The positive buoyancy force allow the SPIN-buoy to travel towards the surface, and the net water velocity passing the patented outer curvature of the buoy fasilitate a turning momentum. A company propritary calculation ensure correct rotation speed versus the ascent velocity, so to pay out a torque free fiberrope. Overall size of SPIN-buoy is generally determined by lift capacity of rope, water depth and selection of 3rd party release-transponder, eg. Sonardyne, Kongsberg or Ixsea.