USS Forrest Sherman Undergoes Underwater Hub Change Out

Carrier Strike Group 12’s commander visited Arleigh Burke-class Aegis destroyer USS Forrest Sherman (DDG 98) during an underwater hub change out at Mid-Atlantic Regional Maintenance Center (MARMC), Naval Station Norfolk, Virginia, Nov. 5.

Rear Adm. Andrew L. Lewis observed divers who were using a new cofferdam to perform the change out.

MARMC Dive Teams Delta and Bravo began working around the clock mid-October to replace Forrest Sherman’s existing propeller blades and hub, in order to keep Forrest Sherman mission ready for 2015.

Lewis said:

Having this ship fixed without any hindrance or restrictions, as soon as possible, within the repair plan and having the ship underway, being able to fight is what it’s all about.

MARMC Diving Officer Chief Warrant Officer 3 Tim Andros said:

Normally, this job would be done in dry-dock, but with the invention of this new type of cofferdam, it allows us to do this job underwater.

The cofferdam provides a dry environment in which divers can work, and protects all equipment so there is no water intrusion when divers remove the hub of the ship.

Andros added:

This is only the second time this job has been done underwater in the Navy, and is the first time this job has been done underwater on an Arleigh Burke-class guided missile destroyer.

MARMC divers completed the first underwater hub replacement to Oliver Hazard Perry-class guided-missile frigate USS Taylor (FFG 50) in Souda Bay, Greece, earlier this year, giving them experience for this job on Forrest Sherman. Although the two jobs are similar, the configuration on the bottom of each ship is slightly different; a frigate has one screw where a destroyer has two, affecting how the cofferdam fits underneath the ships.

The hub replacement is expected to be complete later this month.

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Press release, Image: US Navy