Engine component layout and seat design for watercraft

Abstract

A watercraft includes an improved seat design that allows a rider to better absorb impact shocks with his or her legs as the watercraft bounds over wakes. The seat assembly includes a front seat section and a rear seat section that is sized to accommodate one or more riders in tandem with each rider straddling the seat. The front seat section is narrower than the rear seat section to permit the front rider to place his or her legs more directly in front of him or her. This position improves the rider's comfort and allows the rider to assume a stance in which the rider can better absorb impact shocks on the watercraft. In order to accommodate this seat design, an improved engine component layout is provided so as to reduce the width of the upper end of the engine. The induction and exhaust systems of the engine are laid out on the lower sides of the watercraft, and extend at least partially beneath foot wells that flank the sides of the seat assembly.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a small watercraft, and more particularly to the layout of engine components within the watercraft and an associated seat design.

2. Description of Related Art

Personal watercraft have become very popular in recent years. This type of watercraft is quite sporting in nature and carries a rider and possibly one, two or three passengers. A relatively small hull of the personal watercraft commonly defines a rider's area above an engine compartment. An internal combustion engine frequently powers a jet propulsion unit which propels the watercraft. The engine lies within the engine compartment in front of a tunnel formed on the underside of the watercraft hull. The jet propulsion unit is located within the tunnel and is driven by a drive shaft. The drive shaft usually extends between the engine and the jet propulsion device, through a wall of the hull tunnel.

The rider's area usually includes an elongated seat that extends along a longitudinal center line of the watercraft. The seat has a bench-like shape that the rider and passengers can straddle. Foot wells extend along side the seat. The rider and passengers straddle the seat in a tandem fashion with the rider and passengers' legs positioned on the side of the seat and their feet placed within the foot areas.

Generally, the width of the seat not only provides an ample surface upon which the rider and passengers sit, but also provides space in which to locate an upper portion of the engine, including the engine's exhaust and induction systems. U.S. Pat. No. 5,536,189 illustrates an exemplary engine arrangement beneath the seat with the overall width of the seat generally matching the overall width of the engine. The cylinder head, cylinder block, exhaust manifold, exhaust expansion chamber, carburetors, and air intake are all located between the side walls of the seat and beneath the upper cushion of the seat.

While the position of the rider—with his or her feet positioned wide apart and his or her legs straddling the seat—provides good stability, this stance reduces the ability of the rider to absorb with his or her legs impact forces as the watercraft bounds over wakes. In addition, some smaller riders with less height find it uncomfortable to sit in a position with their feet widely spaced apart when straddling the seat.

SUMMARY OF THE INVENTION

A need therefore exists for an improved seat assembly for a watercraft that improves the comfort of the rider and the ability of the rider to absorb shock with his or her legs.

One aspect of the present invention thus involves a watercraft comprising a hull having a lower hull portion and an upper deck portion. An internal combustion engine is located within the hull and has an output shaft. A propulsion device is carried by the hull and is driven by the engine output shaft to propel the watercraft. The upper deck portion of the hull includes a central elongated seat assembly having a front seat section and a rear seat section. The seat sections are positioned about a longitudinal axis of the watercraft hull with a pair of foot areas extending along side the seat assembly. The front seat section is narrower than the rear seat section, and each of the foot areas extends next to at least a portion of both the front and rear seat sections.

In order to provide a more narrow seat design, at least at some locations along the length of the seat, another aspect of the invention involves a modified engine component layout. In one mode, an internal combustion engine of the watercraft is located within the hull and has at least one exhaust port, at least one intake port, and an output shaft. The engine also includes an exhaust system having an expansion chamber arranged to receive exhaust gases from the engine exhaust port. An induction system of the engine communicates with the intake port and including a plenum chamber. At least a portion of the plenum chamber is arranged beneath one of the foot areas, and at least a portion of the expansion chamber is arranged beneath the other foot area, on opposite sides of the seat assembly. This arrangement of engine components narrows the upper end of the engine, so as to permit a narrower seat assembly, in addition to other advantages.

In addition, other components of the engine can also be arranged in order to reduce the width of the engine that extends upward, between the sides of the seat assembly. For instance, the exhaust system of the engine can include a water trap device and an expansion chamber arranged to receive exhaust gases from at least one exhaust port of the engine. The expansion chamber is positioned on one side of a longitudinal center line of the watercraft and the water trap device is located on the other side of the longitudinal center line. An exhaust conduit extends across the longitudinal center line to connect the expansion chamber and the water trap device together. The exhaust conduit includes a section raised relative to at least an upstream section of the exhaust system. A catalytic device is located in the elevated section of the exhaust conduit to treat exhaust gases from the engine before discharge. This position of the catalytic device, apart from the expansion chamber, permits for a smaller diameter size of the expansion chamber without reducing the cross-sectional flow area through the catalytic device.

