Rensselaer Republican, Volume 12, Number 11, Rensselaer, Jasper County, 27 November 1879 — The Polyphemus. [ARTICLE]

The Polyphemus.

The Polyphemus, now being completed for commission at Chatham, England, promises to be a complete novelty among offensive ironclads. She is to be built entirely of steel, and her deck is to be covered over with threeinch plating of a convex shape. This convex curvature is continued round her sides some distance below the water line, after which her sides converge toward her keel, or rather to where her keel should be in a V shape. Her midship section will thus appear the shape of a kite, the convex deck only rising four feet six inches above her water line. She is two hundred and forty feet between perpendiculars, the extreme breadth is forty feet, and she will have a load draught of twenty feet. The engines are estimated to work up to five thousand five hundred horse power, and to give her a speed of seventeen knots. What a dangerous enemy she will prove is evident from her speed alone, as her principal means of offense are a ram or steel spur and Whitehead torpedoes. Her form of construction is evidently intended to enable her to escape notice, and, even when observed, to escape damage by the deflection of shot rather than by absolute resistance to such impact. There is much of interest and importance in this experiment, for such indeed it is, the vessel being constructed after the idea of Sir George Sartorius, a well-known veteran of the navy. We consider the Polyphemus as one of the first attempts in construction to foil the impact of heavy shot by diversion rhther than by the probably futile resistance of of a heavy armor plating. Another imEortant modification has been made in er construction to enable her to benefit to the full extent by the principle of subdivision into water-tight compartments, which is particularly carried out in her design, and on w’hich she must very largely rely for safety. The modification is that an enormous mass of

cast-iron ballast is carried outside the vessel in a rectangular groove one foot eight inches wide and three feet deep, situated where her keel should be. This mass of ballast amounts to three hundred tons; her total displacement being two thousand six hundred and forty tons, and represents in weight a volume of rather more than ten thousand cubic feet. This ballast is so arranged that it can be released from the vessel at will, so that should one or more of her water-tight compartments be pierced, the loose ballast may be dropped from the part of the vessel corresponding to the flooded compartment. The position or power of flotation may thus be retained undisturbed, even after several compartments may have been pierced. She carries no masts, except for signal purposes, and her guns are a few light shell and Gatling guns on her upper deck.— Marine Engineer.