US3577947A - Multiple hull boat - Google Patents

Abstract

A water craft having a rigid superstructure supported by three deep draft pontoons arranged in a triangular configuration with two forward and one aft, the aft pontoons are elongated in both fore-and-aft and vertical directions and have sidewalls extending in a substantially straight line configuration from top to bottom so as to have a substantially linear depth-buoyancy ratio.

Description

United States Patent Gordon L. Draeseke 1599 Angus Drive 9, Vancouver, British Columbia, Canada Apr. 28, 1969 May 1 l, 1971 May 17, 1968 Great Britain Inventor Appl. No. Filed Patented Priority MULTIPLE HULL BOAT 7 Claims, 5 Drawing Figs.

U.S. Cl 1 14/61 Int. Cl B63b 1/ 10 Field of Search 114/61 [56] References Cited UNITED STATES PATENTS 831,636 9/1906 Suhm 114/61X 942,687 12/1909 White... 114/61 1,422,542 7/ 1922 Creed... 1 14/61 2,998,790 9/1961 Mason 114/61 Primary Examiner-Andrew H. Farrell AttorneyLy1e G. Trorey ABSTRACT: A water craft having a rigid superstructure supported by three deep draft pontoons arranged in a triangular configuration with two forward and one aft, the aft pontoons are elongated in both fore-and-aft and vertical directions and have sidewalls extending in a substantially straight line configuration from top to bottom so as to have a substantially linear depth-buoyancy ratio.

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" saw 2 or 3 Gordon L. Draeseke,

Inator Lyle G. Trorey,

Agent PATENIEDHAH 1 |97| 3577-847 sum 3 OF 3 Gordon L. Draeseke,

I-WOI by 1e G Trorey,

Ager lt MULTIPLE I'IULL BOAT BACKGROUND OF THE INVENTION This invention relates to multiple-hulled vessels and in particular to three-hulled vessels. 7

The construction of water craft having two or more independently buoyant hulls or pontoons is well known. Watercraft employing this construction include rafts, catamarans, outriggers and trimarans. Such craft are so constructed that the buoyant hulls or pontoons, hereinafter termed pontoons, are arranged in side-by-side relationship spaced far enough apart to gain lateral stability and each being elongated fore and aft in order to gain fore-'and-aft stability. The buoyant pontoons are generally rigidly secured to a rigid superstructure so that they will not move independently of each other.

In view of the elongated aspect of the pontoons and in'view of the fact they are generally constructed as shallow displace ment craft each hull will, independently of the pontoon alongside, attempt to conform to the surface of the water. If the craft is quartering the waves the strain on the superstructure, as each pontoon is affected by the wave over which the craft passes, imposes great stresses thereon. The superstructure of this type of craft, often disintegrates under adverse wave conditions.

Although this type of craft usually provides a more stable platform than does a single-hulled vessel, it is still greatly subject to the action of waves. As each of the pontoons are constructed so as to be shallow draft the up-and-down movement of the waves, as the craft passes thereover, causes a corresponding up-and-down movement of thepontoons, and particularly when the craft is quartering the waves, do not move synchronously with each other thereby impart a rolling and rocking motion to the craft.

In order to provide watercraft of this nature with greater stability and in order to reduce the racking of thesuperstructure supported by the pontoons certain watercraft have heretofore been devised wherein the pontoons are-arranged in a triangular formationso as to provide three-point support for the entire craft. The pontoons of this last-mentioned watercraft have been, in the main, of shallow draft design and are consequently, themselves, greatly subject to the up-and-down motion of the waves. Such craft have been designed so that the pontoons although maintained in fore-and-aft parallelism are so connected that they can pivot about a transverse axis. This construction does reduce the racking of the superstructure however in view of their nonrigid connection to the superstructure they result in watercraft which are not capable of being driven at high speeds in relatively rough water. Furthermore as these pontoons are of shallow draft construction so as to ride over the waves rather than cut through them the rocking motion, as the craft attempts to travel at high speeds over rough water, becomes greatly exaggerated thereby causing great inconvenience to pasengers carried by the craft and often results in extensive damage to the craft.

SUMMARY OF THE INVENTION The watercraft of the present invention is a multiple-hulled craft having a superstructure which is carried by three pontoons arranged in a triangular configuration so as to lend three-point support tothe entire craft. By reason of threepoint support the stability of the watercraft both fore-and-aft and laterally does not depend upon the stability of each individual pontoon.

