Medford Historical Society Papers, Volume 6.

Ships, especially the larger ones, were usually launched when the moon was new or full, and consequently near the noon or midnight hour, as the tide was then the highest. To make the launching easy they were built on an inclined plane. In their construction the first act was to lay the keel, a very large, well-smoothed hard wood timber (rock maple being the favorite) extending from stem to stern. It was supported by blocks placed a few feet apart, and on it the vessel was to rest till finished. As the work progressed, shores were placed along the ship's sides to prevent it from careening. The end nearest the water was usually the stern, but sometimes the prow. When it was ready for the launch, ways were laid on each side at a distance, according to the vessel's size, of five to seven feet from the keel, and extended down to the low water mark in the river. These, about eighteen or twenty inches wide, were made of long and strong timbers, and had in the centre a securely fastened strip of wood a few inches in height and width which served as a flange to keep the moving vessel on the track. After these had been given a heavy coating of tallow, sometimes a sprinkling of flaxseed, but oftener a film of castile soap, in addition, heavy timbers, called bilgeways, with a groove on the under side to fit the projection on the ways, were drawn up under the ship, and, by blocking, made to fit well its bottom. A multitude of wooden wedges were then driven between the ship and the underlying timbers, in order to equalize the bearing upon the ways and remove some of the pressure from the blocks under the keel. Then, the before-named shores having been removed, the final act consisted in splitting to pieces with mauls and iron wedges (as the only means of removing) the blocks under the keel, commencing with those nearest the river. When all these or sometimes all but two or three were demolished