Encyclopaedia Perthensis Volume 20 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1816 edition. Excerpt: ...to which tiistinguilhcd fine steering ships from such as had not this quality; and it is in a great measure to be ascribed to this, that, in the gradual improvement us naval architecture, the centre of gravity has been placed far forward. Perhaps the notion of a centre of gravity did not come into the thoughts of the rude builders in early times: but they observed that those boats and ships steered best' which had their extreme breadth before the middle point, and consequently, the bows not so acute as the stern. This is so contrary to what one would expect, that it attracted attention more forcibly; and, being somewhat mysterious, it might prompt to attempts of improvement, by exceeding in this singular maxim. We believe that it has been carried as far as is compatible with other essential requisites in a ship.. This is the chief circumstance in what is called the trim of a (hip; and it were greatly to be wished, that the best place for the centre of gravity could be accurately ascertained. A practice prevails, which is the opposite of what we are now advancing. It is usual to load a ship, so that her ' keel is not horizontal, but lower abaft. This is found to improve her steerage. The reason of this is obvious. It increases the acting surface of the rudder, and allows the water to come at it with much greater freedom and regularity 5 and it generally diminishes the.griping of the ship forward, by removing a part of the bows out of the water, ft has not always this effect; for the form of the harping aloft is frequently such, that the tendency to gripe is diminished by immersing more of the bow in the water. But waving these circumstances, and attending only to the rotatory energy of the rudder, we fee that it is of advantage to carry...