In the present invention the pontoons are narrow and are knife-edged fore and aft so as to have a high wave transparency and are of deep draft construction. The pontoons although being thin are relatively short owing to the buoyancy provided by a deep draft construction and are rigidly secured to the superstructure against fore-and-aft lateral movement. The pontoons have sidewalls which have a straight line verti- V cal configuration so that the buoyancy is generally linear, that is to say if buoyancy at depth H is equal to B, then B equals KH, where K is constant. Preferably the sidewalls of the pontoon extend in vertical parallelism with each other. Each pontoon has a bow, shaped so that it enters the water at an acute angle so that, on impact with an obstacle the obstacle tends to be pushed downwards, the pontoon being pushed upwards. The superstructure furthermore takes the form of a tetrahedon so as to obtain rigidity and strength without great weight.

The watercraft of the present invention includes a rigid superstructure having a triangular horizontal base to which three pontoons are connected in a'triangular configuration so as to lend three-point support to the craft. Two of the pontoons are arranged forward in a rigid spaced-apart parallelism and one pontoon is arranged aft and is pivotally moveable for steering purposes. The pontoons are of deep draft construction and have a linear depth to the buoyancy relationship and have knife-edged bows'extending at an acute angle to deflect obstacles downwards when they are struck. Furthermoredhe superstructure is arranged as a tetrahedon to obtain rigidity and strength with little weight.

BRIEF DESCRIPTION OF THE DRAWINGS of the watercraft taken along line 5-5 of FIG. 2.

DETAILED'DESCRIPTION OF EMBODIMENT OF THE 1 INVENTION Referring to the drawings there is illustrated a watercraft having an aft pontoon 11 and two forward pontoons 12 and 13, a portion of covering being removed from pontoon 12 to show the interior construction thereof.

The forward pontoons l2 and 13 have longitudinal axes maintained in parallel spaced relationship, the axes being aligned interrnediately between the Iongitudinal'axes of pontoons 12 and 13 in a generally equilateral'triangular disposition which is best seen in FIG. 2. The pontoons are maintainedin said relationship by means of a superstructure 14 which has an aft and rearwardly and downwardly sloping structural member 15 and two forward structural members 16 and 17 extending upwards out of a triangular base frame 18 and intersecting at an apex 19. Suitable gusset plates "21 at the apex 19- provide means for securing the structural members I5, 16 and 17 together so that the whole structure takes the form of a tetrahedon. The structural members 15, 16 and 17 preferably extend at about 45 to the horizontal, as'illustrated the base frame 18 is in the form of an equilateral triangle having two forward transversely disposed structural members 20 and 20.1 which extend in slightly spaced apart parallelism, and two side members 22 and 23 which extend rearwardly to an apex 24.

With further reference to FIGS. 1 and 2it will be' seen that the superstructure 14 provided with angle bracing 25 and 26 forming apices 25.1 and 26.1 respectively with forward members l6 and 17, respectively. Angle bracing 27 connects aft structural member 15 and the base frame 18 forming an apex 27.1. Further'angle bracing 28 extendbetween apex 19 and members 22 and 23. The base frame 18 is also provided with horizontal cross bracing 29 for supporting a deck 29.1, shown partially in FIG. 2.

Referring particularly to FIGS. 1, 2 and 3 it will be seen that pontoon 12, when viewed from the side takes the form of a parallelogram having rearwardly and downwardly sloped foreand-aft edges, sloping preferably at to the horizontal. The pontoon 12 has sidewalls 31 and 32which extend in a straight line relationship from top to bottom, said walls being secured to rearwardly and downwardly sloping fore-and-aft posts 33' and 34, respectively. The sidewalls are spaced apart intermediately of the length of the pontoon by a downwardly and rearwardly sloped spreader 35 which extends from top to bottom of the pontoon and which divides the pontoon into foreand-aft compartments which may be employed to hold fuel or water. Both fore-and- aft posts 33 and 34 which have sharp knifelike edges and connected by upper and lower plates 36 and 37.

The sidewalls 31 and 32 which may be made of suitable sheet material such as plywood or fiberglass are secured in a known manner, as is shown in FIG. 3 to said fore-and- aft posts 33 and 34, to spreader 35 and the upper and lower plates 36 and 37, respectively. The forward post 33 is also-fitted with a metal cap 38 for protection against damage due to striking floating obstacles.

