No. XVI.
How to make a sea-castle, or fortification, cannon-proof, capable of a thousand men, yet sailable at pleasure to defend a passage, or, in an hour's time, to divide itself into three ships, as fit and trimmed to sail as before; and even whilst it is a fort or castle, they shall be unanimously steered, and effectually be driven by an indifferent strong wind.
NOTE.
Scheffer, in his treatise entitled De Militiâ Navali, describes a vessel of a somewhat similar construction: it was composed of four floating tanks, or parts of vessels, which could at pleasure be joined together by means of bolts. Bomb-proof batteries of prodigious force were used by the Spaniards in their attack on Gibraltar, in 1782. Their upper decks were at an angle of about forty-five degrees, and composed of successive layers of oak-planking and raw hides. These offered an irresistible barrier to the shot and shells commonly used, till General Elliot decided on the application of red-hot balls, which, by burning a passage through the outer layers, quickly communicated to that part of the hold used as a depository for powder, &c., and the consequence was, the entire destruction of this immense flotilla.