US2917754A - Catamarans - Google Patents

Description

ea. 22, 1959 c. F. GUNDERSON 2,917,754

GATAMARANS Filed Dec. 27, 1955 3 Sheets-Sheet 1 FIG. 2 4| 1959 c. F. GUNDERSON 2,917,754

CATAMARANS Filed Dec. 27, 1955 s Sheets-Sheet 2 Dec. 22, 1959 c. F. GUNDERSON 2,917,754

CATAMARANS Filed Dec. 27, 1955 :s Sheets-Sheet s QATAMARANS Charles F. Gnnderson, West Belmar, NJ.

Application December 27, 1955, Serial No. 555,606

14 Claims. (Cl. 9-2) Catamarans have always been recognized as outstand ing watercraft. Because of their relatively large beamto-length ratio, they are seaworthy, stable and highly resistant to capsize. However this relatively large beam, which is so advantageous when the craft are waterborne, is a serious handicap when the craft are moved ashore. They are then clumsy, bulky and difficult to handle. Many catamarans have been so constructed that their hulls and central deck are substantially rigid relative to each other. To achieve this rigidity, extra structure is necessary, thereby increasing the cost and weight of the craft, and also reducing seaworthiness. Catamarans have always been notoriously difficult to bring about when changing tack. The invention described in the present specification has been designed to overcome these drawbacks of other catamarans.

It is an object of the present invention to provide a watercraft of the catamaran type wherein the hulls and the deck have a sufficient degree offiexibility relative to each other to permit the craft to conform to the movements of the water. This resilience built into the craft acts as a shock absorber and makes the craft more seaworthy. It also makes for savings in weight and cost. Sailing qualities are enhanced because jars to the mast, which would spill wind from the sails, are reduced considerably. The lighter construction not only increases buoyancy, when in the water, but it simplifies the hairdling of the craft when out of the water.

It is another object to provide such a craft which has its hulls coupled to its deck in such a manner that the hulls may be folded over the deck, or they may be separated from the deck, to facilitate storage and handling of the craft when out of the water.

Still another object is to construct hulls largely without frames or ribs generally used in conventional boat construction. In this way both weight and cost are reduced and sailing speed is increased.

Yet another object is to provide a sailing craft without a centerboard or leeboards, thereby again reducing weight and cost. As a result the leaks notoriously present in centerboard wells are eliminated, the drag of a centerboard or leeboards is removed and, not least, the draft is reduced so drastically that the craft may sail in many waters not available to conventional sailing craft.

Other objects will become apparent from the following specification and the appended drawing, wherein;

Figure 1 is a starboard side elevation of a folding catamaran embodying my present invention, shown in its opened operating waterborne condition, except that, only for purposes of illustration, the starboard aft outrigger is shown in its retracted, longitudinally disposed, position, to which it is swung to permit folding of the catamaran;

Figure 2 is a plan view of the catamaran of Figure 1, the starboard aft outrigger likewise being shown in its retracted position as in Figure 1;

Figure 3 is a composite view, the starboard portion of the craft (shown to the left in the figure) being a 1' atenti ice how elevation, and the port portion being shown in section along the line 3-3 of Figure 2;

Figure 4 is an enlarged fragmentary sectional view, also taken along the line 33 of Figure 2, showing details of the starboard hull and forward outrigger;

Figure 5 is a stern elevation of the catamaran in its partly folded condition, with the Outriggers retracted and one hull swung over the deck;

Figure 6 is a starboard elevational view of the catamaran, folded and on top of a motor vehicle; and,

Figure 7 is a sectional view, taken along the line 7--7 of Figure 6, but to a larger scale than Figure 6.

I attain the objects set forth above preferably by building the hulls and deck assembly largely of plywood (although I do not wish to limit myself to that material), thereby achieving strength and lightness. Strength in each hull is further obtained by maintaining the plywood in arcuate configeration. I eliminate frames in the normal sense, but nevertheless achieve suitable strength by providing gunwale coamings and Outriggers, which cooperate to take the place of frames, while also serving their other functions.

I obtain flexibility by using a panel of plywood in the deck assembly, thereby permitting the hulls to move independently of each other within desired limits. Such flexibility insulates the craft from considerable strains inherent in rigid catamarans referred to above.

I obtain foldability by hinging the hulls to the opposite sides of the deck assembly and providing releasable means which secure the bulls in their unfolded operating positions, but which may be released to permit the hulls to be folded over the deck, as for storage or portage.

I-prefer V bottom hulls for simplicity of construction and speed through the water. However, I make them asymmetricaLso that one side of the V is vertical, or at least sufficiently vertical so that it functions as a centerboard or leeboard.

