MARINE & AVIATION

Treatment of Osmosis Problems

Osmosis can be defined as the diffusion of a solvent through a semi permeable membrane from a region of low solute concentration to a region of high solute concentration. Osmosis is a perennial problem affecting the boats and yachts by creating small bumps in the underwater areas. Chances of osmosis are very high in boats which remain in water for a longer period and are dry-docked only for maintenance. Damaging the gel-coat or removing the anti foul also causes osmosis. ‘Osmosis treatment’ thus becomes an integral maintenance aspect of any shipping or marine industry.

Osmosis however does not infect or spread evenly neither does it stop itself. It is a disease which needs to be cured and prevented. Boats use fiberglass mat and a gel-coat layer. Due to osmosis, the water penetrates into the thin vacuum between the gel-coat and fiberglass mat. This solvent now mixes with the binder used to bind the gel-coat and fiberglass making it impossible for it to penetrate inside any further. It then pushes the gel-coat outwards forming a bubble like structure outwards, below the waterline in the boat. This can happen in different areas of the hull requiring osmosis treatment at varied locations. Osmosis can be caused by various factors like poor gel-coat quality, poor laminating, impure fiberglass or even extreme working conditions. Osmosis infection usually starts during the building process of the boat/yacht. Gel coating the hull of a boat sometimes leaves an uneven interior surface. The next step involves fixing the fiberglass on it using a binder. Uneven gel coated surface does not allow the binder to evenly fix the fiberglass mat forming voids due to air bubbles. This causes osmosis.

The cure of osmosis lies with sandblasting. Blasting treats osmosis by removing the rust from areas where the gel coat is not properly backed by the fiberglass. Sandblasting is the best treatment for osmosis as it can be localized to different areas on the hull, reaching out to each affected surface. BlastIt is a mobile blast cleaning company specializing in a range of surface cleaning and etching methods. BlastIt also provides services for cleaning steel, fiberglass and timber hulls, treating them for osmosis problem. Based at Essex, we operate from London and Southeast.
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