Project Deep Ops was a Navy program started in the late 1960s to test whether whales could be used to retrieve unexploded ordnance from great depths. According to the National Archives,
The Navy was looking for more reliable ways to recover lost experimental and exercise ordnance from its ocean test ranges. Objects at a depth less than 300 feet could sometimes be recovered by human divers, while unmanned submersibles could reach depths of 2,500 feet. However, the use of humans or submersibles depended on mild sea and weather conditions. It was believed that whales might be able to dive up to 3,000 feet to retrieve objects in much rougher conditions.
Project Deep Ops concluded that whales could be trained to assist in Naval retrieval tasks, even in the open ocean (although Ishmael did escape during an open ocean exercise and was never seen again). Some of the whales were successfully able “to carry and deploy a hydrazine lift recovery system to a 1000-ft depth.” The report recommends continuing the project with a focus on pilot whales, rather than orcas.
The Ocean Technology Department prepared a brief report on the experiments, Project Deep Ops Equipment Development, and the Naval Undersea Center produced a comprehensive 91-page report Project Deep Ops: Deep Object Recovery With Pilot and Killer Whales documenting the two-year experiment and making recommendations for follow-up research.
The Navy also produced this Technical Film Report on Project Deep Ops.