Further aspects, features, and advantages of the present invention will become apparent from the detailed description of the preferred embodiment which follows.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features of the invention will now be described with reference to the drawings of a preferred embodiment of the present watercraft. The illustrated embodiment of the watercraft is intended to illustrate, but not to limit the invention. The drawings contain the following figures:

FIG. 1 is a partial sectional, side elevational view of a personal watercraft configured in accordance with a preferred embodiment of the present invention, and illustrates several internal components of the watercraft in phantom;

FIG. 2 is a partial sectional, top plan view of the personal watercraft of FIG. 1 , and illustrates in phantom a position of a rider seated on a seat assembly relative to an engine of the watercraft;

FIG. 3 is a cross-sectional view of the watercraft of FIG. 2 taken along line 3 — 3 ;

FIG. 4 is a cross-sectional view of the watercraft of FIG. 2 taken along line 4 — 4 ;

FIG. 5 is a sectional view of a flexible coupling within the exhaust system of the watercraft of FIG. 2 ; and

FIG. 6 is an enlarged cross-sectional view of a portion of an exhaust system of the watercraft of FIG. 2 taken along line 6 — 6 .

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1 through 4 illustrate a personal watercraft 10 which includes a seat design and associated engine component layout configured in accordance with a preferred embodiment of the present invention. Although these features are illustrated in connection with a personal watercraft, they can be used with other types of watercraft as well, such as, for example, but without limitation, small jet boats and the like.

The following describes the illustrated watercraft in reference to a coordinate system in order to ease the description of the watercraft. A longitudinal axis extends from bow to stern and a lateral axis extends from port side to starboard side normal to the longitudinal axis. In addition, relative heights are expressed in reference to the undersurface of the watercraft.

With initial reference to FIGS. 1 and 2 , the watercraft 10 includes a hull 12 formed by a lower hull section 14 and an upper deck section 16 . The hull sections 14 , 16 are formed from a suitable material such as, for example, a molded fiberglass reinforced resin. The lower hull section 14 and the upper deck section 16 are fixed to each other around the peripheral edges 18 in any suitable manner.

As viewed in the direction from the bow to the stem of the watercraft, the upper deck section 16 includes a bow portion 20 , a control mast 22 and a rider's area 24 . The bow portion 20 slopes upwardly toward the control mast 22 and includes at least one air duct through which air can enter the hull. A hatch cover 26 desirably extends above an upper end of the air duct to inhibit an influx of water into the hull.

A fuel tank 28 is located within the hull 12 beneath the hatch cover 26 . Conventional means, such as, for example, straps, secure the fuel tank 28 to the lower hull 14 . A fuel filler hose (not shown) extends between a fuel cap assembly and the fuel tank 28 . In the illustrated embodiment, the filler cap assembly (not shown) is secured to the bow portion 20 of the hull upper deck 16 to the side and in front of the control mast 22 . In this manner, the fuel tank 28 can be filled from outside the hull 12 with the fuel passing through the fuel filler hose into the tank 28 .

The control mast 22 extends from the bow portion 20 and supports a handlebar assembly 30 . The handlebar assembly 30 controls the steering of the watercraft 10 in a conventional manner. The handlebar assembly 30 also carries a variety of controls of the watercraft 10 , such as, for example, a throttle control, a start switch and a lanyard switch.

A display panel 31 desirably is located in front of the control mast 22 on the bow portion 20 and is orientated to be visible by the rider. The display panel 31 desirably displays a number of performance characteristics of the watercraft, such as, for example, watercraft speed (via a speedometer), engine speed (via a tachometer), fuel level, oil level, engine temperature, battery charge level and the like.

The rider's area 24 lies behind the control mast 22 and includes a seat assembly 32 . In the illustrated embodiment, the seat assembly 32 has a longitudinally extending straddle-type shape that may be straddled by an operator and by at least one, two or three passengers.

As best illustrated in FIG. 2 , the seat assembly 32 includes a front seat section 34 and a rear seat section 36 . The front seat section 34 has a width D 1 , and the rear seat section 36 has a width D 2 . The width D 2 of the rear seat section 36 is sized to provide a wide enough seating surface for the buttocks of the rider and passengers. That is, the width D 2 is such that an average-sized rider/passenger can comfortably straddle the seat section 36 . In an exemplary embodiment, the seating surface is generally about 18 inches (46 cm) wide.

The front seat section 34 is narrower than the rear seat section 36 (i.e., D 1 <D 2 ). The width D 1 of the front seat section 34 is sized such that the rider can generally place his legs directly in front of him without spreading his feet too far apart. In one mode, the width D 1 of the front seat section 34 is about half of the width D 2 of the rear seat section 36 (i.e., D 1 =D 2 /2). The front and rear seat sections 34 , 36 though are both symmetrically positioned relative to a central longitudinal axis of the watercraft hull 12 .

