Water intrusion through bridge screws
The second kind of crack we are going to look at is the caused by water intrusion into the wood substructure. This kind of crack is caused when water gets into the wooden roof substructure causing it to swell and crack the fiberglass.
The first thing we need to do to repair this crack is to identify where the water is getting into the roof structure. Here are some places to look. If the crack is around the bridge, look at where the bridge is attached to the roof. Several manufacturers simply screw the bridge directly to the roof. Over time, the silicone used to seal where the screw penetrates the roof can deteriorate allowing water into the plywood substructure. Most of the time, but not always, this will also result in the roof leaking in the salon.
You can fix this problem in 2 different ways. The first and best way to repair this problem is to raise the bridge up and fiberglass a small wood block onto the roof to which to attach the bridge. Once you set the bridge over it, the bridge can’t move. You can also put a screw through the bridge into the side of the block as well. This will insure you will never have this problem again.
The second way would be to simply remove the screw, scrape off the old silicon, and reseal it using new silicon. The problem with this is that you will have the same problem again at some point in time.
Regardless of which method you use, before you place the bridge back in to final position, you will need to open the water damaged area up and let it dry thoroughly. You can do this with a hook bill knife or a grinder. Be sure to remove any loose and delaminated fiberglass, opening the roof up until you find dry wood. Once the wooden substructure is completely dry, you can take a folded 7” grinder disk or a grinder and smooth the area. From here you simply need to apply 2 layers of 1 and ½ ounce chopped strand mat. Mix enough resin to wet out thoroughly. Allow to dry completely, sand sooth and apply a thick coat of gel coat with surfacing agent.
As always, feel free to contact me with any questions. Good luck and happy boating.
- A small amount fiberglass resin
- A small piece of chopped strand fiberglass mat
- A small amount of gel coat with surfacing agent or “wax” in it
- A very small amount of MEK or hardener
- 2- 2” disposable paint brushes
- 2 small paint trays
- 4”- 36 grit grinder pad