Launching and recovery arrangements, davits and release gear
Launching and recovery arrangements, davits and release gear
This domain tests the mechanical chain from grabline to water: davit type, falls, sheaves, winch, tricing and bowsing gear, and the release hook that lets the boat go.
Core rules
- Gravity davits lower by controlled release of the brake; luffing and radial davits use powered or manual luffing. The boat must be able to reach the water with the ship at lightship and listed.
- Falls are wire ropes; they must be turned end for end at intervals not exceeding 30 months and renewed when deteriorated, and at intervals not exceeding 5 years.
- On-load release gear must not release under load unless the boat is waterborne; the hydrostatic interlock is a safety device, not an operating lever.
- Release hooks must be clearly marked, kept free of paint, and tested at intervals in accordance with the maintenance regime.
- Before lowering, check gripes removed, painter secured, drain plug in, engine started and personnel secured.
Worked example
After a drill a lifeboat hangs on one fall. The candidate must decide the immediate action. Reasoning: the boat is still secured by the other fall and the release gear may be partly open. Do not lower or release; secure the area, relieve tension using the winch or brake as instructed, inspect the hook and fall, and report to the responsible officer. The defect must be recorded before the boat is returned to service.
Traps
Assuming the hydrostatic interlock prevents all accidental release; releasing one hook before the other; painting over hook markings; lowering with the painter unsecured; forgetting to remove gripes.