The treaty separately preserved France's already launched Surcouf despite her 8-inch guns and displacement above the general exception. Her long path from a 1926 order to 1934 commissioning shows how demanding such an extreme design could be. Surcouf may be the ultimate big-gun cruiser submarine, built around a weapon closer to surface-cruiser artillery. X-1 followed a different answer to uncertain submarine gunnery by throwing a larger number of rapid-firing shells at a close target.
Notable Point · 12:40-14:28
Surcouf receives a treaty exception for a different gun doctrine
France keeps the 8-inch-gunned Surcouf as a named exception, contrasting one heavy salvo with X-1's emphasis on rapid 5.2-inch fire.