SS Jeremiah O'Brien, Chatham - reversing engine

Image: © Chris Allen Taken: 11 Jun 1994

The Jeremiah O'Brien is a WWII 'Liberty' cargo ship built in 1943 and now preserved in San Francisco. She came to Europe for the 50th anniversary of D-Day. The vessel is 441' 6" long by 57' beam. The displacement tonnage is 14,450 long tons. Propulsion is by a 2,500 horsepower inverted vertical triple expansion engine. The cylinders are 24.5", 37" & 70" bores by 48" stroke. Steam pressure is 220 psi and service speed 76 rpm. This is the lower level of the engine room showing the reversing engine attached to the main engine. The reversing engine cylinder is bottom right and is 5" bore x 7" stroke. It turns the worm and worm wheel more or less in the centre of the view. The diagonal rod running from the worm wheel moves the reversing links. The worm wheel moves continuously in one direction and the reversing gear is therefore known as 'all around gear'. Seen on edge at the right is the flywheel that also doubles a manual reversing wheel if the engine fails or there is no steam (hard work) The flywheel has a circular brass cover that not only looks pretty but prevents the crew getting caught by the rapidly revolving spokes. The engine, two boilers and all the auxiliary plant share one large space amidships. One torpedo amidships would take out the lot. The Liberty ships were a standardised class known as the EC2-S-C1 cargo vessel and 2710 were built. The fastest build time was 4 days, 15 hours and 29 minutes from laying the keel to launch. The actual time from laying the keel to delivery into service was a bit longer at 7 days, 14 hours and 32 minutes. Seeing this gorgeous vessel in the UK was a real treat as I have yet to get to San Francisco, Baltimore or Piraeus to catch up with the survivors in their usual ports. I am using Geograph as a means of sharing this knowledge that would otherwise be less available.

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