As clearly illustrated in FIGS. 2 and 3 pontoon 12 is elongated, the sidewalls 31 and 32 arcuate in shape from fore to aft, being spaced furthest apart at their middle lengths by the spreader 35. The width to length to depth ratio of pontoon 12 is in the order of l to 13 to 8.

Pontoon 12 is located adjacent the starboard front apex of the base 18 extending perpendicular to the forward structural members 20 and 20.1 and rigidly connected to the superstructure 14 by means of angle braces 39 and 39.1 connected to forward transverse structural member 20 and spreader 35 and by a brace 40 extending from apex 25.1 to spreader 35. A brace member 41 extends from an upper end 42 secured in the apex 251 through the forward transverse structural members 20 and 20.1 and downwardly through the upper plate 36 and spreader 35 and is connected to post 33. This brace member 41 is secured between a pair of side braces 43 and 43.1 which are also secured to forward structural member 16 and angle member 25 at their upper ends and to forward transverse structural member 20 and 20.1 at their lower ends. Said brace member 41 maintains the pontoon in rigid fore-and-aft and lateral relationship relative to the base 18.

Pontoon 13 is constructed in the same manner as pontoon 12 and is rigidly connected to the superstructure 14 at the port apex of the base 18 in the same manner as pontoon 12.

Pontoon 11 is constructed in the same manner as pontoons 12 and 13 and is substantially the same shape as, but smaller than the latter, having fore-and-aft posts 45 and 46, respectively, a spreader 47 and upper and lower plates 48 and 49, respectively. Sidewalls 50 are extended from the fore-and-aft posts 45 and 46 on both sides of the spreader 47 in the same manner as their counterparts of the pontoon 12. Aft pontoon 11 however, has extending from top to bottom thereof, between the spreader 47 and forward posts 45, an elongated cylindrical socket 51 which may be formed of a length of pipe closed at its bottom. Extending transversely to the longitudinal axis in the aft pontoon and in intersecting relationship with the axis of the socket 51 is a spreader bar 52. This spreader bar 52 is secured rigidly to upper plate 48 so as to be nonrotatable relative to the pontoon 11.

Fitted over the lowermost portion of the aft structural member 15 is a cylindrical spigot 53 which may be formed of a length of pipe having a smaller outside diameter than the inside diameter of the socket 51. This spigot 53 extends at its upper end 54 from the apex 27.1 through the apex 24 of base 18 and projects downwardly below the base a distance greater than the length of the socket 51. The spigot 53 secured in rigid relationship to the superstructure 14 by means of bolts and clamps at apexes 24 and 27.1, respectively. The aft pontoon 11 is fitted to the structure by slidably inserting the spigot into the socket 51 so that the lower end of the spigot rests on the closed end of said socket so as to space the pontoon below the base 18. The slidable rotatable fit of the socket on the spigot permits the aft pontoon to be pivotally swung about the spigot so as to act as a rudder.

The aft pontoon is operated by means of a steering arrangement 57 operable by a wheel 58 mounted on the deck. As best shown in FIGS. 2 and 5 the steering arrangement includes an elongated rudder bar 59 which is pivotally mounted on a pair of angle braces 60 and 61 secured to and extending below the base 18. As illustrated in FIG. 5 angle brace 61 extends downwardly and forwardly and is provided at its lower end 61.1 with a bolt 62 which is so arranged that its axis extends in parallelism with the axis of the spigot 53. This bolt 62 serves as a pivot point for the rudder bar 59. This rudder bar is connected as by operating cables 63 to the wheel and is also connected by cables 64 to the spreader bar 52. These cables are connected to a bolt 65 fastened to the top plate of pontoon 1 1. The rudder bar and spreader bar are of the same length so that they and the cables 64 form a parallelogram.

The craft may be powered by engine or by sail. When powered by engine a pair of outboard motors 70 and 70.1 are mounted on the side members 22 and 23 just aft of the pontoon 12 and 13, suitable braces 71 and 71.1 being employed to rigidly connect said outboard motors to their associated pontoons. If it is desired to propel the craft by sail, the aft structural member 15 may be extended forwardly of apex 19, as illustrated in FIG. 1, to serve as a support for a mast 72, the latter also supported in a box, not shown, which is secured to the forward transverse structural members 20 and 20.1.

