By Geoff Fein
The Navy is turning to commercial technologies to find ways to reduce fuel consumption in the fleet.
Naval Sea Systems Command has two efforts, one looking at what the Navy is doing now to help reduce fuel consumption and the other looking at technologies that the commercial industry might be using that the Navy could examine to at least validate that concepts are providing fuel savings, how much fuel savings, and if the technologies could be incorporated onto service vessels, Petter Kristiansen, Program Manager Fleet Readiness, Research and Development Program, told Defense Daily in a recent interview.
One technology that has been adopted by the Navy are stern flaps for surface combatants, he said.
“We have done them on CGs, DDGs, FFGs in year’s past, and they have proven to be effective in saving fuel,” Kristiansen said.
Stern flaps on a DDG-51 saves $365,000 to $450,000 per ship on an annual basis, he added.
The stern flap is a relatively small appendage at the stern of a ship that helps the vessels travel through water. “It eliminates resistance…it glides through the water better,” Kristiansen noted.
The Navy is installing stern flaps now on LSDs and LHDs. That effort could result in a cost avoidance of around $6.3 million, he added.
“One of the things we are looking at now is underwater hull coating that helps reduce the bio-fouling that occurs,” Kristiansen said. “When you get barnacles on the hull over a period of time, it can tend to slow the ship down. You have to clean it, so there is a maintenance cost involved with cleaning it. The cleaner you can keep the hull, the smoother it is going to go through the water.”
Commercial industry uses that coating, and while it may work for Navy vessels, there are some things, Kristiansen said, that the Navy will have to take into consideration.
“We operate a different profile. We don’t generally go as fast as commercial ships go on a steady basis…our speeds vary,” he said.
The other commercial technology is in the hull hydrodynamic area–propeller coatings. This coating is used not only by commercial ships but by Military Sealift command (MSC), too, Kristiansen added.
“We were tracking some propeller coatings that MSC has done to see how [they] perform. We have a project looking at coating propellers because they, too, foul and we have to clean those periodically to keep them clean,” he explained. “And, we are not only looking at making the propeller stay cleaner longer, but also [reducing] the cost associated with cleaning those.”
Other areas being considered include improving the efficiency of steam engine boilers. Older, large deck amphibious ships use steam boilers.
“What we are looking at is improving the efficiency of the boiler though monitoring the air-fuel mixture to burn cleaner,” Kristiansen said. “The cleaner you can burn, the more efficient you are. Give it too much air and your efficiency goes down. So that is what we are looking at on the steam boilers.”
The Navy hasn’t put the undersea coating on any ships, he added.
“[We’re] looking to do that, quite frankly, over the next several months to a year. That’s one of the proposals we had to define better over FY ’08,” Kristiansen said. “We just refined that proposal a couple of weeks ago. That’s one I am starting to work on this fiscal year and get it onto a ship.”
Kristiansen wasn’t sure of the exact time frame for getting the coating on a ship since it depends on ship availability because it requires dry-docking.
“We have the propeller plan for ‘a’ ship, starting in the next month or so, but that’s in an availability so it won’t be out for a few months,” he added.
The propeller coating will be evaluated on the USS Gunston Hall (LSD-44), Kristiansen said. ” It’s in her work package.”
Another idea Kristiansen is looking at, and one of the proposals he will look at for next year, is lighting. He is looking at light emitting diodes (LED) as well as solid-state lighting to replace ship lighting.
LEDs could replace fluorescent bulbs used for bunk lights and incandescent lighting used in passage ways.
“We are looking at that to see how we can install solid-state lighting. That has both a maintenance [benefit] and you reduce your energy load,” Kristiansen added. “We do it at home, so we are looking at that in the Navy, too, to see how that can be done in a cost effective way. That’s one people can relate to.”