Thread: HMAS Shropshire, and the not mentioned defect.

British engineering? Sounds like a LANDROVER

I had to look up how a thrust pad worked...

Pre WW1 a solid block was used for a prop shaft thrust bearing that needed a constant oil feed and was one of the main limiting factors in moving to more powerful engines at that time also obviously a pretty short service life. In 1905 an Aussie engineer called George Michell came up with "sector-shaped pads, arranged in a circle around the shaft, and which are free to pivot. These create wedge-shaped regions of oil inside the bearing between the pads and a rotating disk, which support the applied thrust and eliminate metal-on-metal contact" (wikki). This new "Michell bearing" was 10 times smaller, had much longer service life and didnt need an oil pump, the prop shaft rotation distributed the oil. They are still the standard bearing used on turbine shafts in ships and power plants worldwide today.

Originally Posted by squizzyhunter

I had to look up how a thrust pad worked...

Pre WW1 a solid block was used for a prop shaft thrust bearing that needed a constant oil feed and was one of the main limiting factors in moving to more powerful engines at that time also obviously a pretty short service life. In 1905 an Aussie engineer called George Michell came up with "sector-shaped pads, arranged in a circle around the shaft, and which are free to pivot. These create wedge-shaped regions of oil inside the bearing between the pads and a rotating disk, which support the applied thrust and eliminate metal-on-metal contact" (wikki). This new "Michell bearing" was 10 times smaller, had much longer service life and didnt need an oil pump, the prop shaft rotation distributed the oil. They are still the standard bearing used on turbine shafts in ships and power plants worldwide today.

The old Mitchell thrust pads. I'd like a pound for every time I've removed & inspected them. On the DDG Brisbane, back in 1977, It was known that the Port shaft main turbine thrust bearing had an issue with overheating. For a period , every time we came alongside during a trip, we engine room tiffies had to remove, inspect & photograph the thrust pads. Brisbane had to do a pre refit full power trial up the coast from Melbourne to Sydney. And once again, the bearing overheated.

Coming alongside Garden Island, an army of Dockyard boffins descended into 2 Engine room, we removed the pads and displayed them for all to see. There was much scratching of chins, wise murmuring, and then they left. All except a last year Dockyard apprentice. He had the original engineering drawings of the offending article, and seemed genuinely bemused. He called the two of us over, and said " does that look right? " What he was indicating was , on the drawing, a lube oil drain hole was shown on the casing, but wasn't on our bearing casing. A quick call to our Engineer had more dockyard matey's down the hole than you could imagine. A eureka moment. The apprentice was pushed to the rear, in the commotion, but I can't help thinking he had a bright future. Problem solved. It had been supplied like that from new. And yes, Mitchell thrust bearings had an oil supply, supplied by the turbine lube oil pump.

Mitchell thrust bearings

Tilting Pad Thrust Bearings

I still prefer the Aussie accessories on the afterdeck of the HMAS Queenborough!

Originally Posted by bob10

Mitchell thrust bearings

Tilting Pad Thrust Bearings

So are the KingCole LEG bearings standard issue now? I thought that was a lot of faith to have in a sealed system.

Originally Posted by Lotz-A-Landies

I still prefer the Aussie accessories on the afterdeck of the HMAS Queenborough!

The sailors?

Originally Posted by squizzyhunter

So are the KingCole LEG bearings standard issue now? I thought that was a lot of faith to have in a sealed system.

Don't know what they have now. I belonged to the steam era, back in the age of dinosaurs, " up one stokes!" ,splash lubricated shaft bearings, lignum vitae stern bearings. Those were the days, no air conditioned MCR's, hands on steaming. Back in the day when if it was broke, you were told to fix it. No spares? as one infamous Engineer would say " make a bastard! ".