DPM Sales & Service "Quality Marine Repairs

By: Dpm Sales  09-12-2011
Keywords: Boat, fiberglass


Fiberglass hulls were once thought to be impervious to the harsh marine environment, but this is not always the case. All kinds of different problems can be found with today’s hull construction, some only cosmetic in nature, others involving complete hull delamination, resulting in large repair bills if not caught in time !!!

Back in the mid to late 60’s when fiberglass was being introduced as a new construction material to replace plywood and mahogany planked vessels; all was well for a few years. Manufacturers such as Chriscraft used a solid laminate lay-up, with no core materials, just a ton of resin and matting which were put together by hand. Today, these hulls are showing no signs of construction failure. As time went on, other manufacturers got into the glass game and started to develop hulls constructed of a “sandwich” laminate which consisted of an outer layer of FRP (fibre reinforced plastic) then a core material, usually end grain balsa wood and a inner layer of FRP.

This type of lay-up was used for many reasons, mostly because of the cost factor, as a cored construction hull was less expensive to manufacture than a solid laminate of FRP. This also resulted in keeping the boat’s weight down to improve fuel economy. Sandwich cores were the standard type of construction for quite a few years and are still being used today. A few years back, manufacturers started to experiment with different types of core materials such as polyurethane foams and other various man made materials, again to save on costs and to further reduce the vessel’s weight for better fuel economy.

What does this mean to the boat owner??

Over time, water can get into the core material of the hull and decks and cause a multitude of problems, from delamination of the layers to total laminate failure if not noticed and repaired promptly. Water can get into the core material in many ways, from poorly installed thru-hulls, cracks and gouges caused by collision damage or through deck hardware and fittings not properly bedded in the sealing compound. Once the water migrates into the core material it will stay there and, over time will cause all kinds of headaches for the boat owner.

Another big problem with FRP hulls today is “osmosis“. This is a condition that results from water migrating into the outer layer of the hull and creating gelcote blisters below the waterline. The blisters can range in size from small “crescent moon” shaped gelcote cracks to big raised bubbles the size of a pop can bottom. Osmosis is caused by water entering the outer laminate and seeking out the dry areas of the matting, soaking into the strands of fibreglass. Most of the severe cases of osmosis can be contributed to poorly manufactured hulls, where the fiberglass matting was not properly wetted out with resin during the lay-up of the hull, this is a common problem. Boat builders today do not construct boats the way they did back in the 60’s and early 70’s. I have seen boats not even a year old suffer from some of the worst blistering possible !!! All the major boat building companies have blistering problems with some of their hulls; no one boatbuilder is any better than the other.

Most cases of osmosis are not fatal to the structural integrity of the hull, but should be addressed and repaired as soon as possible. The problem with osmosis is that it will create a stumbling block if you ever try to sell your vessel. Most smart buyers will obtain the services of a Marine Surveyor, and upon a “out of the water inspection” this condition will be noticed. I have seen a lot of deals fall apart due to an osmosis problem. Most times the owner will say “I never knew the boat had osmosis” and he is probably right, because he never inspected the hull bottom for blisters. To the layman’s eye this problem could go unnoticed. An “up close and personal” inspection of the bottom may not be possible due to various reasons, such as heavy layers of anti-fouling paint, or the bottom being covered in algae. Marine Surveyor’s have the knowledge and experience to look for these kinds of problems. If you are selling your vessel and you know that your boat has blisters, beware. This problem will be picked up by the Surveyor and will become an issue when negotiating over the price, believe me I have seen this happen many times.

What can you do as a boat owner?

We offer all kinds of services for your fiberglass vessel, which include “guaranteed” professional osmosis repair, delamination solutions, re-bedding of underwater thru hulls and deck fittings, core replacement for hulls and decks, stringer, bulkhead and transom replacement. We also offer full gelcote repair services for any kind of fiberglass boats from PWC’s up full size cruisers.

Keywords: Boat, fiberglass