I also raise the forward and aft ends of each hull out of the water, or at least reduce the draft at the ends of each hull sufficiently, to permitthe craft to come about readily when changing tack. I further improve the crafts ability to come about by providing it with a long sweep type rudder, so supported that it can be operated like an oar to readily spin the craft as desired.

Referring now more specifically to the drawing, the preferred embodiment of my invention illustrated is made up of three main parts, namely, a deck assembly 11, a port hull 13 and a starboard hull 15.

The deck assembly 11 includes a deck 17 which is preferably a panel of plywood, or other suitable sheet material, having a fair degree of flexibility. Secured lengthwise to the under surface of the deck 17 are a pair of spaced parallel longitudinal stringers 19 which add a desired amount of stifiness to the deck 17, in a fore and aft direction, and also act as supports upon which the catamaran may stand when it is stored or is being transported (as on racks 20 on top of a car 22). Secured to the upper surface of the deck 17 are a pair of spaced parallel transversely positioned cross braces 21. The catamaran is provided with four Outriggers 24, two of which are swingably secured to each cross brace 21, by means of a pair of pivot bolts 23. Each outrigger 24 may be swung to its extended operating position, in alignment with the cross brace 21 (three outriggers being so illustrated in Figure 2), or it may be swung inwardly to its retracted, or folded, position, lengthwise of the deck assembly 11 (the starboard aft outrigger being so illustrated in Figures 1 and 2). The under side of the deck 17 may also be provided with a central longitudinal stringer 25 to give the forward end of the deck an additional degree of strength where 'it supports a mast 27.

The deck 17 may also be provided with an outboard 3 rack 29 at its aft end. Preferably a central section 30, of the aft end of the deck 17, is bent downwardly at a slight angle to form an outboard well between the two stringers 19. The outboard rack 29 forms the aft end of this outboard well. I provide the outboard rack 29 with an oarlock 28 which may receive a sweep rudder 32. This rudder 32 may take the form of a conventional car. The forward end of the deck 17 may also be fitted with a pair of forwardly slanting spray shields 31.

For simplicity of construction and reduction in cost, the hulls 13, 15 are preferably duplicates of each other. Hence only the port hull 13 will be described at this point. Said hull 13 includes a keel 33, which is preferably triangular in cross section. Secured to adjacent surfaces respectively of the keel 33 are an inboard planking panel 35 and an outboard planking panel 37, both being of plywood or other sheet material. Each end of the hull 13 terminates in a V-shaped or triangular transom 39. As may be seen in Figure 1, the lower edge of each of the planking panels 35, 37 is arcuate, thereby bringing the fore and aft ends of the hull 13 out of the water, or at least effecting a reduced draft at both ends. It will be understood that the degree of arc is a comprise to achieve a suitable degree of speed and fore and aft stability, on the one hand (both of which characteristics are enhanced by a large radius of arc), and an ability of the craft to come about, on the other hand (which is enhanced by a lesser radius of arc).

In order to strengthen the hull 13, where it is hinged to the deck assembly 11, an inboard sheer strake 41 is provided at the upper edge of the inboard planking panel 35. The inboard sheer strake 41 is preferably a relatively stiff member and is provided with an arcuate lower edge 43 and a straight upper edge 45. The upper edge 45 is preferably positioned, when the craft is waterborne, immediately below one edge of the deck 17 and it acts to support and stiffen the edge of the deck (see Figs. 1 and 4). The upper edge of the outboard planking panel 37 is preferably provided with a gunwale coaming 47. i

The hull 13 is pivotally secured to the deck assembly 11 by a pair of loose-pin hinges 49. Each hinge 49 is secured to the deck assembly 11 at the outer end of a cross brace 21 and is secured to the hull 13 at the'inboard sheer strake 41. The loose pins of the hinges 49 permit the hull 13 to be removed from the deck assembly 11 as desired and also simplifies the building of the craft and the step of coupling the hulls 13, 15 to the deck assembly 11. Each outrigger 24 is provided at its outer end with suitable means to secure it to the gunwale coaming 47, when the craft is in its operating waterborne position. Preferably I provide the outer end of each outrigger 24 with a protruding metal eye 51 (as illustrated in Figures 2 and 4). The gunwale coaming 47 is pierced by a slot 53 to receive the eye 51. A pin 55 is provided to pass through a hole in the coaming 47 and the hole of the eye 51, to thereby lock the outer end of the outrigger 24 to the hull 13. A metal strike plate 56 (see Figures 2 and 4) may be secured to the inside of the hull 13 at each of the two slots 53. Each strike plate 56 strengthens the hull 13 where it receives the eye 51 of one of the outriggers 24 and it also protects the wood of the hull from being scratched by the eye during folding or unfolding of the craft. Each strike plate 56 is pierced by a slot 54, in register with its associated slot 53.

