▁the ▁first ▁three ▁months ▁of ▁ 1 9 2 8 , ▁divers ▁and ▁other ▁salv age ▁personnel ▁were ▁able ▁to ▁raise ▁S - 4 ▁and ▁to w ▁her ▁to ▁the ▁Boston ▁Navy ▁Y ard , ▁where ▁she ▁was ▁dry d ock ed ▁and ▁rep a ired . ▁She ▁returned ▁to ▁active ▁duty ▁in ▁October ▁ 1 9 2 8 ▁and ▁was ▁employed ▁there after ▁as ▁a ▁sub marine ▁rescue ▁and ▁salv age ▁test ▁ship . ▁M oms en ▁went ▁to ▁sea ▁in ▁the ▁re condition ed ▁S - 4 ▁to ▁carry ▁out ▁practical ▁experiments ▁and ▁training ▁with ▁the ▁rescue ▁ch amb ers . ▁ ▁Work ▁with ▁S - 4 ▁helped ▁to ▁develop ▁equipment ▁and ▁techniques ▁that ▁bore ▁fruit ▁a ▁de cade ▁later , ▁when ▁ 3 3 ▁men ▁were ▁brought ▁up ▁alive ▁from ▁the ▁sun ken ▁sub marine ▁S qual us . ▁The ▁first ▁div ing ▁b ells ▁for ▁res cu ing ▁men ▁from ▁sub mar ines ▁were ▁designed ▁by ▁the ▁Bu C & R ▁in ▁ 1 9 2 8 . ▁The ▁div ing ▁bell ▁went ▁through ▁a ▁series ▁of ▁tests ▁off ▁the ▁sh ores ▁of ▁Key ▁West , ▁Florida . ▁Based ▁on ▁these ▁tests , ▁M oms en ▁had ▁several ▁changes ▁in ▁mind ▁for ▁the ▁bell , ▁and ▁after ▁nearly ▁two ▁years ▁of ▁experiment ation ▁full ▁of ▁highly ▁interesting ▁results , ▁the ▁final ▁bell ▁was ▁evol ved ▁and ▁christ ened ▁a ▁" res cue ▁chamber ." ▁This ▁success ▁was ▁catal yst ▁for ▁gain ing ▁appro val ▁for ▁development ▁of ▁the ▁sub