US2942282A - Lap-chine boat construction - Google Patents

Description

June 28, 1960 R. N. THOMPSQN 2,942,282

LAP-CHINE BOAT CONSTRUCTION Filed Nov. 14. 1955 2 Sheets-Sheet 1 IN V EN TOR.

Rob/55 1 N. TB oM soN Attomvsy June 28, 1960 R. N. THOMPSON 2,942,282

LAP-CHINE BOAT CONSTRUCTION Filed Nov. 14, 1955 2 Sheets-Sheet 2 INVENTOR. RObERt .N. Thompson A EtcANE United States Patent LAP-CHINE BOAT CONSTRUCTION Robert Nelson Thompson, Cortland, N.Y., assignor to Thompson Boat Company of New York, Inc., Cortland, N.Y., a corporation of New York Filed Nov. 14, 1955, Ser. No. 546,542

1 Claim. (Cl. 9-6) This invention relates to a method of boat hull construction, and in particular to a novel means of covering the frame of a boat.

Heretofore, it was necessary to sheathe the skeleton of a boat with a series of beveled lap-planks of substantially equal width varying the degree of the angle of the bevel on the lap-planks to conform to the curve of the boat from bow to stern and also the curve of the bilge section. First, a method for producing beveled'strakes which formed a tight, waterproof fit had to be applied. This is a very detailed method requiring skilled labor, good fitting of all faying surfaces, and time consuming planning. The fact, that the curve of each strake varies to conform to the sweep of the hull, presents difficulties in the present method. A great number of properly cut and shaped strakes had to be used in a lap-strake hull, including planks for the garboard, bottom, topside and sheer. It was then found necessary to place 'hese strakes in a series of overlapping planks in a lateral position conforming to the compound curvature of the boat. This method of covering a boat is a very difficult one. and tedious in comparison to the method brought forth in my invention.

This invention has, for one of its objects, the facility of covering the frame of a boat using an easier method, reducing the task of beveling planks in order to entirely cover the frame.

Another purpose of this invention is to provide a means of sheathing a boat which may be easily adapted for use with respect to the type of bilge section used, and which also readily conforms to the size and shape of the frame of the boat.

Still another object of the invention is to reduce the necessity of beveling a large number of planks in varied degrees in order to fit the compound curved structure of the frame. This method also reduces the number of fastenings used.

With this novel method of construction, it is also possible to employ other materials, such as sheet or molded plastic, glass fibers, or sheet or molded aluminum in covering the frame of a boat due to the design and manner in which the boat is covered.

The present invention also assures a safer means of covering the frame of a boat, lessening the danger of leakage apt to be found in the present construction of lapplanked boats.

This invention reduces the time and effort spent in the construction of lap-planked boats and insures correct and exact fit of the seams.

According to the present invention, a fiat sheet of plywood is placed parallel to the skeleton of the boat touching the frame, perpendicular from beneath the hand rail, reaching the location of the spray rail, or better known as the chine section. The lower edge of this sheet of plywood encases the lap-chine construction (narrow sheets of plywood strakes placed and coupled angularly to conform to the bilge section of the boat). This lap-chine construction is held fast and in place by means of screws and nuts, or as an alternative, suitable means such as rivets, wood screws, or nails, and reinforced by a spray rail. A second sheet of plywood is placed at the bottom of the boat running the entire distance of the keel and thwartship from keel to chine. The outer edge of this plywood sheet which meets the chine section is placed angularly to fit into the space constructed, joining the plywood lap-chine construction of the bilge section of the boat.

Other objects and advantages of this invention will be fully set forth in the following description and the novel features thereof will be specifically defined by the appended claim.

Further references are made to the accompanying drawings in which:

' Figure 1 is a cross sectional view of a boat designating lap-chine construction.

Figure 2 is a section taken substantially on line 2- -2 of Figure 3 of the lap-chine construction at the bilge section.

Figure 3 is a side elevational view, in perspective, of a completed boat showing the results of the lap-chine construction method.

In Figure l, a typical cross section of the boat, flat sheets of plywood, light-weight and so grained as to bend and twist readily in conformity with the boats sweeping curve, yet strong enough to take fastenings and hold them without splitting, curling or warping, are used.

