The stampede of buyers away from boats tagged as blister buckets served as a wake-up call for boatbuilders in the 1990s, prompting the adoption of better construction materials and methods. But the changes didn’t happen overnight, and there are still some flies in the ointment.
In 2001, the BoatU.S. Consumer Protection Bureau conducted a survey of warranties from 45 boatbuilders and found only 16 specifically covered blisters. “Some [warranties] are limited to prorated coverage, requirements that the owner pay for the application of an epoxy barrier coat or stipulations that the gelcoat cannot be altered in any way,” according to the survey report.
There is anecdotal evidence that more boatbuilders are offering warranties against blisters, in part because they’ve come up with a good and fairly inexpensive way to defend against them: the application of a vinylester skin coat on boats built with polyester resin, the least expensive when compared to boats built with vinylester or epoxy.
It is all a matter of chemistry. Vinylester and epoxy are closed-chain polymers, while polyester is an open-chain polymer. Essentially what this means is, on a molecular level, vinylester and epoxy are “tighter” than polyester, and the “tightness” makes both types of resins less susceptible to absorbing water. Obviously, the science is more complicated, but that’s the idea. You can use all three types of resins to build fiberglass boats and, because polyester is less expensive, boatbuilders continue to use it, despite its liabilities. Applying a vinylester skin coat represents a compromise between quality and affordability.
“The vinylester skin coats on new boats really do work,” says Bob Turner, a partner at Kelsey & Turner Surveys in Annapolis, Md. “I’ve seen boats treated with skin coats with 15-year-old hulls that were still in good shape. We haven’t seen major problems with new construction.”
“The quality of fiberglass boat construction has improved significantly over the last 10 or 15 years, and that’s been driven by the negative customer reaction to blistered hulls,” says Mark Lindsay, a partner in Boston Boatworks, of Boston, whose company builds mJm’s high-tech cruising powerboats using epoxy resin.
“People said, ‘Hey, I don’t want a boat with blisters,’ ” says Lindsay. “That led boatbuilders to start building boats using vinylester resin, which is an intermediate between a polyester and epoxy boat. When manufactured properly, the hulls could have 10-year warranties without posing much of a risk to the manufacturers.”
Rives Potts, manager of Brewer Pilots Point Marina in Westbrook, Conn., agrees. Boats are built better than they were in the 1970s and 1980s, particularly when boats are built with vinylester or epoxy resins, he says. But he also says it’s not always smooth sailing when it comes to some new boats.
“We’ll have a polyester boat with a single skin coat of vinylester, and the manufacturer will give a warranty of five or 10 years against blistering, but then they won’t let you sand the boat to put bottom paint on it,” Potts says. “A lot [of manufacturers] use a no-sanding primer on top of the gelcoat. It’s very touchy. For some boats it works out well, and for others it doesn’t.”
Potts says in some cases the no-sanding primer doesn’t last very long. When it deteriorates, the bond between the gelcoat and the bottom paint breaks down, causing the paint to peel away. “At that point, we have to make a decision about what to do.” Usually, it means sanding, which voids the blister warranty.