As above stated, our aim was to make the ship as small as possible. The reason of this was that a small ship is, of course, lighter than a large one, and can be made stronger in proportion to her weight. A small ship, too, is better adapted for navigation among the ice; it is easier to handle her in critical moments, and to find a safe berth for her between the packing ice-floes. I was of opinion that a vessel of 170 tons register would suffice, but the Fram is considerably larger, 402 tons gross and 307 tons net. It was also our aim to build a short vessel, which could thread her way easily among the floes, especially as great length would have been a source of weakness when ice-pressure set in. But in order that such a ship, which has, moreover, very sloping sides, shall possess the necessary carrying capacity, she must be broad; and her breadth is, in fact, about a third of her length. Another point of importance was to make the sides as smooth as possible, without projecting edges, while plane surfaces were as much as possible avoided in the neighborhood of the most vulnerable points, and the hull assumed a plump and rounded form. Bow, stern, and keel—all were rounded off so that the ice should not be able to get a grip of her anywhere. For this reason, too, the keel was sunk in the planking, so that barely three inches protruded, and its edges were rounded. The object was that “the whole craft should be able to slip like an eel out of the embraces of the ice.”
The hull was made pointed fore and aft, and somewhat resembles a pilot-boat, minus the keel and the sharp garboard strakes. Both ends were made specially strong. The stem consists of three stout oak beams, one inside the other, forming an aggregate thickness of 4 feet (1.25 m.) of solid oak; inside the stem are fitted solid breasthooks of oak and iron to bind the ship’s sides together, and from these breasthooks stays are placed against the pawl-bit. The bow is protected by an iron stem, and across it are fitted transverse bars which run some small distance backwards on either side, as is usual in sealers.
The stern is of a special and somewhat particular construction. On either side of the rudder and propeller posts—which are sided 24 inches (65 cm.)—is fitted a stout oak counter-timber following the curvature of the stern right up to the upper deck, and forming, so to speak, a double stern-post. The planking is carried outside these timbers, and the stern protected by heavy iron plates wrought outside the planking.
Between these two counter-timbers there is a well for the screw, and also one for the rudder, through which they can both be hoisted up on deck. It is usual in sealers to have the screw arranged in this way, so that it can easily be replaced by a spare screw should it be broken by the ice. But such an arrangement is not usual in the case of the rudder, and, while with our small crew, and with the help of the capstan, we could hoist the rudder on deck in a few minutes in case of any sudden ice-pressure or the like, I have known it take sealers with a crew of over 60 men several hours, or even a whole day, to ship a fresh rudder.
The stern is, on the whole, the Achilles’ heel of ships in the Polar Seas; here the ice can easily inflict great damage, for instance, by breaking the rudder. To guard against this danger, our rudder was placed so low down as not to be visible above water, so that if a floe should strike the vessel aft, it would break its force against the strong stern-part, and could hardly touch the rudder itself. As a matter of fact, notwithstanding the violent pressures we met with, we never suffered any injury in this respect.
Everything was of course done to make the sides of the ship as strong as possible. The frame timbers were of choice Italian oak that had originally been intended for the Norwegian navy, and had lain under cover at Horten for 30 years. They were all grown to shape, and 10–11 inches thick. The frames were built in two courses or tiers, closely wrought together, and connected by bolts, some of which were riveted. Over each joint flat iron bands were placed. The frames were about 21 inches (56 cm.) wide, and were placed close together, with only about an inch or an inch and a half between; and these interstices were filled with pitch and sawdust mixed, from the keel to a little distance above the water-line, in order to keep the ship moderately water-tight, even should the outer skin be chafed through.
The outside planking consists of three layers. The inner one is of oak, 3 inches thick, fastened with spikes and carefully calked; outside this another oak sheathing, 4 inches thick, fastened with through bolts and calked; and outside these comes the ice-skin of greenheart, which like the other planking runs right down to the keel. At the water-line it is 6 inches thick, gradually diminishing towards the bottom to 3 inches. It is fastened with nails and jagged bolts, and not with through bolts; so that if the ice had stripped off the whole of the ice sheathing the hull of the ship would not have suffered any great damage. The lining inside the frame timbers is of pitch-pine planks, some 4, some 8 inches thick; it was also carefully calked once or twice.
The total thickness of the ship’s sides is, therefore, from 24 to 28 inches of solid water-tight wood. It will readily be understood that such a ship’s side, with its rounded form, would of itself offer a very good resistance to the ice; but to make it still stronger the inside was shored up in every possible way, so that the hold looks like a cobweb of balks, stanchions, and braces. In the first place, there are two rows of beams, the upper deck and between decks, principally of solid oak, partly also of pitch pine; and all of these are further connected with each other, as well as with the sides of the ship, by numerous supports. The accompanying diagrams will show how they are arranged. The diagonal stays are, of course, placed as nearly as possible at right angles to the sides of the ship, so as to strengthen them against external pressure and to distribute its force. The vertical stanchions between both tiers of beams and between the lower beams and keelson are admirably adapted for this latter object. All are connected together with strong knees and iron fastenings, so that the whole becomes, as it were, a single coherent mass. It should be borne in mind that, while in former expeditions it was thought sufficient to give a couple of beams amidships some extra strengthening, every single cross beam in the Fram was stayed in the manner described and depicted.
In the engine-room there was, of course, no space for supports in the middle, but in their place two stay ends were fixed on either side. The beams of the lower deck were placed a little under the water-line, where the ice pressure would be severest. In the after-hold these beams had to be raised a little to give room for the engine. The upper deck aft, therefore, was somewhat higher than the main deck, and the ship had a poop or half-deck, under which were the cabins for all the members of the expedition, and also the cooking-galley. Strong iron riders were worked in for the whole length of the ship in the spaces between the beams, extending in one length from the clamp under the upper deck nearly to the keelson. The keelson was in two tiers and about 31 inches (80 cm.) high, save in the engine-room, where the height of the room only allows one tier. The keel consists of two heavy American elm logs 14 inches square; but, as has been mentioned, so built in that only 3 inches protrude below the outer planking. The sides of the hull are rounded downward to the keel, so that a transverse section at the midship frame reminds one forcibly of half a cocoanut cut in two. The higher the ship is lifted out of the water, the heavier does she, of course, become, and the greater her pressure on the ice, but for the above reason the easier also does it become for the ice to lift. To obviate much heeling, in case the hull should be lifted very high, the bottom was made flat, and this proved to be an excellent idea. I endeavored to determine experimentally the friction of ice against wood, and taking into account the strength of the ship, and the angle of her sides with the surface of the water, I came to the conclusion that her strength must be many times sufficient to withstand the pressure necessary to lift her. This calculation was amply borne out by experience.
The principal dimensions of the ship were as follows: Length of keel, 102 feet; length of water-line, 113 feet; length from stem to stern on deck, 128 feet; extreme breadth, 36 feet; breadth of water-line, exclusive of ice-skin, 34 feet; depth, 17 feet; draught of water with light cargo, 12½ feet; displacement with light cargo, 530 tons; with heavy cargo the draught is over 15 feet and the displacement is 800 tons; there is a freeboard of about 3 feet 6 inches. The hull, with boilers filled, was calculated to weigh about 420 tons, and with 800 tons displacement there should, therefore, be spare carrying power for coal and other cargo to the amount of 380 tons. Thus, in addition to the requisite provisions for dogs and men for more than five years, we could carry coal for four months’ steaming at full speed, which was more than sufficient for such an expedition as this.