THE ROYAL ARTILLERY INSTITUTION. 
£37 
11. There is no top gear or standing rigging of any description to be cut by the 
enemy’s shot. Nothing stands above the level of the bulwarks, except a small 
part of the muzzle of the great mortar, and the upper part of the crane for loading 
it. The latter (provided in duplicate) is so secured by secondary guy ropes, that 
in the event of being cut down by a chance shot, the parts would not fall upon the 
men around it. 
12. Although the great strength and stability on the water, and incapability of 
foundering, by division into Water-tight compartments, together with the extremely 
light draught of water, amounting (when light, or with only the large mortar, crew, 
and stores on board) to no more than 5 ft. 6 ins., are obtained by the use of a 
wrought-iron hull, yet the disadvantages incident to iron vessels when exposed to 
shot are in this instance fully met and provided against. The whole of the iron¬ 
work is below the heavy timbered deck, and within the timber sides and bulwarks ; 
so that torn or splintered iron can never injure or touch those on board. 
13. The vessel is so constructed that it is scarcely possible to burn her, while in 
possession of her crew; and even if all her woodwork were burnt off, the hull 
would float and carry her mortar safely, and be capable of perfect restoration—and 
of a temporary restoration, with means at hand, in a very short time. 
14. As the bulwarks stand so high above the deck that a man standing thereon 
cannot see the horizon, a special instrument has been devised for the purpose of 
directing the 36-inch mortar, consisting of a telescopic sight, so combined with an 
azimuth compass of power and accuracy that shelling can be carried on at night 
as well as by day, when the distance and azimuth of the object have been once got 
by daylight. The telescopic sight is such that the directing officer sees his mark 
without being exposed to fire. 
15. The extreme outside range of water-tight compartments, all round and 
immediately inside the timbering of the sides, is filled for the upper half of its 
depth, or to 3-| ft. below the load water plane, with three-fourths sawdust mixed 
with one-fourth of sharp sand by bulk, which, while much lighter than sand alone, 
being only 45 lbs. to the cubic foot, appears to resist shot nearly as well as sand 
alone. 
Within this, the next range of water-tight compartments form a continuous 
wing or passage all round the vessel, of 4 ft. wide and 6 ft. high, divided by a 
bulk-head at every 8 ft., provided with a water-tight door, and forming a ready 
means of access to any perforation, if made by shot, and to all the separate com¬ 
partments in the inboard side forming the 
Two magazines, 
Shell rooms, 
Bread rooms. 
Store rooms, 
Armouries, 
Cordage and cables, &c. &c. 
The spaces between the iron beams beneath the great mortar form the water tanks, 
and give storage for above 11,000 gallons of fresh water. 
16. Any of the compartments below deck may be used as sleeping places, each 
being 8 ft. square by ft. in clear height; but it is proposed that these mortar 
batteries be considered as fighting platforms rather than as vessels intended for 
large crews to live on board for lengthened periods; and hence shelter under 
canvas for sleeping on deck at night might perhaps be found the best and 
healthiest mode in which the complement of men could live while on board. 
17- The following are the calculations of weight and displacement 
