Performing a repair of the #6 main bearing on the Triple Expansion Steam Engine WW2 Steam Liberty Ship "Jeremiah O'Brien". The Bearing is what is known as a "babbitt bearing" which consists of babbitt metal alloy and a steel or cast iron shell. Babbitt usually consists of an alloy of tin, and lead with sometimes copper, antimony, and arsenic. The babbitt is softer than the shaft so any grit or dirt that may get into the bearing will be imbedded in the babbitt, causing no or minimal damage to the shaft. The same goes for if there is a lapse in lubrication, the bearing will wipe causing no or minimal damage to the shaft. Reciprocating steam engines primarily had babbitt bearings and drip-feed lubrication, meaning the oil delivered to the bearings only came in drops at a time, fed through wool wicks from an oil reservoir. With drip lubrication and no pressure lubrication, bearing clearance, concentricity, and mirroring (of the shaft surface) are imperative for the bearing's survival. One does not simply machine the babbitt and slap it in, trusting the "precision machining" to be close enough. One MUST at minimum blue the shaft and check contact. Hand scraping the babbitt until one has at least 80% contact on the top 1/3rd of the shell. It is a very time consuming process that takes an experienced hand and truck loads of patience. One cannot take shortcuts, lest they doom themselves to repeating the process at best or causing irreparable damage at worst.
Liberty Ship Jeremiah O'Brien is One of only two operating Liberty ships in the world out of 2710 that were built for World War Two. She was present at the Normandy D-Day invasion of WW2 and the only ship to return to Normandy under her own power for the anniversary 50 years later. She is also the only ship to steam directly out of the navy reserve "mothball" fleet under her own power. She is powered by two watertube boilers and a massive 2-1/2 story tall 2500hp triple expansion steam engine that was used for the filming of the 1997 James Cameron film "Titanic".
A HUGE thank you goes out to the National Liberty Ship Memorial, all of their employees, volunteers, and donors for making the operation of this ship possible, and in turn this video, possible. A thank you to all the employee, volunteers, and California Maritime Academy Cadets who had a hand in this operation.
A specific thank you to the Chief Engineer Jon Eaton, Operations and Maintenance Manager Seth Adams, and Ship Keeper Steve Butler for their help and trust allowing my father and myself to tackle the task of working on this amazing and irreplaceable piece of history.
The Jeremiah O'Brien is one of only a handful of museum ships that still operate and one of even fewer steam-powered museum ships still operating. She is also the last Liberty Ship in original configuration.
One might ask, "What about the bottom half of the bearing?" Well, to remove that is a task that will take considerable rigging to undertake. AT MINIMUM it would involve disconnecting the connecting rods, eccentric rods, and lifting the 40,000lb crankshaft several feet in the air to make removing the lower bearing halves possible. They are square-shaped shells like the top half, so "rolling out" like on a more modern engine is simply not possible. We determined the lower half is serviceable and will perform many tens of thousands of miles reliable service before needing attention, at which time all the mains will be addressed at the same time. "Why not re-babbitt the bearing?" It was determined the bearing would be serviceable again with some scraping and shim removal to adjust clearance.
The S.S. Jeremiah O'Brien is an amazing piece of history and I highly encourage you to go aboard. One can purchase tickets to go on one of her several cruises a year, or visit her at the dock in San Francisco where she is open to the public. They do also steam her at the dock once a month.
For more information about, to visit and tour, to volunteer on, or to donate to the Liberty Ship Jeremiah O'Brien, or the National Liberty Ship Memorial, please visit:
https://www.ssjeremiahobrien.org/
https://www.facebook.com/ssjeremiahobrien
Also I encourage you to visit her sister ship the Liberty Ship John W. Brown:
https://www.ssjohnwbrown.org/
To learn more about Steam Boats, visit:
http://www.thesteamboatingforum,net/forum/
http://www.steamboatassociation.org.uk/
http://www.northweststeamsociety.org/
http://www.steamboat.com.au/
http://www.spiretech.net/~artemis/NASAhome.htm
#steamboat #steamship #nationallibertyshipmemorial #libertyship #WW2 #WWII #marinesteamengines #museumship #greatestgeneration #steam #steampowered #steampower #steamengine #steamengines #rosietheriveter #ssjeremiahobrienofficial
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