The mast height figures are random in their accuracy, like a US sub skipper would have, in the "fog of war" vein, in that all countries did various things to disguise their ships and try to confuse submarine skippers with altered mast heights, or camouflage paint schemes, including putting high bow waves further back on a black hull, such that the vessel appeared shorter, and traveling at a higher rate of speed than it truly was. We are in the process though, of creating a mast height add-in mod that would make most - not all - of the mast heights more accurate.
