JP2001354195A - Jet propelled planing boat - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a jet propelled planing boat capable of keeping steerage of the boat even if the amount of water jetted from a water jet pump is decreased, without increasing the weight thereof. SOLUTION: This jet propelled planing boat jets water pressurized/accelerated by the water jet pump P from a rear nozzle K so as to propel by the reaction, and keeps a steerage function when a throttle is operated to be OFF. The jet propelled planing boat is provided with a throttle opening detecting sensor Sb for detecting the OFF operation of the throttle, and a steering position detecting sensor Sp for detecting a steerage state of a steering. When a signal indicating that the throttle is operated to be OFF is obtained from the throttle opening detecting sensor Sb and a signal indicating that the steering is operated is obtained from the steering position detecting sensor Sp, a jet timing of a fuel jetting device Fe for an engine is changed to temporarily increase engine speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a personal watercraft (personal watercraft) that jets a stream of water backward and sails on the water in reaction to the jet.
Watercraft (Personal Watercraft); PWC
In particular, the present invention relates to a jet-propelled personal watercraft that can maintain a steering function even when a throttle is turned off.

[0002]

2. Description of the Related Art In recent years, so-called jet propulsion type personal watercraft have been widely used for leisure, sports or rescue. In this jet propulsion type personal watercraft, the water hull is generally propelled by pressurizing and accelerating water sucked from a water inlet provided on the bottom surface of the boat by a water jet pump and jetting backward.

[0003] In the case of this jet propulsion planing boat, the direction of water jetting rearward is changed left and right by swinging the steering nozzle disposed behind the jet port of the water jet pump left and right. This steers the boat right or left.

Therefore, in the case of a jet-propulsion planing boat having such a configuration, when the throttle is closed to almost full closure and the amount of water jetted from the water jet pump decreases,
The thrust available to turn the boat (thrust available for steering) is also reduced, and the ability to steer the boat is reduced until the throttle reopens.

In view of such a situation, the applicant of the present invention has proposed a steering system capable of mechanically maintaining the steering ability even when the throttle is closed to almost full closure and the amount of water jetted from the water jet pump is reduced. Provided a jet-propelled planing boat equipped with a steering member for
-6708).

However, in the case of the jet-propulsion personal watercraft, the number of parts is increased, the structure is complicated, and the weight is increased.

The present invention has been made in view of such a situation, and turns off the throttle (refers to an operation that causes at least a part of the descending line Zb in FIG. 11, the same in the present specification). Provided is a jet-propulsion personal watercraft that can maintain steering even when the amount of water jetted from a water jet pump decreases, and that does not increase the weight easily and without increasing the weight. The purpose is to:

[0008]

According to the first aspect of the present invention, the above object can be attained by a jet propulsion personal watercraft having the following configuration. That is, the jet propulsion planing watercraft according to the first aspect of the present invention provides a water jet pump in which water pressurized and accelerated is jetted from a rear jet port, propelled by the recoil thereof, and when the throttle is turned off, the steering is performed. In a jet propulsion planing boat configured to maintain the function, a throttle opening detection sensor that detects a throttle OFF operation and a steering position detection sensor that detects a steering state of a steering wheel are provided. The throttle is OF
When the signal indicating that the F operation has been performed and the signal indicating that the steering is being operated are obtained from the steering position detection sensor, the injection timing of the fuel injection device of the engine is changed, and the engine speed is temporarily increased. It is characterized by the following.

According to the jet propulsion planing boat constructed as described above, when the steering is operated in a state where the throttle is turned off, the throttle opening detection sensor and the steering position detection sensor detect those states. In order to change the injection timing of the engine's fuel injection device, the engine speed temporarily increases, and the steering function is maintained because the rear injection port injects water in an amount corresponding to the increase. Becomes

In the present specification, when a signal indicating that the throttle is turned off from the throttle opening detection sensor and a signal indicating that the steering is being operated are obtained from the steering position detection sensor, the engine is temporarily stopped. The control for maintaining the steering function by increasing the rotational speed of the vehicle is called "off-throttle steering mode control". In this specification, the “OFF operation” of the throttle means an operation in which the throttle is operated to a “closed” side by a predetermined amount or more.