The seat assembly 32 also includes an intermediate seat section 38 positioned between the front and rear seat sections 34 , 36 . The intermediate seat section 38 includes curved sides 40 that form a smooth transition from the front seat section 34 to the rear seat section 36 . As best seen in FIG. 2 , the width of the fore end of the intermediate seat section 38 , as defined between the sides 40 , generally matches the width D 1 of the front seat section 34 . The sides 40 diverge outward in the lateral direction to gradually increase the width of the intermediate seat section 38 and match the width D 2 of the rear seat section 36 . Each side 40 generally has an elongated S-shape, as seen in FIG. 2 , for this purpose.

These sections 34 , 36 , 38 of the seat assembly 32 are, at least in principal part, formed by a seat cushion 42 supported by a raised pedestal 44 . The raised pedestal 44 has an elongated shape and extends longitudinally along the center of the watercraft 10 . The sides 46 of the pedestal 44 thus are spaced apart by the desired distance D 1 at the fore end of the pedestal 44 , curve outwardly at the transition section 38 of the seat assembly 32 , and extend generally parallel to each other in an aft-longitudinal direction, while spaced apart by the desired distance D 2 .

The seat cushion 42 desirably is removably attached to a top surface of the pedestal 44 and covers the entire upper end of the pedestal 44 for rider and passenger comfort. The seat cushion 42 has a complementary shape to that of the seat pedestal 44 to form the front, intermediate and rear sections of the seat assembly 32 .

In the illustrated embodiment, the seat cushion 42 has a single piece construction and covers the entire upper surface of the seat pedestal 44 . The seat cushion 42 , however, can be formed in sectional pieces which are individually attached to the seat pedestal 44 . In this manner, one of the sectional pieces of the seat cushion 42 can be removed to expose a portion of the watercraft beneath the seat 42 , without requiring removal of the other sections. For instance, part of the rear seat section 36 can be removable to gain access to a storage compartment located beneath the seat without requiring removal of a front sectional piece of the seat cushion 42 .

An access opening 48 is located on an upper surface of the pedestal 44 . The access opening 48 opens into an engine compartment 50 formed within the hull 12 . The seat cushion 42 normally covers and seals closed the access opening 48 . When the seat cushion 42 is removed, the engine compartment 50 is accessible through the access opening 48 .

The pedestal 44 also desirably includes at least one air duct located behind the access opening 48 . The air duct communicates with the atmosphere through a space between the pedestal 44 and the cushion 42 which is formed behind the access opening 48 . Air can pass through the rear duct in both directions.

The upper deck section 16 of the hull 12 advantageously includes a pair of raised gunnels 52 ( FIG. 2 ) positioned on opposite sides of the aft end of the upper deck assembly 16 . The raised gunnels 52 define a pair of foot areas or wells 54 that extend generally longitudinally and parallel to the sides 46 of the pedestal 44 . In this position, the operator and any passengers sitting on the seat assembly 32 can place their feet in the foot areas 54 with the raised gunnels 52 shielding the feet and lower legs of the riders. A non-slip (e.g., rubber) mat desirably covers the foot areas 54 to provide increased grip and traction for the operator and the passengers.

As seen in FIG. 2 , the foot areas 54 extend into the pedestal 44 and follow the curved walls 46 of the seat pedestal 44 at the intermediate and front seat sections 38 , 34 . A fore section 56 of each foot area 54 thus extends toward the central line of the watercraft, within the outermost side surface of the pedestal 44 (i.e., the portion of the pedestal side surfaces that form the rear seat section 36 ), by a distance D 3 , which generally equals half of the difference between the width D 1 of the front seat section 34 and the width D 2 of the rear seat section 36 , i.e., D 3 =(D 2 −D 1 )/2. These fore sections 56 of the foot areas 56 are sized to accommodate the rider's legs and feet when generally positioned directly in front of the rider, as schematically represented in FIG. 2 .

Each foot area 54 also desirably includes an elevated aft section 58 with a step 60 formed between the fore and aft sections 56 , 58 of the foot area 54 . The step 60 preferably is formed at a longitudinal position that generally corresponds to a position of the fore end of the rear seat section 36 along the longitudinal axis.

The lower hull portion 14 principally defines the engine compartment 50 . Except for the air ducts, the engine compartment 50 is normally substantially sealed so as to enclose an engine of the watercraft 10 from the body of water in which the watercraft is operated.

