> If the ballast weight release system fails, stranding the craft on the seafloor, a backup galvanic release is designed to corrode in salt water in a set perio

> If the ballast weight release system fails, stranding the craft on the seafloor, a backup galvanic release is designed to corrode in salt water in a set period of time, allowing the sub to automatically surface. Not much to say about this other than that's particularly elegant.