In many yachts the floors are of cast-iron of the form shown by a (Fig. 24), upon the heads of which the heels of the first futtocks are dowelled, and the heels of the sister timbers are brought down to, and rest on, the top of the keel. There is no denying the strength of the grown floor and cast-iron floor plan, and the keel would be knocked into sawdust before it would come smashing through the cabin floor.
The other parts of the vessel, whether large or small, should be constructed according to the recognised practice. However, it is seldom that a shelf is met with in 10-tonners, a clamp only doing duty as a shelf to take the deck-beams and fastenings and timber-head fastenings. When a clamp only is fitted in a 10-toianer, the top strake (under the covering board) should be of oak, and bolted through timber, clamp and all.
The proper plan of construction for this part of the vessel is shown by Fig. 25; a is a timber or frame ; b a deck beam ; c the shelf ; d the clamp ; e the ceiling; f the outside plank ; g the top strake or sheer strake; h the covering board ; i the deck plank ; j a stanchion ; k k bolts through every beam ; / a dowell ; m a bolt through every frame; n a hanging knee bolted as shown ; o, in the other sketch, shows a section of pieces of timber fitted between deck beams to take the fastenings of the covering board. Each piece of timber is bolted to the shelf.
The number of hanging knees depends upon the size of the yacht, and the minimum number allowable is set forth in the Table E in page 109.
A vessel, although built of good material, is frequently less strong than she ought to be in consequence of the butts of the plank coming too near each other. Lloyd's rule is that butts should not come nearer than 5 feet to each other on adjoining planks; and no butts are allowed on the same timber unless three strakes come between them. This rule should be very particularly attended to, especially in vessels that have but one or two inside strakes, and but few through fastenings.
Various plans have been used for strengthening and binding together the fabric of the hull ; but the diagonal iron braces previously referred to are only used in large yachts of great length. In yachts of eighty feet and under in length, thick strakes of hard wood or pitch pine are worked under the clamp and shelf, and run the whole length of the vessel, and are through-fastened with metal bolts. Similarly two bilge strakes along the curve of each bilge on each side are worked and through-fastened.
Limber strakes are also sometimes worked over the heels of the first futtocks which join the heads of the floors, and are through-fastened. A limber strake in a cruising vessel with a floor construction, such as that shown in Figs. 19 or 20, where there is no keelson, would greatly add to the strength of the vessel ; but in yachts of 50 tons and under it would scarcely be necessary to have a " thick strake " above the bilge strakes. Outside a wale or bend is worked and through-fastened ; but
where all the planking is of hard wood, the wales are dispensed with.
It must be understood, if the yacht about to be built is intended for racing rather than cruising, that it will be an advantage to reduce the scantling, and increase the spacing so far as may seem compatible with ' strength. The plank also (if the owner is not particular about obtaining a long term of years in Lloyd's Register, see Tables A, B, and C), from the bilge upwards, can be of red pine instead of teak or oak, and the deck beams can also be of red pine; the bulwarks of red pine, and the stanchions and rails reduced in size so far as may appear consistent with strength. There are racing vessels, of similar tonnage, with as much as two-fifths difference in the size and height of stanchions ; and in a 200-ton vessel half a ton of weight might very well be disposed of in this way. Of course it is only fair to say that some of our most successful racing vessels, such as Florinda, Corisande, or Gwendolin, are built of the heaviest material and full scantling. However, although this may show that a vessel can be so built and succeed as a racer, it is at least an open question whether she would not have been a still greater success had her scantling been reduced.
The metal fastenings of yachts (see Table D) form a subject about which there is a great deal of opposite opinion. The builder who constructs cheaply contends stoutly that there is nothing like iron ; on the other hand, the builder who always asks and gets a good price for his work would as soon think of fastening a yacht with cabbage stumps as with iron. Others recommend iron for dead-wood bolts, shelf bolts, and floor bolts, with Muntz' metal for plank fastenings. Others recommend Muntz' metal for all bolts, and a mixture of Muntz' metal and trenails for plank fastening. There is no doubt that iron has advantages, so far at least as long dead-wood bolts are concerned. Iron can be driven very much tighter than copper-rod, and its strength is greater. We have seen iron bolts, that had been made hot and dipped in varnish or oil before they were driven, taken out of a vessel thirty years old, long before galvanised iron was heard of, as clean and bright—in fact, the varnish unperished—as they were at the moment of driving. On the other hand, if the iron were driven through a shaky piece of timber, or loosely driven, so that salt water might get to it, decay of the iron would be very rapid ; hence preference must be given to copper or Muntz' metal. Galvanised iron is often used for shelf fastenings, and it is less objectionable there ; but preference should be given to Muntz' metal for all dead woods, as it can be driven as tightly as iron, and, if of the best quality, will clench as well.