Bouncing bombs, Highball, and the development of skip bombing

How often were bouncing bombs used, and how did they differ from ordinary skip bombing?

Upkeep was used against the dams, while the anti-ship Highball weapon was developed but did not reach its intended operational use; ordinary bombs could also be skipped across water without being purpose-built bouncing weapons.

The panel distinguishes Operation Chastise's Upkeep weapon from Highball, the smaller anti-ship design considered for targets including Tirpitz. Highball was overtaken by other attacks before its planned employment. Skip bombing developed as aircrews learned that conventional bombs released low over water could ricochet toward a ship, with an early British example recorded in September 1939. A later follow-up explains that the specialized bouncing bomb used controlled backspin and precise release conditions, while skip bombing relied on the density change at the water surface rather than a bomb designed for repeated bounces.