glass/carbon laminate/hull sucking water without gelcoat?

[Christian_83]

Hi guys.
A friend of mine told a story about his friend who is a boat mechanic, they sold a fiberglass race boat (sailboat) and weighed the boat before it hit the water.
After a few races they weighed again, and they said it gained 300kg/660bs (i don't know the size of the boat) And the reason for this should be, than the hull had not been given gelcoat and therefore had sucked water and added the weight. I think it sounds a little strange or what?

 

[SXIPro]

Vinylester and polyester can absorb water.

 

[Christian_83]

Okai, but not epoxy?

 

[Dalton]

It's my understanding that all resin composites are susceptible to water absorption with vinyl ester and polyester being more so. Exposed fiber ends will slowly wick up moisture over time. Water absorption has a bunch of negative affects aside from weight gain.

Some good reading:
http://www.scielo.br/scielo.php?pid=S1516-14392009000300017&script=sci_arttext

 

[DAG]

I'm no composite guy but shouldn't all fibers be 100% saturated in a binder be it resin/vinyl/polyester

 

[smdubs]

Who makes a boat and sticks it in the water without some kind of coating on the outside? Whether gelcoat or paint or whatever? Was your friend drunk when he told this story? Maybe after they put the boat in the water, they docked it, and loaded it with a couple kegs of beer and some gear.

 

[Kawastyler]

Handlayed vacuumbagged epoxy composite materials can suck a lot off water in it when layup not done well!!!

 

[Vumad]

I'm no composite guy but shouldn't all fibers be 100% saturated in a binder be it resin/vinyl/polyester

Really the fibers don't saturate. They are glass. You seal the glass inside of the resin. The resin does not go inside of the glass.

Sanding the gelcoat off and not resealing will leave exposed fibers. I have a ski that I sanded the gelcoat and left exposed to the elements for years. It got all fuzzy as the smc started to break down. Had to sand off all of that and reseal it. The areas that still had gelcoat on them where smooth and just fine.