"Sparrow": A Remarkable Little Craft
In many ways Sparrow is the most remarkable boat of the past season. Built by the Godshalk Co., of Camden, N.J., she has been entered in every race in which she was eligible since her completion, and has won with remarkable regularity, including the long distance event from New York to Poughkeepsie and return, making a record for reliability of performance, economy and speed which has hardly been equaled in this country. During the season he has covered in races over 450 miles, and has been run under her own power probably well over 1,700 miles. While she has shown remarkable speed, she is by no means an out and out racer, as she has good accommodations for her size and her weight is by no means cut to the limit by using light material or scantlings.
In getting out the lines of Sparrow, her designer adopted the well-known principle of the large midship section and fine ends upon which many of the fastest boats in the world have been designed, and her fore body closely resembles that of the famous liners Paris and New York. This is probably the first instance where this form has been carried to its logical conclusion in a motorboat. A designer has the option, when given a certain displacement, of distributing it well fore and aft, giving a boat either a fairly small midship section or bunching the displacement, so to speak, near the middle of the boat and fining the ends. In either case, as the prismatic coefficient of a well designed speed boat has been found to be about 55 per cent, the consequent variation allowed for the midship section is only a small per centage, as a larger or smaller prismatic coefficient does not give as good results from a speed standpoint, and the variation can be made in the fore and aft distribution of the displacement and the slight variation in the midship section.
In the Sparrow the designer determined upon the form with the fine ends, as is done with torpedo boats, and with his idea in view cut up the keel line at both bow and stern, making an underbody which looks bunchy about the midship section, but which enabled him to lower the motor and obtain a nearly parallel shaft line. At the same time all the weights of the hull are located close to the midship section and the boat is prevented from plunging in a heavy sea. The motor is located just forward of amidships under a hood with the fly wheel at the after end and above and back the gasolene tank with the tanks for lubricating oil placed on top of it. All the control levers are carried through the bulkhead, which is just aft of the tank and aside from starting the motor there is no necessity of entering the forward cockpit. The after cockpit contains the passenger accommodations and has two broad seats which will accommodate six.
The construction of Sparrow is rather heavy for a boat of this type, as the keel and framing are of good size., the former being 1 3/8 by 5 inches tapered at the ends, and the latter 5/8 by 3/4 inches spaced on 6-inch centers, all being made of white oak. The engine beds are yellow pine and are carried well fore and aft from the motor. Several stringers of white oak are worked on either side between the keel and the gunwale to stiffen the boat fore and aft and to insure that she remains her form under severe conditions. The planking is of 5/8-inch cedar laid in single thickness and caulked in the usual manner. The decks are of white pine covered with canvass, and the coaming, seats and other trimmings are of mahogany, he boat being unceiled and varnished inside. The form above the water is very pleasing and shows the wide flaring bow customary with all boats built by this firm. This tends to throw the water away from the hull when going into a head sea and prevents her driving to the same extent as a boat without this feature. Sparrow is equipped with a three-blade 2 1/2 by 25-inch propeller, and when full let out runs at a little over 1,000 revolutions per minute.
The motor used in Sparrow is a regular Packard automobile motor, as used in the cars of the Packard Motor Car Company, of Detroit, with the exception of a few changes necessary to install it in a boat. According to the A.P.B.A. rules it is rated at 31.8 h.p., and by the company it is called 24-h. on the French rating. It is the regular 1906 Packard type, with cylinders of 4 1/2 by 5 1/2 inches bore and stroke, with the four vertical cylinders cast in pairs. The exhaust and inlet valves are on opposite sides and are mechanically operated and interchangeable. The cam mechanism is enclosed in the crank case or a tight extension of it. The crank shaft is cut from a solid block of steel. Its bearing are ground and run in Parson's white metal within bronze bushings. The pistons and rings are ground and the cylinders are lapped. The crank case is in three parts, as in the regular automobile motor. The entire mechanism is contained within the two upper sections, which divide on the crank shaft center line; while the lowest section is merely an oil-well, removable without disturbing any other part of the motor. The top and bottom sections are of aluminum, but the middle section is of bronze and is water-jacketed.
The carburetor used is the regular water-jacketed Packard carburetor with aspirating nozzle, automatic auxiliary air valve, and manually controlled butterfly throttle. Ignition is by jump-spark with the current obtained from a low-tension Eisenmann magneto through the medium of a non-vibrating coil. For starting and emergency there is a storage battery and vibrator coil system. The spark plugs connect with the high-tension wires by knife switches. The magneto is direct gear-driven. Lubrication is by splash from the crank case, the oil-well being provided with partitions to maintain a constant level of oil beneath each cylinder, regardless of motor inclination. The oil is fed to the crank case by a regulatable, gear-driven plunger pump.
The most notable difference from the regular Packard construction is in the water-cooling system, and this is also a departure from the ordinary boat motor practice. The pump is gear-driven from the crank shaft, being at the forward end of the motor, and is sufficiently low to be below the water line and thus secure gravity feed. The water is taken into the pump from outboard, is pumped to the starboard crank case jacket and thence through a by-pass to the port jacket. it passes forward in this jacket and then rises by a pipe to the bottom of the jacketed exhaust header, whence it passes to the cylinder jackets at their lower ends. >From the tops of the cylinders the water goes to the forward end of the exhaust header, there being discharged into and with the exhaust gases, interiorly cooling the header. The water may be discharged outboard directly from the cylinders, if desired. the starting crank is on an elevated bracket with sprocket, chain and ratchet connecting with the crank shaft. the Packard Company built a few of these motors this season, but on account of the volume of their automobile business will not definitely enter the marine motor field at present.
(Transcribed from The Motor Boat, Nov. 10, 1906, pp. 30-32. )
[Thanks to Greg Calkins for help in preparing this page. LF]
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