"Kraka" is a sea-going, diesel-electric submersible originally launched April 12th 2005.   She is capable of charging her own batteries and compressed air tank, hence only dependent on supply of diesel oil.   A 2-3 man crew can sleep on-board in turns.   With the sail hatch closed and air intake through the snorkel it is possible to navigate in quite rough weather.   She is equipped with a button hatch for deploying and retrieving divers while submerged.   She is also equipped with a GPS chart plotter, a gyro compass, and echo sounder. She also has a photo optical mast ( periscope) with four cameras, each covering a 90 degree view and providing 360 degrees of visibility outside the sub.