The jet propulsion watercraft according to the second aspect of the present invention is characterized in that water pressurized and accelerated by a water jet pump is jetted from a rear jet port, propelled by the recoil thereof, and the throttle is turned off. A jet propulsion planing boat configured to maintain a steering function includes a throttle opening detection sensor for detecting a throttle OFF operation and a steering position detection sensor for detecting a steering state of a steering wheel. When a signal indicating that the throttle is turned off from the degree detection sensor and a signal indicating that the steering is being operated are obtained from the steering position detection sensor, the ignition timing of the ignition device of the engine is changed, and the engine is temporarily stopped. It is characterized in that the number of revolutions is increased.

According to the jet propulsion planing watercraft constructed as described above, when the steering is operated in a state where the throttle is turned off, the throttle opening detection sensor and the steering position detection sensor detect those states. In order to change the ignition timing of the engine ignition device, the engine speed temporarily increases, and the rear injection port injects an amount of water commensurate with the increase, so that the steering function is maintained. Become.

The jet propulsion personal watercraft according to the third aspect of the present invention is characterized in that water pressurized and accelerated by a water jet pump is jetted from a rear jet port, propelled by the recoil thereof, and the throttle is turned off. A jet propulsion planing boat configured to maintain a steering function includes a throttle opening detection sensor for detecting a throttle OFF operation and a steering position detection sensor for detecting a steering state of a steering wheel. When a signal indicating that the throttle is turned off from the degree detection sensor and a signal indicating that the steering is being operated are obtained from the steering position detection sensor, the injection amount of the engine fuel injection device is changed to temporarily It is characterized by increasing the engine speed.

According to the jet propulsion planing boat constructed as described above, when the steering is operated in a state where the throttle is turned off, the throttle opening detection sensor and the steering position detection sensor detect those states. In order to change the injection amount of the fuel injection device of the engine, the engine speed temporarily increases, and the steering function is maintained because the rear injection port injects water in an amount corresponding to the increase. Becomes

The jet propulsion watercraft according to the fourth invention is characterized in that water pressurized and accelerated by a water jet pump is jetted from a rear jet port, propelled by its recoil, and the throttle is turned off. A jet propulsion planing boat configured to maintain a steering function includes a throttle opening detection sensor for detecting a throttle OFF operation and a steering position detection sensor for detecting a steering state of a steering wheel. When a signal indicating that the throttle is turned off from the degree detection sensor and a signal indicating that the steering is being operated are obtained from the steering position detection sensor, the injection timing of the fuel injection device of the engine and the ignition timing of the ignition device are determined. Change, and change the injection amount of the fuel injection device,
It is characterized in that the engine speed is temporarily increased.

According to the jet propulsion personal watercraft constructed as described above, when the steering is operated in a state where the throttle is turned off, the throttle opening detection sensor and the steering position detection sensor detect those states. In order to change the injection timing of the fuel injection device of the engine and the ignition timing of the ignition device, and to change the injection amount of the fuel injection device, the rotation speed of the engine temporarily rises and the Injecting an amount of water commensurate with the ascent will maintain the steering function.

The jet-propulsion personal watercraft according to the first to fourth aspects of the present invention includes a sensor for directly or indirectly detecting the speed of the boat, and adjusts the number of revolutions of the engine according to the detected value. By changing the temporal timing of the ascending, it is possible to adopt a configuration in which favorable steering characteristics can be obtained.

In the jet-propulsion personal watercraft according to the first to fourth aspects of the present invention, a sensor for directly or indirectly detecting the speed of the boat is provided, and the engine speed is adjusted according to the detected value. By changing the length of time for raising, it is possible to obtain a configuration in which preferable steering characteristics can be obtained.

In a preferred embodiment of the jet-propulsion personal watercraft, the engine speed when the engine speed is increased is 2500 to 3500 rpm.

In the jet-propulsion personal watercraft, the control for temporarily increasing the engine speed is such that the engine is in an idling region (a region where the engine speed is slightly higher than the idling speed from the idling speed). In the case of the same in the present specification), an embodiment in which no injection is performed from the injection port when no propulsive force is required can be obtained by configuring so that the injection is not performed.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a jet-propulsion personal watercraft according to an embodiment of the present invention will be specifically described with reference to the drawings, taking a small personal watercraft as an example.

