A significant problem is that submariners lack Internet access while at sea.  The problem is generational and something higher-ups don't readily appreciate.  Young technically-inclined sailors *expect* to interact with the world online and being deprived of this access heightens their sense of isolation as compared with their predecessors despite the fact they're kept busy.  Or so I hear ;>)

To add FWIW:

A savvy navy might install an isolated COTS teraflop server on its long duration boats.  Each boat will get wired with quieted and stowable thin-client laptops at each berth, zero ports and sound available only through headsets.  Build "secure" virtual community spaces, each individual can choose what to share from his war chest compiled on land, and can also include boat proprietary toolkits.  Sailors will receive thumb drives in advance of a cruise to which they can dump everything public sector from SP threads to happy hunting photos (panty shots) to gag photoshops, classic texts and contemporary music.  Less coverage but ultimately greater detail.  Onshore officer review and scan, then a thumb transfer into each crewman's "secure" space on the boat's crew server.  Email to family and friends gets stored until the boat is in a position to transmit.  Underway the crew can choose to mail one another, share files (music, diaries, etc), open threads, tease and chat through the local segregated network.  They can communicate thoughts and files re technical training and personal issues.  Play MMRPGs.  What happens on the boat network mostly stays on the boat network, assuming no criminal suspicions by the officers, until purged just prior to landfall - no offloads enabled.  Create a surrogate Internet, boost morale and retain the technically-inclined.  Costs less than bonuses alone.  Plus the officers can figure out a way to use the extra capacity in a pinch for whatever serves the boat and the navy.  0.02

v^2