Elements of 40-Raters (Length and Sail Area Rule)

In 1890 'Iverna' was built, of practically the same length as, and of less beam than, 'Thistle,' and no great advance was made until the present year (1893) in the adoption of beam in the larger classes; but the progress in this direction may be easily traced in the 'forty' and 'twenty' rating classes, where the growth of beam and decline in displacement are very well marked, as the table and diagram show.

How far under the present rating rule beam may yet be increased with advantage to speed is still matter for debate and experiment. Personally I am inclined to think we have pretty nearly approached the limit. But of this much I am confident, that we have long ago exceeded the limit where beam improves a yacht as a comfortable sea-going craft, and that we should have a much more wholesome and useful vessel for all purposes, except possibly for international racing, with somewhat less beam and somewhat more displacement.

The diagram given ante may serve to give the reader an idea of the influence that the various tonnage or rating rules have had on the proportions and form of yachts.

British Yachts, 1893

American Yachts, 1893

But an entirely false impression has been conveyed should it be understood that the only advance made in yacht designing was due to more or less ingenious methods of evading the existing measurement rule; and it will be sufficient if the fact has been impressed, that a designer is as unlikely to make a successful vessel if he ignores the measurement under which the yacht is to race as by failing to recognise those laws of nature which govern the stability of bodies in water and their resistance in passing through it.

What has to be done by the yacht designer, besides getting the very utmost out of the tonnage rule, has never been more happily put than by Lord Dunraven in an article on International Yachting, from which I venture to quote:—

It has been shown, then, how from the three beam yachts of fifty years ago, the proportions drew out, under the 94 rule, to five, five and a half, and in some instances six beams in length, the 'Evolution' reaching even 7.8 beams; and even more rapidly, under the length and sail-area rule, fell back to something like three again. But the proportions are about all that remain in common to the clippers of 1845 and 1893 and it will be interesting now to trace how form, mode of construction and equipment have developed, as well as proportions.

Prior to 1820, what yachts there were afloat seem to have presented but little individuality of form, and showed, in common with the faster smugglers and fishing vessels of the day, a round barrel-like bottom, full round bow and fairly clean run, the buttock lines and after riband lines being generally fair and easy. These yachts were, one and all, built of timber, were ballasted with stones or gravel, the more advanced possibly with ore, while the sails and equipment were of a piece with the hull, the main rigging being of hemp, and no attempt being made after flatness in the sails.

The original 'Arrow,' of 84 tons, built somewhere about 1823 by Mr. Joseph Weld, seems to have been a fairly representative craft of that time, and raced with considerable success, even against much larger vessels than herself.

This original 'Arrow' was 61 ft. 9½ in. long by 18 ft. 5-¼ in. beam, with a depth of hold of 8 ft. 8 in.—that is, she had a proportion of length to breadth of 3.35—not very much differing in proportion from our present cutters of 1893: 'Calluna,' the 40-raters 'Lais' and 'Vendetta,' being about 3.4 and 3.5 beams to length, and the American 'Vigilant' about 3.32.

'Arrow' had the usual round barrel-like bottom, and, so far as can be learned, a round, short bow, the run being fair and easy, the small midship section lending itself pleasantly to this.

In 1848 'Mosquito' was built and fairly tackled the older ship, but the 'Arrow' was not yet the boat she now is, or as represented in the plate, as it was not till 1852, and until after the advent of the 'America,' that she appeared with her present long, hollow bow, having been pulled out some 17 feet in the winter of 1851, as indeed was pretty well everything else that aspired to be in the fashion. As is often the case, the pendulum swung too far the other way; bows were built on old boats, and new boats were designed with fore bodies, altogether out-Heroding Herod; and the 'America's' graceful, well-proportioned and moderately hollow bow was caricatured in some instances to a ridiculous extent. The 'America' showed also a decided departure in form of midship section, the bottom being much straighter than in our British-built craft, and the bilge higher and quicker—altogether a fine form for stability. The run, though somewhat short, was very fair, the buttock lines especially (as will be seen by the plate given in the second volume) showing beautifully easy curves.

