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Coatings
Box cooler maintenance : From a 21- day schedule to an 8-day turnaround
Cooling various strong engines and motors of a vessel with only limited space in the hull available requires compact heat exchangers .
The box cooler with its compact design installed in the sea chest on the side of a ship ’ s hull is a space-saving and efficient solution .
By Christoph Fischer-Zernin - Commercial Director , SÄKAPHEN
Due to the use of sea water as coolant and since the box cooler requires lesser energy to operate , the box cooler can be considered an eco-friendly choice , helping to reduce a ship ' s carbon foot print . Their rugged design enhances the resistance to the harsh operational conditions in the marine environment and in combination with the good maintainability it makes the box cooler a sustainable solution throughout the life cycle of vessel . The expected life cycle of a box cooler is usually 15 years , even though Nederlandse Radiateuren Fabriek ( NRF ), inventor of the box cooler , has found units from the 1960s that are still in operation .
Coating under harsh conditions Since box coolers are made of a copper nickel alloy and are installed in carbon steel sea chests , there is a huge potential
A box cooler coated with Säkatonit Extra AR-F after 5 years in service , prior to pressure washing . The vessel operated in cooler water which can be derived from the amount of marine growth .
A box cooler coated with Säkatonit Extra AR-F after 5 years in service . The cooler has only been pressure washed to remove marine growth . The smooth surface of the coating eases the removal of barnacles and other organic growth .
of galvanic corrosion due to the dissimilar metallurgy . Thus , it is very important to apply a protective coating not only in the sea chest but also on the surface of the box cooler to avoid such galvanic corrosion . The importance of a very good insulation between box cooler and ship hull was stressed in 2016 by DNV GL , an internationally renowned classification society . Hence a coating solution for box cooler not only has to be resistant to the harsh operational conditions in the marine environment , which is not only sea water or brackish water , but also has to withstand the mechanical stress caused by the flow of water through the cooler tubes with the velocity of the sailing vessel as well as the vibrations and air bubbles potentially causing cavitation . Moreover , the coating has to withstand the permanent electrical stress caused by the ICAF system , a system impressing an electrical current into a copper anode to reduce fouling and marine growth on the coolers .
Case study : Scandinavia Having applied baked phenolic coating on box coolers since the early 1970s , Säkaphen was contacted by a Scandinavian vessel operator back in 2016 to provide a re-coating solution that is available in all geographical key regions of operation of their fleet of offshore supply vessels . The vessel operator not only wanted to reduce docking times but also wanted to avoid sending coolers , partly by air freight , back to Europe for maintenance – a costly but still understandable undertaking considering the immense docking costs that can accumulate to up to 50.000 € per day for an extension due to delays . www . heat-exchanger-world . com Heat Exchanger World April 2023
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