The lower hull 14 is designed such that the watercraft 10 planes or rides on a minimum surface area at the aft end of the lower hull 14 in order to optimize the speed and handling of the watercraft 10 when up on plane. For this purpose, the lower hull section generally has a V-shaped configuration formed by a pair of inclined sections that extend outwardly from a keel line of the hull to the hull's side walls at a dead rise angle. The inclined sections also extend longitudinally from the bow toward the transom of the lower hull 14 . The side walls are generally flat and straight near the stern of the lower hull and smoothly blend towards the longitudinal center of the watercraft at the bow. The lines of intersection between the inclined section and the corresponding side wall form the outer chines of the lower hull section.

Toward the transom of the watercraft, the incline sections of the lower hull 14 extend outwardly from a recessed channel or tunnel 62 that extends upward toward the upper deck portion 16 . The tunnel 62 has a generally parallelepiped shape and opens through the rear of the transom of the watercraft 10 , as seen in FIG. 2 .

In the illustrated embodiment, a jet pump unit 64 propels the watercraft 10 . The jet pump unit 64 is mounted within the tunnel 62 formed on the underside of the lower hull section 14 by a plurality of bolts. An intake duct 66 of the jet pump unit 64 defines an inlet opening that opens into a gullet of the intake duct 66 . The intake duct 66 leads to an impeller housing assembly in which the impeller 68 of the jet pump 64 operates. An impeller housing assembly also acts as a pressurization chamber and delivers the water flow from the impeller housing to a discharge nozzle 70 .

A steering nozzle 72 is supported at the downstream end of the discharge nozzle 70 by a pair of vertically extending pivot pins. In an exemplary embodiment, the steering nozzle 72 has an integral lever on one side that is coupled to the handlebar assembly 30 through, for example, a bowden-wire actuator, as known in the art. In this manner, the operator of the watercraft can move the steering nozzle 72 to effect directional changes of the watercraft 10 .

A ride plate covers a portion of the tunnel 62 behind the inlet opening to enclose the jet pump unit 64 with the tunnel 62 . In this manner, the lower opening of the tunnel 62 is closed to provide a planing surface for the watercraft 10 .

An impeller shaft 74 supports the impeller within the impeller housing of the jet pump unit 64 . The aft end of the impeller shaft 74 is suitable supported and journalled within the compression chamber of the jet pump unit 64 in a known manner. The impeller shaft 74 extends in the forward direction through a front wall of the tunnel 62 and/or through a bulkhead.

An internal combustion engine 76 of the watercraft powers the impeller shaft 74 to drive the impeller 68 of the jet pump unit 64 . As seen in FIGS. 1 through 3 , the engine 76 is positioned within the engine compartment 50 and is mounted behind the control mast 22 , beneath the seat assembly 32 . In the illustrated embodiment, the engine 76 is arranged within the engine compartment 50 at a longitudinal position behind the front seat portion 34 with an axis of a forward-most cylinder generally corresponding with a fore end of the rear seat section 36 . Vibration-absorbing engine mounts 77 ( FIG. 3 ) secure the engine 76 to bosses 79 on the lower hull portion 14 in a known manner. The engine 76 is mounted in approximately a central position in the watercraft 10 .

In the illustrated embodiment, the engine 76 includes three in-line cylinders and operates on a two-stroke, crankcase compression principle. The engine 76 is positioned such that the row of cylinders lies parallel to a longitudinal axis of the watercraft 10 , running from bow to stem. The axis of each cylinder is generally parallel relative to a vertical central plane of the watercraft 10 , in which the longitudinal axis lies. This engine type, however, is merely exemplary. Those skilled in the art will readily appreciate that the present seat design and engine component layout can be used with a variety of engine types having other numbers of cylinders, having other cylinder arrangements (e.g., inclined) and operating on other combustion principles (e.g., four-stroke principle).

As best seen in FIG. 3 , a cylinder block 78 and a cylinder head assembly 80 desirably form the cylinders of the engine 76 . A piston reciprocates within each cylinder of the engine 76 and together the pistons drive an output shaft 82 (FIG. 1 ), such as a crankshaft, in a known manner. A connecting rod links the corresponding piston to the crankshaft 82 . The corresponding cylinder bore, piston and cylinder head of each cylinder forms a variable-volume chamber, which at a minimum volume defines a combustion chamber. A coupling 83 couples the crankshaft 82 to the impeller shaft 74 , as best seen in FIG. 2 .

The crankshaft 82 desirably is journalled with a crankcase, which in the illustrated embodiment is formed between a crankcase member 84 and a lower end of the cylinder block 78 . Individual crankcase chambers of the engine are formed within the crankcase by dividing walls and sealing disks, and are sealed from one another with each crankcase chamber communicating with a dedicated variable-volume chamber.

