Chapter XII: Ship Design, Construction, and Repair

Ship design, prior to the opening of the 19th Century, was based very largely on rule-of-thumb methods. In ancient times, before Greece became a sea power, this was particularly true. Shipwrights and sailors came to know from experience what qualities were good and what were bad, and after many years at their work were able to construct ships with some understanding of what the ship could be expected to do.

It took only a little while for them to learn that narrow ships were easier to propel than broad ones but that broad ships possessed carrying power superior to that of narrow ones. Thus the merchant ships were “tubby” while warships were narrow. If a ship proved to be unseaworthy in heavy weather shipwrights naturally did not build other ships like her if they were looking particularly for seaworthiness. If a ship was able, it was only natural that her characteristics should be incorporated in other ships. If a ship otherwise satisfactory permitted seas to come aboard over bow or sides or stern, the sailors and shipwrights tried to correct the difficulty without losing her good qualities. Thus from generation to generation ships improved, although the process was slow.

When Greece was at her zenith there seems to have been a more thorough study made of structural design, and many things about ships were more or less standardized. Just how far the Greeks carried their study of ships it is impossible to say, but crude methods gave way to finer ones, and Greece passed its understanding of ships on to Carthage, and from the Carthaginians it went to Rome. But the Middle Ages lost this information, as it seems to have lost almost everything else, and a new beginning had to be made.

_While a ship may look large on the water, she looks gigantic when on land. The great hulls and the collection of scaffolds and machinery in a shipyard are always a source of surprise to the visitor who is unfamiliar with the construction of ships._ ]

The Norsemen went through a similar development. The seas their ships were called upon to sail were almost always boisterous. The principal use to which their ships were put was war. They had, then, need to be both seaworthy and fast. The early crude attempts of the Norsemen, therefore, grew slowly into those beautiful ships for which they are famous. To-day the seaworthy whaleboat is very similar to the finest examples of the old Norse “serpents.” These old ships were long, narrow, pointed at bow and stern, and had both ends raised, while amidships they were low. The sheer, that is, the line from the high bow to the low section amidships, and from there up again to the stern, was a beautiful sweeping curve. Such ships readily rode rough seas, while their low “freeboard” amidships permitted the oars to be used to good advantage, and their narrow hulls presented a minimum of resistance to the water. This refinement, however, can hardly be said to have resulted from thought so much as from experience. By that I mean that these ships at the highest stage of their development were not consciously designed, but were outgrowths from experience, and that the shipwrights, only after many generations, had learned that such a design combined the advantages they particularly desired.

It was with the Crusades, as I have said before, that ships began to improve more rapidly. This was due to the broadening spheres of travel of western European sailors. They visited the Mediterranean and Asia Minor, and found in that part of the world ships that were strange to them. But in these strange ships they found characteristics that they deemed desirable, and, combining these desirable points with those of their own ships that were equally desirable, they produced improved types. Thus they profited by the experiences of others who, in their own little spheres of activity, had gradually developed ships that answered, at least to a considerable extent, the requirements of their own localities.

It hardly needs to be pointed out that the British, who sailed the rough waters of the North and Irish seas and the English Channel, developed ships far different from those developed by the peoples of Mediterranean countries, where the distances sailed were shorter and the weather conditions were so radically different.

After the Crusades had introduced the peoples of western Europe to those of the Mediterranean, trade between the two increased, and, so far as ships were concerned, each learned from the other. Thus it was that by the time Columbus sailed on his famous voyage, the sea-going ships of all the European countries had grown somewhat similar in design and appearance.

_And a ship undergoing repairs._]

A few glimmerings of the complicated subject of naval architecture became evident in the years that included and followed “the age of discovery,” and ships, or at least _some_ ships, were “designed” by men who made a study of them. The designs, however, were largely little more than the transfer of rule-of-thumb methods to paper, and a real understanding of the subject was still far distant. Phineas Pett, during the 17th Century, designed many ships for the British Navy, and from these designs the ponderous ships of later days developed. In France, however, naval architecture seems to have been a better-understood art than in England, for many times British designers improved their ships after studying captured French ships.

The designers in England for many years were guilty of one error in particular which, while later corrected, proved to be the cause of the loss of several of their very greatest ships. This fault was the placing of the lowest tier of gunports so close to the water that when the ships were under a press of sail the ports on one side or the other, and they were not watertight even when closed, were under water. During the reign of Henry VIII, a British ship named the _Marie Rose_ heeled over when getting under way, and the ports, which were open and were only sixteen inches above the water when she was on an even keel, permitted the water to enter in such quantities that she sank. Years later Sir Walter Raleigh wrote that this defect was being corrected, yet later still the _Royal George_ was lost because of the same fault.

