Not the least important of the types of steamers which throng the ports of the world—or which used to do so, for their number is decreasing—is the tugboat. Up to a few years ago it played a most important part in the work of a port; every sailing ship entering port usually engaged the services of a tug; many ports, like that of London, could not be entered at all by a large sailing ship without the services of “a fair wind ahead,” as sailors often call the tug, and in the waters outside the Port of London the tugboats found one of the best “pitches” in their business. To be towed safely into port might mean a saving of many days in avoiding the waiting for a wind. The tug was equally useful to a ship leaving port, as she might not only tow her into the open sea, but might even take her right out of sight of land altogether, in helping her along until a favourable slant of wind was met. At ports like Liverpool sailing-ship masters often, when wind and tide were favourable, brought their ships into port under full sail without a tug, though probably three or four of them kept her company in the hope that their services would be required, as they generally were when the time came to enter dock.

Nowadays sailing ships are few in number and are becoming fewer, and steamers seldom require aid. They enter and leave port under their own steam and even at times dispense with a tug when passing through the dock entrance, their own steam or a steam capstan ashore being found sufficient.

But a certain amount of towing has still to be done, and the tug is then able to prove herself indispensable. She has often to tow a ship from one coast port to another, while for rescue work on the coast their services mean all the difference between success and failure. A lifeboat is towed to a wreck or vessel in danger. The tug, which has perhaps been several hours fighting her way forward against a howling gale and a terrific sea which threatens to overwhelm her, then stands by, and a paragraph in the papers to that effect is about all the recognition she gets, yet the perils undergone by the men on the tug are no less real than those of the lifeboatmen. Year in and year out the tugs pursue their calling, and it must indeed be bad weather that will induce a tugboat captain to seek the shelter of a harbour if his bunkers are fairly full and he sees a chance of doing business.

The feats performed by some tugs are extraordinary. They will undertake a voyage of a few thousand miles as serenely as one of as many yards. Cleopatra’s needle, in its strange cylinder ship, was towed to this country, after being lost adrift in the Bay of Biscay, by a well-known London tug. Among the most remarkable recent feats are the towing of immense unwieldy floating docks from this country to South American west-coast ports; it is not too much to say that a tug-owner will cheerfully undertake to tow anything that will float from any one seaport to any other.

The cargo steamer until ten or fifteen years ago possessed no special features. It was simply a big box carrying propelling machinery and as much cargo as possible on the smallest attainable registered tonnage. Such vessels were usually loaded and discharged by the necessary machinery on the quay side, while if the transfer of cargo had to be to or from barges alongside, the operation was likely to be tediously performed by means of a derrick or two, or a gaff with tackle that might or might not be worked by a steam-winch. The increasing size of vessels and the use of steel for steamer building rendered imperative the adoption of faster methods, and the demands for special steamers adapted for particular trades brought about the development in cargo steamers of special types. These types have to a very large extent taken the trade away from the steamer of the “tramp” class, which wandered from port to port taking cargoes of anything or everything from anywhere to anywhere. They were usually slow and uncomfortable boats and the complaints made as to the condition of some of them were fully justified. The demand for better cargo accommodation was met by the supply of vessels of various types which are a tremendous advance upon the old “tramp,” and their advent compelled the builders of ordinary cargo carriers to produce a better and larger steamer in every way, and fitted with modern appliances for the rapid and satisfactory handling of cargo.

The cargo “tramps,” built about 1902, were on an average about 350 feet long, 2800 tons gross and 4000 tons dead weight. In build they were of the poop, bridge, and forecastle deck type with main deck below the upper deck, and fitted with double bottoms. The appliances for working cargo are extraordinarily complete and effective. To each hatch there are usually two winches and two derricks, having 5 tons lift each, with, as a rule, a heavy derrick capable of lifting from 20 to 30 tons; the last is portable, so that it can be used at either of the two main hatches. Cathead davits have been dispensed with as, with stockless anchors, they are not required owing to the anchors stowing up the hawse pipes. Officers, &c., are berthed in deckhouses built on the bridge deck, leaving the bridge ’tween deck clear for cargo. Electric light and steam-heating are fitted to all rooms, advantages not enjoyed by older boats.

About the year 1904 the shelter-deck type reached its present stage of perfection, the advantage of this type being increased cargo capacity on a small net tonnage. The accommodation of officers and engineers is fitted in midship deckhouses and side houses. Much more attention is now paid to the ventilation of the holds and ’tween decks, more especially in coal-carriers, where efficient ventilation is of the highest importance. The adoption, within very recent years, of wide-spaced pillars in holds and ’tween decks has greatly improved the facilities for stowage of large cargo.

The four desiderata of a modern cargo-boat are that she should have a low registered tonnage in comparison with her capacity, ample water-ballast tanks, large hatchways, and holds as free from obstruction as possible. Three or four methods are practised by builders for attaining these objects, and every builder has made modifications of them as time has shown the necessity of the changes to meet varying trade conditions.

