Wired – by Keith BarryA new Norwegian ship aims to counteract rough seas by making its own waves with internal water tanks.
The so-called “hotel ship” is being built for marine services provider Østensjø, and is designed to accommodate workers servicing offshore oil platforms. It’s 500 feet long and has room to house and entertain 800 workers, complete with a gym, sauna, two pools, and office space. And those accommodations should be comfortable no matter how high the seas get, thanks to U-shaped water tanks integrated into the ship’s hull that create waves to stabilize the vessel.
“The tanks are filled with water, which is set in motion in opposing phase to the wave forces acting on the hull,” said Sverre Anders Alterskjær, a research scientist at Marintek, the Norwegian maritime research and development agency that tested models of the new ship.
Air valves at the top of the tanks determine the movement of the water in the tanks. Just as a sailor’s sea legs constantly adjust to the pitch and roll of a boat, the motion of the water in the tanks is calibrated to match the strength of the waves on the sea. That helps the ship stay stable.
But stability isn’t just for comfort. Oil platforms can need service even in the roughest seas, and getting from the maintenance ship to the platform can be dangerous.
“The most important thing has been to improve the efficiency and safety of the connection between the offshore installation and the gangway, which is as much as 55 meters [180 feet] long,” said Johannes Eldøy of SALT, the maritime design firm who penned the new ship. “This is a critical point because the vessel must display the least possible vertical motion in response to the waves while at the same time maintaining its position.”
In order to keep the ship from moving, designers added six GPS-controlled azimuth thrusters propellers that can rotate on a vertical axis for maximum maneuverability. They’ll also work to counteract moving waters to ensure the ship stays in one spot.
The ship is currently being constructed by Hyundai Heavy Industries, and is expected to be delivered by June of 2015.
Photo and video courtesy of Marintek.