Each crankcase chamber also communicates with an intake pipe 86 of an induction system 88 of the engine 76 through a check valve (e.g., a reed-type valve). In the illustrated embodiment, the intake pipes 86 are separate from the crankcase and from each other; however, the engine 76 can use an intake manifold equally well, or can integrally form the intake pipes with the crankcase member 84 .

A plurality of charge formers 90 (e.g., a carburetor) of the induction system 88 communicate with inlet ends of the corresponding intake pipes. The charge formers 90 receive fuel from the fuel tank 28 and produces the fuel charge which is delivered to the cylinders in a known manner. An air intake silencer or plenum chamber 92 of the induction system 88 is connected to an air inlet end of a throttle passage of each charge former 90 .

In order to reduce the width of an upper portion of the engine 76 , the intake silencer 92 is arranged at least partially beneath one of the foot areas 54 . In the illustrated embodiment, the intake silencer 92 lies entirely beneath the foot area 54 , as best seen in FIG. 3 . The intake silencer 92 desirably lies at about the same vertical level or above the vertical level of the corresponding check valve (e.g., reed valve) of the engine 76 . The flow path from the air intake silencer 92 , through the charge former 90 and intake pipe 86 and into the corresponding crankcase chamber is along a lateral flow axis that lies generally normal to an axis of the corresponding cylinder. In this manner, the induction system is arranged to extend from the lower side of the engine 76 and does not occupy the space on the upper side of the engine 76 .

An air intake conduit 94 communicates with the intake silencer 92 . The air intake conduit 94 extends upward from the intake silencer 92 , and terminates in a generally upwardly facing opening 95 . In the illustrated embodiment, as best seen in FIG. 2 , the air intake conduit 94 is arranged on the aft end of the intake silencer 92 and extends inward and upwardly in an inclined manner at a position on the rear side of the engine 76 . The upper end 95 of the air intake conduit 94 thus terminates at a position above the level of the corresponding foot area 54 , as understood from FIG. 3 .

The jet pump unit 64 supplies cooling water through a conduit to an engine cooling jacket. For this purpose, an outlet port is formed on the housing of the pressurization chamber assembly of the jet pump unit 64 . The conduit is coupled to the outlet port and extends to an inlet port to the engine water jacket. In the illustrated embodiment, the inlet port desirably lies at the lower rear end of the engine 76 , either on the cylinder block 78 or on an exhaust manifold 96 (see FIG. 2 ) of the engine 76 which is attached to the cylinder block 78 .

The cooling system of the engine extends through the exhaust manifold 96 , through the cylinder block 78 , about the cylinders, and through the cylinder head assembly 80 . Either the cylinder head assembly 80 or the exhaust manifold 96 can include a coolant discharge port through which the cooling water exits the engine 76 and thence flows through at least a portion of an exhaust system 98 that communicates with the exhaust manifold 96 . In the illustrated embodiment, the cooling jacket about the exhaust manifold 96 communicates with a cooling jacket that communicates with a downstream portion of the exhaust system 98 .

The exhaust system 98 discharges exhaust byproducts from the engine 76 to the atmosphere and/or to the body of water in which the watercraft 10 is operated. As best seen in FIGS. 1 , 2 and 4 , the exhaust system 98 includes the exhaust manifold 96 that is affixed to the side of the cylinder block 78 and which receives exhaust gases from the combustion chambers through exhaust ports in a well-known manner. For this purpose, the exhaust manifold 96 desirably includes a number of runners equal in number to the number of cylinders. Each runner communicates with the exhaust port(s) of the respective cylinder. The runners of the exhaust manifold 96 thence merge together at a merge point A ( FIG. 2 ) to form a common exhaust path that terminates at an outlet end of the manifold 96 .

The exhaust manifold 96 has a dual shell construction formed by an inner wall and an outer wall. As briefly mentioned above, water jacket W is formed between the two walls and communicates with one or more water passages within the engine block 78 or cylinder head 80 . Cooling water therefore flow from the engine block 78 into the water jacket W of the exhaust manifold 96 . This dual wall construction desirably is formed along each runner of the manifold, as well as about the common flow section of the manifold 96 .

An outlet end of the exhaust manifold 96 communicates with an exhaust expansion chamber 100 via a flexible coupling 102 . As best seen in FIG. 2 , the outlet end of the manifold 96 turns downward to mate with an up-turned inlet end of the expansion chamber 100 .

As best seen in FIG. 5 , the flexible coupling 102 connects the outlet end of the exhaust manifold 96 to the inlet end of the expansion chamber 100 . The flexible coupling 102 includes an inner, generally tubular flexible member 104 formed of a material capable of withstanding the effects of hot exhaust gases passing through the inner member 104 . In the illustrated embodiment, the inner member 104 is formed of a metallic (e.g., metal alloy) having a generally corrugated shape with an undulating pattern (i.e., having bellows). The inner member 104 has an inner diameter that generally matches that of the exhaust path through the outlet end of the exhaust manifold 96 , as well as that of the inlet to the exhaust path through the expansion chamber 100 . The inner member 104 thus has an outer diameter that is less than the outer diameters of the outlet end of the manifold 96 and the inlet end of the expansion chamber 100 , and does not interfere with the cooling water flow path between these components of the exhaust system 98 .