The principal types of cargo vessels are the turret, trunk, cantilever, and side tank.

The earlier modern ocean-going steamers were usually flush-decked. This left the machinery openings bare in the deck, so a bridge was added for their protection, and the flush deck was further encroached upon by the addition of a forecastle and poop. In some cases the quarter deck was raised, which was an awkward arrangement on account of the change it necessitated in the structure and framing, and in others the bridge and poop were joined. What is sometimes called the “three island” type, a very appropriate name in rough weather when the steamer takes a sea on board, came into great favour; it consists of a forecastle, bridge, and poop, and many vessels of considerable size have been built in that style. The cattle trade was responsible for some important changes in design, the “wells” where the cattle are carried being given iron and steel shelters, which thus form the shelter decks, a type of light deck introduced into the superstructure of most ocean-going steamers.

The secret of the turret steamer is strength without unnecessary weight. Every ton of steel that can be kept out of a ship without reducing her strength adds a ton to her carrying capacity. This object is partly achieved in the turret steamer by the large amount of flanging adopted in the construction of these vessels. This is shown in the whole of the sheer strake and stringer plates, in the deck and frames of the cellular bottom work, and with great success in the joggled plating of the hull. Since 1895, when the Doxfords introduced a new method of rolling ships’ plates with joggled edges, they have built all their vessels under this system, making “packing” unnecessary. The turret gives longitudinal strength in the hull and leaves the hold clear. The strength is so great that in a steamer in which, by the substitution of deep for ordinary frames, all internal supports, beams, and girders are dispensed with, a clear hold is obtained. The firm claims that 58 cubic feet per ton dead weight under hatches is secured against 52 to 54 cubic feet per ton in the ordinary type. Thus the turret carries more on a given displacement, and having a lower registered tonnage, can earn more freight and save expenses. There are several designs of turret steamers adapted to different trades. Their suitability for bulk cargo, such as coal, or for large and heavy packages, is evident, while other types are equally suitable as passenger steamers, not a few lines having adopted them. Another advantage is that deck cargoes of wood can be carried with perfect safety on the turrets. Some of the cargo-boats designed for the ore and coal trade have their machinery right aft, and their holds are absolutely clear of obstruction of any kind whatever. Many of these are mastless but are fitted with twin derricks, a 10,000-ton boat carrying as many as seven pairs. The first of the mastless type was the Teucer. Convention fixed the depth of hold at about 15 feet, but now a depth of 26 feet and more is becoming fairly common. All cargo vessels are built on the box-girder system, which ensures great strength and capacity, and permits of enormous hatchways, and marine engineers have solved the problem of providing greater speed without additional expense.

Messrs. Doxford, in their latest attempt to solve the problem of the easily-shifting cargo in bulk, proposed that vessels intended for this trade should have inner upright walls fitted some distance from the hull, and so arranged that when the vessel is heeled over within the usual range of inclinations of a vessel at sea, the weight of the cargo and the buoyancy create a restoring couple in all conditions of loading. The spaces between the cargo-hold and the outer shell may be left empty or used for water-ballast as required. In some instances the bottom is reduced in depth as much as the loading regulations will allow.

Among the more notable features of recent years in cargo-boats specially adapted for the coal, iron ore, and other dead-weight trades is the patent cantilever framed type of steamer built by Sir Raylton Dixon and Co., Ltd., Cleveland Dockyard, Middlesbrough, on the Harroway and Dixon patents. This type of boat has the advantage of having totally unobstructed holds with very large hatchways and an additional 75 per cent. water-ballast, which is placed in the tanks inside the cantilever construction at the top of the holds under the deck. In these steamers the space on either side and under the decks is used for water-ballast, which is carried in triangular tanks at either side of the vessel, immediately beneath the main deck. The tanks extend from the coamings to the sides of the ship, the greatest side of the triangle being towards the cargo and supported by the cantilever framing; the tank framing and plating increase the strength of the hull materially. The sloping topsides thus formed prevent bulk cargo shifting. An advantage to the owner is that the tanks are exempt from tonnage measurement. When these tanks are filled with water and also the lower and peak tanks the vessel is seaworthy even if the cargo-space is empty.

This additional water-ballast has the special merit of immersing the ship deeper when in ballast only, consequently giving more power to the propeller and rendering the ship more manageable when light, as well as supplying unique security in case of damage, for when one of these boats is loaded and the topside tanks are empty, they correspond to the air tanks of a lifeboat and thus prevent the ship from sinking.

These vessels in some cases have been fitted with shelter decks right fore and aft for the carriage of cattle and horses, and indeed would be suitable for passenger service, for which the very easy rolling movement would be a great recommendation.

