The model selected for the Roosevelt was intended to meet the requirements of lifting under pressure, of being short enough to handle easily, and of being able to ram a passage through heavy ice effectively and continuously.
Detailed features of these requirements are as follows:
For lifting under pressure, steel-sheathed sides, sloping bilges, flat floor to prevent heeling when lifted, flush stem and keel, raking stem, raking stern (this a new feature). For forcing a way through loose ice: sharp wedge bow, and full counter to keep ice from propeller. For ramming ice: a sharply raking stem, steel-sheathed.
From this general description, it will be understood that while the hull model contained the best features of preceding ships, it was not a departure from ordinary models, like the Fram and Gauss, but rather a modification of them to meet special requirements.
When the question of power was approached, there was a radical departure, in fact a complete reversal of previous practice in Arctic ships, and the adoption of ordinary commercial practice.
Hitherto Arctic ships have had full sail power (full-rigged bark being the favourite rig) and auxiliary engines, often of surprisingly puny power. The object of this has been economy of coal, and the consequent ability of the ship to cover long distances at slow speed, and remain away from home for a period of years.
The Roosevelt is a powerful steamer, with all the engine force she could contain, and with only moderate sail area. There is no question in my mind but that this is the correct principle upon which to build a modern Arctic ship for effective results.
The Smith Sound or “American” route is especially advantageous for this method, presenting a coasting voyage, facilities for placing coal depots, the key of the route condensed in a few hundred miles of heavy ice navigation, and the possibility of even obtaining coal in situ along the route.
The Roosevelt had engines capable of developing one thousand horse-power. They were of the inverted, compound type, driving a single eleven-foot propeller, and steam was supplied by two water-tube boilers and one Scotch boiler. Her sail plan is a light, American, three-masted schooner rig, possessing the advantage of light weight (it is to be remembered that every pound of weight saved in rigging or fitting means a pound of coal in the hold), and small surface to be forced through a head wind; yet sufficient to materially help the engines in a favouring wind, and to enable the ship to make her way home should her coal be exhausted.
As to construction: The strength of the hull must be such that it will resist the terrific pressure of the ice-floes, and keep its shape intact until the lifting of the ship bodily releases the pressure; such that if supported at each end only, or in the middle only, or thrown up on the ice and resting upon her bilge, during the paroxysms of the floes, she will not be strained or injured; and such that she can ram the ice by the hour when necessary, without injury to seams or fastenings.