The Main Deck is the primary working platform with access to the five cargo holds aboard the ship and are numbered from bow to stern. It forms a singular, flush-deck construction, acting as an overhead or "ceiling" to the hull of the vessel.
Numerous activities took place here, including loading and unloading of cargo. Cargo handling combined the use of a set of steam-powered cargo winches, block and tackle, booms, and masts. The ship’s crew would ready the gear and open the hatches as the ship came into port. The process of loading or unloading a Liberty ship could sometimes take weeks to complete. When the work was finished, the crew made the ship ready for sea again by closing all the hatches and lowering the cargo booms into their cradles.
The first thing you’ll notice as you visit the Main Deck of the O’Brien is all the deck machinery which was steam-powered on Liberty Ships.
Deck machinery includes cargo winches and capstans used to lift cargo aboard or ashore and to pull in the mooring lines as well as the anchor windlass to raise the ship's anchors. The machinery also operated the rigging made of up booms, block and tackle, and hooks.
Specialty and heavy cargo often required modifications. When carrying locomotives, the O’Brien had train tracks welded to the main deck. They were loaded and unloaded using either shoreside or floating heavy cranes.
There are three masts and their booms for loading and unloading each of the ship’s five cargo holds. The Main Deck also features the Midship house and Aft house, armament platforms, numerous ventilation funnels, and life rafts.
Note: The ship’s Museum Entry is located between No 3 and No. 2 Cargo Hatches.
Explore this Station's Gallery
The first station on the Main Deck is No. 3 Cargo Hatch, which is to your left. It is one of five that you will encounter. Note the Museum entrance, which we will direct you to later.