Prince Consort Class Ironclad - Conversion

Conversion

"The two-decked wooden ship which were turned into armoured frigates had their sides cut down considerably, and the main deck and its battery removed; while the armour, although about equal in weight to the parts removed, is not as high above water. the iron-clad is, therefore, less top-heavy than the wooden ship was previously to be converted; in other words the conversion has the effect of bringing down the centre of gravity of the ship."

As part of the conversion they were lengthened by 21 feet. "The object of lengthening was to provide more space for an armament mounted entirely on one deck except for chase guns. Such extensions are carried out by a process well recognised in naval architecture; which is quote possible at any stage in the building of a ship, not by adding to the extremities, but in cutting her in two at the point of greatest beam and separating the halves sufficiently to insert a new section between them. This is usually done by erecting a launching cradle round the stern half, moving it down the slipways on the cradle as far as required and building up the gap. In such fashion the Prince Consort, Caledonia and Ocean (as well as the Royal Alfred and Royal Oak) were each drawn out 23 feet when already partially on the frame... But as the midship portion of a hull is always the part subjected to the greatest sagging and hogging strains in a head or following sea, special care is necessary to ensure the inserted section is sufficiently strongly built in; particularly if it has to bear the burden of the engines as it did in the Prince Consort class. Exceptionally stout timbering was therefore used for the purpose in those ships; even with that their central structure someitmes exhibit signs of stress giving rise to trouble in a minor degree." "Although the added central section had a full bilge throughout, their floors rose in the old fashion forward and aft, because their underwater lines had taken shape before conversion was ordered and could not be altered without an almost entire rebuilding of the ship. This reduced the carrying capacity of the hull compared with that of a full bodied vessel such as the Bellerophon; but retained a good model for easy movement and contributed to their excellent steering qualities alike under steam and sail."

The bows of the Bulwark class were of the normal knee-shape for wooden warships. When they were converted to ironclads, the Prince Consorts and the Royal Oak were completed with stems approaching the upright above water, and this style, which was so much decried at first, had by the late-1860s won aesthetic approval. "The bow has been modified in order to dispense with overhanging weight, to increase its fitness to cleave and surmount waves, and to adapt it for ramming purposes." Though they did not have underwater rams.

"The stern has been modified in order to give protection to the rudder-head, to deflect raking shot, and to render it more fit to receive easily the blows of following waves."" "Aft the overhang of the counter was narrowed to an oval termination foreshadowing what became the normal battleship type of stern thirty years later, except that the counter was above water instead of below. As these were the first vessels with that novel design of stern they were often called 'double-enders' until the design became so common as to suggest no peculiarity." "The upper parts of the wooden rudder... showed above water, and the rudder was of the old narrow unbalanced type with a bronze neck socket to receive an iron double-tillered norman head."

As wooden-hulled ships the Prince Consorts and the Royal Oak lacked the double bottom and water-tight bulkheads given to iron-hulled vessels. However, at the time people did not consider these things necessary for wooden ships, whose sides and bottoms were very thick, and for which there was much experience. With an iron-hulled ship the "bottom is without any doubt very thin and liable to penetration by a rock or any other hard substance; but the danger resulting from penetration is very greatly reduced by the adoption of a proper number of watertight divisions or bulkheads in the ship's hold, while it may be almost got rid of by the cellular bottom, now given to all our iron-clads, which prevents the entrance of water into the hold even when the outer plating is penetrated." It should be added that before the introduction of the bracket-frame system with the Bellerophon, double-bottoms on British iron-hulled iron-clads were very partial.