Osmosis Treatment and Prvention

Almost all glassfibre boats which are not protected will develop some degree of osmotic symptoms at some point in their lives. Pedros Yacht Refinishing is an approved Osmosis treatment centre for Blakes able to treat any problems you may find.

Osmosis is the physical process whereby a liquid is drawn through a semi-permeable membrane. The degree of osmosis will depend on different factors such as the temperature of the water, type of water, how much time the boat is afloat and also the quality of the original GRP. Osmosis can also be caused by bilge water from the inside so it is worthwhile trying to keep your bilges dry.

The first signs an owner will see are blisters forming in the gel coat and a good guide as to whether or not the blisters are osmotic will be to pierce them – the liquid content will have a sour smell similar to vinegar. Once the gelcoat is breached, the underlying laminate is capable of absorbing water like a sponge.

Professional advice should be immediately sought to find out the degree of the problem and any action which should be taken. But prior to actually finding the blisters, the moisture content of a hull can be checked by using a moisture metre and treatment therefore carried out at an earlier stage. Once a boat has osmosis, full treatment consists of the total removal of the gelcoat so the hull can dry out.

Pedros use different drying methods as part of the treatment process for osmosis. HotVac drying machines removes and absorbes water from the affected hull along with acids, glycols and other organic compounds which cause corrosion, weakening of the glass and resin bonds, delamination and blistering.

HotVac heaters are held in place against a boat’s hull and apply an intimate and uniform heat to a tolerance of ±1°C. The high vacuum created lowers the vaporisation temperature of moisture and impurities and pumps away the materials as a vapour which ensures there is no surface contamination and no extra cleaning is needed.

Steps can also be taken to ensure boats do not get osmosis. Although this is sometimes carried out at the boat building stage, a preventative epoxy coating can be applied to used boats.

At Pedros Yacht Refinishing, Blakes products are applied to a new or sound hull to protect it from osmosis. This costs a fraction of the possible re-laminating treatment once a hull has osmosis and needs a full repair.

If you wish to carry out the work yourself, Pedros can supply the products needed.
While this preventative work is being undertaken, the moisture levels can be tested which will detect a potential problem in its early stages so treatment can be carried out.
If you are buying a used fibreglass boat, always have it checked for osmosis.

Why not contact Pedros for a quote?