It is interesting to quote a few lines of Raleigh’s writings on ship design. Commenting on improvements in lines he said that ships with these improvements “never fall into the sea after the head and shake the whole body, nor sinck a sterne, nor stoope upon a wind.” He also suggested that the lowest tier of gunports should not be less than four feet above the water. Furthermore, he objected to the high sterncastles which made the ships of the time both unseaworthy and ridiculous.

Modern scientific naval architecture can properly be said to date from the latter part of the 17th Century, for it was then that the first studies were made of the passage through the water of various shaped hulls. Before this, ships were built and if they were successful were copied; if unsuccessful they had less influence on later design. Now began a study that has been carried down to to-day, and scientific deductions began to be made, and upon these investigations and the results of them an important part of naval architecture has been founded.

Still, however, this new science was crude. One reason for this was that ships depended upon the wind for power, and it was a slow task to compile comparative data. That this was not impossible, though, is proved by the brilliant American designers of the first half of the 19th Century, who suddenly evolved the clipper ships that so far surpassed all previous sailing ships that comparison became mere contrast.

But it was steam that made it possible for naval architects to develop their profession to so high a point as it has reached. It was during the 19th Century, then, that naval architecture made its greatest progress. Since the 19th Century great improvements have been made, it is true, and many facts have been discovered, and naval architecture still is progressing, but the 19th Century made a profession of it, and the 20th Century is only continuing its development.

The profession of the naval architect is one that is not widely recognized or understood. When Cass Gilbert designs a Woolworth Building we recognize him as a great architect, and realize, to some extent, the great task he has so successfully completed. When the building is built we view it with interest, perhaps with awe, and comment on the brilliance of the architect and the ability of the constructor. And they deserve all the credit they get—and more.

But how often have you ever heard mention made of the architects from whose brains were evolved the _Mauretania_ and the _Leviathan_, the _Belgenland_ and the _Majestic_? True, it is commonplace to marvel at their size. But who thinks of the titanic task that faced their designers?

And now imagine a Woolworth Building being built on a sloping runway, and, when completed, slid bodily into the water, across thousands of miles of which mighty engines placed inside could drive her at express-train speed. Imagine such a structure, with all the magnificence of appointments that are to be found in the Woolworth Building, forcing its way through winter storms with waves pounding madly at its sides—waves which, striking the ironbound coasts of Maine or Wales, sometimes tear away tons of the living rock and hurl it about in a smother of foam. And then compare such a structure with the greatest ships of to-day. There are several far longer than the Woolworth Building is tall, but these vast steel hulls do not rest on foundations of steel and concrete—immovable. They float in the water, and may pitch and roll in the giant swells of the deep sea, but still their huge steel frames easily bear the strain, and while a tremor of the earth might dash skyscrapers disastrously about our ears, the almost constant motion of the sea, whether violent or weak, affects them little. For such work as this the architects of ships deserve all praise.

In such huge and complicated structures as ships have grown to be, repairs, naturally, are frequent and vital. The ordinary wear to which the machinery is subjected necessitates constant adjustments and replacements. Improved mechanical apparatus sometimes is installed to take the place of less reliable or less economical apparatus. The action of sea water on the exposed metal and the collection below the water line of barnacles and other marine growths require periodic attention, while paint seems for ever necessary and, at least on warships, wet paint is omnipresent.

Before the introduction of iron and steel, ships were comparatively small, and consequently it was a simpler job to haul them out of water or ground them at high tide in order that, when the tide had gone out, their underbodies could be examined and repaired. Sometimes, again, tackle made fast to their masts and led to anchors dropped well away from their sides or to points ashore made it possible for ships to be hauled over to one side or the other, bringing a large part of their underbodies above water, where their crews could make the necessary repairs, or scrape off most of the accumulation of marine growth.

_A sister ship of the ill-fated_ Titanic, _and operated by the White Star Line._]

Nowadays, however, when the very smallest of our ocean-going steamers is many times the size of Columbus’s largest ship, such methods avail little. Sometimes, still, in harbours where there is a large rise and fall of tide the smaller ships avail themselves of it for minor repairs, but for most modern ships such methods are impossible and dangerous.