The starboard hull 15 is a duplicate of the port hull 13 just described and it is pivotally secured to the deck assembly 11 in the same manner.

When the parts are assembled in their operating positions, as shown in Figures 1-4, the outriggers 24 hold the hulls 13, 15 in such positions that the boat is a unitary integrated operating structure. The mating surface between the cross braces 21 and the outriggers 24 should be as long as possible in an athwartship direction, so as to maintain the desired relatively rigid alignment between each of the cross braces 21 and its outriggers 24. Nevertheless the catamaran illustrated may be readily and instantaneously folded by merely releasing the four pins 55, swinging the four outriggers 24 inwardly and swinging the two hulls 13, 15 inwardly over the deck 17, one at a time (as illustrated in Figure 5), so that one nests partly within the other (as illustrated in Figures 6 and 7).

The mast 27 is of the type that may be separated into two pieces (not shown) to permit storage within the folded catamaran. The mast may be supported by stays (not shown), in conventional fashion, or it may be otherwise supported, as by a tripod 57. If a tripod 57 or the like is used, it should be of such a size and structure that it will not interfere with the folding and unfolding of the craft. More particularly it should not interfere with the swinging of the outriggers 24 and it should fit within the hulls 13, 15 when they are in their folded nested positions, as shown in Figures 6 and 7. It will then be possible to fold or unfold the hulls 13, 15 quickly with the tripod 57 in place.

If the catamaran, in its folded condition, is to be carried, some means should be provided to keep the hulls 13, 15 from swinging upwardly. This can be accomplished for example by merely tying a rope 59 completely around the folded craft (as illustrated in Figures 6 and 7).

It will now be seen that my catamaran is an unusual but useful craft. When opened up into its operating position, it may be propelled either by sail or outboard motor (not shown). When under sail it is steered by the sweep rudder 32, which is removed when an outboard motor is used on the outboard rack 29. It will be noted that the craft has neither centerboard nor leeboards, as the outboard planking panels 37 of the two hulls 13, 15 serve the purpose of minimizing slippage to leeward when under sail. Thus the extra structure and weight of such boards and the accessory equipment necessary to sustain them are saved, with a resulting saving in cost, and a leaking centerboard trunk is avoided. The craft draws very little water without a centerboard and therefore can sail almost anywhere. The reduced draft at the ends of the hulls 13, 15 permits the hulls to pivot about their mid-points, as when coming about, and the extra leverage provided by the sweep rudder 32 permits the craft to be readily spun about when changing tack or when otherwise required during maneuvering. This is also facilitated by the fact that the sweep rudder 32 (unlike a conventional rudder) can be pivoted out of and into the water and used like a normal oar in the spinning procedure.

The tremendous beam-to-length ratio makes the craft most stable under sail so that capsize is virtually impossible. Also the great beam provides far greater useful space and carrying capacity than conventional craft of similar length.

The flexibility of the deck 17 allows each hull 13, 15

to adjust itself somewhat independently to wave formations, thereby imparting far less strain to the craft than that received by rigid type catamarans. The foldability of the mast 27 permits that it, along with the boom (not shown), sweep rudder 32, sail (not shown) and other gear, may be stored on the deck 17 within the folded craft. The greatamount of space available for storage within the folded craft may be seen in Figure 7. Because of the simplicity of the craft, it may be folded or unfolded in a matter of minutes. Also, because of this very simplicity of construction, the weight can be kept so low that the craft, when folded, may be placed easily upon a trailer or car top, or even on a two-wheeled hand cart, for transportation. It should be noted that, although the hulls 13, 15 need not incorporate any frames as such, in the smaller sizes of my craft, the gunwale coamings 47, the inboard sheer strakes 41, the transoms 39, and the outriggers 24 act as frames as they coact to stifien, strengthen and support the hulls, without however adding more weight.

What I claim is:

1. A watercraft comprising a central deck member, first and second hulls pivotally secured to the deck mem her along respective spaced substantially parallel pivot axes, each hull being pivotable about its pivot axis to an upright position alongside the deck member and to an inverted position over the deck member, and means to retain the hulls in their upright positions, the first hull having a concavity, the hulls when in their inverted positions being at least partly nested so that the second hull extends into the concavity of the first hull and the first hull is positioned at least partly over the second hull.