This type of vessel has been on the market for about four years and already some 200,000 tons have been built. One of the largest steamers built on this plan is the Echunga, 405 feet long, 56 feet beam, and 28 feet 8 inches moulded depth. She was built in 1908 for the Adelaide Steamship Company. Her net register is 2245 tons, her dead-weight capacity 8400 tons, and her measurement 11,000 tons. Her topside tanks contain 1350 tons, and her total water-ballast is 3200 tons.

In the steamers built by Messrs. William Gray and Co., Ltd., of West Hartlepool, water-ballast is carried not only in the double bottoms but in side tanks, the inner skin of the double bottoms being carried a considerable distance up the sides. A hull within a hull is thus formed, the intervening space being used as water-ballast tanks. Not the least advantage is the great additional strength the ship is given. The trunk system of shipbuilding adopted by Messrs. Ropner and Sons, Ltd., of Stockton-on-Tees, differs from the turret by having a double wall on each side, and has not the rounded turret base. The steamer Thor, built for a Norwegian owner, has only one hold, no less than 250 feet in length, the engines being placed aft.

Messrs. R. Craggs and Sons, Ltd., of Middlesbrough, have made a speciality of building tankers, and were the designers and contractors for the first ocean steamer to load oil in bulk. Their stringerless system of construction is, they claim, the last word in transverse framing, and has numerous advantages for single-deck vessels.

During the last three years three distinct innovations in steam-ship construction have been made. All three are of a revolutionary character, and two are likely to have no small influence upon the construction of both passenger and cargo steamers, while the third is of great importance for the rapid loading and discharging of coal and ore cargoes. The first of these is the Isherwood system of longitudinal ship construction, in which the transverse frame as ordinarily understood is dispensed with, but deep transverse web frames are placed at intervals of 15 to 18 feet apart and extending right round the ship, forming both frame and beam together. These frames are intersected by longitudinal frames consisting of sections of convenient form, preferably bulb angles, spaced about 20 to 30 inches apart, just as transverse frames are under the ordinary system. The fore and aft frames are fitted beneath the deck also, and are spaced from 30 to 50 inches apart. In the double bottom the fore and aft girders are formed of plates and angles.

The first general cargo vessel on this plan was the Craster Hall, launched in February 1908 by Messrs. William Hamilton and Co., Ltd., Port Glasgow. Her length is 392 feet 6 inches; breadth, 50 feet; depth, 29 feet to the upper deck; dead weight, 7300 tons.

Two oil-tankers, the Paul Paix and Gascony, have been built by Messrs. Craggs and Sons on this system. One of them grounded off Calais with a cargo of oil or benzine on board, and on being dry-docked for examination was found to have no damage to her plates whatever. All the steamers built on the Isherwood plan have a marked absence of vibration even when running light.

The corrugated steam-ship Monitoria, launched in the summer of 1909 by Messrs. Osbourne Graham and Co., Sunderland, to the order of the Ericsson Shipping Company of Newcastle-on-Tyne, is another departure from accepted ideas. She is an ordinary “tramp” steamer so far as dimensions and engine-power go; her only difference, and it is an important one, is that she has two corrugations running along each side between bilge and load water-line, and extending from the turn of the bow to the turn of the quarter. These corrugations do not project very greatly, but according to the inventor, they so affect the stream and wave action around and under the vessel that a source of wasted energy is prevented, and more power becomes available for propulsion. The Monitoria’s dimensions are: length, 288 feet 6 inches over all; breadth, 39 feet 10¹⁄₂ inches; the breadth over the corrugations is nearly 42 feet. The space for bulk cargoes is greater than on her sister ships by the cubic contents of the corrugations, but the tonnages remain unaltered. As a sea-going ship it was found that the corrugations made her much steadier, acting as though they were bilge keels, and that the coal consumption was less, notwithstanding that she made faster time than her sister vessels under precisely similar conditions.

The third innovation is the application of the belt-conveyor principle to a collier. The steamer Pallion, in which the machinery is installed, is equipped throughout with twin belt conveyors which, travelling fore and aft the vessel in a space under the cargo, carry the cargo towards the stern, whence it is carried on other belts at the front of the poop for delivery. The latter belts are carried on swivel booms which can be raised or lowered or moved sideways, so that the cargo is delivered direct by the belts into railway trucks on the quay or into barges, and the operation can be conducted at the rate of 250 tons an hour on each side of the vessel simultaneously. Under this system no shoots are used, and there is no handling of the coal. The Pallion requires only about six hours to discharge a full cargo with six men, as against over a hundred men and eleven hours in the ordinary way. Her water-ballast tanks can be emptied or filled as fast as the cargo is placed in her or taken out. She was built by the Doxford firm at Sunderland for a Newcastle Shipping Company.

