CONTINUOUSWAVE

I am new to this and looking for advice fixing the cracks [shown below in a close-up image]. They are only on the port side of the hull and showed up just last summer. I presume fatigue from running fast through whitecaps.

Gel coat will crack from movement of the underlying laminate. If you had some very hard impacts from encountering high seas, I suppose the hull could flex somewhat.

From the image captions I presume the boat is a 1975 model. That's a 41-year-old boat. The gel coat could also crack just due to lack of proper care. If the gel coat dries out and is not refreshed with treatment with compounds it can develop cracks like that.

Where are the cracks located? The images are such close-up shots that I can't tell what I am looking at.

The general method to repair a crack is as follows:

--stabilize the underlying laminate layers if movement of that layer was the cause of the cracks;

--repair according to instructions from Boston Whaler: see

http://continuouswave.com/whaler/reference/repairInstructions.html

--for cracks, the crack is often intentionally made wider by gouging it with a V-shaped tool; this give the new gel coat resin a better area to adhere to.

Use a gel coat resin with proper color match; when matching colors, first very lightly sand, clean, and polish an area of the existing gel coat so you get the proper color and lustre to use for color matching the new gel coat resin.

If there are a lot of cracks in one area, you may just want to re-finish that whole area.

Thank you both. The cracks are on the port side with a few running 4-5 # on the bottom and a few on the Transom.
Once the ground firms up a little, so I can get trailer out, I will sand a few and see whether it is gelcoat cracking or prior owners paint over gelcoat. Either way, I will probably have the whole hull sanded and re-gelcoated, since the area of cracks is so large, and as you say, it is 41-42 years old and can use the TLC as the core seams to still be dry.
John MacAllister