Nothing At All Sexual About This Photo
Navy NewsStand has a series of photos of USS Dallas (SSN 700) in action with the Seal Delivery Vehicle in Norfolk (here, here, here, here, and here). The third photo in the set shows the SDV being loaded into the Dry Deck Shelter:
Yep, just a large cylindrical object being inserted into its natural home, and nothing else. Anyone who thinks differently really needs to get their minds out of the gutter.