One fiat sheet 2 of this type plywood is fastened between the keel 1 and the turn of the bilge, or chine 12. In this manner the entire bottom of the boat length is covered with this flat sheet 2 of plywood, running from the edge of the transom (not shown) to the stem (not shown) of the boat. The plywood 2 also extends thwartship from the keel 1 to the chine 12, and is fastened to the flooring ribs 8 by suitable means here illustrated as machine screws 13 and nuts 14, eliminating the need for separate bottom planking. The fact that the plywood 2 is of such pliable nature, makes it possible to cover one half of the bottom longitudinal section of the boat with a single sheet 2 of plywood. In a boat construction, where it is desired to use a single sheet for the bottom, this plywood sheet 2 could cover the entire bottom.

Along the bilge section 15 of the boat, a lap-chine construction 16 is introduced, covering the area of the boat known as the chine 12. For example, as shown in Figure 1, three narrow sheets 4 of beveled plywood strakes 4 are fastened angularly by means of machine screws 6 and nuts 7. The overlap 20 of these strakes 4 are so beveled as to produce perfect overlaying of the strakes 4 and to insure leakproof seams at this section. The strakes are suitably chamfered on their inboard edge to cooperate with the adjacent surfaces of the ribs 8. A special marine sealer (not shown) is used to further insure leakproof seams. The size of these lap-chine strakes 4 are dependent upon the type of bilge section 15 used on the boat. The finished surface of this lap-chine construction 16 is a compact series of overlapping strakes 4 that are successfully screw fastened to one another; the definite amount of overlap 20 is pre-determined.

Another pair of fiat sheets 3 of this same type plywood are placed along the topside 22 of the boat, adjoining the ribs 8 of the boat, from the hand rail 23 down to the chine section 12, running the entire sweep of the boat from the stem 24 to the transom 25. These are fastened to the ribs 8, stem 24, and transom 25 with machine screws 6 and nuts 7. As an alternative means of fastening, rivets, wood screws, or nails may be employed. The lower edge 26 of sheets 3 overlap the lapchine construction '16 sufiiciently to provide a perfect encasing of the boat frame. The plywood sheets 3 are the "ahg'les where t'he plywood sheets 3 and 2 meet and overlap the lap-chine construction 16 of the bilge 15.

, 'It'will of course be understood that various modificatem maybe rn'adejinithe form, details, arrangements and 'iiroportions'oftlie apparatus andin the steps and sequence "er steps of theiiietliod without departing from the scope of the applicants invention, which, generally stated, consists in a method capable of earryin'g out'the objects above set 'forth,stic'h as disclosed and defined in the appended claim.

A boat hull including a stem, 21 k'e'el an'd "a rear transom parallel to a plurality 0i transverse "ribs, a single 'b'e'ridable sheet secured to said ribs and to the lower edge of said transom and conforming to the shape there- 6 f, said sh'eet "extending forwardly from said transom and symmetricallyalong the keel of said 'hull, said sheet extending upwardly and converging forwardly into the stem of said hull the side edges of said sheet defining a chine semen "on said hull, a plurality of vertically overlapped strake elements secured to said transom and ribs "ahdm'erg'irigintofsaid stern, longitudinal edges of said bendable sheetand upper edges of said strake elements being chamfered for sealingly engaging the inboard side of an adjacent "element single 'b'endabl'e side panel elements on opposite sides of said hull and secured to said transom and ribs and extending from said transom and merging into said stem, said side panels including a lower longitudinal edge overlapping the upper chamfered edge of the uppermost st'rake'e'lement and a spray rail extending from said transom to said stem and overlying the outer surface of said side paiiels opposite "the 'chamfered edge of said uppermoststrake element.

References Cited -in the iile'of this patent UNITED STATES PATENT S 396,776 Sprague J an. 29, 1889 661,246 Holloway Nov. 6, 1900 1,941,586 Snadecki Jan. 2, 1934 2,677,139 Canazzi May 4, 1954 Yates '1-":a 224, FOREIGN PATENTS 345,455 Great Britaih 'Mar. 26, 1931 579,035 Great-Britain 1iily'-22, 1946 762,895 Great Britain Dec. 5, 19 56 OTHER REFERENCES I Bo"atbuilding ohapel ej) pi blished by Mo'rton ace. New York), -191,'- 5age=47s =reli'ed en.

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