Thor-Coat
Thor-Coat was specifically developed to complement Thordon's COMPAC seawater lubricated propeller shaft bearing system by providing corrosion protection for a ten-year period in service, potentially eliminating the need for the current 5 year shaft withdrawal and inspection. A toughened, 2-part epoxy coating, Thor-Coat is three to nine times more flexible than existing products currently in use. Thor-Coat addresses the problem of premature coating failure resulting from reversing rotational loading. It is also used as a coating for rudder stocks.
Thor-Coat was subjected to the full scale 180° bend and did not crack. All other coating products tested showed initial cracking at a much lower bend angle. In a propeller shaft application, or in other similar applications where a coating must be durable, yet flexible, Thor-Coat’s enhanced elasticity and toughness provide enhanced corrosion protection over longer service periods.
The fiberglass/epoxy-based coatings commonly used are quite brittle and not sufficiently flexible to withstand long term shaft flexure resulting from bending and torsional stresses that occur during operation. This failure usually occurs initially at the joint between the coating and shaft liner. Once the coating cracks, seawater often migrates along the shaft resulting in significant non-visible corrosion. This is a major concern with open system propeller shafts that, currently, must be withdrawn and inspected every 5 years. If there is evidence, or even suspicion, that the coating is cracked or damaged, the shaft must be stripped, repaired if necessary and re-coated.
Should Thor-Coat suffer impact damage, it tends to fail locally resulting in some of the coating remaining on the shaft continuing to offer corrosion protection. If the coating is damaged to the point where corrosion does occur, the corrosion is limited to the damaged area only and will not migrate along the shaft under the coating to unexposed areas. Localized damage can be easily repaired if necessary.
Thordon is also working closely with the Classification Societies to develop approval for techniques, such as borescoping, that facilitate inspection at the five year docking with the shaft in situ.
Thor-Coat can only be applied to shafts using certified Thor-Coat applicators.