Polyester boats?

[OrwellTiggerToo]

Have been looking at a Starrat 45 built in polyester... as a hull material what are the upsides and downsides over more conventional make-ups?
Cheers
Steve

 

[B175Chris]

I prefer cotton hulls, although sometimes it makes the steering go a little wooly.

 

[B175Chris]

*taps* Is this thing on?

 

[PuffTheMagicDragon]

Agree about the first bit, not about the second. Poly-cotton is also good in 35-65. None of the problems of pilling that one gets with straight polyester.

 

[oldsaltoz]

[ QUOTE ]
Have been looking at a Starrat 45 built in polyester... as a hull material what are the upsides and downsides over more conventional make-ups?
Cheers
Steve

[/ QUOTE ]

G'day Steve,

Poly ester resin is a standard resin most fibreglass boats afloat today are polyester resin.

Upsides: low maintenance, strong and light.

Downsides: Osmosis.

Avagoodweekend......

 

[nimbusgb]

Polyester cheaper but osmosis prone.

Epoxy, expensive but almost totally free of pox problems

 

[Norman_E]

True, but early GRP boats used gelcoat resins that were more permeable than recent ones, so there is less chance of getting osmosis in a reasonably recent boat, by which I mean no more than 10 to 15 years old, or whenever the manufacturer adopted the newer resins. Another factor is whether the boat had an epoxy hull treatment from new.

 

[castaway]

Generally older GRP boats used orthophthalic resin whilst more recent boats use isothalic resin.

My GRP boat is coming up to 40yrs old and is still absolutly fine although I would be more conserned if I was leaving her in the water year round.

Regards Nick

 

[Norman_E]

40 years proves that even the older resins were perfectly OK if properly and evenly mixed with the right proportion of hardener. I suspect much osmosis is down to poor mixing and unsatisfactory layup practices, rather than the actual resin used.

 

[oldharry]

Shown it here before, but proud anyway:

V nearly 50 years old now. The hull is repainted, but no trace of Osmosis, and still going strong. Polyester through and through (all 2 inches of it!).