There has been growing market uncertainty about the ability of new TBT-free (Tributyltin) antifouling to offer the same range of benefits as TBT-based antifouling.
Jotun Paints has responded to this by advising shipowners and operators to seek the recommendations of coating manufacturers before applying TBT-free antifouling treatment to ship hulls.
In the past, the antifouling option was more or less a clear-cut decision, says Jotun, as the market offered products based on either synthetic polymers or rosin.
Currently, however, shipowners face an increasing range of diversified technologies.
"Determining the correct antifouling and the appropriate pre-paint procedure is becoming a very complicated issue. Jotun Marine Coatings is being approached by an increasing number of shipowners and operators seeking advice on new products now flooding the market and how these new technologies will affect the treatment of underwater hulls," says Frank Mohn, director of Jotun Marine Coatings.
"This requires a detailed understanding of the various types of antifouling technologies being supplied by all manufacturers of anti-fouling.
Owners can expect
self-smoothing, self-polishing, no build up of leached layers, predictability and tailor-made solutions from the antifouling system, says Jotun.
Since 1999, when the IMO adopted the resolution to phase out organotins used in marine coatings, paint suppliers have been scrambling to develop and introduce alternative anti-fouling paints in time to meet the 1 January 2003 deadline, something that has proved far from easy, says the company.
The result, according to Jotun Marine Coatings, has been a "divergence in technology offered for sale."
Along with this has come questions about the mechanism and properties of new TBT-free products.
Now, many end-users are concerned about making wrong decisions and having to live with less than good results, says Mohn.
From now until 2008, thousands of vessels with TBT-based antifoulings will drydock.
The way these are handled, prior to application of new antifouling, will remain uncomplicated and offer no more challenge than it does today.
The real challenge for end-users is the wading through the wide choice-range of new TBT-free coatings and finding the best solution in order to control and limit the presence and extent of a leached layer on existing antifouling, says Mohn.
Applying a TBT-free antifouling where one is unable to control the leached layer development, will result in drastic consequences such as popping or cracking/detachment of newly applied coating.
This gives a surface covered in pin-holes, unbroken bubbles and craters that contributes to increasing surface roughness, says the firm.
"It is natural and easy, to understand a shipowner's concern when proven products are being replaced by alternative technology, some of which have only been recently developed.
"End-users have taken excellent antifouling performance and smoothing properties for granted but one should not assume that new TBT-free paint arrivals will offer both of these properties, some may not offer either of them," Mohn comments.
The best TBT-free antifouling offers a precise balance between the rate of release of soluble components and the polishing rate, but "some technologies on the market may not give the same degree of control as others," says Mohn.