Here are a couple of shots of a Seal Delivery Vehicle (SDV) being loaded onto USS Dallas (SSN 700):
Norfolk, Va. (Feb. 6, 2006) – A SEAL Delivery Vehicle (SDV) is loaded aboard the Los Angeles-class fast attack submarine USS Dallas (SSN 700) in preparation for a Special Warfare Training exercise. SDV is a “wet” submersible, designed to carry Seals and their cargo in fully flooded compartments to provide a dry environment while preparing for special warfare exercises or operations. U.S. Navy photo by Chief Journalist Dave Fliesen (RELEASED)
For more info on the SDV, follow this link.
Note that this is not the Advanced SEAL Delivery System, a mini-sub whose woes were recently covered on Defense Industry Daily.