Marine Link
Wednesday, December 13, 2017


THE last hundred years have marked an epoch in which incalculable benefit has accrued to mankind from the innumerable inventions which have had their inception during that period. It is true that we owe to the artist, using the term in its widest sense, much that makes life fuller and richer in the realm of the mind, but it is. the genius of the inventor which has made possible the marked improvement that has taken place in the lot of the average man during the last century. The artist, insofar as he gives to his age something that is original in its presentment, may, of course, be classed as an inventor, but a woi-k of art can never make the working hours of men shorter by a single second; whereas the inventive genius of a Watt will bring unlimited material advantage to the world, and will, directly or indirectly, shorten hours of labor, increase the wealth of nations, and improve the whole social fabric. Mr. Joseph William Isher- wood, although he would not consider himself as ranking in the same category as Watt or Stephenson, can claim a place in the forefront of those who have made important contributions to industry, in that he has introduced the "Isherwood" system of longitudinal framing for ship construction, now so widely adopted.

It was in the drawing office at the shipyard of Messrs. Furness, Withy & Co., Ltd., at West Hartlepool (now owned by Irvine's Shipbuilding & Dry Docks Co.", Ltd.), that Mr. Isherwood commenced his career. At the conclusion of his apprenticeship with this firm he continued in their service in various responsible positions, eventually leaving them to take up an appointment as ship surveyor with Lloyd's Register of Shipping. He was associated with this classification society for eleven years, for the greater portion of which time he acted as a surveyor on the Chief Ship Surveyor's staff in the head office, in London, the duties attaching to this position being to examine and consider the various structural plans of vessels submitted to Lloyd's Register for approval.

In the course of Mr. Isherwood's association —;di the British premier classification society, he became convinced that the then prevailing system of ship construction was not all that could be desired when viewed from the scientific standpoint. Up to that time the building of ships had followed, almost slavishly, on the lines which had prevailed from the early days of ship construction. From that far-off period the principle of fitting a series of closely-spaced transverse frames extending from the keel up to the decks, in association with closely-spaced transverse beams, had been observed with very little variation. This method was the obvious one, and probably the only practicable one, for wooden ships; but when the transition stage from wood to iron, and later to steel, was reached, no alteration was made in the system of building, and it was this style of construction which appeared to Mr. Isherwood to be deficient. In his opinion, a ship built after the ordinary transverse method was weak in the longitudinal direction, and he set himself the task of remedying this, ultimately evolving a system of construction which would provide all the desired longitudinal strength. The result is seen in the longitudinal method of construction which is now known throughout the world as the "Isherwood" system, and which he patented in England in 1906, since when patents have been granted for the system in many other countries, including the United States of America.

It must not be thought that Mr. Isherwood claims to be the first originator of longitudinal framing. For a great many years it had been the dream of naval architects and shipbuilders to produce a commercially practicable system of longitudinal framing, and even the great Scott Russell applied his genius in this direction and built a number of longitudinally-framed ships, the best- known example being the famous "Great Eastern." The fact remains, however, that, up to the time Mr. Isherwood entered the field, this type of ship construction had not proved to be a commercial proposition; and great credit, therefore, is due to the inventor of the "Isherwood" system in that, despite the failures of predecessors and undaunted by the non-success of such a giant in the history of shipbuilding as Scott Russell, he persevered with his efforts and succeeded where others had failed.

In order to proceed with the development of his system, Mr. Isherwood severed his connection with Lloyd's Register in 1907, and he had not long to wait before owners were forthcoming who had the courage of their convictions, and who instructed him to go ahead with the construction of vessels for them on his new system. The first vessel so constructed was the oil-tank steamer "Paul Paix," of some 6,600 tons deadweight. This boat was looked upon as in the nature of an experiment, and was watched with great interest by practically the whole of the shipbuilding and shipowning community throughout the world. The "Paul Paix" was completed in August, 1908, while the first general cargo liner to be constructed on the "Isherwood" system, the "Gascony," was completed in the early part of 1909.

The "Isherwood" system was first introduced in the United Kingdom, but it was not long before builders and owners in other countries realized its great possibilities, and the shipbuilders of Holland in particular were very quick in making a commencement, shortly afterward to be followed by builders in the United States, Canada, Germany, Belgium, France, Sweden, Italy, Spain, and even in faraway Japan. In all these countries "Isherwood" vessels have been constructed; and, judging from the number of vessels launched for American lake ownership, it would appear that the system has gained great favor in the eyes of lake owners, while many more large "Isherwood" freighters, also intended for service on the Great Lakes, have quite recently been completed. As evidencing the firm footing this method of construction has gained in Japan, it may be mentioned that no less than sixty vessels, aggregating about 450,000 deadweight tons, have recently been constructed for on this system in the land of the Rising Sun. The United States, however, has played a greater part in the adoption of the system, there now being over 500 vessels, aggregating 4,500,- 000 tons deadweight carrying capacity, under con-struction and on order in this country.