FIG. 1 is a block diagram showing a control-related configuration of a jet-propulsion personal watercraft according to an embodiment of the present invention.
4 is a flowchart showing the control contents of the components shown in the block diagram of FIG. 1; FIG. 3 is a table used for control;
Is an overall side view of the personal watercraft according to the embodiment of the present invention,
FIG. 5 is a plan view of FIG. 4, FIG. 6 is a partially enlarged sectional view of the vicinity of the steering wheel of FIG. 4, FIG. 7 is an exploded perspective view of a main part of the steering wheel, and FIG. FIG. 4 is a diagram showing the relationship with an engine.

In FIGS. 4 and 5, A is a hull, and this hull A is composed of a hull H and a deck D covering the hull H. A connection line connecting the hull H and the deck D all around is a gunnel line. G, and in this embodiment, the gunnel line G is located above the waterline L of the personal watercraft.

At a position slightly behind the center of the deck D, as shown in FIG. 5, a substantially rectangular opening 16 is formed on the upper surface of the hull A in a plan view and extends in the longitudinal direction. As shown in FIG. 5, a seat S for riding is arranged above the opening 16.

The engine E is disposed in a space 20 having a "convex" cross section surrounded by the hull H and the deck D below the seat S. This engine E is a multi-cylinder (three-cylinder in this embodiment) engine E. As shown in FIG. 4, the crankshaft 10b is mounted so as to extend along the longitudinal direction of the hull A. An output end of the shaft 10b is integrally and rotatably connected via a propeller shaft 15 to a pump shaft side of a water jet pump P to which the impeller 21 is attached. The impeller 21 has its outer periphery covered with a pump casing 21C, takes in water taken in from a water supply port 17 provided on the bottom surface of the personal watercraft through a water suction passage, and adds water through a water jet pump P. Pressure, accelerate,
The pump is configured to discharge through a pump nozzle (jetting part) 21R whose water cross-sectional area becomes smaller as it goes rearward and to be discharged from an injection port 21K at a rear end to obtain a propulsive force.

In FIG. 4, 21V is a stationary blade for rectification. 4 and 5, reference numeral 10 denotes a steering handle, which is a steering operation means. By operating the handle 10 right and left, the steering nozzle 18 behind the pump nozzle 21R is swung right and left. When the water jet pump P is operated, the boat can be steered in a desired direction.

As shown in FIG. 4, a bowl-shaped reverse deflector 19 is provided above and behind the steering nozzle 18 so as to be able to swing downward about a horizontally arranged swing shaft 19a. (Refer to FIG. 1), and the water discharged from the steering nozzle 18 is turned forward by swinging the deflector 19 to a lower position behind the steering nozzle 18.
It is configured to be able to move backward.

4 and 5, reference numeral 12 denotes a rear deck. The rear deck 12 is provided with an openable / closable hatch cover 29, and a small-capacity storage box is formed below the hatch cover 29. I have. 4 and 5, reference numeral 23 denotes a front hatch cover. Below the hatch cover 23, a box (not shown) for storing equipment and the like is provided. Also, this front hatch cover 2
Above the third hatch cover 25, another hatch cover 25 is arranged to form a two-layer hatch cover.
An opening (not shown) provided on the rear end surface allows a life jacket or the like to be stored therein.

In the personal watercraft according to the embodiment of the present invention, as shown in FIGS. 6 and 7, the rotating shaft 10A of the handle 10 has proximity switches on the rotating side and the fixed side. Steering position detection sensor S
p is arranged. In this embodiment, the steering position detection sensor Sp has a permanent magnet 40 disposed on a part of a disk-shaped member on the rotation side, and is turned on when the permanent magnet 40 approaches two places on the fixed side. 41 are formed. Further, as shown in FIG. 8, a throttle opening detection sensor Sb is arranged near the butterfly valve 51 arranged in the intake passage 3 of the engine E. Further, FIG.
As shown in FIG. 2, an engine speed detection sensor Se is arranged near the crankshaft Cr. Although a specific position is not shown, a boat speed detection sensor (boat speed meter) Ss for detecting the boat speed of the personal watercraft shown in FIGS. 8 and 1 is arranged. As shown in FIG. 1, the steering position detection sensor Sp, the throttle opening detection sensor Sb, the engine speed detection sensor Se, and the boat speed detection sensor Ss are respectively connected to the engine control unit Ec by electric wires. A signal detected by each of these sensors is transmitted to the engine control unit Ec. The engine control unit Ec is connected to the fuel injection device Fe arranged on the cylinder head Hc of the engine E by a signal line (electric wire). The engine control unit Ec is connected to the ignition coil Ic by a signal line (electric wire). The ignition coil Ic is connected to the ignition plug Ip by an electric wire (high-voltage electric cord). In FIG. 8, reference numeral 4 denotes a fuel tank, and 5 denotes a fuel pressure pump.

