ICE-BOATS. There are two descriptions of boats which come under this denomination ; namely, those that are designed to sail upon the surface of the ice, and those that are employed to open the navigation of frozen rivers or canals, by breaking up the ice. The first-mentioned kind of boats is much used in Holland, on the river Maeze and the lake Y. These ice-boats are propelled, it is said, with incredible swiftness, sometimes so quick as to render respiration difficult; they are found very useful in conveying goods and passengers over lakes and great rivers in that country. For this purpose a boat is fixed trans versely over a thick plank, or three-inch deal, under which, at the extremities, are fixed irons, turned up forwards, resembling and operating as skates ; upon this board the boat rests, with its keel at right angles to it ; and the extremities of the boards serve as out-riggers to prevent the boat from upsetting, whence, therefore, ropes are fastened that lead to the head of the masts, in the nature of shrouds, and others passed through a block across the bowsprit. The rudder is
made somewhat like a hatchet, with the edge placed downwards, which, being pressed down, cuts the ice, and serves all the purposes of a rudder in the water, by enabling the helmsman to steer, tack, &c.
The other kind of ice-boat alluded to, is a strong and heavy-laden canal boat, fitted up for the purpose of breaking the ice, by arming the fore-part of the keel and the bows with iron, which penetrate and break down the ice as the boat is drawn forcibly along by an adequate number of horses towing it on the path. This measure of opening the navigation of a canal is seldom adopted, except when the ice is only a few inches in thickness, or when a thaw has ren dered thicker ice of little tenacity.