Motor lifeboat
47 ft Motor Lifeboat
United States Coast Guard · United States
Self-righting surf boat rated for 20 ft surf and 30 ft seas.
Survivor capacity: USCG handbook figure of 34 persons aboard (4 crew + 30 passengers). The USCG Historian's 1989 design data lists "4 plus 5 survivors" for the enclosed survivors' compartment.
Specifications
Hull & dimensions
- Manufacturer / builder
- —
- Hull type
- —
- Hull material
- Aluminium
- Watertight compartments
- —
- Length overall
- 14.6 m (47.9 ft)
- Length at waterline
- —
- Beam
- 4.3 m (14.1 ft)
- Draught
- 1.4 m (4.6 ft)
- Freeboard at bow
- —
- Freeboard at stern
- —
- Displacement
- 18 t (19.8 US tons)
- Gross tonnage
- —
- Net tonnage
- —
- Min vertical clearance
- —
- Height to highest unfixed point
- —
- Height to highest fixed point
- —
- Number built
- 117
- Year introduced
- 1997
- Year retired
- —
Machinery & propulsion
- Propulsion type
- Twin propellers
- Engines
- 2 x Detroit Diesel 6V92, 435 hp
- Engine manufacturer
- —
- Total engine power
- —
- Fuel type
- —
- Total fuel capacity
- —
- Fresh water capacity
- —
- Launch method
- Afloat
Members-only
Operating limits (seas, surf, wind), towing and stability data, and detailed engineering specifications are available to Members.
Performance & capabilities
- Maximum speed
- 25 kn (46.3 km/h · 28.8 mph)
- Range
- 200 nm (370 km · 230 mi)
- Endurance
- —
- Crew complement
- 4
- People capacity
- 30
- Self-righting
- Yes
- Self-bailing
- —
- Ice operations capable
- —
- Max ice-breaking thickness
- —
- Medical facilities onboard
- —
Members-only
Operating limits (seas, surf, wind), towing and stability data, and detailed engineering specifications are available to Members.
Operational envelope & limits
Members-only
Operating limits (seas, surf, wind), towing and stability data, and detailed engineering specifications are available to Members.
Source citations
| # | Source | Type | Supports | Accessed |
|---|---|---|---|---|
| [1] | USCG https://www.uscg.mil/Portals/0/documents/boat-forces/47-MLB.pdfImported at initial compilation; not yet checked against source. | official | General | Not yet checked |
| [2] | Wikipedia https://en.wikipedia.org/wiki/47-foot_Motor_LifeboatImported at initial compilation; not yet checked against source. | reference | General | Not yet checked |
| [3] | 47-foot Motor Life Boat (MLB) USCG Historian's Office https://www.history.uscg.mil/Browse-by-Topic/Assets/Water/All/Boats-Less-than-65-ft/Article/2028253/boat-47-motor-life-boat-mlb/ | official | survivor_capacity | 2026-09-30 |