Generally, WW II US boats had 10 tubes, and the space for reloads was 18, 10 forward(2 in the pit [possibly 1 extra in the middle],4 on each of two room levels) and 8 aft (4 on each level). So, the total would be 28 torpedoes total, assuming the 10 tubes were loaded. Perhaps the guide meant re-loads--not potential total. The 17 figure seems to be one off. Two, if one extra was in the FTR pit.