Yet even the greatest ships must from time to time be taken out of the water for repairs and for the inspection of the hulls, and for this purpose dry docks, or, as they are sometimes called, graving docks, came to be designed.

Dry docks are long narrow basins, the dimensions of which are slightly larger than the largest ships they can accommodate. Nowadays they are usually built of reenforced concrete, although brick and stone are sometimes used, and formerly timber dry docks were not uncommon in the United States. The entrances to these basins are equipped with hinged gates, or a floating or sliding caisson. Dry docks in the United States ordinarily use the floating caisson. European dry docks commonly use the other two. These seal the mouths of the dry docks, preventing the entrance of water from the outside as powerful engines pump the water from the dock itself.

The sides of dry docks are usually built in steps, so that at the top they are wider than at the bottom. The bottom is very nearly level, but there are careful arrangements made for draining all the water into pits from which it is pumped out.

Extending almost the length of the centre of a modern dry dock is a row of large wooden blocks, called keel blocks. These can be moved and are made fast when they are put in place. Often this row of blocks is paralleled on each side by a row of somewhat similar blocks called bilge blocks which run along tracks laid at right angles to the line of keel blocks. The bilge blocks can be moved individually along these tracks by means of ropes and pulleys. These ropes are extended up the sides of the dock so that, even when the dock is filled with water, each individual bilge block, and there are scores of them in each row, can be moved back and forth by men beside the dock.

When it is necessary for a ship to be docked her docking plans are given to the man in charge of the dock. He then arranges the keel blocks so that the line along their tops is the same as the line along the keel of the ship. Certain marks are then made at the top of the dock’s side walls to show just how far the ship is to be hauled into the dock. When these arrangements are completed the dock is flooded, the gates are opened, or the caisson is floated out and the ship is very carefully and very slowly hauled into the dock. She never goes in under power, for the clearance between her sides and the sides of the dock is often very small, and the greatest of care must be taken to keep her from coming in contact with the masonry.

When she has been hauled up to the point marked on the dock side she is carefully made fast with cables, and the entrance to the dock is closed. The ship must be riding on an even keel, for if she is listing—that is, leaning to one side or the other—she may damage herself when the water is pumped out and she comes to rest on the keel blocks.

As the water level is reduced her keel slowly settles on the keel blocks which support the whole weight of the ship, but in order to prevent the ship from toppling over sideways the bilge blocks are pulled carefully under her. As they are slightly higher than the keel blocks they touch her bottom at some distance from the keel, and as there is a row of them on each side they keep her securely upright. Care must be taken that none of these bilge blocks come in contact with the ship where any of her numerous underwater valves project, for if that happened the valves would be damaged. The docking plan referred to, however, shows where such protuberances are and such accidents need not occur.

In dry docks where bilge blocks are not used, the ship is supported instead by “shores.” A “shore” is a long timber which is placed with one end against the ship and the other against the side of the dock. In order to make them fit snugly great numbers of varying lengths are kept on hand and are chosen so that they come within a few inches of filling the space between the ship’s sides and the dock wall. Then large wooden wedges are driven in between the dock wall and the end of each shore. Dozens of these are placed about a ship and serve the same purpose as is served by the bilge blocks.

A ship I was on some years ago was rammed by a coal barge while at anchor in the harbour of Brest, France, and was forced to go into dry dock for repairs. Being familiar with dry-dock procedure only in the United States I was unprepared for what has always since seemed to me to be a thoroughly picturesque method of placing the shores.

Our ship was hauled into the dock, the gates were closed, and the pumps began to lower the water. Finally she settled on to the keel blocks and the shores were floated into place, each end being held from above by a line. As the water sank lower the wedges were inserted between the shores and the dock walls, and a man with a large wooden mallet took his place at each wedge. Then the foreman, standing at the head of the dock began a song which the mallet bearers took up, singing beautifully in unison, their voices booming upward from the dry dock, halfway down the sides of which they stood. And as they sang they kept time with great strokes of their mallets on the wooden wedges, the musical wooden sound ringing in unison with their song as every man drove his crashing blows with every other man.

I stood on the bridge of the ship listening to the lilting song, and the great musical crashes that punctuated it, every man striking at exactly the same instant that every other man struck. Never before or since have I seen a more practical demonstration of the uses of song or heard so beautiful a song of industry. It was an “Anvil Chorus” with a different setting.

