Fuel Costs Drop with New Generation of Coatings

File image courtesy International Paint

Published Nov 16, 2016 3:33 AM by The Maritime Executive

Cost-conscious shipowners are always looking to cut fuel consumption, especially when day-rates are low. This demand drives innovations in hull coatings, as less fouling means less drag – but better coatings have historically come at a cost, either for the owner or for the environment.

In decades past, organotin-based paints kept the flora and fauna off at an affordable price, but they also had negative effects on aquatic life in general. These coatings have long since been banned and replaced by paints containing copper-based biocides, which conform to regulations but are typically less effective than the organotins of yesteryear.

AkzoNobel’s International brand has come up with a coating that they say can solve the problems of cost, fuel efficiency and environmental impact all at once. The firm's new Intersleek 1000 promises up to six percent fuel savings over conventional coatings; uses no biocides; has an available performance guarantee; and yields carbon credits for shipowners – credits which can be sold on carbon trading exchanges. All of this comes at about the same price point as a common SPC coating.

How did AkzoNobel get this low-cost, high-impact combination? Its researchers looked to sheep.

The waxy surface of the new paint comes from lanolin, also known as “wool grease,” a natural substance produced by sheep and widely used in skin creams. “Our lanolin supplier removes impurities and guarantees its quality, but it's still essentially a wax from sheep's wool – inherently biorenewable and biocide free. That wax is what gives the coating an ultra-smooth, low-drag surface,” says Robert Wong, director of marketing for AkzoNobel's Marine Coatings Business.

Wong adds that it also has benefits over conventional antifouling paint during periods of layup because it's less prone to hard fouling: it is much easier to clean off barnacles and other difficult-to-remove growth with Intersleek 1000 compared with a typical SPC coating, because it is almost impossible for marine life to stick to the waxy lanolin surface.

Cleaning for speed

Subsea Industries has a different strategy for a smoother hull: cleaning. Subsea’s Ecospeed coating is a hard-wearing, non-toxic paint that is intended to be installed and maintained for the entire life of the ship, like a piece of capital equipment. Ecospeed does not contain biocides to fend off growth, but it can be cleaned as often as required. It is often specified for ice-class vessels, where its abrasion resistance is especially useful and fouling is not an issue.

Interscan, a German firm that operates in the waters of the North Sea and the Baltic, has been using Ecospeed on its ice-classed freighters for years. “Cleaning has not been needed for the northern routes we use. For our ships that sail in warmer waters, the Ecospeed hull does need underwater cleaning from time to time, but we know that after an underwater clean the fuel consumption goes down to what it was when the paint was new,” says the firm's head of chartering, Michael Tensing. In addition, hulls which used to require repainting annually can now go a decade without coating replacement, he says.

For cruise lines, which need to present a clean appearance to their customers, the ability to scrub the waterline as needed and where needed is a valuable asset, Subsea says. The coating is also well-suited to offshore facilities with decadal service cycles, like FLNGs: with the correct application, and with proper maintenance, it can last for a generation or more. 

A silicone-based alternative

Hempel has developed another promising option for long-lasting fuel savings. Its Hempaguard coating – a silicone hydrogel containing a biocide – offers an average of six percent fuel savings and up to 90 months between dockings. The manufacturer recommends it for ships in any trading area and at any speed, including no speed at all. Hempel is so confident in its multipurpose, top-of-the-line coating that it offers a performance satisfaction guarantee: it will remove the coating at the next docking if the shipowner is not satisfied.

“After slow steaming, a good and appropriate hull coating is normally the best fuel saving initiative an owner can implement; and with efficiency gains in mind, return on investment in this sector has never been greater,” says Claes Skat-Rørdam, the firm's fouling control marketing manager. ”Cruise ships, ferries and passenger ships are the fastest adopters of Hempaguard. But increasing numbers of container vessel operators are realising the advantages of Hempaguard’s unique combination of fuel saving and long idle time ability in a single coating.”

Skat-Rørdam says that customer satisfaction with the coating has been consistently high over the three years it has been on the market, and that the firm is pleased to be able to offer its guarantee program. ”We were very proud to be able to offer such a pioneering guarantee and we did it because we have 100 percent trust in the coating’s performance. We will continue to offer the guarantee,” he says.