Larger galleys required more time to train their crews. Rome was rebuilding after heavy losses, so the complexity of operating a new fleet mattered as much as hull size. Alternating military and civil service left experienced people outside the active forces who could return when needed. This provided a reserve of leadership for expansion. Adding more rowing levels also made coordination harder, giving builders a reason to place more people on stronger oars instead.
Notable Point · 1:10:57-1:13:14
Experience reserves and the cost of larger galleys
Rome could draw on experienced personnel, while increasingly complex rowing arrangements made giant ships harder to introduce.