This will allow the fuel being under deck, or a considerable portion of it. The depth of the vessel will thus be, from the outside of the bottom plank to the top of the deck plank, eight feet ten inches in the middle and eight feet seven inches at the side, the round of the deck being three inches. An extreme breadth of twenty-eight feet has been assumed, and a length on deck of 170 feet; both ends of the vessel to be alike, and a rudder at each end. The bottom plank may be five and one-half to six inches, the planking of the sides three and one-half to four inches. The timbers below, or the floor timbers, six inches thick by twelve inches deep, and eighteen inches asunder in the clear, the knee connecting the floor and upper timber to side six inches; the upper timber to set on the floor and alongside the knee, thus making a frame. The upper or side timber to side six inches and mold at the heel nine and one-half to ten inches, and at the top seven and one-half to eight inches. These sizes to extend for a length of seventy feet in the middle of the vessel, from which to each end they may be molded less.

The thick clamp or shelf piece under the beam to be nine inches in thickness and about fourteen inches deep. The bilge keelson in the throat of the knee to be twelve or thirteen inches square; the middle keelson fourteen inches thick by eighteen inches high. The beams to side and mold ten inches. The deck plank to be four inches thick. The guard beams to be secured below by iron braces from the outer ends, reaching as far under water as may be, and above by iron rods across the vessel. The diameter of the wheel about twenty-four feet, and the face of the bucket about seven feet. Cylinder, eighteen inches in diameter and eight feet stroke. Boilers, three in number, four feet external diameter and twenty-six feet long. Such an engine might give a speed of nine miles in still water. The wheel to work as usual for snap, with arms and braces to remove. The weight of the hull will probably be from 200 to 210 tons; 100 men and effects, twelve equipments, twelve tons; steam machinery, thirty-five tons; fuel for five days, at sixteen tons per day, eighty tons; armament of four 8- inch guns, with powder, shot, &c., forty tons-making in all, 395 tons.

For a draft of water of five feet, the displacement or total weight is, be the accompanying sketch,* 436 tons, and the weight above given will then only immerse the vessel four feet seven to eight inches, the displacement per inch at the water line of five feet being eight and one-tenths tons. The probable cost of the hull may be from $9,000 to $10,000; that of the steam machinery from $10,000 to $12,000. The fastening of the hull to be of iron, varying from three-quarters to one inch.

It is difficult for any one practiced in sea-going shipping to give precise instructions for river boats, as no doubt the experience of persons engaged in this kind of work was led them to many things that are not to be reached in any other way. It would be well for the proper officer of the War Department to be authorized to call to his aid the naval constructor of the Navy Department now at Cairo, or on the Ohio (Mr. Samuel M. Pook), who is a person of experience in building ships of war, and with him he would readily ascertain what could be done. Mr. Pook is permanently attached to the Navy Department, and is thus under pay. He is an industrious man, and to be rallied on.

---------------

*Omitted.

---------------