Apparently another sub was made with carbon fiber and it worked fine, however that one only had a single dive because they knew that it would lose strength afte

Apparently another sub was made with carbon fiber and it worked fine, however that one only had a single dive because they knew that it would lose strength after each dive. It may be feasible if they had replaced it more often (I don't think they ever replaced it, and there were former staff who claim to have brought up concerns about its condition).