7590 Hempadur Fibre 4760 brochure_REN2.indd - Net

Example of the development of cracks and subsequent corrosion in a
conventional epoxy coating applied with an excessive dry film thickness.
The ballast tank challenge
Ballast tanks account for a significant part of the total surface
area of a ship on which protective coatings are required. Yet
ballast tanks are among the most complicated areas to coat
because of their sheer size and design, and because access
is often difficult.
The design and location of ballast tanks also make them difficult
to inspect while the vessel is in service, as well as making
maintenance and repair both difficult and expensive. It is therefore
important to ensure that only a minimum of maintenance is ever
required by applying coatings that are extremely durable.
The combination of vibration in the hull structure, alternate
wet and dry cycles and the ship’s movement in the water
often causes or enhances cracks in the conventional types of
coatings used for ballast tanks.
Another common source of stress on the ballast tank coating is
the thermal variations caused by loading and unloading ballast
4
water or cargo, with temperatures often very different from
that of the tank structure. The parts of the tank most severely
affected are normally along edges and in corners, where the
coating is often applied in a thicker – sometimes excessive
– layer, which greatly increases the risk of cracking.
HEMPADUR FIBRE 4760 is designed to drastically reduce the
likelihood of such cracking, due to the greater flexibility and
tensile strength of this special coating.
Vibration in the hull and the ship’s
movement in the water often
cause cracks in conventional
ballast tank coatings.