The carrying of petroleum in bulk has spread enormously of late years in both steamers and sailing vessels specially designed for the purpose. In all such vessels the method of the subdivision of the holds into tanks is of the greatest importance, together with that of ventilation, and every builder and owner of such vessels has his own theories as to the best means to be adopted. A later type of tanker has the engines astern. A further innovation in this class of steamer is to fit them for burning oil fuel, the two big tankers Oberon and Trinculo having had the necessary installation placed in them last year at Smith’s Dock, North Shields, sometimes called “the home of tank-steamer repairing work.”

An economical method of transporting oil in bulk across the Atlantic is adopted in the case of the steamer Iroquois, which herself carries about 10,000 tons of oil in bulk, and also tows with her the sailing barge Navahoe, carrying an equal quantity, one set of engines thus doing duty for both cargoes. The Navahoe is the largest sailing ship in the world, is schooner-rigged on all her six masts, and is able to make her way to port in case she becomes separated from her consort.

The floating dock is one of the most interesting of the many developments in connection with the naval and mercantile marine of the second half of the nineteenth century. Like all innovations, floating docks were received with derision.

Now they have proved their worth, but circumstances are easily conceivable in which all the marvels they have already accomplished will be far eclipsed by what they may be called upon to do. In the case of a naval battle, for instance, it may be a matter of impossibility for a crippled warship to enter a dry dock, or even to get to one; but a floating dock can be sent to meet the injured warrior and possibly save it from going to the bottom altogether.

The floating dock is a sort of raft, and the first man who ever hauled a boat from the water upon another boat or raft to repair, it started the idea of the floating dock. The first real floating dock, as the term is now understood, was probably that which was improvised in the Baltic Sea, so tradition says, by the skipper of a vessel which had sustained some damage in those waters. He bought an old hulk, removed the stern, and in its place constructed a flap gate. His vessel was then floated into the hulk, the flap gate was closed and the water pumped out. Floating docks of this type were almost the only kind known up to the beginning of the nineteenth century, and are in use to-day at some ports for small yachts, fishing-boats, and vessels of similar dimensions.

With the growing size of vessels, greater docking facilities became necessary, and, as the commerce of the world increased and ports were developed, demands arose for docking accommodation which could not always be met, owing in some cases to financial difficulties, and in others to the engineering difficulties connected with the localities. As a solution of the problem, the floating dock, as it is known to-day, was invented. In spite of the opposition with which it was greeted, the new contrivance held its own, and its merits became generally recognised.

The difficulties and the cost of constructing dry docks are very great, and the time taken in the work may run into years; one dock, indeed, is stated to have taken fifteen years to complete.

As an instance of rapidity of floating-dock construction, the Vulcan Company of Stettin required a dock 510 feet long and of 11,000 tons lifting power at short notice. The complete dock with all machinery and fittings was launched within seven and a half months, and within eight months and thirteen days of the inception of the project, the dock, after being towed across the North Sea and moored in place at its site, was sunk ready to receive its first ship. The Havana dock was delivered at Havana within eleven months after the signing of the contract for its construction; the actual time expended on it, dating from the day the first plate was laid until the complete dock was launched, was six months and a day. Both these docks are of over 10,000 tons lifting power. How long would it have taken to excavate and build graving docks capable of receiving vessels of the size that these docks can accommodate?

No dry dock can take a vessel larger than itself, and in reckoning the dimensions of a dock for receiving purposes it must be remembered that its cill is a fixture, that the width of the entrance at the cill must not be made greater than the strength of the structure will permit, and that though a dock may in other respects be able to receive a vessel it cannot do so if that vessel through any mishap should draw as much water as that at depth of cill, or if in heeling over, its bilges should be wider than the width of the dock entrance. None of these drawbacks apply to the floating dock. These immense modern structures of steel and iron can receive vessels longer than themselves, and in the case of the off-shore docks, can receive vessels wider than themselves.

Should a vessel be heavily down by the head or stern, a floating dock can be tilted to lift it, and should the vessel be heeling over, the dock itself can be inclined so that it shall receive it without difficulty. Yet another advantage is that the floating dock can be used in any kind of ordinary weather. Lying at its moorings it is head on to wind and sea. The amount of surface it opposes to the direct action of wind and sea is comparatively slight. The very massiveness of its structure reduces longitudinal and lateral motion to a minimum, especially when submerged. Even with a fairly heavy sea running, a damaged and leaking vessel can be brought upon the dock where its weight, added to that of the dock itself, makes the combined structure additionally stiff, so that the necessary repairs can be undertaken in safety as soon as the vessel is lifted, and with as much ease as if the dock and its burden were in still water. Floating docks also can be used at any state of the tide, but he would be a rash man who attempted to warp a vessel into an ordinary dry dock with the tide running past the entrance with any degree of strength.

