WATERFORD (ARD-5) ballasting down to receive a submarine

This picture shows WATERFORD as she begins to ballast down to a draft that is sufficient to safely haul a submarine into the dock. You can see the centerline keel blocks and the moveable side blocks. The side blocks are moved into the sides of the submarine after the submarine has been "set" on the centerline blocks and are primarily put in place to prevent the submarine from falling over while in the dock.

WATERFORD could force flood the basin by pumping water with her four main dock pumps from the river to the basin. Each pump was capable of pumping 15,000 gallons of water per minute. It still took 45 minutes to an hour to submerge the dock to the required drafts which gives a good indication of the volume of the dock.