The ends of the inner member 104 include annular flanges with through-holes. Bolts 106 pass through the holes and thread into the corresponding ends of the exhaust manifold 96 and the expansion chamber 100 . Gaskets or seals desirably are placed between the flanges and the corresponding ends to inhibit leakage of exhaust gases outside the inner member 104 .

An outer flexible member 108 is attached to the exteriors of the exhaust manifold 96 and the expansion chamber 100 , at their respective opposing ends. In the illustrated embodiment, the flexible member 108 is an elastic hose attached to the opposing ends of the manifold 96 and the expansion chamber 100 by conventional hose clamps 109 . Other types of flexible tubing and securement mechanisms can be used as well. As seen in FIG. 5 , the outer member 108 encloses the inner member 104 to define a cooling jacket W about the inner member 104 . This cooling jacket W receives coolant from the cooling jacket about the manifold 96 , and delivers it to the cooling jacket of the expansion chamber 100 .

With reference to FIGS. 2 and 4 through 6 , the expansion chamber 100 has a generally tubular shape with an enlarged cross-sectional flow area as compared to the exhaust manifold 96 to allow the exhaust gases to expand and silence, as known in the art. A thick-wall, which is defined between an inner surface and an outer surface, forms the tubular shape of the exhaust chamber 100 . The inner surface defines the exhaust flow passage through the exhaust chamber 100 . A plurality of water passages W ( FIG. 5 ) extend along side the flow passage through the thick wall of the exhaust chamber 100 . The water passages W desirably are spaced about the inner surface 104 and communicate with the cooling jacket of the flexible coupling 102 .

The expansion chamber 100 is secured to the lower hull portion 14 in the illustrated embodiment, as best seen in FIG. 6 ; however, it is understood that the expansion chamber 100 can in addition or in the alternative be secured to the engine 76 or to the upper deck 16 . Securing the expansion chamber 100 to the lower hull portion 14 though simplifies the assembly process.

With reference to FIG. 6 , the lower hull portion 14 includes an inner boss 110 that has a generally semi-cylindrical indentation that forms a cradle 112 . An elastic insulation layer 114 lines the surface of the cradle 112 with the expansion chamber 100 set on top of the insulation layer 114 . Desirably, this layer 114 generally thermally and vibrationally decouples the expansion chamber 100 from the lower hull portion 14 . One or more elastic straps 116 , which are secured to the lower hull portion 14 by bolts 118 , hold the expansion chamber 100 within the cradle 112 .

At least a portion of the expansion chamber 100 lies beneath the corresponding foot area 54 . In this position, as understood from FIGS. 2 and 3 , the exhaust flow path from the engine 76 extends downward and outward proximate to the lower end of the engine 76 so as to reduce the lateral width of the engine between the side walls 46 of the pedestal 44 . In the illustrated embodiment, the expansion chamber 100 lies almost entirely beneath the corresponding foot area 54 on a side of the longitudinal center opposite of the induction system 88 . Thus, as seen in best seen in FIG. 3 , these components 88 , 98 of the engine 76 do not extend next to or above the upper portion of the engine 76 so as to enable a narrowed front seat section 34 and a tapering intermediate seat section 38 .

An exhaust pipe 120 connects to an outlet of the expansion chamber 100 and extends across the longitudinal axis of the watercraft 10 . In the illustrated embodiment, the exhaust pipe 120 lies behind the engine 76 and extends over the tunnel 62 . In particular, as best seen in FIG. 6 , the exhaust pipe 120 includes a first upstanding section 122 , an intermediate section 124 and a second upstanding section 126 . The first upstanding section 122 extends upward from the expansion chamber 100 . The intermediate section 124 extends laterally (and generally horizontally) over the tunnel 62 . A bracket 128 , which is mounted onto the upper surface of the tunnel 62 , desirably supports this section 124 of the exhaust pipe 120 . The second upstanding section 126 of the exhaust pipe 120 communicates with an opposite end of the intermediate section 124 and lies on the other side of the longitudinal axis. The second upstanding pipe 126 communicates with a water trap device 130 . The resulting generally inverted U-shape forms a “goose-neck” section in the exhaust pipe 120 that functions to inhibit water flow through the exhaust passage toward the engine 76 .

