KNOWLEDGE OF SHIPS AND THE SEA, of design and engineering brought to bear, with imagination, on the problems posed in the reconciling of requirements with limitations; calculations; drawings —of profile, section and plan—building up on flat sheets of paper a threedimensional form; large scale drawings of detail; and more calculation. . . .

That is naval architecture, its end result the design of a boat and the working plans from which she will be built.

Very often one design will grow naturally out of another; meeting new requirements; building in improvements suggested by experience or made possible by development of available materials and equipment. In just such a way the 37' 6" Rother lifeboat grew out of the 37' Oakley. The 37' Oakley was the first modern lifeboat with a self-righting capability, achieved by the transference of water ballast from beneath the engine room to a righting tank under the port deck. Later, modifications were made to give the boat enough inherent buoyancy for self righting without the need for water ballast transference. The superstructure, now of aluminium alloy, was extended over the forward well, and a wheelhouse, open at the after end but carrying buoyancy blocks in its roof, was added.

Other advantages gained were a forward cabin for survivors and more protection for the crew. This modified Oakley was re-named the Rother.

A full set of working plans is made up of many sheets of detailed drawings, but it is only possible here to reproduce one or two key examples; a deck plan and centreline elevation and two sections, numbered so that their positions can be located on the full length plans. Section 6 is looking aft at the main watertight bulkhead from inside the engine room. Section 7 looks forward from the steering position to the outside of the same bulkhead; note radio and D/F loop to port and the compass binnacle under the coxswain's eye forward. Note, too, buoyancy blocks beneath the wheelhouse sole and in its roof, and the beginning of the run aft of the propeller tunnels.

So much can be learnt from even one view. The elevation shows not only the main layout of foredeck, cabin, engine room, wheelhouse and after deck, but also such detail as how the radar on the after end of the wheelhouse roof and the mast, forward, pivot down so that the Rother can be housed; a look at the deck plan shows that the mast is in fact a tripod. From different views of thesame detail a rounded picture can be built up. For instance, the propeller shafts can be seen in both sections 6 and 7 and in the elevation.

(To be continued).