Thus, the jet-propulsion personal watercraft according to the embodiment of the present invention configured as described above performs off-throttle steering mode control when the throttle is turned off, as described below. Function can be maintained. Hereinafter, the control contents of the control program recorded in the memory of the computer incorporated in the engine control unit Ec will be described with reference to the flowchart of FIG. That is, when the rider turns off the throttle of the personal watercraft in a state where the personal watercraft, which is a jet-propulsion watercraft, is running, the throttle opening detection sensor Sb detects the OFF operation (step 1 ( S1)), and the signal is transmitted to the engine control unit Ec. And
In such a state, the rider moves the handle 1
When 0 is operated to the right or left by a predetermined angle (in this embodiment, the rotation angle is set to about 20 degrees left and right, respectively),
The steering position detection sensor Sp detects the steering operation (step 2 (S2)), and transmits the signal to the engine control unit Ec. Next, the engine control unit Ec detects the boat speed at that time from the boat speed detection sensor Ss (step 3 (S3)). Next, the engine control unit Ec uses a table shown in FIG. 3 (a table in which the relationship between the ship speed, the delay time, and the operation time is predetermined).
, A time period to be controlled and a continuation time of a state where the rotation speed of the engine E is temporarily increased by controlling, that is, a time length (operation time) are determined (step 4).
(S4)). That is, as shown in the table of FIG. 3, the "delay time" increases in proportion to the magnitude (speed) of the boat speed, and the "operation time t" increases in proportion to the increase in boat speed. Long and determined. Further, instead of the boat speed, the engine speed may be converted to the boat speed. However, in this case, since the correct boat speed cannot be obtained only by the instantaneous engine speed, the engine speed is continuously obtained as data, taking into account the inertia of the personal watercraft, and based on the data. It is desirable to convert to ship speed. Next, it is checked whether it is the timing to be controlled (step 5 (S5)). When the timing comes, off-throttle steering mode control is started to change the fuel injection timing and the ignition timing ( In this embodiment, for example, the timing is advanced.), And the engine E is temporarily increased to a predetermined rotation speed (step 6 (S6)). At this time, control may be performed such that the fuel injection amount is changed (for example, “increased”) together with the change of the timing. The predetermined number of revolutions is determined in consideration of the characteristics of the personal watercraft (turning characteristics or characteristics caused by the boat shape) and the like. In this embodiment, the predetermined number of rotations is set to 3000 rpm. This set value is appropriately set (for example, 2500-3500 rp).
m). Further, the set value may be a fixed value, or may be such that the value is selectively changed depending on the boat speed at that time.

Next, it is checked whether or not the operation time t determined by the above calculation has elapsed (step 7 (S
7)) After the operation time t has elapsed, the fuel injection timing and the ignition timing are returned to the original state (normal operation state) (step 8 (S8)), and the off-throttle steering mode control is ended. Therefore, as a result, the state returns to the normal operation state.

By performing the series of off-throttle-steering mode control, the steering function is maintained even when the throttle is turned off.

According to the jet propulsion personal watercraft constructed as described above, the throttle opening detection sensor Sb, the engine speed detection sensor Se, and the boat speed detection sensor Ss are different from the conventional jet propulsion personal watercraft. Engine control unit E
Since c is also provided, only the steering position detection sensor Sp consisting of a proximity switch is newly provided and only the control program of the engine control unit Ec needs to be changed, so that it can be easily realized.

According to the jet propulsion planing boat, the delay time is controlled in accordance with the ship speed, that is, the delay time is short at a low speed and long at a high speed. As shown in FIG. 9, in each case, the vehicle can turn while maintaining a preferable posture.

In the above embodiment, both the fuel injection timing and the ignition timing are changed in order to increase the engine E to a predetermined rotational speed. In addition to this, the fuel injection amount is changed. Or only one of them may be performed.