The earliest type of the modern floating dock is that known as the box dock. It consists of a pontoon divided into cells or compartments, and having on either side a large wall also divided into compartments arranged in tiers, the ends of the structure between the walls being open. The earliest of these docks were made of wood, and compared with those of later date were of small dimensions. One of the most noteworthy wooden docks was that at Rangoon, launched in February 1866, and having a length of 300 feet, with a breadth of 90 feet, and an inside breadth of 70 feet, and able to take vessels drawing from 15 to 16 feet of water. There is also at Altona a wooden floating dock built in 1868 and still in active use; it is 138 feet in length, and can lift vessels up to 420 tons register. The early floating docks were usually in transverse section like the capital letter U, and followed fairly closely the form of the round-bottomed ships of the time. As the girder principle, however, became introduced in shipbuilding it was recognised that floating docks must be constructed approximating to that shape, and modern floating docks are now built rectangular in transverse section, though in constructional details this form is a modification of the U shape.

Floating docks themselves are in occasional need of repair, and when it was found that they could be constructed of a greater size than any then existing dry dock, it being customary to dry dock them for repair, the necessity arose of devising a means whereby the repairs could be made without taking the floating dock out of the water. Sometimes a dock can be tilted endways or sideways as occasion requires, for a portion of its under-water surface to be exposed, but there is obviously a limit to this operation and to the effectiveness with which work under these conditions can be carried out. This difficulty was met by constructing docks on the sectional principle, whereby any two sections of a floating dock constructed in three sections can lift the other one; while with off-shore docks, which are usually built in two sections, either can lift the other. An attempt to careen the old U-shaped Bermuda dock nearly capsized her altogether.

One of the earliest—if indeed not the earliest—of self-docking double-sided docks is that associated with the name of Mr. Rennie, and now generally known as the Rennie type, or, in an attempt made at uniform classification of self-docking docks by Messrs. Clark and Standfield, who probably have had greater experience of floating-dock designing than any other firm in the world, the “sectional pontoon” dock. This is an extremely simple form of dock, consisting of a series of similar pontoons connected together into a whole by the walls or side girders, which run along each side on top of the pontoon, to which they are attached by bolts. In self-docking, any particular pontoon can be unbolted from underneath the walls, allowed to sink slightly, and then be drawn out sideways, turned half round, and lifted on the rest of the dock. The type is also very suitable for erection abroad, for the pontoons can be built and launched separately, and, being but light structures, require no expensive launching slips, whilst the side walls can be erected on top of the pontoons after they are afloat.[100]

The first Bermuda Dock, launched at North Woolwich by Messrs. Campbell, Johnstone and Co., in September 1868, was the largest built up to that time, and was ordered by the Admiralty for the use of British ships in the West Indian Squadron. It was 381 feet in length, 123 feet 9 inches in extreme breadth, and had a total depth of 74 feet 5 inches. Caissons enclosed a dock space of 333 feet by 83 feet 9 inches in width, capable of receiving a vessel of 3000 tons. The section of the dock is of U form throughout, though for convenience of towing, a tapered bow of wood was added, and remained until it rotted off at Bermuda. The dock was designed by Mr. Campbell. The sides consisted of a cellular space 20 feet in width, and midway between the inner and outer skin was a water-tight bulkhead, running the whole length of the structure. Each side was subdivided by longitudinal bulkheads into three compartments, named from the bottom, the “air,” “balance” and “load” chambers, and was further subdivided into twenty-four water-tight cells. The dock was fitted with four steam engines and pumps on each side. Hitherto all floating docks had been built in sections, shipped to their destinations and erected there. The Bermuda dock, however, was towed there, experimentally, and so successfully was the work accomplished that the towing of floating docks across the ocean has become the rule, and some wonderful feats of towing have been performed. This dock, becoming unequal to the requirements of modern shipping, gave place to the present dock built at Wallsend in 1902.

The length of the present Bermuda dock is 545 feet over the keel blocks, its width of entrance 100 feet, and it is capable of normally taking vessels drawing 33 feet of water over keel blocks 4 feet high. The walls themselves are 53 feet 3 inches high, and 435 feet in length, and they form girders of enormous strength. Three pontoons, secured to the lower portions of the walls by fish-plate joints, lugs, and taper-pins, form the bottom or deck of the dock. The middle pontoon is a rectangle 96 feet by 300 feet; the end pontoons, each 120 feet long, taper for 49 feet towards their outer extremities to facilitate towing.