Among the more interesting vessels constructed on the "Isherwood" system, mention should be made of the coal and ore carriers "Rose Castle" and "Lord Strathcona." These vessels, which have been specially designed for the carriage of coal and ore, are the largest single-deck vessels ever built in England. In the United States the high-class colliers "Achilles" and "Ulysses" have not long been placed on service by the Panama Canal Commissioners, for whom they were specially built. These two vessels are 500 feet long, and are very similar to the colliers "Orion" and "Jason," which were designed and are operated by the United States Navy Department. That the "Isherwood" system should be selected for the construction of what are undoubtedly the six finest colliers in the world indicates unmistakably that the claims made for it in connection with this class of steamer are thoroughly well-founded.

As may be readily imagined, the advantages of the "Isherwood" system have not been overlooked by the British and American Governments, orders for a considerable number of cargo and oil- carrying vessels having been placed by them to be built on the "Isherwood" system, while the United States Government have placed contracts for large troopships to be constructed on this system. Other types of vessels on the system have been constructed for the Indian Government.

Such, in brief, is the story of the success of the "Isherwood" system of ship construction, a story which represents one of the modern romances of the shipbuilding industry. Xor is the success likely to diminish, for shipowners have not adopted this method of construction as a passing fancy, and the volume of tonnage building on this system will certainly increase as the advantages of the longitudinally-framed ship become more widely appreciated by conservative owners and their advisers.

Mr. Isherwood is a member of the British Institution of Naval Architects, a member of the North East Coast Institution of Engineers and Shipbuilders, a member of the Cleveland Institute of Engineers, and of the American Society of Naval Architects and Marine Engineers.

The "Isherwood" system, which has now won a world-wide reputation, is a radical departure from the old-fashioned transverse method of ship construction, as will be seen from the following brief description:

In the "Isherwood" system of construction the transverse frames and beams are fitted at widely spaced intervals, the general practice, so far, having established this at about twelve feet. These structures form complete transverse belts around the ship. They are directly riveted to the shell plating and deck of the vessel, and are made of not less strength than the number of transverse frames that are fitted in ordinary vessels for a corresponding length of ship. These strong transverse girder frames are slotted around their outer edges, in order to admit of continuous longitudinal stiffeners being fitted not only at the decks, but on the sides, bottom, and tank top.

The fitting of these longitudinal stiffeners directly on to the plating prevents damage to the decks through buckling, which has frequently occurred in vessels of the ordinary construction which have had no fore and aft support to the plating in between the transverse beams. In vessels with double bottoms transverse floor plates are usually fitted intermediate to those at the sides and decks of the vessel. These intermediates enable sectional materials, such as bulb angles, being utilized as longitudinals both at the tank top and on the outside plating, thereby providing a double- bottom construction which is much more ready of access than one built on the ordinary system.

To all who are acquainted with the art of shipbuilding it is at once apparent that here is a method of constructing vessels which opens up vast possibilities and is a step in the right direction, operating directly in the interests of both owners and builders, in striking contradistinction to the manner in which longitudinal stiffening is being ruthlessly eliminated from ordinary transverse vessels now being built. Side stringers, found necessary by the result of years and years of experience, are being cut out wholesale in face of the fierce competition ruling in normal times, the compensation—if any—demanded by classi- .cation societies being only nominal to satisfy rule requirements fore and aft girders in double bottoms have been reduced in number, and the longitudinal resistance to buckling and tearing seriously impaired. It is not claimed, and has never been claimed, that the "Isherwood" system is a panacea for all the ills that ships are heir to, but it is contended—and the experience with hundreds of steamers has fully justified this contention—that this longitudinal method of framing, lending itself to a correct distribution of materials, gives a vessel incomparably superior strength to the old-fashioned transverse type. In support of this contention it might be advisable to briefly enumerate a few of the chief advantages which experience has proved conclusively are obtained by adopting the "Isherwood" system.

