TRADITIONALLY, when building a boat in wood, the first operation is the laying down of the keel from which is built up a framework of stem, transom, bulkheads and other transverse and longitudinal members. When building a small boat in steel, however, the approach is sometimes entirely different, the order of construction being reversed, and the fast slipway lifeboat hull is being built upside down on a deck jib, to be turned right way up when the plating is complete. All the structural members have to be welded together and the plating of the hull welded into place. It is much easier for a welder if he can look down on his work, rather than having to reach up to it and, working down-hand, he will be able to get better results. So the gunwale is laid down first, on which is built the framework of transom, bulkheads, frames and longitudinal stringers; next come engine bearers and floors; then the keelson, stem, 'deadwood' and, last of all, the keel.

The first of the two prototypes of the Institution's new 47ft fast slipway lifeboat started building at Fairey Marine (Cowes, Isle of Wight) in the early autumn. Working from the lines plan and a table of offsets provided by the RNLI design office, Faireys first had to draw the new lifeboat's plans full size on their loft floor. From these full size drawings, templates were made for all the individual component parts which go together to make up the structural members of the boat's 'skeleton'.

Each separate part is cut out, from the appropriate type of steel, to match its template and each structural member is then assembled from its component parts on the workshop floor (see Figs 1 and 2) before being offered up in its final position in the growing hull. Thus, for instance, each bulkhead is a complete, welded, watertight unit before it is erected in place (see Fig 3).

The web frames, spaced between the bulkheads, are prepared and erected in the same way. The stringers, made of T bar mild steel are bent to take up the fore and aft curvature of the hull and they are then passed through notches inthe outboard ends of the transom, bulkheads and frames, and welded in place (see Fig 4).

Full size templates are also used for cutting out the plates which will form the boat's 'skin'. The shell plating has, of course, to be 'moulded' to fit the shape of the boat. Each plate is prepared individually in a rolling mill; its edges are carefully stretched out to exact measurements so that when the plate is offered up in its final position it will be just the right size and shape to take up the fore and aft and the athwartships curves of the hull in that area.

While construction of the hull began, other preparatory work was under way elsewhere. At Romsey the lifeboat's twin GM8V71 marine diesel engines were already built and undergoing bench tests, witnessed by members of the RNLI technical team. At the RNLI depot, Poole, a mock-up of the after cabin was made so that members of the Institution's Medical and Survival Committee could satisfy themselves that enough space will be available for handling a stretcher. And back at Fairey's, a mock-up of the wheelhouse was built so that any problems that might arise with the placing of instruments could be ironed out before the lifeboat herself is fitted out.

(to be continued).