The Passaic Class of monitor, as with the preceeding original Monitor had a small factor of positive buoyancy.
This was known to Ericsson, the designer, and addressed by installing two large Worthington pumps made in Newark, New Jersey. This with the intent to have the ability to pump the volume of the hull dry in two minutes. This ability evidently did the U.S.S. Weehawken no good. Swells poduced by the weather sank her.

The hull of the U.S.S. Keokuk, another type of ironclad, still rests south of the main channel in the Atlantic Ocean after being hit by shot at least 93 times on an abortive attack on Fort Sumter on April 7, 1863. She was in danger of crossing bows with the U.S.S. Nahant, another of the Passaic Class, and turned into the fort putting her point blank to fire. Valiant efforts to pump her and tow her were to no avail.

Thanks for another neat article, Alice.