Definition
A B‑class lifeboat is a type of inshore rescue craft operated principally by the Royal National Lifeboat Institution (RNLI) of the United Kingdom and Ireland. It is a fast, rigid‑inflatable boat (RIB) designed for rapid response to incidents close to shore, in estuaries, rivers, and coastal waters.
Overview
B‑class lifeboats form part of the RNLI’s “inshore lifeboat” fleet, complementing larger all‑weather lifeboats (ALBs). Introduced in the early 1970s, the class has undergone several design evolutions, the most widely recognised being the Atlantic 21, Atlantic 75 and Atlantic 85 series. The vessels are launched from slipways or kept afloat in dedicated launch cradles, enabling launch times of under a minute. Their speed (up to 35 knots for later models) and manoeuvrability make them suitable for rescues in shallow water, near cliffs, and in surf conditions where larger vessels cannot operate.
Etymology/Origin
The RNLI classifies its inshore lifeboats alphabetically (A, B, D, etc.) based on size, capability, and construction. The “B” designation was assigned to the first generation of rigid‑inflatable rescue boats introduced by the RNLI in 1972, distinguishing them from the earlier “A‑class” inflatable lifeboats. The term therefore originates from the RNLI’s internal naming convention rather than from any external linguistic source.
Characteristics
| Feature | Typical Specification (Atlantic 85, the latest B‑class) |
|---|---|
| Hull | Rigid fiberglass hull with two inflatable sponsons |
| Length | 8.5 m (28 ft) |
| Beam | 3.5 m (11.5 ft) |
| Displacement | Approximately 1 t (dry) |
| Propulsion | Twin outboard diesel engines, each 115 hp |
| Maximum Speed | 35 knots (≈65 km/h) |
| Crew | Typically 3–4 (helm, crew, rescue swimmer) |
| Capacity | Up to 12 persons rescued (including crew) |
| Navigation/Communication | GPS, VHF radio, radar reflector, night‑vision equipment |
| Self‑righting | Built‑in self‑righting capability via sealed cabin and buoyancy chambers |
| Launch Method | Slipway carriage or floating‐dock cradle; launch time ≤ 60 seconds |
Earlier B‑class models (Atlantic 21 and Atlantic 75) were shorter (≈6.4 m and 7.3 m respectively) and powered by a single outboard engine, achieving top speeds of 30–32 knots. Successive upgrades have focused on increased payload, improved ergonomics, and enhanced safety systems.
Related Topics
- Royal National Lifeboat Institution (RNLI) – the charitable organisation that operates the B‑class lifeboats.
- Inshore lifeboat (ILB) – the broader category encompassing B‑class, D‑class, and other small‑craft lifeboats.
- D‑class lifeboat – an inflatable rescue craft used for shallow‑water operations, complementing the B‑class.
- All‑Weather Lifeboat (ALB) – larger, ocean‑capable lifeboats such as the Severn, Tamar, and Shannon classes.
- Rigid‑inflatable boat (RIB) – the generic boat type on which the B‑class is based.
The B‑class lifeboat remains a key component of the United Kingdom’s maritime rescue infrastructure, providing rapid, versatile response capabilities for a wide range of coastal emergencies.