Alvin the submarine, now 50 years old, underwent a thorough overhaul and upgrade last May: the iconic sub was redesigned and rebuilt, piece by piece, by a one-of-a-kind team of engineers, technicians, and pilots at the Woods Hole Oceanographic Institution. WCAI's Jenny Junker and Samantha Broun of Atlantic Public Media paid a visit to the Hi Bay to see the work happening. They didn't say no to a chance to get inside the sub's personnel sphere. Here's a short "Audio postcard" from that visit. Sound recording by Samantha Broun, audio postcard production by Jenny Junker