At this immersion the walls have a freeboard of 3 feet 6 inches, which in urgent cases might be safely reduced by a foot or more in order to increase the depth of water over the blocks. Its lifting power up to pontoon-deck level is 15,500 tons, but by utilising the “pound” formed by the bulwark surrounding the pontoon decks, additional lifting power up to 17,500 tons can be gained. The dock, without its machinery, weighs 6500 tons. When called upon to perform its maximum lift the dock is sunk until the summit of its walls is but 2 feet 6 inches above sea-level. Water is admitted into the three pontoons and the two side walls, and from them removed by eight 16-inch centrifugal pumps at a rate sufficient to lift an ironclad of 15,000 tons in three and a half hours. In order that the dock may not tilt as it rises, the whole is divided into fifty-six divisions, each of which is separately connected with the pumps. By turning off cocks, water can be left in any desired divisions, and the dock forced to incline in any direction for purposes of cleaning and repairs. When undergoing its official tests the Bermuda dock lifted H.M.S. Sans Pareil over 11,000 tons, and after its arrival at Bermuda it received and raised completely out of the water H.M.S. Dominion, when that vessel was badly damaged through stranding and was so down in the water as to displace nearly 17,000 tons.

It is specially important that a structure of this kind should be self-docking, that is, able to lift any part of itself clear of the water. To expose the bottom of one side the dock is first lowered to a depth of 20 to 21 feet, the water inside the wall compartments being brought to the same level as that of the water outside. The dock is then raised by emptying the pontoons, and when these are exhausted the water is released from the side to be exposed until the outer corner is two feet or more clear. The pontoons are lifted in turn by withdrawing the pins of one, and allowing it to float, while the rest of the dock sinks. The pontoon is then made fast to the walls at its floating level, and the dock emptied, so exposing the whole of the bottom of the raised pontoon. The two end sections can be treated simultaneously, and floated if required on to the central portion, but the latter must be moved only when the other pontoons are in position. Electric lights and hauling machinery are distributed over the dock. A crane capable of lifting five tons runs along each wall from end to end.

A somewhat similar dock to that at Bermuda, slightly shorter but of greater lifting power, was designed for the Navy Department of the United States of America, and constructed by the Maryland Steel Company at Baltimore, and stationed at Algiers near New Orleans. Its length is 525 feet over blocks, its entrance 100 feet, and its lifting power up to pontoon-deck level no less than 18,000 tons, making it as regards lifting power then the most powerful dock in the world. This lifting could be increased to 20,000 tons by using the “pound.” Its hull weight is 5850 tons.

It is interesting to note the different methods adopted by the Governments of the two countries for the shoring or berthing of the ships on the dock. The English custom in the case of ironclads of the pre-Dreadnought era, and also that of Italy and Japan, is to support the armour belt on more or less vertical shores inserted under an angle-iron firmly attached to the belt.

These shores are put into position as the ship is rising, and, as the water recedes, more and more shores are inserted. The Bermuda dock has large and heavy altars constructed for this purpose. The American custom is to strengthen the bilges of their ironclads with strong bilge docking keels, forming, with the keel proper, a level bottom. No shores are required beyond those necessary to centre the vessel, and no great care is required in adjusting the berth, and one set of bilge blocks does for all sizes of vessels. The American plan affords a great saving in weight and quantity of shores, and, what is more important, a great saving in time, not only in the preparation of the berth and centreing of the ship, but also in the actual lifting. With the American plan it would be perfectly feasible to dock a vessel completely in the time required to centre and adjust her with shores disposed according to English practice.

The Penarth Floating Dock was constructed in 1909 at Wallsend to the order of the Penarth Ship Building and Ship Repairing Company, Ltd. The dock is of the off-shore or single-walled type, and is one of the finest of its kind. It has an over-all length of about 380 feet, an extreme width of 75 feet, and is capable of accommodating vessels having a beam of 55 feet, with a draught of water up to 18 feet, and a displacement of 4200 tons. Its pumping machinery consists of four centrifugal pumps and engines, for which steam is supplied by two large Babcock and Wilcox boilers, working at 160 lb. pressure. This plant can lift a vessel of 7000 tons dead weight in three-quarters of an hour. For self-docking, the dock is divided transversely into two equal portions, each with its own pumping plant, so that either section can be docked by the other portion. A powerful steam capstan is fitted at each end of the top wall to assist in warping vessels into position when lifting or otherwise. It has eight mechanical side shores in addition to the usual accessories for facilitating the rapid handling of vessels, such as bilge shores, roller fenders, rubbing timbers, and bollards. A duplex reciprocating pump, with a capacity of about 100 tons per hour, has a connection to the main drain of the dock, and enables practically the whole of the water to be pumped out of the dock. On the delivery side the pump is connected to a service-pipe, which has connections at intervals for 3-inch delivery hose. The pump is capable of throwing three jets of water to a height of 40 feet.

To enable this floating dock to enter the wet dock in which it was to work, the entrance to which is several feet less than the width of the dock, a joint was provided running the whole length of the pontoon. On arrival of the dock in Penarth roads this joint was disconnected, and the separate sections towed into the wet dock, and reconnected, and the necessary attachment made to the quay wall.

