Which fuze type would be used for underwater applications like depth charges?

The use of a barometric fuze for underwater applications like depth charges is fitting due to its reliance on changes in atmospheric pressure to function. Depth charges are intended to detonate at a specific depth underwater, and a barometric fuze can accurately detect the surrounding pressure levels as the device descends. This capability allows the fuze to activate precisely at the desired depth, maximizing the effectiveness of the charge against submerged targets, such as submarines.

Delay fuzes are designed to provide a predetermined delay before detonation upon impact or after a specified time has passed, which makes them less effective for underwater applications where immediate pressure changes must trigger the detonation. Impact fuzes activate upon impact, which may not be suitable for depth charges that need to explode at a certain underwater depth. Combination fuzes, which incorporate characteristics of both barometric and impact fuzes, can provide versatility but are generally more complex and may not be as reliable as using a dedicated barometric fuze for the specific requirement of underwater detonation.