Fodor's Expert Review South African Naval Museum
The naval museum is filled with model ships, old navigational equipment, old South African navy divers' equipment, a few real, life-size boats, and, oddly enough, a helicopter. You can also climb to the top of the building's clock tower. If you haven't been on a submarine before, a visit to the SAS Assegaai, moored against a pier in the harbor, is of serious interest (nice warm beanies with the sub's insignia are on sale). It's staffed by naval personnel and volunteers.