Fiberglass - A Fact Check

Amongst popular boat building mediums, what we call “fiberglass” is no doubt the best suited for today’s pleasure vessels. Fiberglass composites afford the manufacturer repeated production out of the same base investment and the material lends itself to forms difficult to achieve in other mediums, such as metals. For owners, composites mean affordability and a relative ease of maintenance.
There is a caveat however and few boat owners are made aware of it, as yacht brokers and most builders consider it counter productive to their sales to ever mention such a thing. Those of us who inspect and maintain the boats can see the problem quite clearly though, and some of us even try to put the point across, but it seldom hits home to an owner, until it’s too late.
The greatest pitfalls of fiberglass construction, is without doubt improper maintenance practices, resultant of a false sense of security in the material. (Barring of course the few makes and models, that turn out to be an unhealthy experiment in the first place, such as balsa coring below waterline…) What must be realized is, that fiberglass may be the best material, but is far from the perfect material. There is no such thing as a “perfect material” that can stand up to the ingression of water. Over time, moisture will enter most anything that man or even nature can concoct.
Professionals in the Marine Industry use such abbreviation as FRP and GRP. Owners would be doing themselves a world of good by putting the word “fiberglass”, which had become synonymous with perfection, out of mind once in a while, and delve into the meaning of the abbreviations. Whether you use FRP or GRP, it boils down to fiberglass or glassfiber reinforced polyester.
Yes skippers, captains and mates, our boats are made from a variation of the oil product that also produces the cheap sweaters that some of us would not be caught wearing! Truth be told, even today’s new composites are for the most part, simply variations of the old polyester resins, and only time and many years of it, will tell how good the new material will stand up on the long run.
Consider this: The only thing impervious to moisture ingression in the composition of our fiberglass boats’ building material is the glass fibers! The polyester resin, used to bond the glass fibers together, actually has water soluble components. And, gelcoat or epoxy between the glassfiber hull and the ocean, is the only paper thin barrier that keeps the moisture out of our hulls. So, is it important to keep an eye on that moisture barrier? You bet your bottom! Rightly so, a lot of owners keep a vigil on their hull bottoms, because there actually is a lot of discussions in the media and dockside in regards to osmotic conditions that manifest in blistering. Unfortunately however, the majority of well meaning and caring owners stop at the exterior waterline, not thinking about what may be taking place elsewhere.
Here is the heads up! The hull bottom and topsides of your boat, especially considering today’s improved lay-up techniques and if it is of non-cored single series laminate, may be the least of your worries. When a Surveyor discovers unusually high moisture levels and blistering on your bottom, chances are the gelcoat had failed. This is par for the course in the life of most all FRP structures. The gelcoat can be removed, the laminate dried out and an epoxy moisture barrier applied, returning your hull bottom to perfectly acceptable condition. Remember, your hull bottom’s skin contain some of the most robust laminates of the entire structure, thus stand up the best. But when stringers, frames, transoms and decks are ignored, very major deficiencies can develop unseen and undetected until it is way too late, and repairing requires such involvement that may not even be feasible to undertake. In most cases engine and hull stringers, transverse frames, bulkheads and decks will incorporate some kind of coring. In the case of transoms, stringers, frames, and bulkheads it is usually some wood, such as fir timbers or fir plywood that is encased in relatively thin FRP. Decks will be a sandwich of balsa, a wood that is not unlike a sponge, or in better cases some closed cell foam. Through invisible laminate cracks or a poorly laid laminate, moisture can and will enter and wet the core, and if left alone, will progress into saturation and loss of structural stiffness. When this happens, repairing of the damage can be very expensive, and most of the time this sort of thing comes as a surprise to an owner who thinks his or her boat is in perfect shape. To get at a vessel’s stringers and frames, her interior must be removed. To repair decks, they have to be cut open and completely rebuilt from the exterior. All skilled work and all very costly. Powerboats are more so at risk than sailboats, as flat bottom sections, hard chines and transom sterns require more internal stiffening support. Powerboats under around 35 feet especially, since builders naturally put less heft into the framing of smaller boats than they do larger vessels. Powerboats equipped with sterndrive units stand a very good chance of developing transom core problems because of the stresses involved and the penetrations requiring absolute, perfect bedding to seal. Decks are equally problematic with sail or power craft. Decks will always be cored to keep down the weight, and will always be penetrated by hardware fastenings that invite wetting of the core. Builders seldom take the time to properly bed deck hardware fastenings, because to do it right it is messy job, and it takes time to clean up after. Owners never think of pulling and re-bedding deck hardware or such items as transducer or trim tab fastenings into transoms, in spite of the fact that even the most well respected polyurethane or polysulfide marine caulks have a limited service life.
With what we know today about laminates constructed of polyester resins, taking preventive steps of early detection becomes the most imperative action in fiberglass boat ownership.
Owners of boats with expensive internal combustion engines, like larger diesels, take precautionary measures by conducting regular oil analysis in order to determine wear trends, and they do it by comparing annual results. Actually, this goes for not only boats, but heavy equipment, locomotives, aircraft, highway trucks, even cars. Why? Because diesel propulsion engines are expensive equipment. Are the hulls and structural components of our boats not considered expensive?
Fiberglass boat owners simply must wake up to the fact that they should be doing the same for hull and structure – don’t take it for granted, look and see if all is OK. That is, if they care about preserving a vessel’s integrity, if they want their boats’ structural components to remain within the acceptable and normal processes of gradual deterioration, and if they care to ensure expected resale values. Today, we have moisture detecting instruments that in the right hands, can be used to gain knowledge of chemical processes taking place within a laminate, induced by moisture. Put it plain, we can point a finger at trouble brewing. Literally brewing within the laminate...mostly out of sight and out of mind. The old fashioned method of acoustical sounding, which this writer has some good twenty years of experience with and still considers very much a useful tool in our profession, can only discover conditions that have already deteriorated to soggy proportions. A good low frequency instrument, properly interpreted by an experienced user can save a vessel’s life and the owner’s investment, simply by detecting moisture when it is not yet a wide spread or saturated situation. It only makes sense, that if we are able to detect a deficiency at early stages of progression, then we can repair it in a more feasible manner. Most reputable Marine Surveyors will be happy to engage in a dialogue with a vessel owner in regards to taking moisture readings of certain structural components on an annual basis, producing a written record of such readings, and doing it at an affordable rate, reflecting the limited nature of the assignment. My Marine Surveying practice is in the Province of Ontario, so I can speak only for my region. I see a major problem with some of the older boats we survey, and I hear the cries of Buyers and Brokers: “There is nothing out there”. I agree. The eighties boats are getting old and troublesome, and many sales are lost due to discoveries of show stopping magnitude, made by attending Surveyors. My experience shows that there are no winners when this happens. I get paid, and I see everyone walking away disappointed.
Including the would be buyer.
For the sake of the nineties boats, I think it is in the interest of all of us involved with boats and boating to realize, that healthy competition amongst manufacturers may build a better boat, but the end users must learn about the product, it’s limitations and it’s realistic maintenance needs.
There may be a “perfect” plastic in the world of credit cards, but when you take a piece of plastic imbedded with wood, foam, all kinds of dissimilar metals weighing tons, lube oils, fuels, two different kinds of electrical current, add lots of internal and external forces and throw it repeatedly against a hard surface such as water…well, you get the picture. With proper maintenance, which involves caring not only for the obvious but also for what is out of sight and is out of mind, unpleasant surprises can be avoided, and we can bring that fiberglass structure a little closer to our preconceived state of perfection.