The exhaust system 98 also includes a catalytic device 132 . The catalytic device 132 desirably includes a catalyst bed to convert at least a portion of the exhaust gases into harmless gases (e.g., carbon dioxide and water). The catalyst bed lies within the exhaust gas flow through the exhaust pipe intermediate section 124 at a position that mandates that all exhaust gases must pass through the catalyst. The catalyst 132 reduces the emissions of hydrocarbons and other exhaust byproducts (e.g., carbon monoxide and oxides of nitrogen) from the watercraft engine.

For this purpose, the catalyst bed is formed of a catalytic material, which is designed to render harmless either all or some of the exhaust byproducts. For example, the catalyst bed can be made of a metal catalyst material, such as, for example, platinum. The catalyst bed, however, can be made of different types of catalytic materials for treating different exhaust byproducts or lubricant.

The catalyst bed, in the illustrated embodiment, takes the form of a honeycomb-type catalyst bed. A tubular shell desirably supports the catalyst bed with an annular flange (not shown) supporting the shell. The flange is held between the corresponding ends of the exhaust pipe 120 that are separated at the center of the intermediate section 124 . Bolts can secure together the juxtaposed ends of the exhaust pipe 120 with the flange interposed therebetween.

The exhaust pipe 120 desirably includes a cooling jacket that surrounds at least the catalytic device 132 . The cooling jacket can receive coolant from the coolant jacket surrounding the expansion chamber 100 or from another source (e.g., directly from the jet pump unit 64 ). The coolant jacket desirably discharges coolant into the exhaust system 98 at a point downstream of the catalytic device 132 . For example, the coolant can be discharged into the exhaust gas flow through the second upstanding section 126 of the exhaust pipe just upstream of the water trap 130 .

With reference to FIGS. 1 and 4 , the outlet end of the exhaust pipe 120 is connected to an inlet section of the water trap device 130 . The water trap device 130 also lies within the watercraft hull 12 on the same side of the tunnel 62 as the second upstanding section 126 of the exhaust pipe 120 . As best seen in FIG. 4 , at least a portion of the water trap device 130 is located beneath the corresponding foot area 54 . Conventional strap couplings secure the water trap 130 to the lower hull portion 14 .

The water trap device 130 has a sufficient volume to retain water and to preclude the back flow of water to the expansion chamber 100 and the engine 76 . Internal baffles within the water trap device 130 help control water flow through the exhaust system 98 .

An exhaust discharge pipe 134 extends from an outlet section of the water trap device 130 and wraps over the top of the tunnel 62 to a discharge end 136 . The discharge end 136 desirably opens into the tunnel 62 or through the transom of the watercraft 10 at an area that is close to or actually below the water level with the watercraft 10 floating at rest on the body of water.

The foregoing description of the exhaust and induction systems 88 , 98 of the engine 76 provide for an engine layout that extends more in a lateral direction at the lower end of the engine, than in a vertical direction. As a result, the upper end of the engine 76 is narrowed in comparison to conventional engine designs for small watercraft. This arrangement permits a seat assembly with a narrowed section so as to improve the rider's ability to absorb impact shocks on the watercraft with his or her legs.

Although this invention has been described in terms of a certain preferred embodiment, other embodiments apparent to those of ordinary skill in the art are also within the scope of this invention. Accordingly, the scope of the invention is intended to be defined only by the claims that follow.

Claims

1. A watercraft comprising a hull having a lower hull portion and an upper deck portion, an internal combustion engine located within the hull and having an output shaft, a propulsion device carried by the hull and driven by the engine output shaft to propel the watercraft, the upper deck portion including a central elongated seat assembly having an operator's seating surface positioned about a longitudinal axis, a pedestal having a first portion supporting the operator's seating surface and a second portion disposed forward from the operator's seating surface, and a pair of foot areas, the second portion of the seat pedestal being narrower than the first portion, and each of the foot areas extending next to at least a portion of both the first and second portions of the pedestal.

2. A watercraft as in claim 1, wherein the second portion of the pedestal is located generally forward of the engine.

3. A watercraft as in claim 2, wherein the second portion of the pedestal includes curved side surfaces that diverge in a lateral direction toward an aft end of the watercraft, and form a smooth transition with the first portion of the pedestal supporting the operator's seating surface.

4. A watercraft as in 3, wherein the foot areas extend next to the curved side surfaces of the second portion.

5. A watercraft as in claim 2, wherein a lateral width of the second portion is less than a lateral width of the engine.

6. A watercraft as in claim 5, wherein the engine includes an induction system and an exhaust system, and at least part of one of the induction and exhaust systems is located beneath one of the foot areas.

7. A watercraft as in claim 1, wherein the engine includes an induction system having a plenum chamber that is located at least partially beneath one of the foot areas.

8. A watercraft as in claim 7, wherein the foot area includes a front section and an elevated rear section, and at least a portion of the plenum chamber is located beneath the rear section of the corresponding foot area.

