Until the late 1960’s, 1970’s and 1980’s wood was the material of choice for building a water borne vessel. However, once fibreglass and resins had been engineered, proven and developed, it was realized that craft could be built at a reasonable cost with structural integrity easily obtainable with correct engineering.
Older fibreglass vessels from this period tend to be over-engineered compared to modern vessels and are usually heavy for their type. Early companies also tended to have limited laminating techniques and experience, so a good, accurate survey must be carried out prior to purchase. It must be observed though that some of these older, heavily built GRP vessels make very robust, sea worthy cruisers.
Older vessels of this era are also prone to osmosis. This is very basically described as moisture ingress through the fibreglass substrate, causing a chemical reaction with the laminate resins. This in turn creates voids and visible blisters in the substrate. However, modern repair techniques have been developed to counter osmosis and provide longevity to the vessel.
Like wooden vessels with rot though, sometimes buying a second hand, reasonable priced GRP vessel may require additional refurbishment, repairs and maintenance. Like all vessels, the hull material may be the least of the problems with un-serviced, corroded systems and fittings being the actual deciding factor for the purchase.
Modern GRP vessels however, are usually well designed, well built, and well thought out in regards to use, servicing and maintenance. With the advent of modern fibreglass systems and gel coats, the newer GRP craft are hardy and robust, with ease of cleaning being very evident. Important in the marine environment after a hard days fishing!
Also with new GRP designs and common brands, all of the bugs have been ironed out in earlier models so chances of bad design and use are minimized. Because these craft are also mass produced from molds, prices are often very reasonable with many clients being able to afford new or recent second hand vessels.