While one of the submersibles is conducting its dive, the other remains at readiness should there be an emergency, needing to be boarded on ship and hurried to the site of the problem.

Such an emergency could include the submersible becoming tangled in fishing nets or entrapped in rocks or debris on the ocean floor.

[1] In August 2002, Pisces V and her sister vessel Pisces IV discovered a Japanese midget submarine; sunk on December 7, 1941 by the destroyer USS Ward in the first American shots fired in World War II, the submarine was hit by a 4"/50 caliber gun shot and depth charged shortly before the attack on Pearl Harbor began.

In 2008, two members of the Tampa Bay Chapter of SCUBAnauts were invited to team with HURL and to visit the historic wreck of the Japanese submarine.

[7] A mock-up of the control panel of Pisces V can be visited by the public at the Mokupāpapa Discovery Center in Hilo, Hawaii.