The US Navy has found and tested a fix for an engineering problem that sidelined USS Zumwalt (DDG-1000) several times during the ship’s voyage to its homeport, Zumwalt-class program manager Capt. Kevin Smith said on Tuesday.
During its transit, Zumwalt’s lube oil chillers failed resulting in water leaking into the propulsion system several times – once resulting in loss of power moving through the Panama Canal. The seawater lube oil coolers prevent the lubrication of rotating shafts from breaking down due to heat and friction “Like other ship platforms today, when you mix seawater with steel… bad things can happen,” Smith said.
“What we did was shift to fresh water for the coolers. Before we got to San Diego we realized that’s one way of fixing this problem. It’s not a large demand on cooling so we decided to go down that path.” While the complex electrical propulsion system on the ship was extensively tested pier-side at the General Dynamics Bath Iron Works shipyard, the lube oil chiller problem was only discovered after the ship had spent time underway, Smith said. The Navy tested the fresh water fix to the chillers during two underway periods the ship has had since it arrived in San Diego in December. Smith said the periods proved the repair worked and the change has been implemented on the under construction MICHAEL MONSOOR (DDG-1001) and LYNDON B. JOHNSON (DDG-1002).
“As far as ships two and three – and Bath can attest – we’re making sure to make the temporary changes now to make sure we don’t have any issues with the class,” he said. In the longer term, Naval Sea Systems Command is evaluating a longer-term solution to ships beyond the three-ship class. “We are looking at next generation, what do we want to do as far as new cooler design,” Smith said “Not just for this ship but for other ships in the Navy. There are other things we’re looking at a better MILSPEC standard cooler that we can put in that will last the lifecycle of the ship – 30 plus years.”
Zumwalt is in San Diego undergoing a maintenance period in which the ship’s combat systems will be activated and tested ahead of a planned first deployment in 2021.