The anti-torpedo bulge is a form of defence against naval torpedoes occasionally employed in warship construction in the period between the First and Second World Wars. It involved fitting partially water-filled compartmentalized sponsons on either side of a ship's hull, intended to detonate torpedoes, absorb their explosions, and contain flooding to damaged areas within the bulges.

Sponsons are projections extending from the sides of land vehicles, aircraft or watercraft to provide protection, stability, storage locations, mounting points for weapons or other devices, or equipment housing.