By Commander Tyrone G. Martin, U. S. Navy (Retired)
Designing a ship is somewhat like doing your income tax: you must manipulate a great number of values in such a way that they present a unified result reasonably satisfactory to all concerned. The first consideration is the purpose to which the ship will be put: merchantman or man-of-war? For cargo? To be in the battle line? To do what? Having decided that, the marine architect must then decide which characteristics are to be emphasized: Speed? Carrying capacity? Weaponry? Endurance? Then, he must think about how many will be required in the crew; how much food, fuel, and ammunition will be carried; and many, many other things that will result in the creation of a mobile, floating, largely self-sustaining community fulfilling some useful purpose.
When Congress authorized the construction of the first warships for the United States Navy in 1797, it already had made a major decision for the naval architect when it decreed that the ships would be frigates, the middle size of warship in those days, like cruisers in the modern Navy.
Secretary of War Henry Knox had the task of selecting the designer of the frigates. With no warships having been built in the United States since independence was gained more than a decade earlier, his choices were rather limited. Too, a Quaker shipbuilder right there in Philadelphia, known to a number of politically powerful people, some months before the Congressional action had written a letter to one of these politicans that seems to have been accepted as the philosophic basis for it. He wrote: “…[A]s our navy must for a considerable time be inferior in numbers, we are to consider what size ships will be most formidable and be an over match for those of an enemy; such Frigates as in blowing weather would be an overmatch for double deck ships, and in light winds to evade coming to action, or double deck ships as would be an over match for common double deck ships and in blowing weather superior to ships of three decks, or in calm weather or light winds to outsail them. Ships built on these principles will render those of an enemy in a degree useless, or require a greater number before they dare attack our ship. Frigates, I suppose, will be the first object and none ought to be built less than 150 feet keel to carry 28 32-pounders or 30 24-pounders on the gun deck… These ships should have scantlings [the structure] equal to 74s [line of battle ships]…”
Thus did Joshua Humphreys’ proximity and outspoken good sense gain him the job of designing Constitution and the other five frigates newly authorized.
Humphreys had been born in Haverford, Pennsylvania, in 1751, and he had been apprenticed to a Philadelphia shipwright in 1765, becoming a Master in his own right six years later. Shortly before the Revolution, we went into partnership with his older cousin, John Wharton, and they subsequently built the frigate Raleigh, 32 guns, for the Continental Navy. Humphreys not only gained experience in the design and construction of frigates from this association, he also gained introduction to people in positions of power, like Robert Morris, sometimes called the “financier of the Revolution.” In the years following the peace, Humphreys became an established shipbuilder in Philadelphia.
Humphreys first undertook to make a half model of his proposed hull design so that both politicans and other shipbuilders could see what he intended and offer suggestions. This he did as the result of a request from Secretary Knox on 12 April, well before his formal appointment as Master Builder, dated 1 June 1794. In accordance with his earlier letter, he proposed a frigate rated to carry 44 long guns on a hull some 175 feet long at the waterline and more than 44 feet wide. The resultant ship would be both longer and wider than most English or French counterparts, with over fifteen percent more guns of larger caliber. It would be a “heavy frigate,” the battle cruiser of her day.
Humphreys had to come up with a hull form that would be stable, when fully loaded, under most conditions of wind and weather. It had to be of adequate volume to be able to carry her guns, shot and powder, as well as the sails and rigging to provide her with adequate propulsion, the men to operate the guns and handle the rigging, and the food, water, and supplies to permit operations independent of the shore for an extended period of time. Except for water, the ship should be able to operate for six months without recourse to outside assistance. The ship also had to have reasonably good speed to meet the designer’s own criteria of being able to outmaneuver an opponent or get out of the way of one stronger. And it had to have sturdy construction to withstand storms and enemy gunfire (the “scantlings of a 74”). What he had to come up with was a fast, powerful ship with heavy armament and the capability to operate independently just about anywhere in the world.