But the lesson hinted at by 'Menai,' reiterated by 'Mosquito' and 'Tiara,' insisted upon by Scott Russell, but only brought home to us by the American schooner, was not the only one to be gleaned from that graceful vessel. Previous to her advent, our British-made sails were most baggy productions, kept decently flat only by drenching the luffs with water, a process called 'skeating.' This defect could not altogether be laid at the door of our sailmakers, as they did fairly well, considering the material they had to work with; but flax canvas at that date was still made by hand and was little firmer in texture, if indeed as firm, as the unbleached merchant canvas of the present day. The 'America's' sails were of machine-spun cotton, and, farther, were laced to the booms as well as the gaffs and masts, the staysail also being laced to a boom. These flat sails certainly suited the easy form of the 'America'; but here again the reaction was too strong, and it is undoubtedly the fact that for some years afterwards sails were got too flat, at least, for many of the full-bodied boats that they were put over, and the want of flow of the older-fashioned loose-footed sails was sadly missed when there came to be any work off the wind.

For some years then after 1851 (the year of 'America's' début here), sails were probably flat enough for the forms they had to drive; and American sailmakers apparently arrived at this conclusion, as they first of all gave up lacing the head sails, and later cut those rounder and rounder, until now American head-sails are cut much fuller than our own, and their mainsails also somewhat fuller. But while the 'America' was undoubtedly the great epoch-making vessel in yacht designing, the cutter 'Mosquito' possessed quite as many original features, and had she only come from abroad instead of being a home production, would have made a far greater stir than the schooner.

The 'Mosquito,' besides presenting novelties in form, in the way of an easy and hollow bow, large displacement, well-raked post and deep heel, also upset all preconceived notions of what was yacht fashion, by being built of iron. Great was the discussion over this departure; but, among many prophets of evil, a writer in 'Hunt's Magazine,' in 1854, discussing wood versus iron, predicts that 'the "Mosquito" is likely to be well and hearty when the present wooden craft have gone to that "bourne from which no traveller returns."'

This prediction has been exactly fulfilled, as 'Mosquito,' after as long and brilliant a career as has fallen to any yacht, is now, or was a few years ago, doing good work as a pilot boat off Barrow-in-Furness.

In 1852, Mr. William Fife, of Fairlie, in Ayrshire, who, with his father before him, had for some years been turning out fast and weatherly boats, produced 'Cymba,' a notable cutter. His father had made Scotch-built yachts, well known by his 'Gleam,' built in 1832, though only fitted out for racing by Sir Robert Gore Booth in 1837; but 'Cymba' was a marked improvement on this model, having a far longer and easier bow, larger displacement, considerable rake of post, and great drag aft.

The dimensions of 'Cymba' are appended, and it will be seen that she was just under four beams in length.

'Cymba', built 1852, by Fife

Meanwhile in matters of equipment steady progress was being made. Wire rope was rapidly ousting hemp for all standing rigging. Sailmaking, in the hands of Messrs. Lapthorn and of Charles Ratsey, was rapidly becoming a science. Machine-spun and woven flax canvas was in universal use, even cotton canvas was fitfully tried, and from the first strongly upheld by Charles Ratsey, of Cowes; but prejudice was too strong as yet for this material, and flax held the day for many a year to come. It is gratifying that Mr. Ratsey should have lived to see his favourite material triumphant, and to have looked, as he might have done in 1893, at the finest fleet of racing yachts the world has seen, clothed, from the Prince of Wales's majestic 'Britannia' to the tiny half-rater, entirely with cotton.

Among the most successful builders of these ships were Messrs. Robert Steele & Co., of Greenock, who had, so early as 1807, built yachts for the Excise and for various Scotch owners. Mr. William Steele of that firm being an able designer of yachts as well as of ships, it was natural that this method of construction should be adopted by him in the building of 'Nyanza,' 'Oimara,' 'Garrion,' and the majestic 'Selene,' to-day one of the handsomest schooners afloat; while many of that firm's large steam yachts, notably the 'Wanderer,' 850 tons, the finest auxiliary yacht of her day, were built on this plan.

