He tested the free-diving self-propelled submersible - one of only two in existence at the time - on increasingly deep dives off the California coast.

VOA: standard.2010.06.21

Walsh spent eight years in academia. The retired Navy captain continued to pursue his passions as a scuba diver, private pilot and explorer, participating in dozens ocean dives and expeditions to the polar regions.

VOA: standard.2010.06.21