The dimensions of the pontoons are such that under normal operating conditions they will be submerged for substantially half their depth. Consequently in view of their relatively deep draft they can be materially shorter than shallow draft conventional pontoons of substantially the same width. In view of their relatively short length, the pontoons of craft 10 will impose lesser strains upon the superstructure than the greatly elongated pontoons of conventional watercraft when passing through rough water. Consequently this permits much lighter superstructure construction than would ordinarily be required.

The pontoons, also, the sidewalls of which extend in a straight line, substantially parallel relationship from top to bottom, have a linear buoyancy. That is to say, if buoyancy of depth H is equal to B, then B=KH, where K is constant. This feature lends the watercraft high stability particularly where the craft travels in a quartering direction relative to the waves, as due to their linear buoyancy the pontoons will vary in their depths of submergence as the craft moves over rough water so as to permit the superstructure to remain in a substantially horizontal attitude. Furthermore, in view of the width to length ratio of the pontoons and in view of their fore-and-aft knife-edged configuration the pontoons have a high wave transparency, that is, the ability to knife through waves, with very slight increase in drag.

The high wave transparency of the pontoons together with the directional stability provided by the aft pontoon, largely overcomes the effect of the varying and alternately acting drag on the pontoons as the craft passes through the waves in a quartering direction. The craft can therefore remain on a substantially true course as the pontoons, in succession, knife through a wave when the craft is moving in a quartering direction relative thereto.

Due to the high wave transparency of the pontoons which gives the craft its great stability the pontoons, particularly the front pontoons, will have varied depth of submergence as the craft passes through waves. The craft is so designed, therefore that the total depth of the pontoons is not less than the height of the waves, measured from crest to trough, that the craft is likely to encounter in any particular area. This will insure that the deck will, at substantially all times, ride above the surface of the water.

It will be seen that the watercraft as herein described is strong, light and may be driven at high speed through relatively rough water. Furthermore its design is such that the craft may be easily constructed by the average home builder. The superstructure may be formed of wooden or aluminum members. These members are all straight and it is only necessary for the builder to ensure that they are the proper length. The only curves in the craft are found in the pontoons, and even here as the sidewalls of the pontoon have a straight line top-tobottom configuration only fore-and-aft curvature is involved.

The builder need not concern himself with compound curvature problems that he is generally confronted with when building a conventional watercraft.

lclaim:

l. A water craft including:

a. a rigid superstructure,

b. three pontoons arranged in a triangular configuration beneath the superstructure for bouyantly supporting the latter,

c. the superstructure including a plurality of structural members arranged in the form of a tetrahedron, one side of the said tetrahedron constituting a base, said superstructure being orientated so that a pair of structural members constitute two sides of said base and extend rearwards to an aft apex.

2. Structure as defined in claim 1 wherein the sidewalls of each pontoon extend in vertical parallel relationship from top to bottom.

3. Structure as defined in claim 1 wherein each pontoon has moveable for steering purposes.

6. Structure as claimed in claim 4 wherein each pontoon has a rearwardly and downwardly sloped stem.

7. Structure as in claim 1 wherein each of said pontoons is elongated in a fore-and-aft direction and has sidewalls extending in a straight line relationship from top to bottom so as to have a linear depth to bouyancy relationship.

Claims (7)

1. A water craft including: a. a rigid superstructure, b. three pontoons arranged in a triangular configuration beneath the superstructure for bouyantly supporting the latter, c. the superstructure including a plurality of structural members arranged in the form of a tetrahedron, one side of the said tetrahedron constituting a base, said superstructure being orientated so that a pair of structural members constitute two sides of said base and extend rearwards to an aft apex.

2. Structure as defined in claim 1 wherein the sidewalls of each pontoon extend in vertical parallel relationship from top to bottom.

3. Structure as defined in claim 1 wherein each pontoon has a rearwardly and downwardly sloped bow.

4. Structure as defined in claim 1 wherein each pontoon is knife edged fore and aft and wherein the bouyancy of each pontoon is such that each pontoon is submerged substantially half its total depth when the craft operates under normal operating conditions.

5. Structure as defined in claim 1 wherein the pontoons are arranged in a two forward and one aft configuration, the two forward pontoons being rigidly secured in spaced-apart fore-and-aft parallelism and wherein the rear pontoon is pivotally moveable for steering purposes.

6. Structure as claimed in claim 4 wherein each pontoon has a rearwardly and downwardly sloped stern.

7. Structure as in claim 1 wherein each of said pontoons is elongated in a fore-and-aft direction and has sidewalls extending in a straight line relationship from top to bottom so as to have a linear depth to bouyancy relationship.

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