2. A watercraft as defined in claim 1 wherein the hull retaining means include an outrigger swingably secured to the deck member, the outrigger being swingable to an extended retaining position and to a retracted position, the outrigger when in its extended position retaining one of the hulls in its upright position and locking the hull against pivoting to its inverted position, and the outrigger when in its retracted position permitting the hull to be pivoted to either its upright position or its inverted position.

3. A Water craft as defined in claim 1 wherein each hull includes one side which is sufficiently vertically oriented that it acts to minimize leeward movement of the craft in one leeward direction.

4. A water craft as defined in claim 1 wherein each hull includes an inner side and an outer side, the inner side having a greater dimension from its upper edge to its lower edge than the outer side to permit the hulls to nest when in their inverted positions, and the outer sides when the hulls are in their upright positions being more nearly vertically disposed than the inner sides to act to minimize leeward movement of the craft.

5. A water craft as defined in claim 1 wherein each hull is V-bottomed and includes a keel and inner and outer sides secured to the keel, each hull being asymmetrical in that the inner side is longer in a direction from keel to waterline than the outer side, and the outer side is more vertically disposed than the inner side to act as a leeboard.

6. A water craft as defined in claim 1 wherein each hull in transverse cross section is V-shaped and includes an inner planking panel and an outer planking panel, the outer planking panel being positioned more nearly vertically than the inner planking panel to function as a leeboard.

7. A water craft comprising a central deck member, two hulls coupled respectively to opposite sides of the deck member, each hull being movable to operating and non-operating positions, the hulls when in their operating positions being upright on opposite sides of the deck member and when in their non-operating positions one hull extending at least partly between the other hull and the deck member, releasable means to retain the hulls in their operating positions and, upon release, to permit the hulls to be moved to their non-operating positions.

8. A water craft as defined in claim 7 wherein each hull has its outboard side disposed sufiiciently vertically to act as a leeboard.

9. A water craft as defined in claim 7 wherein the hulls when in their non-operating positions are positioned substantially over the deck member.

10.A water craft as defined in claim 9, wherein the hulls when in their non-operating positions are at least partly nested one Within the other.

11. A water craft as defined in claim7, wherein the releasable means include an outrigger pivotally secured to the deck member for pivoting about a generally vertical pivot axis to a transverse position across one hull and to a longitudinal position over the deck member, and means to secure the outrigger to the hull when in its transverse position.

12. A catamaran comprising a deck member and two hulls pivotally secured to the deck member, the deck member including a deck panel having some flexibility, two longitudinal stringers secured to the deck panel to give it some stiffness, two transverse braces secured to the deck panel to give it some stiffness, outriggers swingably secured to the cross braces and swing able to transverse and longitudinal positions, the outriggers in their transverse positions acting to lock the hulls in their operating positions and in their longitudinal positions permitting the hulls to be pivoted about a pivot axis over the deck member to folded positions, each hull including an outer side provided with a gunwale along its upper edge, said outer side being positioned sufficiently vertically to act as a leeboard, and an inner side provided with hinge means which pivotally couple the inner side to the deck member and provide a pivot axis adjacent the upper edge of the inner side, said inner side having a dimension from its pivot axis to the keel greater than the dimension of the outer side from its gunwale to the keel, the hulls when in their folded positions being at least partly one above the other and at least partly internested.

13. A hull for a folding catamaran comprising a keel, inner and outer planking panels secured to the keel and drawn into curved configurations and each extending in a generally longitudinal direction, a V-shaped transom closing each end of the hull, a strengthening gunwale coaming along the sheer of the outer planking panel, a relatively stiii sheer strake along the upper edge of the inner planking panel, pivot hinge members secured to the sheer strake and defining an axis about which the hull may be pivoted, the distance from the keel to the pivot axis being greater than the distance from the keel to the gunwale coaming.

14. A folding catamaran for car top portage comprising a central deck member, two hulls hingedly coupled to the deck member, the hulls being; swingable inwardly over the deck member into folded positions, the hulls when folded being at least partly one above the other, the lower hull being nested at least partly within the upper hull, the folded catamaran presenting to the wind at least at one end an inclined leading aspect shaped to urge it downwardly on a car top upon which it is positioned for portage, when traveling at relatively high speeds.

References Cited in the file of this patent UNITED STATES PATENTS 596,685 Quist Jan. 4, 1898 1,625,579 Walters Apr. 19, 1927 2,464,957 Wood Mar. 27, 1949 2,585,599 Tchetchet Feb. 12, 1952 2,588,084 Bushfield Mar. 4, 1952 FOREIGN PATENTS 2,093 Great Britain Ian. 30, 1899

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