In addition, the control for changing the fuel injection timing and the ignition timing is executed by the ship speed detection sensor with the timing being delayed in accordance with the ship speed at that time. The basic operation and effect of the present invention can be obtained.

Further, the "off-throttle steering mode control" for temporarily increasing the engine speed is performed in an idling region (for example, 800
(2000 rpm), it may not be executed. This configuration is a preferred embodiment in that the engine speed does not rise from the idling region when no extra propulsion is required.

In the control according to the above-described embodiment, a delay time is provided in the control process. Alternatively, when the control content is made simpler (simple),
For example, as shown in the flowchart of FIG. 10 and described below, the above control is performed earlier, that is, the throttle
When the FF operation is detected, the control may be started when the engine is still at a relatively high rotation speed in the downward trend. In other words, the rider turns the small planing boat's throttle
When the F operation is performed, the throttle opening detection sensor Sb
Detects the OFF operation (refer to the descending line Zb in FIG. 11 when indicating the change state of the engine speed and PS (horsepower) resulting from the OFF operation) (step 1a (S1a)),
The signal is transmitted to the engine control unit Ec. In such a state, when the rider operates the steering wheel 10 to the right or left by a predetermined angle (in this embodiment, the rotation angle is approximately 20 degrees left and right, respectively), the steering position detection sensor Sp is activated. , The steering operation is detected (step 2a (S2
a)), and the signal is transmitted to the engine control unit Ec. Then, the engine speed detection sensor Se detects the engine speed at that time (step 3a (S3a)). Next, the engine control unit Ec checks whether or not the detected engine speed is equal to or lower than a predetermined engine speed, for example, is equal to or lower than 5500 rpm (step 4a (S4a)). The engine speed is equal to or less than a predetermined speed, for example, 55
If it is less than 00 rpm, the off-throttle steering mode control is started to change the fuel injection timing and the ignition timing, or to change the fuel injection amount together with the above-mentioned change of the tamping (in this embodiment, the fuel injection amount is increased). ), The rotation speed of the engine E, which tries to descend to the idling state in a very short time,
A predetermined number of rotations (for example, 3
000 rpm) (Step 5a (S5
a)). That is, even if the engine speed is 5500 rpm on the descent line Zb in FIG. 11, the output is very low, so that the water jet pump P cannot be driven. In order to drive the water jet pump P by the above-described off-throttle steering mode control, the engine E is rotated at a predetermined speed on the increase line Za in FIG. The number is increased to, for example, 3000 rpm. In FIG. 11, a broken line U represents the thrust of the water jet pump P at that time, and this line U
And the difference h in the vertical axis direction between the increase line Za and the descending line Zb is PS (horsepower) which causes acceleration or deceleration.
Represents the size of Therefore, the descending line Zb at 5500 rpm
In order to start the off-throttle steering mode control in the state shown in (1) and bring it to the state shown in the increase line Za of 3000 rpm, the rotational speed of the engine E is substantially increased by changing the fuel injection timing or the like. Such an operation is required. Also, in FIG. 11, the arrows of the increase line Za and the descent line Zb indicate the direction of change in increase and decrease of the engine speed. Next, the fuel injection timing and the ignition timing are returned to the original state (the state of the normal operation) (step 6a (S
6a)), end the off-throttle steering mode control. At this time, for example, as a condition for returning to the original state, for example, when a predetermined time (for example, 15 seconds) elapses or when the steering position detection sensor Sp detects that the rider has returned the operation of the steering wheel 10. May be returned.

With this control, an embodiment can be obtained in which the control can be simplified.

Although the above two embodiments do not particularly limit forward or backward travel, the present invention can be applied to either case.

[0041]

According to the present invention, the throttle opening is in the idling region with a simple structure and without increasing the weight by making full use of the equipment already provided in the prior art. It is possible to provide a jet propulsion personal watercraft that can maintain steering of the boat even when the amount of water jetted from the jet pump is reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a control-related configuration of a jet-propulsion personal watercraft according to an embodiment of the present invention.

FIG. 2 is a flowchart showing control contents of components shown in the block diagram of FIG. 1;

FIG. 3 is a table used for the control in FIG. 2;

FIG. 4 is an overall side view of the personal watercraft according to the embodiment of the present invention.

5 is an overall plan view of the personal watercraft shown in FIG.

