DL 105 Marine Survival Davits BT Elliott 2011

Davits A system to move a lifeboat from the stowed position, outboard for launching and recovery Davits A system to move a lifeboat from the stowed position, outboard for launching and recovery  Radial  Obsolete  Mechanical  Obsolete  Gravity

Radial Davits Manually swung out, first one then the other, manila falls, two person operation

Mechanical Davit Hand cranked out, manila falls, 2 man op.

Gravity Davits  Industry Standard  One man operation  Wire rope falls  No power needed to launch  Brake controlled lowering speed  Electric winch for hoisting  Manual cranking gear with safety device  Launch able with vessel listing and trimming

Types of Gravity Davits  Roller Gravity  Single Pivot  Multi-Pivot  Free-Fall  Fixed

Roller Gravity

Single Pivoting

Multi-Pivoting

Multi-Pivoting Used when height is restricted, deck above

Free Fall

Fixed Drill rigs, no concerns about listing and trimming

Training Ship  Lifeboats 1, 2, 3, 4 use Roller Gravity Davits  Lifeboats 5, 6 use Single Pivot Gravity Davits

Roller Gravity Davit Lifeboats #1, 2, 3, 4

Pivoting Davit Lifeboats # 5, 6

Roller Gravity Davits  Most common on TSGB  Style of Davit that the USCG is basing their testing on

Main Components Track way and Davit Arm

Track Way  Each supports and guides an arm  Transfers weight and forces to ship  Provides mounting surfaces accessories such as winches, grips, locking bar and limit switch

Davit Arm  Moving part of system using rollers  Cradles lifeboat  Attachment point for wire sheaves, span wire and tricing pendent

Electric Winches Not needed to launch  Track way or Deck Mount  Closed gearing  2 Drums  Centrifugal Brake 120 ft/minute maximum  Dead Man brake  Overhauling Wheel  Emergency cutoff switch  Operating Controls on Rail

Drums Sized for 6x19 wire, Fleet Angle ≤ 8۠

Davits 1, 2, 3, 4  Centrifugal Brake  Dead man Brake  Manual Cranking with Safety device  Overhaul Wheel

Emergency Cutoff Operating Controls

Gripes Secures lifeboat to Davit Arm in stowed position

Tricing Pendent: brings boat alongside for loading Frapping Line: replaces tricing and controls boat while lowering

Limit Switch Cuts power to winch before final Securing