The hatchways were used mostly by the ship's mechanics when they needed to get to the rudder or propellers from the outside. The posts are attachments for ropes. The rings that look like big life preservers are floats on tethers that could be lowered into the water. The sailors as well as their tools could be tied to the floats. When they were done, they'd be hoisted back up.

Can anyone tell me what these odd structures are?

Brooklyn Navy Yard dry dock, probably early September. Giddy patriots line up for a tour. Everyone happy after throttling Spain in Santiago.

Amazing pic of how to tame the steel beast of a ship. You get enough wood and ropes in place and there you go.

After participating in the Cuban blockade earlier in the year, she was briefly dry docked for refitting. As she was leaving NY Harbor, she struck a reef and returned right back to dry dock for more extensive repairs lasting three months! Today she is a favorite diving spot just off Pensacola.