As Joshua Humphreys set about this task, two additional burdens were placed upon him. The Secretary of War directed him, on 21 June, to negotiate a contract for the construction of a building in which the full-size patterns, called “moulds,” for the principal pieces of the ship could be laid out and created. (These would be first used by the woodcutters to ensure they cut trees of adequate and proper shape, and later by the shipwrights for the shaping of the actual pieces.) A short time later, an itinerant English Quaker shipwright by the name of Josiah Fox was hired as a clerk in the War Department to be Humphreys’ skilled draftsman-assistant. Instead of helping, in the coming weeks Fox repeatedly tried to change Humphreys’ ideas in accordance with his own until, finally, he was removed from any work on the drafts (plans). Humphreys ended up drawing them himself, and had Fox oversee the making of the moulds. He completed the drawings of both the 44-gun frigates and the smaller 36-gun frigates, also authorized, in September. Fox, and a draftsman who had worked for Humphreys before, William Doughty, were tasked with making copies of Humphreys’ originals for each of the six shipyards involved in building the frigates. It was November 1794 before they finished the task.
Unlike today, when the plans for a warship will run to thousands of sheets, that for Constitution appeared on but a single sheet. On it appeared three views of the ship.
The uppermost one was the sheer plan, the side view or profile of the ship. It showed the longitudinal curve of the ship and the curve of the decks to match it. It also showed the length and depth of the keel, the lengths and slopes (“rakes”) of the stem and stern posts, as well as the positions for the frames (the ship’s ribs), which were called “stations.” And it showed the heights and spacings of the gun ports, and positions of masts, railings, channels, and wales (the thickest planking on the ship’s side).
Directly below the sheer plan appeared the half-breadth plan, which was an overhead view of one-half of the ship’s hull lengthwise. Here, the frame stations were repeated, and flowing curves marked positions of equal height above the keel, so that one could see the changing shape of the hull from keel to deck line.
Finally, off to one side, was the body plan. This was a split view, the left side showing the ship from astern and the right from ahead. This plan showed the shapes of the frames progessing from either end of the ship toward the main frame, the broadest frame in the ship.
Creation of the scale draft began with the keel length decided upon, the beam (width), and the location of the main frame on the keel. Having established these, the naval architect proceeded to develop his three plans simultaneously, drawing in an item on one, then transferring it to each of the others to ensure harmony and unity before going on with another item. You might think of it as building a house of bricks, where, after laying each brick, you inspected it from the side, the top, and both ends to be sure it was harmonious in all planes and would fulfill its purpose in that position in the total structure. The test for one of these drafts was that, except for the keel, every line in it should appear straight in two views and smoothly curved in the third.
Accompanying the draft, was a “table of dimensions,” sometimes called the “table of offsets.” Here were listed all the ship’s major dimensions, together with an item-by-item description of the hundreds of shaped pieces of wood that would go into building the ship, together with some specific directions as to how they ought to be fitted and/or finished. Humphreys also provided an estimate of the quantities of timber necessary, from 50,000 locust treenails in 18-, 24-, and 30-inch lengths, to 18,000 feet of four inch plank for bottom and ceiling planking, to one live oak stern post thirty feet long and twenty-two inches square.
From this single sheet of drawings and the list of materials, shipwrights in six ports would build the first frigates for our Navy. Because of their individual interpretations of the plans, Constitution and her “sisters” were similar in appearance, but not identical.
Joshua Humphreys had given his 44-gun frigate design the name “Terrible,” meaning “Awesome,” long before President Washington picked the name Constitution for the frigate to be built in Boston. When you recall that she never lost a fight, got away the three times she was chased by British squadrons, and could clip along at fourteen knots, it is evident she made good on all of Humphreys’ design characteristics. She proved herself worthy of his chosen name, too. She is, indeed, awesome.
Chapelle, Howard I. The History Of The American Sailing Navy. New York: Bonanza Books, 1949.
Dodds, James, and James Moore. Building A Wooden Fighting Ship. New York: Facts on File Publications, 1984.
Martin, Tyrone G. A Most Fortunate Ship. Revised edition. Annapolis: Naval Institute Press, 1997.
—. Creating A Legend. Chapel Hill: Tryon Publishing Company, 1997.
A TIMONIER Publication
1990, 1997, TGM