F2, F3, and Nelson trade speed against armor

All three designs share a 106-foot beam, but F2 is 760 feet long overall, F3 is 740 feet, and Nelson is 710 feet. The longer F2 and F3 hulls accommodate more than twice Nelson's shaft horsepower while retaining two shafts. At deep displacement, the quoted speeds are 29.5 knots for F2, 28.5 for F3, and 23 for Nelson. F2 has a 13-inch belt over the magazines and 12 inches over machinery, while F3 has a uniform 12-inch belt. Nelson raises those figures to 14 and 13 inches respectively. The comparison places preliminary F2 and F3 designs against the modified design that became Nelson, so details such as torpedo tubes and additional anti-aircraft guns were still open to change. Forced draught offered a possible emergency speed increase at the cost of greater machinery wear.