The Chatham and Birmingham hulls have length-to-beam ratios of about 9.37 and 9.16, compared with 10.33 for the Tribals and 9.77 for the L and M classes. In this comparison, the lower ratios favor maneuverability while the longer, narrower proportions favor speed. Four shafts would spread the proposed power increase across more shafts than the two-shaft destroyers. Replacing the mixed coal-and-oil boilers could improve performance and range. Additional deck armour is also considered feasible without a major reconstruction.
Notable Point · 41:30-43:53
Hull proportions and four shafts
The broader proportions and four-shaft arrangement make the old Town hulls candidates for a faster, more maneuverable escort.