Dan Hatcher of Southampton carried out this system in building several vessels, commencing with a schooner, the 'Bella Donna,' of 119 tons, in 1867; 'Seabird,' 126 tons, 1868; 'Lizzie,' of 20 tons, 1868; then, in one of his finest craft, 'Muriel,' which he built for Mr. Bridson in 1869; and in the famous 'Norman' he also adopted this construction. But, owing to the steel frame being considerably more expensive than timber, the composite build has never become popular until within the last few years, when the naturally weak shape of the modern yacht, the fact of all the lead being outside, and her enormous stability, have so increased the racking strains on the structure, that a merely wooden frame cannot be got to hold together without making the weight of the hull altogether prohibitive; and the composite racing yacht, for everything except very small vessels, seems likely to push all the others from the field. As illustrating this method of construction, a midship section is given of 'Lethe,' 163-ton yawl, and one of the finest of our cruising yachts. The photograph shows the lead keel, the heaviest ever cast, and also the method of securing the same to the bottom of the ship.

Since 'Mosquito' astonished the yachting world in 1848, until to-day when 'Navahoe' and other American racing yachts have been constructed of metal, iron and steel yachts have been more or less successful; but the difficulty of keeping a smooth and perfectly clean bottom is a considerable source of expense and worry, although the immense strength of the steel shell, and in a large yacht its lightness, will always be a set-off to the trouble of the uncoppered bottom.

In a lecture on 'Progress in Yachting and Yacht-building,' which I delivered early in 1881, in a fanciful specification of the yacht for the season 2000, I required that the plating below water should be of manganese bronze. Curiously enough, a few years later saw an attempt to combine the strength of steel and the smoothness, anti-fouling, and non-corrosive properties of copper, in the building of a torpedo-boat of this material; while this year the chosen defender of the America Cup has been plated with a similar bronze on a steel frame, the builders claiming, and not without reason, that the additional smoothness of bottom gives her an advantage of five to seven minutes on a forty-mile course. But such a practice seems hardly likely to become general for ordinary racing yachts built for men with a normal depth of pocket, and whilst, as in the old Mississippi steamboat days, it sometimes paid to burn hams, most of us have to try and get along with good coal.

I was going to build the topsides, frames, and beams of my ideal vessel of aluminium, and the other day a small yacht has been built, on the Continent, of this lightest of metals; but the present cost of this material, and, as yet, its unreliability, place it, for the present at least, outside the range of practical material for yacht-building. There seems more hope for some of the very beautiful and immensely strong alloys of aluminium, but they too are expensive, and also heavy. It may be some years before the complete realisation of my design is accomplished, and platinum is substituted for lead as ballast, though when syndicates of millionaires start yacht-building there seems very little limit to extravagance in construction.

In nickel-steel there is promise of a very perfect material. This is an alloy of the ordinary Siemens-Martin steel with nickel, and called by the makers Yolla metal. It can be made to comply with all the ordinary tests applied to ship steel, in the way of ductility under stress, and at the same time have a breaking strength of 40 tons to the square inch as against 27 for ordinary steel. This metal was used by Mr. Fife in 1893 for the frames and beams of the 20-rater 'Dragon' (third), and although the few pounds of weight saved by no means accounted for the phenomenal success of this little ship, yet the gain was all in the right direction.

Wire standing rigging continued to improve in quality, and very rapidly pushed out the old hemp rigging. From being made at first of good charcoal iron wire, it is now manufactured of the very highest class of steel, of such perfect character that the breaking strength of each wire is equal to 130 tons per square inch.

Used at first for standing rigging only, flexible wire rope takes the place of Manilla or hemp for the runners, and runner tackles, topping lifts, bobstay falls, outhauls, topsail and jib-topsail halliards, and latterly even for throat and peak halliards.

Other details were also perfected. Instead of the heavy and clumsy windlass, neat and light capstans are arranged of cast steel and gun metal, made so that the whole thing can be lifted away and stowed below while racing.

Right- and left-handed screws have superseded the old dead-eyes and lanyards, although these held their own desperately for many years. Introduced first in the 10-tonner 'Verve,' in 1877, the chain-plates were torn up in an extra heavy squall; but this occurred from the great stability of the boat and the fastening having been insufficient; the rigging screws, however, were blamed for all the trouble, and were laid aside for ten years or thereabouts, until re-introduced in the 5-tonner 'Doris.' Now no racing boat is without them.

