Great Lakes Ice Coverage Is The Smallest In Decades
by John Konrad (gCaptain) The U.S. rang in the new year with an unusually mild January 2021 that tied with 1923 for the ninth-warmest January on record. The warmth was...
In keeping with the arctic theme, this weeks Interesting Ship is the United States Coast Guard Cutter Healy (WAGB-20). The ship is a research icebreaker that was first put into commission on November 10, 1999. Healy provides more than 4,200 square feet of laboratory space, numerous electronic sensor systems, oceanographic winches, and accommodations for up to 50 scientists. It is capable of breaking 4 1/2 feet of ice continuously at three knots and can operate in temperatures as low as -50 degrees F.
After Healy’s construction by Avondale Industries in New Orleans, LA, Healy performed sea trials off of San Juan, Puerto Rico and in the Baffin Sea between Canada and Greenland. It finally joined the rest of USCG Cutter fleet, Polar Sea and Polar Star, at its home port in Seattle and put on “Commission, Active” in August of 2000 following a transit of the Northwest Passage.
The USCG Cutter “Healy” utilizes technology provided by OmniTHRUSTER Marine Maneuvering and Propulsion Systems. gCaptain.com had the opportunity to speak with Kurt Widmer, President and COO of Omnithruster Inc., about their Omnithruster’s JT2200IB and its use on the USCG “Healy”.
Kurt, could you tell us about how the Omnithruster JT2200IB works?
“The operating principle of the waterjet thruster is based on Newton’s third law of motion, which states, “to every action there is an equal and opposite reaction.” When the prime mover starts, seawater is brought into the thruster through the inlet grating/seachest at relative low velocity in order to minimize the ingesting of debris. Seawater travels through the kinetic converter at high head and moderate velocity thus reducing the losses due to turbulent flow. It then flows through the discharge ports which contain two 54″ hydraulically actuated butterfly valves. These valves modulate the discharge flow to the port side, starboard side, or both sides of the ship. At the ship’s hull, seawater is accelerated through converging nozzles, accelerating the water velocity. The accelerated water mass provides a reactive force acting on the ship’s hull. The direction and thrust magnitude is controlled by actuating the steering valves. The Healy thruster is also designed to operate in hull lubrication mode. In this mode of operation, 24″ valves open to allow water to pass through approximately 20 specially designed nozzles located along the bow of the vessel. Discharged sea water is introduced at the hull/ice interface reducing the friction during ice breaking operations.”
What other notable ships employ your Omnithruster water jet maneuvering systems?
Omnithruster systems are in use worldwide. Some notable installations are on the US Navy MCM (Mine Countermeasure) class vessels, as well as in all the Japanese Maritime Self Defense Force mine sweepers (MSO and MSC class).
Do you have any interesting facts or stories related to the Omnithruster JT2200IB for our readers?
“One interesting fact… The Omnithruster JT2200IB discharges 135,000 gallons of water per minute of operation. This is enough water to fill up an olympic size swimming pool in 4.89 minutes!”
You can find out more about Omnithruster’s at Omnithruster.com
(Healy is currently still active in the USCGC fleet and its missions, along with the rest of the fleets can be found HERE.)
Great Video from Healy from 2007 Summer Cruise
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