Separate treaty quotas for specialist submarines

What if the London Naval Treaty gave separate tonnage allowances to ordinary, cruiser, and minelaying submarines?

Navies would likely use each allowance, with cruiser submarines surviving as a small multipurpose branch combining gunnery, torpedoes, and minelaying.

The panel first corrects the treaty setting: submarine restrictions belong with the London rather than Washington negotiations. Separate allowances would encourage navies to use every category and maintain specialist branches instead of forcing every type into one tonnage ceiling. The discussion then turns to a Royal Navy cruiser submarine that combines large guns, minelaying capacity, and extra internal torpedo tubes in a multipurpose hull. Comparing X1, the T class, and the Grampus class shows why the cruiser type might survive as a small recurring branch even if its guns were later removed.