Certain vessel areas typically receive more attention than others when it comes to the selection of the coatings system. For instance, an inappropriate coatings scheme in the holds of a bulk carrier can decrease cargo carrying flexibility, increase corrosion potential and survey frequency plus reduce the asset value of the vessel.
Equally, if the vessel’s antifouling system does not perform there can be a significant rise in vessel fuel consumption and associated cost. Whilst stained, faded, mechanically damaged and corroded external above water areas do not normally impinge on the asset value of the vessel (and are not on the critical list for surveyors or port authorities), they too can incur considerable cost if not properly protected, as well as contributing to a vessel that does not maximize a positive image of the ship operator.
The condition and appearance of the topsides, external decks and superstructure is largely dependent on the attitude of the operator concerned. Aesthetics are critically important to some operators e.g. cruise, ferry and container vessel operators, while of less significance to others. Despite this, the topsides, external decks, and superstructure are an important advertisement for any operator and may be judged as an indicator of the general standard of vessel maintenance and operation.
Whilst most vessels leaving the drydock generally look good with newly applied coatings, exposed areas will be subjected to a wide range of operational and climatic conditions:
Vulnerable areas, in particular on decks and around the bow and boottop will be regularly subjected to mechanical damage, caused for example by cargo loading and unloading, fender damage, anchor chains and cables. Conventional coating systems offer little protection against mechanical damage – and can give rise to the rapid onset of corrosion and unsightly rust staining.
Whilst the basis of a good topsides coatings system is theanticorrosive, the choice of cosmetic finish should also be carefully considered. Single pack alkyds for instance have very good initial gloss characteristics but cannot withstand chemical attack. Acrylic finishes have better chemical resistance (e.g. to acids and alkalis) than alkyds but tend to soften at higher temperatures, quickly lose gloss and have poor solvent resistance. Such finishes are usually chosen for their lower cost per litre rather than long term durability.
Coatings Build Up
Extensive and frequent repairs with inappropriate coating systems will, with time, lead to coatings build up with a possible loss of system integrity and potential detachment. As traditional coatings offer only limited protection and cosmetic longevity, coatings choice for such highly visable areas should be very carefully considered.
Interfine 979 inorganic acrylic polysiloxane represents the latest advances in super durable, high performance cosmetic finish technology.
Polysiloxane Technology: Interfine 979
Originally developed for the very demanding offshore market and the result of many years of dedicated research, proven and patented Interfine 979 inorganic polysiloxane represents the latest advances in super durable, high performance cosmetic finish technology. When applied in conjunction with the unique Intershield 300 abrasion resistant, aluminium pure epoxy primer the system offers excellent cosmetic properties and corrosion resistant protection – even in the most aggressive marine environments. The chemical bonding within organic coatings such as epoxies and polyurethanes is carbon based. The main chemical bond in inorganic polysiloxane Interfine 979 is silicone based which is relatively much more stable and better able to resist attack from the ultraviolet (UV) radiation present in sunlight.
Polysiloxane coatings are usually modified in order to improve flexibility, application properties and appearance. The first generation of polysiloxane coatings were modified with epoxy resins. Interfine 979 is a second generation polysiloxane and is modified with an acrylic resin. In comparison to epoxy modifications this acrylic modification results in a polysiloxane coating which is more resistant to degradation by UV light. Despite showing slightly lower initial gloss than polysiloxanes modified with epoxy resins, this increased UV resistance results in improved gloss retention and colour retention over time producing a polysiloxane coating with excellent durability.
Interfine 979 offers unrivalled durability on extended atmospheric exposure. In comparison, typical organic cosmetic finishes (including recoatable polyurethanes) are relatively less durable losing both gloss and colour at a rate up to four times quicker than Interfine 979.
Interfine 979 Test Data
The following graph shows typical values of gloss retention for the same colour (shade) of different cosmetic finishes subjected to accelerated (QUV-A) weathering testing over a 60 week period.
In the future, Interfine 979 inorganic acrylic polysiloxane technology will revolutionise the standards by which high performance cosmetic finishes are measured.
Interfine 979/Intershield 300
When applied in conjunction with Intershield 300 abrasion resistant, aluminium pure epoxy primers, the system offers excellent overall cosmetic properties and protection from corrosion.
Additional Key Features
The patented Interfine 979 inorganic acrylic polysiloxane polymer network also provides additional key features, including good edge coverage, flexibility and resistance to mechanical damage, high volume solids content, low VOC* emissions, high film build capabilities and complete freedom from isocyanates. The outstanding long term cosmetic properties of Interfine 979 offer enhanced operator image and control of maintenance costs. Interfine 979 is suitable for external above water areas (including boottops) on all vessel types but is of particular benefit where operator image and premium asset protection are of critical importance, e.g:
• Cruise Ships
• Government Vessels
• Passenger Ferries
• Container Vessels
• Ro-Ro Vessels
• Reefer Vessels
Interfine 979 is suitable for all vessel types but is of particular benefit where operator image and premium asset protection are of critical importance
Epoxy Acrylic Technology: Interfine 691
For vessel operators and shipyards currently using two-pack recoatable polyurethane finishes – and where an alternative product, offering equivalent long term cosmetic properties and durability but without the use of isocyanate curing agents is of interest, International Marine Coatings offer Interfine 691. Interfine 691 is an epoxy acrylic cosmetic finish suitable for external above water areas (including boottops) on all vessel types. Interfine 691 is especially suitable where typical recoatable polyurethane performance is required over extended in-service periods, but the use of isocyanate cured coatings is not acceptable and the additional durability offered by Interfine 979 is not required.
Interfine 691 Test Data
The following graph shows typical values of gloss retention for the same colour (shade) of different cosmetic finishes subjected to accelerated (QUV-A) weathering testing over a 2,600-hour (16 week) period.
Interfine 691 has been developed to provide an alternative isocyanate free finish to the well established Interthane recoatable polyurethane systems
Additional Key Features
Interfine 691 is surface tolerant, offers extended recoatability and can be applied directly to most existing cosmetic finishes and a range of anticorrosive systems. Practical applications have confirmed excellent application properties and the product has good resistance to early water spotting.
Interfine 691 may also be applied at temperatures down to -5°C. At these lower temperatures, the product drying times are faster than typical recoatable polyurethane systems.