Attention was also given to the lightening of deck fittings, skylights, companions, and the like, these in the racing vessels being kept lower and flatter, and the scantling reduced perhaps rather farther than advisable, as one certainly thinks on getting a stream of water down the neck from a leaky skylight.

Bulwarks have been reduced so as to save weight and windage, until in the smaller yachts they have become a mere ledge or foothold, whilst even in the largest class the rail is less than a foot from the deck.

Below, fittings have been lightened correspondingly. Cedar, yellow pine, and cretonnes or tapestries stretched on frames or light panels, take the place of the good solid oak and mahogany framing of the years gone by. Indeed, in some of the classes under 40-rating, cabin fittings have been dispensed with altogether; although this is not altogether a novelty, as the Marquis of Ailsa, in 'Bloodhound' (built 1874), and 'Sleuthhound' (built 1881), had at first no fittings beyond a seat along each side. 'Thistle' in 1887 was similarly arranged, nor had 'Valkyrie' or 'Vigilant' much more inside than a coat of paint when racing for the America Cup; but these last are of course special cases, where everything was sacrificed so that the uttermost second of speed should be taken out of the yachts. In cruising yachts the cabins are infinitely more elegant and comfortable now than formerly. The good old birdseye maple panelling with rosewood mouldings and gilded 'egg and dart' cornice has given place to tasteful cabinet-work designed in many cases by high-class artists. The main cabin of the 'Lethe,' designed by Mr. T. L. Watson, F.R.I.B.A., is a good example of this, and the 'Thistle,' now called 'Meteor,' the property of the German Emperor, has since been very beautifully fitted up from designs by the same gentleman, the photographs reproduced here giving but an indication of the elegance and richness of the interior.

One of the happiest combinations of lightness of structure with taste and comfort is in the Prince of Wales's 'Britannia.' The fittings throughout are of polished yellow pine and mahogany, with tapestries and cretonnes above the polished wood dado, the effect being extremely bright, cosy, and unostentatious.

Prior to 1870 but little was known of the laws governing the resistance to bodies moving through water. It is true that eighty years before this, towards the close of last century, Colonel Beaufoy had made an elaborate series of experiments in towing bodies through water, beginning first in one of the tanks of his father's brewhouse. These were elaborated in the Greenland Dock near London, and included the determination of the resistance of all manner of shapes, except unhappily shipshape ones, the nearest approach to these being double wedges, and double wedges with a straight amidship piece inserted. But while Colonel Beaufoy also made experiments for the determination of the value of surface friction on planes pulled through the water, no great importance seems to have been attached to these by shipbuilders in general, and the subject of surface friction was more or less lost sight of by them until again brought forward by Maquorn Rankine, first in a series of papers in the 'Mechanic's Magazine,' and more elaborately in his 'Shipbuilding, Theoretical and Practical,' published in 1866. In this Rankine, basing his deductions on Weisbach's experiments on the flow of water through pipes, concluded on mathematical principles that the entire resistance at moderate speeds of a fair and easy formed vessel was due to surface friction—i.e. the rubbing of the water against the sides and bottom of the ship. Rankine showed also that at higher speeds the forming of waves was a material and ever-increasing element in the resistance.

It is fully twenty years ago that the late Mr. William Froude began to give to the world the results of his experiments on the resistance of planes of different lengths, coated with various substances and towed at varying speeds through the water. These experiments were conducted under the most favourable conditions, and with the nicest regard for accuracy, and practically confirmed Maquorn Rankine's deductions, although it was found that Rankine had somewhat overestimated the value attachable to surface friction, and had also overestimated the increase in frictional resistance, due to increased speed. Still the great fact remained that practically the entire resistance to a fairly formed body, moving through water at moderate speeds, is due to friction and to friction alone.

Rankine's reasoning, early in the sixties, had been too subtle for those fathers of shipbuilding at that date engaged in the art. Able, honest, practical men, most of them could have handled an adze, or maul, with the best of their workmen, and were more at home fairing a sheering batten, or directing a launch, than in analysing speed curves, or investigating strength calculations.

