Hi,

I'm obviously doing something wrong. I have a Mystere 5.5 16ft catamaran.
http://www.mysterecomposi…e-catamarans/mystere-5-5

Every year after winter (second year, I'm new to this), I get stress crack at the bottom of the hull. The hull is very V shaped and clearly some water manages to get inside... freeze up ... and well cracks start to show up after winter.

So I was wondering what am I to do ?

The idea I have are:
1- Keep the catamaran almost at vertical so that it drains constantly (not very practical specialy since the snow will pile up)
2- Put some anti-freeze product to prevent water from freezing... (i would pump it out and dispose of it after each winter properly)

Anyway does someone know whats the best practice and product to use if any.

Thanks.

I disassemble everything and store the hulls upside down under cover on a pontoon boat. As far as best practice, I would pressurize the hulls and find out where they leak, and fix that.

--
Tom
NACRA 5.7 (1984 Sail 181)
Pennsylvania
--

Are you sure that the stress cracks are coming from freezing water and not from improper support on the trailer? Do you have cradles for the hulls? From what I am seeing, the Mystere 5.5 doesn't appear to have more V in the hulls than any other typical symmetrically hulled catamaran. It seems very unlikely that water would be causing the cracks unless you are storing the boat bow down and water is running forward, freezing, and stressing the very tip of the bow. Heavy snow load combined with improper support, on the other hand, could definitely be damaging the hulls.

sm



Edited by Dogboy on Apr 16, 2017 - 08:31 AM.

Quote

I'm obviously doing something wrong. I have a Mystere 5.5 16ft catamaran.
http://www.mysterecomposi…e-catamarans/mystere-5-5

I see your mistake. Mystere 5.5's are 18'3", not 16'

I would look for how the water is getting in (could be your beam bolts, hatch covers, deck lids may be leaking, etc

you could remove the mast and store the boat upside down for the winter, but i would think removing the beams and putting the hulls in a garage would be your best bet

PS what year is your mystere?