Matt, It is well documented that many boats have developed blisters after epoxy barrier coats--the vast majority of these already had blistering. It is rare that boats are adequately dryed out before being repaired. A proper dry out take months--and often involves tenting the boat, the ground, drying the bilge and using both heaters and dehumidifiers. There are other ways, including heat and vacuum. The formation of blisters is NOT because of the epoxy--but because the boat was not dryed out properly.
For the most part builders do not use all vinly ester resin, even though it is more desirable--same as they do not use epoxy--although it is even more desirable than vinly ester. The reason is cost. For example one common supplier charges $350 for a 5 gallon pail of Vinyl ester resin and $121 for a 5 gallon pain of polyester resin. This 3/1 price holds pretty much through out the industry! All boats are built to a price point to be competative in the market. Most good builders use a layer or two of vinly ester--not all vinyl ester layup.
For the most part builders do not use all vinly ester resin, even though it is more desirable--same as they do not use epoxy--although it is even more desirable than vinly ester. The reason is cost. For example one common supplier charges $350 for a 5 gallon pail of Vinyl ester resin and $121 for a 5 gallon pain of polyester resin. This 3/1 price holds pretty much through out the industry! All boats are built to a price point to be competative in the market. Most good builders use a layer or two of vinly ester--not all vinyl ester layup.