Cold temperatures heat up development
Fri, 09 January 2015
Although cold-climate deck machinery design may remain superficially the same as more traditional equivalents, “it often takes a very different philosophy” said Marijo Bućan of Adria Winches.
Adria has so far been involved in 43 cold-water projects which means the company has installed around 120 or so different types of anchor, towing and specialised winches alongside other deck machinery on everything from arctic research and offshore vessels to Russian military craft.
However, he told MJ that ‘cold’ doesn’t translate easily into just one set of parameters and challenges remain diverse.
There’s the more obvious issues like the need for redundant capacity on elements like oil bath heating, simply because in these conditions, temperature becomes critical. Further as hot water is often used to de-ice the gearbox these have to be completely enclosed to avoid the hot water stripping the grease from the gears - and polluting the surrounding water.
But less obvious is what happens to the electronics explained Mr Bućan: this starts to display some distinctly odd behaviour as the temperature drops. “Semiconductors in particular have different characteristics, one will be fine down to -20°C degrees, but there’s another kind for the -20°C to -40°C band, and yet another type for temperatures below that,” he said.
Further, gaskets and sealing elements can run into trouble at low temperatures, forcing a change in materials: silicon for example is often used to take over from the more common elastomeric products.
Then there’s the well-known difference in metals: the impact resilience of most steel starts to drop at -20°C. Mr Bućan added: “If you don’t install the proper material, it can become as brittle as glass.” Because of this, failure is catastrophic; the metal snapping without warning.
Further, while finding metals to deal with temperatures down to -40°C degrees isn’t so difficult, if there’s any chance at all that the vessel may encounter extreme cold, down to -50°C working temperatures, class society certified steels become a challenge. “These are hard to come by simply because the demand is not so great,” said Mr Bućan, plus of course sources have to be found for every kind used; plate, bar, forging and casting metals.
And then there’s the relative difficulty in finding certified, explosion-proof motors: “It’s not that they are so hard to make, but that certification is a long, expensive process, and very few manufacturers are willing to take on the burden for such a limited market.”
Finally, it seems that getting hold of the right elements with the necessary documentation means getting the suppliers lined up: “You simply can’t leave finding your sources till the last minute,” concluded Mr Bućan.