▁speech ▁to ▁the ▁Harvard ▁Engineering ▁Society ▁on ▁ 6 ▁October ▁ 1 9 3 9 ▁cred its ▁All an ▁Rock well ▁McC ann ▁with ▁the ▁improvements ▁which ▁made ▁the ▁bell ▁oper ational , ▁safe ▁and ▁large ▁enough ▁to ▁hold ▁up ▁to ▁eight ▁res cu ed ▁crew men ▁and ▁two ▁operators . ▁ ▁The ▁S qual us ▁rescue ▁In ▁▁ 1 9 3 9 , ▁the ▁McC ann ▁Res cue ▁Chamber ▁made ▁its ▁debut ▁when ▁it ▁was ▁used ▁to ▁successfully ▁rescue ▁ ▁thirty - three ▁surv iv ors ▁from ▁S qual us , ▁At ▁the ▁time ▁of ▁S qual us ▁accident , ▁Lieutenant ▁Commander ▁M oms en ▁was ▁serving ▁as ▁head ▁of ▁the ▁Ex perimental ▁D iving ▁Unit ▁at ▁the ▁Washington ▁Navy ▁Y ard . ▁The ▁sub marine ▁rescue ▁ship ▁USS ▁Fal con ▁( AS R - 2 ), ▁commanded ▁by ▁Lieutenant ▁George ▁A . ▁Sh arp , ▁was ▁on ▁site ▁within ▁twenty - four ▁hours . ▁It ▁lower ed ▁the ▁Res cue ▁Chamber ▁— ▁a ▁re vised ▁version ▁of ▁a ▁div ing ▁bell ▁invent ed ▁by ▁M oms en ▁— ▁and , ▁in ▁four ▁div es ▁over ▁the ▁next ▁ 1 3 ▁hours , ▁recovered ▁all ▁ 3 3 ▁surv iv ors ▁in ▁the ▁first ▁deep ▁sub marine ▁rescue ▁ever . ▁McC ann ▁was ▁in ▁charge ▁of ▁Chamber ▁operations , ▁M oms en ▁command ing ▁the ▁divers . ▁Although ▁there ▁was ▁no ▁reason ▁to ▁believe ▁anyone ▁was ▁alive ▁in ▁the ▁a ft ▁part ▁of ▁the ▁ship , ▁a ▁fifth ▁d ive ▁was ▁made