There is another type of dry dock that is widely used and is of great importance where it is too expensive or difficult to build the type to which I have just referred. This other type is the floating dry dock. In principle it is a huge barge, rectangular in shape, and with highly raised and very thick sides and open ends. Its bottom is built up of many compartments and its “reserve buoyancy” must be at least a little greater than the total weight of the largest ship it is designed to accommodate. That is, it must be able to float while carrying a load of 15,000 tons if it is meant to be used by ships up to that displacement.

_A British built ship operated by the Cunard Line._]

These floating dry docks need only to be placed in a sheltered spot where the water is deep enough for the dock to be sunk so that the dock floor is a little farther beneath the surface than is the keel of the ship that is to be docked. When everything is in readiness—that is, when the keel blocks are properly placed and the incoming ship has been otherwise prepared for—water is allowed to enter the inner compartments of the dry dock. Gradually the whole thing sinks until only the two high sides are visible above the water. When it has sunk until there is enough water over the dock floor for the incoming ship to float in, the valves are closed and the ship is hauled in and made fast. Then giant pumps begin to expel the water that has been allowed to enter the compartments. This causes the dry dock to come once more to the surface, and as it rises beneath the ship the keel blocks press up on the ship’s keel, shores or bilge blocks are put in place, and when the ponderous float regains the surface there is the ship, high and dry, where men can scrape and paint and repair her or accomplish the other tasks assigned to them.

It is interesting to watch the labours of a crew of workmen in a dry dock. If a ship looks large in the water, it looks startlingly gigantic in a dry dock, especially if one walks down to the dock floor and views the high bow or the overhanging stern from the level of the keel. Propellers from a distance look small, but with half-a-dozen men realigning their blades or working about them, they look huge indeed.

_The greatest French Merchant ship, operated by the French Line._]

A hundred men may be swinging on scaffolds which are hung over the ship’s side by lines from the deck, and they remind one who is watching from a distance of flies or ants on a wall. A regiment of workmen may disappear beneath the huge bulge of the ship’s underbody in order to scrape or paint or repair. Fathoms of cable may follow an anchor from the hawse pipes to the dock floor as the “ground tackle”—that is, the anchors and cables—is cleaned, painted, and examined. Propellers or sections of propeller shafts may be swung over the yawning dock and lowered into it by great cranes, to take the places of others lost or damaged. Sections of the ship bent or cut by collision may be replaced to the raucous tune of nerve-shattering riveting hammers. Rivets loosened by the “working” of the plates or by galvanic action may be renewed. Plates damaged by any of a hundred causes may be replaced, and great piles of barnacles scraped from the steel skin of a ship that has been overlong between dockings may accumulate on the dock floor. Sea valves are reground, the rudder is examined, propeller-shaft supports are looked over, and, when the work on the ship’s great underbody is completed, the workmen take their tools and depart, great valves are opened in the dry dock walls, the water enters, and once more the great ship floats. The dock gate or the caisson is removed, and carefully the monster of the sea is backed from her gigantic hospital, fit, so far as her underwater parts are concerned, for another round of duty at sea.

But dry docks are not necessary for all the repairs a ship might need to undergo. To replace or repair engines she may go alongside a quay or a pier, and for any of a thousand jobs she need never stop her regular voyages. But repairs or changes are always under way. To the voyager on a handsome liner little of this is apparent, but it is always known to the crew, and rare indeed is the time on a steamship when repairs are neither under way nor contemplated.

This continuous round of repairs does not mean, though, that the steamships of to-day are not properly designed and built. It only means that a great ship is so vastly complicated that some part of it is always just a bit below par. A small town needs repair men to keep its electric-light system properly working. Its water system is similarly under constant supervision. Its gas, its paving, and a dozen other parts of its equipment are always being repaired, renewed, or extended. The same is true on board ship, except that, at least on the giant liners, the ship’s equipment is more complicated than the town’s.

This wandering discussion presents a few of the difficulties that face the designer, the builder, and the operator of ships. Such difficulties are all but infinite in number, and constant vigilance is vital to the efficient operation of the ships of to-day. But so reliable have these great structures grown to be that one of the greatest—the _Mauretania_—while launched in 1907, was able after fifteen years of constant and efficient service consistently to defeat newer ships of greater size and greater power in her constant voyages to and fro across the Atlantic. Such results as this must be credited to the designer, the builder, and the officers and crews of these complicated structures of the sea.