Atlantic 21 RIB
Technical Specifications

Rigid Hull

The rigid portion of the hull, is made of GRP (Glass Reinforced Plastic). GRP is a composite material consisting of plastic (polyester resin) with glass fibre reinforcement.

This material is used because it is strong (stronger than wood), non-corroding (virtually maintenance free), invulnerable to attack by marine organisms and easily moulded into complex shapes.

The bow has a deep-V forward with the flare decreasing to a straight-sided hard chine hull with a transom stern.

The bottom of the hull is shaped from the deep-V bow to a flat run aft.

The flat run assists in getting the lifeboat up on the plane quickly, enhances directional stability and in the event that the lifeboat is beached, allows her to sit upright.

The deep-V bow gives the lifeboat excellent directional stability when underway.

Spray Rail

A 'spray rail' runs from forward to the stern on each side of the hull to deflect water away from the sponson and to stop spray being taken aboard.

On later Mk hulls the rail has been modified to run from the bow to the stern and has been flattened - SSILB is a later Mk. On later Mk hulls have also had added a V shaped stem protector extending from the bow and is made of rubber
- SSILB is a later Mk.

Inflatable Sponson

The sponson material is made up of a 'sandwich' construction comprising a Nylon 66 weave, impregnated and coated on both sides with Hypalon.

The Hypalon coating is very tough and is resistant to ultra-violet radiation, ozone, petrol and oil.

The sponson gives the lifeboat its overall length and beam when it is fixed to the rigid hull and inflated to the correct pressure.

A rubber fender is fitted to the outer edges of the bow and side of the sponson to help protect the sponson side walls.

Lighting

In addition to the fixed navigation lights and Blue Flashing light, the Atlantic has low level capsize lamps fitted to each side of the console and are operated by a Mercury switch to illuminate the upturned lifeboat should a capsize occur.

A high power 'spotlight' is carried, also a high powered hand torch and a second rubber covered torch.

The Console

The Console is fitted almost amidships on the fore and aft centre line of the deck, and provides fixing for controls and seating for the three man crew.

Seating is of a triangular or Delta configuration with the coxswain sitting forward of the other two crewmen.

Behind the coxswain to the port side sits the Radio Operator/Crewman and the remaining crewman sits to the starboard.

All crew positions have 'foot-straps' fitted to the deck, each crewman being able to 'ride the bumps' by raising himself slightly above the seat, taking the shocks through his leg muscles.

Anchors and Cordage

A sea anchor and warp are carried.

A 6kg Delta anchor, galvanized chain and 82.3 metre (45 fathom) x 12 mm plaited nylon anchor warp are carried.

The stowage position for the anchor & warp is with the anchor stowed vertically on the starboard forward corner of the console, the warp is on a reel on the fore part of the console and a fairlead is fitted to the peak of the bow sponson for use when anchoring.

The main purpose of this anchor is it keep the bows of the lifeboat head-on to the sea in the event of complete motor failure or a capsize.

A manually released sea anchor stowage is fitted and in the event of a capsize can be released when the crew are about to leave the underside of the lifeboat or when the crew reach the after end of the lifeboat.

Two 18.3 metre (ten fathom) mooring ropes, a general purpose 36.6 metre (20 fathom) rope on reels are also fitted to the aft and fore.

The General Purpose rope is 66 metres (36 fathoms).

Throwing lines fitted to quoits are fitted on either side of the sponson.