THE SCENE OF ACTION now moves from the design office to the boatyard (William Osborne Ltd, Littlehampton) which will have been sent the lines plan of the boat (illustrated at very small scale at the foot of this page). It is the lines plan which delineates the shape of the hull; and as a hull is three-dimensional it is reasonable that it should be drawn in three different planes. There are waterlines (curved bottom drawing) which show the projection of the boat viewed from the sheerline above; the buttock lines (curved, centre drawing) which show the projection of the boat viewed from the centreline, abeam; and then the sections (curved, top drawing) which show the projection of the boat viewed from the bow. The shape of the hull in any one plane can be visualised 'looking through' the lines, letting them fall back in order, one behind the other.

Buttock lines appear on the waterline plan, and waterlines on the buttock lines plan, as straight horizontal lines.

The three different views are related to each other by the stations: the ten vertical lines drawn across both waterlines and buttock lines at equal distances along the datum waterline (at which the boat is designed to float) between the fore perpendicular and aft perpendicular.

The section drawings are made at these same ten stations.

With the lines plan the yard will also receive a table of offsets. Wherever a station crosses a water or buttock line, the draughtsman will have laid off the measurement between that point andthe centreline and/or datum waterline of the boat on each of the drawings.

Using the table of offsets for continual reference the yard now 'lofts' the lines plans, drawing them out full size on the black loft floor with a white chinagraph pencil. First, at each point where two lines cross, the measurement will be laid off and two nails driven into the floor. By slipping a long, flexible batten between these sets of markers it is possible to see whether a line is 'fair' with no bumps or dips. At the scale at which the original drawings are made it would be impossible to achieve the complete accuracy to a fraction of-an inch necessary to achieve fair lines, and this 'easing' has to be done on the loft floor. If a line is not fair, the nails are taken out, the batten allowed to take up its natural curve and the nails replaced; the new measurement is taken, checked back on each of the drawings on which the intersection appears, checked with any related measurement in the area and, if all is well, altered on the table of offsets. Every slight difference must be reconciled until the true, fair shape of the hull is there for all to see. It is a highly skilled job and will probably take several weeks to complete, but on the quality of the work put in at this stage will depend the ultimate quality of the boat.From the full size lines plans now on the loft floor will be made the templates, or patterns, for the construction of the hull: a half template for each section at each station (making allowance for the thickness of planking, which will vary according to the curve of the hull at any one place); and templates for all the members which will make up the backbone of the boat—stemhead, stempost, stem apron, fore deadwood, keel, after deadwood, stern knee and sternpost.

The keel is made of teak; stempost, stem apron (to which the planking will be fastened) and sternpost of oak; stemhead, fore deadwood and stern knee of laminated oak; after deadwood of mahogany. All the wood will have come from the RNLI timber store at Cowes where it will have seasoned.

The teak for the keel is put through the planing machine to bring it down to the correct thickness, 3|", and a rabbet (to which, once again, the planking will be fastened) will be cut out by hand along each upper edge, using chisel and plane.

Blocks on which the keel will be laid are now built up, at each station, to the correct height below the datum waterline.

To check that these blocks have been set up at the right angle a declivity pattern will have been made from the lines plan, its top representing the horizontal datum waterline, its bottom the sloping line of the underside of the keel. The pattern is laid along the top of the blocks and if the datum waterline, checked with a spirit level, is in fact horizontal, all is well. The keel is laid down and building has begun.

(To be continued).