The Way The U.S. Coast Guard Replaces Its Largest Ship's Motor Is Mind-Blowing

[mahatmakanejeeves]

Just like locomotives, it's a diesel-electric. I had no idea.

I can't link to pictures in Jalopnik, due to way they're formatted. The pictures are everything in this article.

BOATLOPNIK

The Way The U.S. Coast Guard Replaces Its Largest Ship's Motor Is Mind-Blowing

David Tracy
Tuesday 11:30AM • Filed to: BOATLOPNIK

A fire broke out on the United States Coast Guard’s largest ship last summer, destroying one of the vessel’s enormous electric motors. Now the Coast Guard, one of the five service branches of the U.S. military, is replacing that motor and documenting the entire process, which involves cutting a giant hole in the hull. The whole thing is fascinating. Check it out.

The USCGC Healy is the biggest and most advanced ship in the Coast Guard’s fleet, capable of breaking 4.5 feet of ice at three knots, and it’s equipped with over 4,000 square feet of laboratory space. On August 18, during an Arctic research mission, a fire broke out and ruined a propulsion motor, forcing the research ship to return to Washington State. The Coast Guard breaks down what happened in its memo:

The Healy was 60 nautical miles off of Seward, Alaska, en route to the Arctic when an electrical fire was reported at 9:30 p.m. A fire team disconnected the affected motor, and the fire was confirmed extinguished by 9:56 p.m. The cause of the fire is currently unknown.

[...]

Due to the fire, Healy’s starboard propulsion motor and shaft are no longer operational, and the ship is transiting back to its homeport in Seattle for further inspection and repairs.

Luckily, there were no injuries reported, and there’s still no word on the cause of the fire. What is known is that the Coast Guard will have to replace that broken starboard propulsion motor. It is one of the electric motors that spin the propellers, powered by juice from generators spun by the ship’s diesel engines. “This Design,” the Coast Guard writes, “protects the engines from variations in shaft speeds inherent to ice operations.”

The Coast Guard’s Facebook page for Healy describes the research ship’s powertrain setup and why it uses 35,000 horsepower (combined) electric motors instead of the diesel engines to spin the props:

{snip}

ARCTIC OCEAN
Our mission on Healy
509 views•Oct 3, 2020

Trevor Layman
17 subscribers

Our work is made possible by the members of the engineering and support departments who are not featured in this video.
Music: much respect for Sam Hulick for "Uncharted Worlds" and Lorne Balfe for "Selenocentric."
www.facebook.com/cgchealy

{snip}

[Abnredleg]

1. The Navy has used similar technology since WWI

The main difference being they used steam to power the electrical generators. They built several classes of battleships with turbo-electric power plants.

[underpants]

2. Very interesting

Thanks.

[grumpyduck]

3. Mind-blowing is putting it mildly. Wow.

So is this the big-ship equivalent of a knee replacement?

[KT2000]

4. Amazing!

thanks for posting this.

[krispos42]

5. "parking job"

*twitch*

As an aside, destroyer escorts during WW2 were diesel-electric. Fleet destroyers had to be able to move fast to keep up with carrier battle groups (30 knots or more), but destroyer escorts only had to be fast enough to catch submarines (they moved about 17 knots n the surface; convoys usually did less than 10 knots). So the fleet destroyers uses steam turbines (with expensive gearboxes) and destroyer escorts used cheaper diesel-electric propulsion.

Some of the retired DEs were used after the war as floating powerplants; they'd dock them in some remote city and hook the generators up to the power grid.

[CRK7376]

6. Very cool article and photos

This landlubber is curious as to how the welders reassemble and reweld the pieces they cut out to remove/install the engine. How do they make the ship watertight and able to withstand stress as an Icebreaker. Fascinating story, photos helped.