Technical information for the D-Class/Ib1 Class Lifeboats
The Old D-Class
Utilization For more than 40 years the D-Class Lifeboat has served as the workhorse of the RNLI Inshore Lifeboat (ILB) fleet.
Significantly smaller in comparison to the rest of the Inshore Fleet, the D-Class is also the only vessel not to feature a rigid hull. The main aspect of the boat would be both its size and weight. The D-class has been specifically designed as a light and highly maneuverable rapid response craft.
Design and Construction The D-class lifeboat is comprised of two sponsons, together housing 7 inflatable segments intersected by baffles. The main construction fabric is Hypalon-coated Nylon which provides a durable, non-tear surface. T
his is one of the smaller classes of lifeboat operated by the RNLI, and they are a common sight at Lifeboat Stations around the coast.
The D-Class normally has a crew of three or four and is primarily used for surfer/swimmer incidents as well as assisting in cliff incidents where the casualty is near the water.
The very nature of its work requires a swift response, and the D-class can normally be afloat within five minutes of the pagers going off.
| Length: | 16 ft |
| Weight | 436 kg |
| introduced | 1963-2002 |
| Construction: | FRC with Hypalon coated polyester collar |
| Engines: | 40 hp Mariner Outboard |
| Speed: | 20 knots |
| Endurance: | 3 hours at top speed |
| Crew: |
Min 2 Max 4 |
The Ib1 D-class
| Length: | 4.9 m |
| Beam: | 2 m |
| Displacement: | 338 kg |
| Construction: | FRC with Hypalon coated polyester collar |
| Engines: | 50 hp Mariner Outboard |
| Speed: | 25 knots |
| Endurance: | 3 hours at top speed |
| Crew: | Min 2 Max 4 |
Ib1 D-Class Lifeboats are Inflatable Lifeboats serving in the UKs RNLI Inshore Lifeboat (ILB) fleet. Although they are known as the Ib1 at times, they are the latest development of the D-Class Lifeboat.
This class of lifeboat is one of the smallest operated by the RNLI, and they are becoming a common sight at Lifeboat Stations round the coast slowly replacing the old D-Class. Unlike other members of the ILB fleet the Ib1 (D-class) does not have a rigid hull, all others with the exception of the Arancia, hovercraft & ALB Tenders are Rigid Inflatable Boats (RIBS).
Improvements over the D-Class include a new POD at the bow which houses the First Aid Equipment/Oxygen, the Anchor, Radio and new addition to this class of boat a Northstar GPS Navigation System.
The Floor has and Transom are now made from modern Composite materials replacing the marine ply board previously used.
The Engine is now a Two Stroke Three Cylinder 50hp Mariner which replaces the Two Cylinder 40hp Mariner used previously. The benefits being more torque and better pick up with an improved top speed.
There are further small improvements however overall the look and design of the boat remains the same.
Overall the Ib1-Class Lifeboat is crewed by the same amount of persons and is still used primarily for Inshore work.