The Callao floating dock, the towing of which to its destination from the Tyne was the most hazardous towing feat ever accomplished, merits special attention, both on account of the completeness of its equipment and of the extraordinary interest which was manifested in its journey. It is one of the double-sided self-docking type, known as “bolted sectional,” and is divided into three separate portions. It is capable of lifting vessels having a displacement of 7000 tons, but it is so designed that this lifting capacity may be increased to 9500 tons at some future period by the addition of a fourth section, making the over-all length about 510 feet, the present length being 385 feet. Its extreme width, i.e., the clearance between the rubbing fenders, is 70 feet, and the draught over keel blocks is sufficient to take vessels drawing 22 feet. As in previous floating docks built on the Clark and Standfield principle, each section has its own independent pumping machinery and steam-supply. Such usual accessories as keel and bilge blocks, mechanical side shores, rubbing timbers, flying gangways, head capstans, &c., are supplied, and there is also a heavy mooring outfit of anchors and cables. The dock was launched in June 1908, and at that time satisfactorily completed a self-docking trial by lifting one of the end pontoons alongside the Wallsend shipyard. For this purpose the three sections of the dock were disconnected, and the two end sections were turned round end for end, so that their points came opposite to the central section which is square-ended. They were then lowered under the water and drawn in under the central section. On pumping out the end sections they rose, bringing up with them the central section, which was then resting on their pointed ends. The dock left the Tyne on August 20 of that year, in charge of the powerful Dutch tugs Roodezee and Zwartezee, each of which has an indicated horse-power of 1500, their bunker capacity being 650 tons and 600 tons respectively. The dock in its journey to Callao was manned by a captain, mate, engineer, and nine sailors.

It was fastened to the tugs by extra superior Manila ropes of 18 inches, with 30 fathoms of flexible steel wires of 4¹⁄₂ inches circumference on both ends, while each tug had on board a new spare rope of precisely the same size and quality. One tug broke down on the way, and another had to be sent to Monte Video to take her place.

The time taken on the journey was 225 days, but after deducting the delays in the Thames and at Monte Video, the time occupied on the passage was only a little over four months.

The long voyage down the Atlantic, culminating in the passage of the dreaded Straits of Magellan, caused the vessel to be kept upon the marine reinsurance list almost from start to finish.

The distance from the Tyne to Callao does not represent a world’s record for a tow of this nature, inasmuch as it has been exceeded by the Dewey Dock built by the Maryland Steel Company of Baltimore for the United States Government, which, in the summer of 1906, was towed from America to the Philippines, a distance of 13,089 miles, in 150 days.

Great Britain, though a large builder and the principal designer of floating docks, does not possess very many; possibly the number and excellence of the dry docks scattered round her coasts may be the explanation. But as dry docks are costly to make or alter, the British Admiralty has ordered the construction at Wallsend of a floating dock which will take the largest battleship afloat or likely to be built for some years to come. In anticipation of the possible needs of the mercantile marine, plans have been prepared for a floating dock with a lifting power of 45,000 tons.

The largest floating dock in existence at present is at Hamburg, which has a better equipment in this respect than any other port in the world. It was built by Messrs. Blohm and Voss, the shipbuilders, for their own use, and was completed last year and can lift 35,000 tons. Hamburg has altogether eighteen iron and steel floating docks. Bremen has three large floating docks, two of which, if used together, have a lifting power of 3300 tons. The third dock, 385 feet long by 83 feet inside measurement, can lift a vessel of 10,500 tons.

Other countries also have provided themselves with floating docks; indeed there are few nations of any importance which have not several floating docks, modern in type, of great lifting power, and thoroughly equipped. A few, like Austria, reserve the docks for naval purposes only.

The life of the iron or steel floating dock of whatever type is likely to be far longer, if care be taken of the structure, than might at first be supposed. Rennie’s Cartagena dock, built of iron in 1859, was in such splendid condition when the proposal was made to build a Havana dock that as a counter-proposal it was suggested to send the Cartagena dock there. The Nicolaieff built in 1876, has been uninterruptedly employed ever since in lifting the vessels of the Russian Navy. The Victoria Dock is 310 feet in length, and of the hydraulic-lift type, with a lifting power of 3000 tons, and has nine pontoons or trays of a total length of 2185 feet, and an aggregate lifting power of 17,060 tons; the pontoons were constructed between 1857 and 1876, the largest of them being of 5000 tons. The Malta dock, also of the hydraulic type, is 340 feet in length, with a lifting power of 4000 tons, and was built in 1871. It has two pontoons of 4000 and 2500 tons respectively. The hydraulic floating dock at Bombay, built in 1872, was rather larger, being 400 feet in length with a lifting power of 8000 tons, its pontoon of the same length lifting 6500 tons. These lifts were designed by the late Edwin Clark, M.I.C.E., who introduced floating docks from which the present types have directly sprung. These hydraulic docks are no longer at work.