But one or two of the younger and brighter minds in the profession, more especially those who had the advantage of Rankine's direct tuition, felt that the old beliefs as to resistance presented such anomalous and unreconcilable results that they could not be founded on any true law of nature. John Inglis, jun., then a mere boy, instituted in Pointhouse Shipyard Rankine's method of estimating the resistance of ships, and for many years was alone in this mode of investigation.

But with Froude's experiments all doubt on the matter vanished. It was no longer a question of 'condemned mathematics.' Froude had the happy knack of writing so that the proverbial schoolboy could understand him; and the schoolboy could see the value of resistance to motion through water weighed out as simply and accurately as a pound of currant bun. These experiments for the determination of the frictional resistance of water, published in 1874, were supplemented presently by experiments on models of actual ships, and also by towing a full-size ship, the 'Greyhound,' her resistance at various speeds being recorded by means of a dynamometer on board the 'Active,' the vessel towing her. The results of the experiments on model and ship were set out in a curve, when it was found, after the necessary corrections were made, that both curves were of precisely similar character. A basis of comparison between model and ship was thus established, the measure of this being set forth in what is known as Froude's law of comparison, which may thus be stated. The equivalent speed of a ship and the model it represents will vary as the square root of their lengths. Thus, in the case of a ship 100 feet long represented by a model 4 feet long, the equivalent speed of the ship would be five times that of the model, and at these equivalent speeds would present similar phenomena connected with resistance as the model does. This fact enormously increased the knowledge of investigators, and it was belief in it that gave the writer absolute confidence in carrying out the design of the 'Vanduara,' though he possessed experience in small boats only. Mr. Froude also split up the several elements of resistance to motion through the water into their component parts, assigning a value to each, and showing what was due to surface friction and eddy-making, and what to wave-making. Scott Russell had already argued for a given length of fore and after body for any given speed, and this was recognised by yacht-builders to some extent by their gradually lengthening out their vessels; but the disadvantages as well as the advantages of length could only be thoroughly realised on investigating Froude's experiments. An example is given of such an experiment in the diagram, which shows the resistance curve of a model of the 'Merkara,' built by Messrs. Denny Bros., at Dumbarton, where the several resistances are shown, each in its place. In this diagram the resistance due to surface friction is indicated by the dotted line, and the total resistance by the full line. Up to a speed of 250 feet per minute (for the model) the resistance is almost entirely due to skin friction, but after that the wave-making becomes more and more serious until at 370 feet per minute the wave-making takes more power than the surface friction.

While surface friction thus plays a very large part in the resistance of all vessels, and more especially in that of ocean-going steamers and ships, which from their large dimensions seldom attain serious wave-making speeds, yet undue importance may be placed upon friction, and, in the smaller yachts, especially, surface may be inordinately cut away. A notable example of this was the 'Thistle,' built in 1889 to compete for the America Cup; here the surface was so cut down that sufficient lateral plane was not left to hold her to windward, and although she sailed the water as fast as the American champion, the 'Volunteer,' she drifted bodily to leeward.

A short history of Mr. Froude's discoveries in resistance was advisable before touching on 'Jullanar,' as this wonderful vessel, whether the result of intuition or of early and immediate appreciation of Froude's investigations, was a remarkable example of the modern theories regarding naval architecture.

The same year that 'Jullanar' was built, I designed my first racing yacht, the 5-ton 'Clotilde,' but whilst I had the advantage, through my friend Mr. John Inglis, jun., of specially early access to Professor Froude's investigations, I cut her away in a somewhat timid fashion, though sufficient for her at that time to be compared to a 'cart-wheel,' with the accompanying prediction that she might 'run on land, but would never sail in salt water.'

Meanwhile, with splendid audacity, and with no timid reverence for precedent, Mr. Bentall built the 'Jullanar.'

An Essex plough and agricultural implement maker, Mr. E. H. Bentall had but little training in naval architecture, but from boyhood had been fond of yachting and of yacht modelling. He fancied he could do something in the way of improving the form of the existing racing yacht. After cutting several half-models, he got one that pleased him, and on a piece of his own property adjoining the Blackwater river in Essex, the famous yawl, afterwards to be known as 'Jullanar,' was laid down.