At close order the bridge will pass any part of a heavy train.
Dimensions, and weight of cylindrical pontoons, manufactured in the arsenal at Woolwich.
| Extreme length. | Diameter. | Weight. | |||
| ft. | in. | ft. | in. | cwt. | |
| Large Pontoon, | |||||
| with hemispherical ends | 22 | 3 | 2 | 8 | 4 |
| Small Pontoon, | |||||
| with conical ends | 15 | 0 | 1 | 8 | 1¼ |
| ONE CARRIAGE LOAD. | |||||||||||
| Dimensions. | |||||||||||
| Number. | Length.* | Breadth. | Depth. | Weight. | |||||||
| ft. | in. | ft. | in. | ft. | in. | cwt. qrs. lb. | |||||
| Pontoons | 2 | 22 | 2 | 7 | 2 | 7 | 9 | 1 | 9 | ||
| Baulks | 12 | 14 | 2 | 5 | 3 | 5 | 1 | 1 | |||
| Chesses | 8 | 12 | 1 | 2 | 1½ | 1 | 3 | 19 | |||
| Half-chesses | 4 | 11 | 5 | 1½ | 1 | 3 | 0 | ||||
| Gunnels | 2 | 12 | 1 | 2 | 4 | 1 | 3 | 19 | |||
| Side-pieces | 5 | 10 | 4 | 5 | 2½ | 1 | 1 | 0 | |||
| Anchor | 1 | 3 | 1 | ||||||||
| Buoy | 1 | 3 | |||||||||
| Cable (20 fathoms) | 1 | 168 | 3 | 3 | 1 | 18 | |||||
| Oars | 7 | 14 | 3 | 14 | |||||||
| Boat-hook | 1 | 14 | 7 | ||||||||
| { Body | 3 | 8 | 9 | 4 | 20 | ||||||
| Lashings | { Gunnel | 4 | 15 | 1 | 1 | } | 8 | ||||
| { Carriage | 4 | 22 | 1 | 1 | } | ||||||
| Rack-sticks, and lashings | 8 | 14 | |||||||||
| Buoy-line | 1 | 60 | 1½ | 1½ | 5 | ||||||
| Breast-line | 1 | 60 | 1½ | 1½ | 5 | ||||||
| 31 | 1 | 0 | |||||||||
| Weight of Carriage | 1 | 13 | 3 | 20 | |||||||
| Total | 45 | 0 | 20 | ||||||||
| * The length includes the hemispherical ends. | |||||||||||
2.—SMALL PONTOONS.
Five pontoons, with their appurtenances, form the load of one carriage. Length, 15 feet; diameter, 1 foot 7 inches; displacement, 27½ cubic feet; buoyancy, 1718 lb., or 15¼ cwt., from which deduct 2 cwt. for the weight of pontoon, and share of superstructure. A bridge of this nature is so light that it may be made on shore, and carried by hand entire. It will support as many men as can be placed on it, and, by removing the chesses over the gunnels, it may be bent so as to be passed without difficulty down a steep bank, or counterscarp.
| ONE CARRIAGE LOAD. | ||||||||||
| Dimensions. | ||||||||||
| Number. | Length.* | Breadth. | Depth. | Weight. | ||||||
| ft. | in. | ft. | in. | ft. | in. | cwt. qrs. lb. | ||||
| Pontoons | 5 | 15 | 1 | 7 | 1 | 7 | 5 | 0 | 0 | |
| Gunnels | 5 | 8 | 4 | 9 | 3 | 3 | 12 | |||
| Baulks | 30 | 6 | 6 | 3 | 1½ | 1 | 1 | 9 | ||
| Chesses | 20 | 8 | 1 | 4 | 1½ | 4 | 0 | 20 | ||
| Paddles, used as side-pieces | 5 | 1 | 27 | |||||||
| Rack-sticks, and lashings | 10 | 6 | ||||||||
| Carriage lashings | 2 | 5 | ||||||||
| Anchor, and cable | 1 | 2 | 0 | |||||||
| 12 | 1 | 23 | ||||||||
| Weight of the Carriage | 1 | 9 | 0 | 0 | ||||||
| Total | 21 | 1 | 23 | |||||||
| * The length includes the ends. | ||||||||||
SCALING LADDERS.