6 is a partially enlarged cross-sectional view showing the arrangement position and configuration of a steering position detection sensor in the vicinity of the steering wheel shown in FIG. 4;

FIG. 7 is an exploded perspective view of a main part of a steering portion, showing an arrangement position of a steering position detection sensor shown in FIG. 6 and a configuration in the vicinity thereof;

8 is a diagram showing the configuration of the control relationship shown in FIG. 1 in relation to an actual engine.

FIG. 9 is a schematic diagram showing a state of the personal watercraft according to the present embodiment from a state in which the throttle is turned off to a state in which the personal watercraft turns at low speed, medium speed, and high speed.

FIG. 10 is a flowchart showing control contents according to another embodiment having control contents different from those of FIG. 2;

FIG. 11 is a graph showing the relationship between the increase in the engine speed, the descent state, and the horsepower, with PS (horsepower) or load on the vertical axis and the engine speed (k represents “1000”) on the horizontal axis. FIG. 4 is a diagram illustrating a state of thrust of a water jet pump.

[Explanation of symbols]

 P: Water jet pump 21K: Injection port E: Engine Sp: Steering position detection sensor Sb: Throttle opening detection sensor

Claims (8)

[Claims] 1. A jet propulsion type in which water pressurized and accelerated by a water jet pump is injected from a rear injection port, propelled by the reaction thereof, and can maintain a steering function when a throttle is turned off. The boat includes a throttle opening detection sensor that detects a throttle OFF operation, and a steering position detection sensor that detects a steering state of a steering wheel. A signal indicating that the throttle has been turned OFF from the throttle opening detection sensor. A jet propulsion type, in which when a steering operation signal is obtained from a steering position detection sensor, the injection timing of an engine fuel injection device is changed to temporarily increase the engine speed. Planing boat. 2. A jet propulsion type in which water pressurized and accelerated by a water jet pump is injected from a rear injection port and propelled by the reaction thereof, and a steering function can be maintained when a throttle is turned off. The boat includes a throttle opening detection sensor that detects a throttle OFF operation, and a steering position detection sensor that detects a steering state of a steering wheel. A signal indicating that the throttle has been turned OFF from the throttle opening detection sensor. Jet propulsion-type skidding, wherein when a steering operation signal is obtained from a steering position detection sensor, the ignition timing of an engine ignition device is changed to temporarily increase the engine speed. Boat. 3. A jet propulsion type water jet pump, wherein water pressurized and accelerated by a water jet pump is jetted from a rear jet port and propelled by the recoil thereof to maintain a steering function when a throttle is turned off. The boat includes a throttle opening detection sensor that detects a throttle OFF operation, and a steering position detection sensor that detects a steering state of a steering wheel. A signal indicating that the throttle has been turned OFF from the throttle opening detection sensor. Jet propulsion, characterized in that when a steering operation signal is obtained from a steering position detecting sensor, the injection amount of an engine fuel injection device is changed to temporarily increase the engine speed. Type planing boat. 4. A jet propulsion type in which water pressurized and accelerated by a water jet pump is injected from a rear injection port, propelled by the reaction thereof, and can maintain a steering function when a throttle is turned off. The boat includes a throttle opening detection sensor that detects a throttle OFF operation, and a steering position detection sensor that detects a steering state of a steering wheel. A signal indicating that the throttle has been turned OFF from the throttle opening detection sensor. When a steering operation signal is obtained from the steering position detecting sensor, the injection timing of the fuel injection device of the engine and the ignition timing of the ignition device are changed, and the injection amount of the fuel injection device is changed. Jet propulsion characterized by temporarily increasing the engine speed Watercraft. 5. The apparatus according to claim 1, further comprising a sensor for directly or indirectly detecting the speed of the boat, wherein a timing of increasing the engine speed is changed in accordance with the detected value. 4. The jet propulsion planing boat according to any one of the items 4. 6. The apparatus according to claim 1, further comprising a sensor for directly or indirectly detecting the speed of the boat, and changing a length of time for increasing the rotation speed of the engine according to the detected value. 4. The jet propulsion planing boat according to any one of the items 4. 7. The jet propulsion planing boat according to claim 1, wherein the engine speed when the engine speed is increased is 2500 to 3500 rpm. . 8. The control for temporarily increasing the number of revolutions of the engine is performed when the engine is in an idling range.
The jet propulsion planing boat according to any one of claims 1 to 7, wherein the jetting is not performed.