The demand for high speed launches has had its influence on the designers and builders, and has led to the production of a new type of launch to which the name "auto boat" has been quite appropriately given. As a rule these boats are equipped with motor outfits turned out by the automobile manufacturers, which give high power with a very small weight of machinery. This very naturally has led to cutting down the weight of hull as much as possible in order to reduce the displacement, as the primary considerations in the quest for speed are a maximum of power and minimum displacement. With the small displacement, length is necessary and the result is a long, narrow hull with a sharp entrance and a long clean run. With the automobile motor its fixtures have also been adopted and in the auto boats we find the horizontal steering wheel with the controlling devices, oilers, etc., for the motor conveniently placed within reach of the man at the wheel.
 |
The speed of these boats varies from twelve to twenty miles per hour, depending upon the size of hull and the power installed and with a reasonable construction, a most useful and generally satisfactory type of launch can be produced.
The accompanying plans show the lines of a small launch building for a resident of Potowomut, R. I. While intended for speed she was not built with only that end in view, as the owner is a thorough yachtsman, and when a clay is set for a spin he goes, in spite of wind or rain. The restrictions made by the owner were very few, thus giving the designer practically a free hand. The motor power for which the boat was designed was a four-cyinder motor of the "Mercedes" type, of about 25 H. P. The owner, however, decided to make a slight change, and put in a motor that would develop more power, namely, a four-cylinder machine with a bore of six inches and eight-inch stroke.
While the construction of the boat is light it is by no means a mere shell. The planking is of cedar, finished one-half inch in thickness; the frames are of oak, three quarters of an inch square, spaced six inches center to center; where possible these frames were in one piece from sheer to sheer. The engine bed was to be of oak, sixteen feet in length, tapered as shown in the plans, but when the larger engine was substituted it was found necessary to put in two long stringers, which are mortised over the frames and securely bolted. The engine bed is set in side of these stringers, and is also mortised over the frames and securely bolted through frames and planking and to the heavy stringers. There are two outboard bearings of bronze fastened securely through heavy floors with Tobin bronze bolts; the stuffing box is inboard. There is a bulkhead at forward end of cockpit and one at the after end; there is also a galvanized-steel bulkhead forward of the tiller quadrant. Her decking is three-eighths of an inch in thickness and covered with six-ounce canvas. Coaming and seat of mahogany. She will be finished in a light-gray color with a dark-green underbody.
There are two tanks, one situated under the after end of the forward deck and one under the after deck. They will be connected in such a manner as to maintain an equal level, thus keeping the weight in the same position as the supply of gasoline is consumed. The steering wheel and controlling levers are within easy reach of the operator. There is to be a Carlisle & Finch electric search light situated on the forward deck, a spray hood of the naval type will keep the operator from getting an occasional shower bath. The weight of the motor with reverse gear and all necessary piping will not exceed one thousand pounds. The dimensions are as follows:
|