The great drawback of ordinary transverse vessels has always been a serious lack of strength in a longitudinal direction. This might be expected in a ship built with a series of closely spaced transverse frames extending from keel to deck and with practically no longitudinal stiffen-ing apart from the support afforded by a few side stringers, and the modern tendency is to leave out even these. In the "Isherwood" system the strong transverses fitted at a wide distance apart provide more than sufficient transverse strength, and the continuous longitudinals attached directly to the shell and decks give a proper amount of longitudinal strength, the two sets of frames combined with the plating giving a tremendously strong structure, obviating entirely deck damage due to buckling, which is so prevalent in ordinary transverse vessels. From the strength point of view alone the "Isherwood" vessel is infinitely superior to the transverse vessel, and this advantage claimed in the theoretical stage has been substantiated by experience.

The cost of maintaining their vessels in a fit condition to meet all calls made upon them is a very serious matter for shipowners. This has always been a more or less (generally more) expensive matter in transverse ships, and here again the "Isherwood" system offers substantial relief.

Perhaps the most important advantage from the shipowner's point of view, and one to which too much thought cannot be given, is the increased deadweight carrying capacity which accompanies the "Isherwood" system. It may seem paradoxical, but it is nevertheless true, that by using less steel material an "Isherwood" ship gains in strength. The material dispensed with consists of a number of those parts found so objectionable in transverse ships, but which are nevertheless necessary—namely, beam knees, bilge brackets, tank knees, packing, and many transverse connections. By thus dispensing with a lot of unnecessary steel and the consequent lightening of the hull, the "Isherwood" vessel is enabled to carry a correspondingly increased amount of cargo without any increase in the draught. To take an example of what is meant, assume an ordinary cargo steamer of about 9,000 tons deadweight. This vessel, if built on the "Isherwood" system, would carry approximately 200 tons more cargo than the same vessel built on the ordinary transverse system, Lloyd's classification being the basis in both cases. If, as might be the case in some instances, it is not desirable to increase the deadweight, advantage of the saving in weight might be taken toward fining down the model, and so producing a vessel which could be driven in a more economical manner as regards coal consumption, while retaining the same cargo capacity in proportion to the deadweight of the steamer. The extra deadweight gained in each vessel is of course governed by the dimensions, therefore the larger the vessel the greater is the increase in deadweight capacity. If deadweight is the only important point, advantage can be taken of the saving and produce a smaller vessel, thus increasing the saving in steel weight and still maintaining the deadweight. This may be important where restricted dimensions are necessary.

Another happy feature accompanying the "Isherwood" system is concerned with the matter of vibration, or perhaps it would be more accurate to say with the diminution of same. Whether in the most humble little coaster unostentatiously plying her trade around our coasts, or the most palatial liner engaged in passenger-carrying to all corners of the world, the matter of vibration is one which the owner must look squarely in the face. Undue shaking in a vessel can only have one result, and that is to increase the cost of maintain^ the steamer in a proper state of repair. If it can be shown that the "Isherwood" system almost, if not altogether, eliminates vibration, surely on this point alone there can only be one choice left to those concerned with the purchase of new vessels. The cargo boatowner must as-suredly admit that if his ship is subject to less wear and tear he has a superior profit-earning vessel, and if the owners of larger passenger liners can offer their patrons vessels which are practically free from this objectionable vibration, the popularity of their ships is assured. That the "Isherwood" system of framing practically, if not altogether, eliminates vibration from the hull structures of steamers is now beyond doubt.

These are but a few of the many advantages which appertain to the "Isherwood" system, but they will probably be considered sufficient to support the view of those far-seeing shipowners who, in increasing numbers, are steadily adding "Isherwood" vessels to their fleets.

The ore trade on the Great Lakes of America and Canada is undoubtedly one of the most severe trades in which steamships are engaged. The vessels laid up by ice in the winter are worked at top pressure during the remaining months of the year, and it is indeed a case of the survival of the fittest. When the "Isherwood" construction was first introduced onto the lakes considerable interest was aroused, and the advent of the first vessel was eagerly awaited. The result of this ship's working has been so successful that several repeats are now also in commission, and the "Isherwood" system has been adopted in the construction of practically all new vessels engaged in the ore-carrying trade on the Great Lakes.

That the "Isherwood" system provides everything claimed for it cannot be denied if the amazing developments since its inception be studied. The "pioneer" "Isherwood" ship was completed toward the end of 1908, and to-day there are about 1,200 ships aggregating 9 million tons deadweight carrying capacity built, under construction or on order on the "Isherwood" system.

Mr. Isherwood is to be congratulated on the commercial success which has attended his system from the first, and which has now far surpassed his most sanguine hopes. But the personal benefit that has come to him is only a small matter compared to the benefits it has brought to the shipowner, the commercial world and the traveling public.

Maritime Reporter Magazine Cover Dec 2017 - The Great Ships of 2017

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