|Over Russia and Around the World|
Part 2: Hull plating more than half-inch thick
Story and Photographs by Alex McMullen — February 2002
Cowper decided at an early stage that Polar Bound should be built of aluminum because of its strength-to-weight ratio as well as other reasons. "It's better in ice because it's more ductile; it will bend rather than crack or tear," he explains. "And aluminum welding stands up much better to extreme low temperatures." Hull plating is more than half-inch thick, three quarters of an inch where it's most likely to come into contact with ice. A honeycomb of closely spaced frames and stringers gives the whole structure rigidity and enormous strength.
The builder, New Century Marine in Scotland, specializes in aluminum construction, but Polar Bound still represented a major challenge. Managing director Edwin Payne reckons the boat is 12 times stronger than any conventionally built aluminum boat. His expert team spent nearly 5,000 hours applying the continuous welding that holds the boat together; there's more than a mile and a half of the stuff along the frames and stringers alone.
The boat's designer, Dennis Davidson of Murray Cormack Associates, another Scottish company, gave the hull a rounded, flared shape that, instead of being squeezed by the ice, should be forced upwards, relieving its vise-like pressure. The deck and superstructure are also designed to cope with the worst the elements can throw at them. Deck fittings, such as the high swan-neck vents and heavy-duty guardrail stanchions, wouldn't look amiss on a small freighter. The windows in the purposeful wheelhouse derive their strength as much from their small size as from the thickness of their glass and Makrolon polycarbonate construction.
Determined to install a single Gardner diesel in the boat, Cowper had to buy a remanufactured one; these classic, famously reliable engines, two of which powered his old lifeboat, are no longer made. Since mechanics will not exactly be lining the route of her long voyage, reliability is of paramount importance. "With a Gardner you shouldn't have any problems if you have clean fuel and oil filters and keep the fuel in the tanks clean," Cowper says. "I will be filtering all the fuel as it goes into the vessel."
The 170-hp Gardner 8LXB pushes Polar Bound up to 9 knots at its maximum 1500 rpm. On long passages Cowper will set the throttle to give 1100 rpm and about 7 knots, for a fuel consumption of less than 3 gph. With 2,380 gallons in the main tanks and another 900 gallons in jerry cans, the boat has a potential safe range of about 7,000 miles.
This article originally appeared in the January 2003 issue of Power & Motoryacht magazine.