam is any adhesive that will not dissolve the foam and will obtain adhesion to both the foam and wood and will be waterproof.

jimh
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Re: 1985 SPORT 15 Deck Repair: Best Adhesive; Best Sealant

Postby jimh » Tue Apr 06, 2021 10:01 am

Florida15Sport wrote:Q2: what is the best product and the best method for sealing holes in the fiberglass cockpit deck sheet?
For advice on repairs to hull gel coat and laminate surfaces, see:

INSTRUCTIONS -- HULL PATCH KITS

jimh
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Re: 1985 SPORT 15 Deck Repair: Best Adhesive; Best Sealant

Postby jimh » Tue Apr 06, 2021 10:09 am

Florida15Sport wrote:Q3: what is the best product and best method to re-install the fiberglass deck that was cut out for repair of the underlying wood?

Assuming the section of deck that was cut out has been repaired with the underneath reinforcement wood bonded to the deck, I would just lay the deck section back into place on the foam. It should fit perfectly if the wood replacement is the same thickness as the original. If the gap between the cut-out deck section and original deck section is not perfectly aligned vertically, you will have to make adjustment.

As for bonding the cut-out laminate and wood to the underlying foam, I cannot offer any advice based on my own or on reported methods. Perhaps others can give some guidance.