Best way to repair this.

[cofooter]

I have a few stress crack areas on my Sanger flatbottom I am restoring. I plan on addressing the hard spots that caused these from underneath so they hopefully don't come back. What is the best way to repair the surface? Grindout each crack and fill? Grind out the whole area and fill? Or grind out the whole area, lay in some thin cloth and fill/fair. Thanks!

 

[lenmann]

In my experience cracks like that mean that the composite structure under the gel coat has yielded to some form of stress (the hard point vs. gravity, g-loads, etc.). If you can remove the hard point, then you can grind out and replace the damaged composite structure from the underside. Then grind off the gel on the outside and re-coat. Then reinstall the original source of the hard point (bulk head, etc.) in a manner that doesn't create a new hard point.

 

[cofooter]

In my experience cracks like that mean that the composite structure under the gel coat has yielded to some form of stress (the hard point vs. gravity, g-loads, etc.). If you can remove the hard point, then you can grind out and replace the damaged composite structure from the underside. Then grind off the gel on the outside and re-coat. Then reinstall the original source of the hard point (bulk head, etc.) in a manner that doesn't create a new hard point.

Thanks, that is exactly what is happening. There is a plywood strip running down the inboard side of the gunnel and the cracks are where it curves away from the fiberglass at the back and where it terminates. I do plan on addressing those areas when I turn it over as you suggest. Thanks for your response!