The design of a surface launch and recovery fender for DSRV "Alvin"

Abstract

Surface recovery of small submersibles could be made safer for personnel and hardware with the installation on the submersible of an inflatable, pneumatic bumper which acts also as main surface buoyancy. Tne use of such a bumper in the recovery of DSRV ALVIN by her catamaran mother ship, LULU, is the subject of this study. It was determined, from first order analysis of the surge velocities of these two vessels in recovery position in a sea state 6, that any such bumper or combination of bumpers (i.e. bumper on LULU) would have to absorb 10,000 ft.-lbF., of energy. In order to protect the mechanical arm, keep the forces of collision at an acceptable level and retain present surface buoyancy, an increase in ascent and descent time must be tolerated since the uninflated vertical projected area of the forebody must increase. Large trim moments, due to the presence of the air bumper at the bow can be eliminated by use of a partially submerged bumper.