1973 OUTRAGE 21 Stress Cracks on a Remodeled Hull

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madmax781
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1973 OUTRAGE 21 Stress Cracks on a Remodeled Hull

Postby madmax781 » Tue Oct 30, 2018 11:06 am

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.

stress4a.jpg
Fig. 1. Gel coat cracks on transom of 21 OUTRAGE c.1973
stress4a.jpg (22.01 KiB) Viewed 2319 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?

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Phil T
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Re: Stress Cracks on a remodeled 73 Whaler

Postby Phil T » Tue Oct 30, 2018 11:14 am

Long gel coat cracks like those in the photo can be from a thick coating. You could grind each out a bit and reapply gelcoat or just leave as is.
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jimh
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Re: Stress Cracks on a remodeled 1973 OUTRAGE 21

Postby jimh » Tue Oct 30, 2018 4:08 pm

I don't know that having stress cracks occur in the gel coat layer over long flat surfaces is evidence of the thickness of the gel coat being too great or that this happens on Boston Whaler boats in such frequency that the brand is notorious for it.

I suspect that if you found another 1973 boat that had been operated in the same manner for 45-years as the boat you are looking at, then that boat might have some stress cracks in the gel coat, too.

I would interpret those cracks as probably occurring as the result of some impact of the stern quarter of the hull with significant force with some larger and immovable object, such as a dock when the boat was in the water or a wall when the boat was on a trailer.

The mention that the boat has "a new transom" could have an association with the cause of those cracks. Perhaps there was some damage to the transom which resulted in the hull being likely to flex or bend at surfaces that would otherwise not have been subject to the same loads.

As for making a determination of the effect of the cracks on the structural integrity from a photograph, that is not really possible. I recommend you assess the structural integrity of the transom and stern by trying to move the engine gear case up and down. If the trim system is working properly, you should exert a bending force onto the transom. Look for any deflection or movement, particularly in the area of those cracks. If no movement is detected, the cracks are probably surface cracks and were created by some event when too much stress occurred.

Again, you are looking at a 45-year-old hull. Some stress cracks in the gel coat are likely to be seen in a boat that old which has had active use for 45-years. The reason you might see this more in Boston Whaler boats is that they are among a few boat brands that actually have 45-year-old hulls still in useful condition.