Gelcoat Stress Crack Repair
Fiberglass Stress Cracks Repair
Are Stress Cracks Normal On Boats

Hi Everyone,--I am new to this web site. I may buy a 1973 Boston Whaler 21 Outrage. The boat was remodeled in 2013 with a new transom, new fuel tank, a Yamaha 150-HP engine, and new cushion seating. I went over the whole boat. My only concerns are stress cracks in the stern.

Re: Stress Cracks. The boat is a 2005, I had had the cracks for a while but did not mention it to the dealer until last summer. He made an appointment with the factory, they took the boat back grind down a few feet of the back and sides and rebuilt the area. They had the boat for 6 weeks but I was out of the country for 3.

If the cracks on your boat were caused by impacts, such as around rub rails or where a heavy object was dropped, move on to Step 1. If, however, the spider cracks appeared at an attachment point or in a high-stress area, there's a good chance they'll simply return after you fix them.
Stress cracks can be identified as long(er) parallel surface cracks on the hull or deck. Most common location for these to occur is on corners and radius’s where the layup of fiberglass is typically thinner, and the amount of resin is usually more than what it should be.

Gelcoat Stress Crack Repair

Fig. 1. Gel coat cracks on transom of 21 OUTRAGE c.1973

stress4a.jpg (22.01 KiB) Viewed 929 times

I suspect [the cracks seen above] are from applying gel coat too thickly. Do you think differently?
I know Boston Whaler boats are notorious for this.
Is this just cosmetic?

Fiberglass Stress Cracks Repair

05-11-12, 14:09

Are Stress Cracks Normal On Boats

On recent inspection a series of concentric rings of very fine cracking in the gelcoat on the hullside have appeared. Evidently non-structural, but according to the surveyor, probably caused by some weight locally compressing part of the outside of the hull, generating an area of expanding rings of stress cracks, about 2-3' across, presumably when the deformation pressure released. Probably created some time ago, but becoming more obvious as material penetrated the cracks, oxidised & blackened.
A general wash & hand polish with some Farecla G3, doesn't seem to have had much impact. Any suggestions for a more effective DIY treatment, short of re-gelcoating the area?

Stress Cracks On Boats