The carrying of railway trains by ferry-steamers across stretches of water too large to be bridged over is no new thing, there being several such in the United States and Canada. Many of the vessels thus employed are of considerable size. These waters are comparatively landlocked, and the traffic, except in unusually stormy weather, is seldom interrupted. The American ferry-boats are double-ended, so that a train can enter at one end and leave at the other after crossing the water, the ends of the ferry-boat and of the pier supporting the shore lines being constructed to fit exactly. Most of the modern American ferry-boats taking railway trains have two, three, or four sets of rails on their decks, and accommodate their passengers on a deck above, where the saloons and cabins are situated. Where the railway-level is different on the two sides of the water, the boat or the landing-stage is provided with hoisting machinery which raises the train to the desired level, a truck or two or a passenger coach at a time.

The nature of the work these railway ferry-steamers have to perform, and the fact that every one has to be built to suit the special conditions of the ferriage where it is to be employed, make it inevitable that no two of them are alike, except such as may be sister vessels employed on the same station. In Russia the conditions are very difficult. The current of the River Volga is swift, the height of the water-level varies as much as 45 feet, and as the ice is frequently two feet in thickness the work of maintaining the ferry is not to be undertaken lightly. The vessel by which the service is performed was built by Messrs. Armstrong, Mitchell and Co. To enable it to be sent to its destination it was constructed in four parts, so that it would pass through the Marinsky Canal to get to the Volga. The boat is 252 feet long by 55 feet 6 inches broad, and 14 feet 6 inches deep. It has four lines of rails, converging at the bow into two, and altogether can accommodate twenty-four trucks. At the bow is a high framework for a hydraulic hoist which lifts the trucks between the deck and the rails ashore, a distance of 25 feet, the difficulty of negotiating the remaining portion of the difference in the level being overcome by there being two levels of rails on the landing-stage. The propelling machinery, of the surface-condensing type with twin screws, gives the vessel a speed of nine knots an hour. The bronze propellers are unusually strong and heavy to withstand blows from the ice in the river; the actual ice-breaking to keep the passage clear is performed by another steamer.

A ferry-steamer of a different type is that which plies across Lake Baikal in Central Asia in connection with the Transasiatic Railway. As the lake is frozen over for nearly half the year and the vessel has to do duty as an icebreaker as well, the hull has been made extraordinarily strong and heavy. The stem and stern are of massive steel castings. The vessel, which is of steel throughout, is 290 feet in length by 57 feet beam, and the draught of water is rather over 18 feet. The hull bears an outer plate an inch thick and 9 feet wide, placed from end to end along the water-line as a further protection against the friction of the ice. The vessel is also subdivided extensively into water-tight compartments in addition to the usual bulkheads. Over the railway deck are large and sumptuous public and private staterooms. Three sets of triple-expansion engines have been installed with boilers working at a pressure of 160 lb.; there are twin propellers at the stern, and a third propeller at the bow.

This vessel is also remarkable as being probably the most rapidly constructed vessel of her size in existence. Not six months elapsed from the time the order was received until the steamer was built, unbuilt, and packed on board a steamer ready for departure to Russia, this including also the making of the engines. The packages were conveyed as far as possible along the Siberian Railway and thence by sledges to Lake Baikal, where the ship was re-erected.

The only sea-going railway ferry-steamer in existence is the Drottning Victoria, launched in January 1909 from the Neptune Works of Messrs. Swan, Hunter, and Wigham Richardson, Ltd., to the order of the Royal Administration of the Swedish State Railways. She was built to ferry trains across the Baltic, between Sassnitz in Germany and Trelleborg in Sweden, a distance of 65 nautical miles. High sea-going qualities were necessary as the voyage is occasionally a very rough one. The vessel is 354 feet in length by over 50 feet beam, and is propelled by twin-screw triple-expansion engines, supplied with steam from four large boilers working under Howden’s system of forced draught. The trains are carried on two tracks on the car deck, occupying nearly the whole surface of the deck. Above and below this deck is very luxurious passenger accommodation. The vessel has been designed to be very steady at sea, and has unusually large bilge keels fitted to minimise the rolling. Spring buffers and other necessary appliances are arranged to prevent the cars from moving when at sea. A bow rudder is fitted as well as the stern rudder, and both are controlled by steam from the captain’s bridge. The steamer has been divided into a very large number of water-tight compartments, which, with the bulkhead doors with which she is fitted, render her practically unsinkable. She is also to be fitted with a submarine signal installation. The ventilating and heating are ensured by an installation of thermo tanks, enabling fresh, warm air to be forced into all the rooms in winter and fresh cool air in summer. Her speed is over 16 knots per hour, and the journey is made within four hours.

The performances of this boat are being watched with no small amount of interest, as it has been suggested that if she should prove equal to all requirements a modification of this form of steamer might be successful in the cross-Channel service between Dover and Calais, or other ports on either side of the English Channel.