Excerpts from obituary published in New York Times on 8/26/2014:

CAPT Walter Francis Mazzone played a pivotal role in two underwater Navy exploits during the 20th century.  In World War II he kept a waterlogged submarine from going belly up while it was carrying 40 Americans rescued from the Philippines.  Twenty years later he helped organize the first Sealab tests of human endurance at crushing ocean depths — conducting the first tests on himself — which established the deep water diving protocols still used by military and commercial divers today.  CAPT Mazzone, who died on August 7 at age 96 in San Diego, was considered one of the Navy’s most exacting detail men in the underwater realm where a millimeter’s leak, a workaday tangle and a molecule-size mistake are life-or-death matters.  On submarines, Mazzone was the diving officer, in charge of taking the sub down, surfacing it and keeping it on an even keel when under attack.  On Sealab experiments he was the life-support man — helping divers descend hundreds of feet, stay below for weeks at a time and come back alive through a method he helped develop called “saturation diving.”

The submarine rescue was kept secret during the war, and remained relatively little known afterward.  In May 1944 the Navy ordered his sub, the USS CREVALLE, to surface just off the Japanese held Philippine island of Negros where it was to pick up two cargoes ferried out to it by Philippine resistance fighters.  The first was a cache of Japanese battle plans they had captured.  The second was a group of 40 Americans who had been in hiding on the island since the beginning of the war.  Before reaching Australia 10 days later the CREVALLE’s commander spotted a Japanese convoy and despite the danger it posed to his passengers, moved closer to attack.  CREVALLE was spotted by the Japanese who attacked first damaging and partly flooding the sub.  With the sub listing, Mazzone kept it under control for five hours as it maneuvered to escape while under almost continuous attack, according to an official account cited in a 2001 book, “The Rescue: A True Story of Courage and Survival in World War II.”

Captain Mazzone, who was awarded the Silver Star and other medals, left the Navy after the war but rejoined it in the late 1950s to work on research that would become the backbone of the Navy’s Sealab project.  In 1962 the team launched the 57-foot-long sausage-shaped underwater chamber known as Sealab I, which upended the conventional wisdom that even with oxygen tanks divers could not survive at a depth of more than 150 feet for more than a half-hour.  The four divers in Sealab I remained at a depth of 192 feet for 11 days.  The technique that made it possible, saturation diving, virtually rewrote the chemistry of human respiration and temporarily transformed human divers into marine mammals.  The method involved replacing the sea-level mix of air (about 80 percent nitrogen and 20 percent oxygen) with a different mix (90 percent helium and 10 percent or less of oxygen) that could sustain human life underwater at great depths.  CAPT Mazzone organized experiments showing that animals and humans (he was one of the first to try) could breathe the helium-oxygen mix and that divers (he was again one of the first testers) could acclimate to it in hyperbaric chambers.  Sealab II, launched in 1965, kept crews at a depth of 205 feet for weeks at a time.  From the late 1950s to 1969 CAPT Mazzone was a detail-obsessed overseer of the Sealab project.  Crewmen called him Uncle Walter and it has been said that the Navy would not have gotten anywhere without him and that he was the anchor of the whole project.

Walter Francis Mazzone was born in San Jose, Calif., on Jan. 18, 1918, the only child of Frank and Pearl Mazzone, immigrants from Italy.  His mother was a department-store sales clerk, and his father worked in canneries.  Mazzone had earned a degree in biological and physical sciences from San Jose State University and intended to go to medical school when World War II began in 1941.  The Navy sent him to submariner school.  He reprised his role in the CREVALLE rescue in August 1944 when, again as the diving officer, he safely maneuvered the submarine USS PUFFER during a 30-hour attack by Japanese destroyers.  CAPT Mazzone received a degree in pharmacology at the University of Southern California in 1948.  While working on the Sealab project he received a master’s degree from the Harvard School of Public Health.  He retired from the Navy in 1970.  He is survived by a son, a retired Navy captain, two grandchildren and five great-grandchildren.  His wife, Lucie Margaret Oldham Mazzone, died in 2012.

Submitted by CDR Roy A. Mosteller, USNR (Ret)