The Holy Grail of hull coatings

Many shipowners have been asking for one thing – bring back TBT antifoulings. To say that the now-banned biocidal coatings were perfect is certainly an exaggeration, but the general feeling is that however hard the industry has tried, it hasn’t produced a hull coating that works as well. TBT is still used as a benchmark against which other coatings are measured, and mostly found wanting.

There are those who say that the ban was not necessary. They have a good point; the areas where TBT caused serious damage to the marine ecosystem were mostly where vessels were moored for long periods, i.e. yacht marinas. It’s a fact that most pleasure craft spend most of their time at their moorings, whereas merchant ships are continually on the move. So the TBT that leached into the sea from ships was widely dispersed. But whatever the rights and wrongs of this argument, such is the strength of the ecological lobby that we can forget about having the TBT ban reversed.

There could be good news on the horizon, though. One paint company, International, has just launched a product range which it says replicates the performance of TBT virtually exactly. That means it is an efficient biocide, with constant performance throughout the lifecycle – which can be extended to 90 months where this is appropriate. It is apparently only slightly affected by changes in sea temperature, and it works to provide, and maintain, a smooth, low-drag surface to help save fuel. Is this the Holy Grail of hull coatings? If it does what the makers claim – and we are told that the claims have been put to the test in trials carried out with some of the big names in shipping – the answer could be yes.

Of course, premium performance comes at a high up-front cost. But International maintains that the system’s benefits result in vary fast payback of the high capital investment, and we do need to consider the cost per square metre of application – including surface preparation – as well as just the cost of the paint. This does mean that only those owners in a position to afford the investment will fully benefit; potentially bad news for those who rely on bankers to provide the scarce finance.