9. A watercraft as in claim 1, wherein the engine includes an exhaust system having an expansion chamber that is located at least partially beneath one of the foot areas.

10. A watercraft as in claim 9, wherein the foot area includes a front section and an elevated rear section, and at least a portion of the expansion chamber is located beneath the rear section of the corresponding foot area.

11. A watercraft as in claim 9, wherein the expansion chamber is attached to a portion of the hull.

12. A watercraft as in claim 9, wherein an exhaust pipe of the exhaust system extends in a lateral direction across a longitudinal axis of the hull, the exhaust pipe including a section elevated relative to the expansion chamber, and a catalytic device located in the elevated section of the exhaust pipe.

13. A watercraft as in claim 1 additionally comprising a rear seat section positioned rearward from the first portion of the pedestal, a lateral width of the rear seat section being dimensioned so as to permit a passenger of the watercraft to straddle the rear seat section with the passenger's feet placed in the foot areas on the sides of the rear seat section.

14. A watercraft as in claim 1, wherein each of the foot areas includes a step located rearword of the front seat section.

15. A watercraft comprising a hull having a lower hull portion and an upper deck portion, an internal combustion engine located within the hull and having at least one exhaust port and an output shaft, the hull defining a tunnel with a downwardly facing inlet, a propulsion device mounted in the tunnel and driven by the engine output shaft, an exhaust system including a water trap device and an expansion chamber arranged to receive exhaust gases from the engine exhaust port, the expansion chamber positioned on one side of a longitudinal center line of the watercraft and the water trap device located on the other side of the longitudinal center line, an exhaust conduit extending across the longitudinal center line to connect the expansion chamber and the water trap device together, the exhaust conduit including a section raised relative to at least an upstream section of the exhaust system and extending over the tunnel, and a catalytic device located in the elevated section of the exhaust conduit over the tunnel to treat exhaust gases from the engine before discharge.

16. A watercraft comprising a hull having a lower hull portion and an upper deck portion, the upper deck portion including an elongated seat assembly an a pair of foot areas located on the sides of the seat assembly, an internal combustion engine located within the hull and having at least one exhaust port, at least one intake port, and an output shaft, a propulsion device driven by the engine output shaft, the engine including an exhaust system including an expansion chamber arranged to receive exhaust gases from the engine exhaust port, and an induction system communicating with the intake port and including a plenum chamber, at least one of the expansion chamber and the plenum chamber being arranged substantially beneath one of the foot areas.

17. A watercraft as in claim 16, wherein the induction system includes an intake duct connected to the plenum chamber, and the intake duct extends upwardly.

18. A watercraft as in claim 17, wherein at least a part of an upper end of the intake duct is arranged higher than the foot area beneath which the plenum chamber is located.

19. A watercraft as in claim 17, wherein the foot area above the plenum chamber includes a step.

20. A watercraft as in claim 16, wherein the induction system includes at least one intake pipe that extends in a lateral direction, generally normal to a rotational axis of the engine output shaft.

21. A watercraft as in claim 16, wherein the exhaust system includes an exhaust manifold communicating with the exhaust port of the engine, and the exhaust manifold arranged to guide exhaust gases generally in a lateral direction toward the expansion chamber.

22. A watercraft as in claim 21, wherein the exhaust system includes a flexible coupling that connects the exhaust manifold and the expansion chamber together.

23. A watercraft as in claim 16, wherein the expansion chamber is secured to a portion of the hull.

24. A watercraft as in claim 16, wherein the foot area, which extends above the expansion chamber, includes a step that is located forward of the expansion chamber.

25. A watercraft as in claim 16, wherein the exhaust system includes a laterally extending exhaust pipe connected to the expansion chamber, the exhaust pipe including an elevated section, and a catalytic device located within the elevated section of the exhaust pipe.

26. A watercraft as in claim 25, wherein the seat assembly includes a narrowed section arranged generally forward of the front end of the engine.

27. A watercraft according to claim 15 additionally comprising a bracket supported by the tunnel, the bracket supporting the elevated section of the exhaust conduit.

28. A watercraft according to claim 15, wherein the elevated section of the exhaust conduit extending over the tunnel is “U” shaped.

29. A watercraft according to claim 28 additionally comprising an enlarged portion of the elevated section of the exhaust conduit, the catalytic device being disposed in the enlarged portion.

30. A watercraft according to claim 29 additionally comprising an upstream portion of the elevated exhaust conduit being upstream from the catalytic device and a downstream portion of the elevated exhaust conduit being downstream from the catalytic device, the upstream and downstream portions having a smaller diameter than a diameter of a portion of the elevated exhaust conduit containing the catalytic device.

31. A watercraft according to claim 15, wherein the catalytic device is positioned rearward from the internal combustion engine.