Control system for watercraft and method for controlling watercraft

Abstract

A control system for a watercraft includes a marine propulsion device, a load sensor, and a computer. The load sensor is operable detect load data regarding a drive source of the marine propulsion device. The computer is configured or programmed to store a decision logic to determine whether or not a malfunction or trouble of the watercraft has occurred, obtain the load data, and determine whether or not the malfunction or trouble of the watercraft has occurred based on the load data with reference to the decision logic. The load logic includes at least one of a foreign object attachment decision logic, a propeller matching decision logic, a damper slippage decision logic, or a water landing decision logic.

What is claimed is: 
     
         1 . A control system for a watercraft, the control system comprising:
 a marine propulsion device including a drive source;   a load sensor to detect load data indicating a load acting on the drive source; and   a computer configured or programmed to:
 store a decision logic to determine whether or not a malfunction or trouble of the watercraft has occurred; 
 obtain the load data; and 
 determine whether or not the malfunction or trouble of the watercraft has occurred based on the load data with reference to the decision logic; wherein 
   the decision logic includes at least one of:
 a foreign object attachment decision logic to determine whether or not attachment of a foreign object to the watercraft has occurred; 
 a propeller matching decision logic to determine whether or not a propeller appropriately matches the marine propulsion device; 
 a damper slippage decision logic to determine whether or not slippage of a propeller damper has occurred in the marine propulsion device; or 
 a water landing decision logic to determine whether or not a water landing of the watercraft has occurred. 
   
     
     
         2 . The control system according to  claim 1 , wherein
 the drive source includes an engine;   the load sensor includes:
 an intake pressure sensor to detect an intake pressure of the engine; and 
 an engine speed sensor to detect an engine rotational speed; and 
   the computer is configured or programmed to:
 obtain the intake pressure and the engine rotational speed as the load data; and 
 determine whether or not the malfunction or trouble of the watercraft has occurred based on the intake pressure and the engine rotational speed. 
   
     
     
         3 . The control system according to  claim 1 , wherein the computer is configured or programmed to:
 store initial load data indicating a relationship between a vessel speed of the watercraft and a load acting on the drive source in an initial state of the watercraft;   obtain the vessel speed of the watercraft; and   determine that the attachment of the foreign object to the watercraft has occurred with reference to the foreign object attachment decision logic when the load acting on the drive source during steady navigation of the watercraft is higher than the load indicated by the initial load data by a predetermined value or greater.   
     
     
         4 . The control system according to  claim 3 , wherein the computer is configured or programmed to:
 obtain cargo data indicating a weight of a cargo on the watercraft; and   determine whether or not the attachment of the foreign object to the watercraft has occurred with reference to the foreign object attachment decision logic and the cargo data.   
     
     
         5 . The control system according to  claim 1 , wherein
 the drive source includes an engine;   the load sensor includes:
 an intake pressure sensor to detect an intake pressure of the engine; and 
 an engine speed sensor to detect an engine rotational speed; 
   the computer is configured or programmed to:
 obtain the intake pressure and the engine rotational speed as the load data; and 
 determine that the propeller does not appropriately match the marine propulsion device with reference to the propeller matching decision logic when the intake pressure and the engine rotational speed are plotted outside of a predetermined range in the load data during steady navigation of the watercraft. 
   
     
     
         6 . The control system according to  claim 1 , wherein
 the drive source includes an engine;   the load sensor includes:
 an intake pressure sensor to detect an intake pressure of the engine; and 
 an engine speed sensor to detect an engine rotational speed; 
   the computer is configured or programmed to:
 obtain the intake pressure and the engine rotational speed as the load data; and 
 determine that the slippage of the propeller damper has occurred in the marine propulsion device with reference to the damper slippage decision logic when plotting the intake pressure and the engine rotational speed indicates a reduction in the load by a predetermined value or greater. 
   
     
     
         7 . The control system according to  claim 1 , wherein
 the drive source includes an engine;   the control system further comprises a throttle operator to control an output of the engine;   the load sensor includes an engine speed sensor to detect an engine rotational speed; and   the computer is configured or programmed to:
 obtain the engine rotational speed and an operating amount of the throttle operator as the load data; and 
 determine that the water landing of the watercraft has occurred with reference to the water landing decision logic when the engine rotational speed has increased by a predetermined value or greater even though the operating amount of the throttle operator has been kept constant. 
   
     
     
         8 . A method for controlling a watercraft including a marine propulsion device including a drive source, the method comprising:
 obtaining load data indicating a load acting on the drive source; and   determining whether or not a malfunction or trouble of the watercraft has occurred based on the load data with reference to a decision logic to determine whether or not the malfunction or trouble of the watercraft has occurred; wherein   the decision logic includes at least one of:
 a foreign object attachment decision logic to determine whether or not attachment of a foreign object to the watercraft has occurred; 
 a propeller matching decision logic to determine whether or not a propeller appropriately matches the marine propulsion device; 
 a damper slippage decision logic to determine whether or not slippage of a propeller damper has occurred in the marine propulsion device; or 
 a water landing decision logic to determine whether or not a water landing of the watercraft has occurred. 
   
     
     
         9 . The method according to  claim 8 , wherein the drive source includes an engine, and the method further comprises:
 obtaining an intake pressure of the engine and an engine rotational speed as the load data; and   determining whether or not the malfunction or trouble of the watercraft has occurred based on the intake pressure and the engine rotational speed.   
     
     
         10 . The method according to  claim 8 , further comprising:
 recording initial load data indicating a relationship between a vessel speed of the watercraft and a load acting on the drive source in an initial state of the watercraft;   obtaining the vessel speed of the watercraft; and   determining that the attachment of the foreign object to the watercraft has occurred with reference to the foreign object attachment decision logic when the load acting on the drive source during steady navigation of the watercraft is higher than the load indicated by the initial load data by a predetermined value or greater.   
     
     
         11 . The method according to  claim 10 , further comprising:
 obtaining cargo data indicating a weight of a cargo loaded on the watercraft; and   determining whether or not the attachment of the foreign object to the watercraft has occurred with reference to the foreign object attachment decision logic and the cargo data.   
     
     
         12 . The method according to  claim 8 , wherein the drive source includes an engine, and the method further comprises:
 obtaining an intake pressure of the engine and an engine rotational speed as the load data; and   determining that the propeller does not appropriately match the marine propulsion device with reference to the propeller matching decision logic when the intake pressure and the engine rotational speed are plotted outside of a predetermined range in the load data during steady navigation of the watercraft.   
     
     
         13 . The method according to  claim 8 , wherein the drive source includes an engine, the method further comprises:
 obtaining an intake pressure of the engine and an engine rotational speed as the load data; and   determining that the slippage of the propeller damper has occurred in the marine propulsion device with reference to the damper slippage decision logic when plotting the intake pressure and the engine rotational speed indicates a reduction in the load by a predetermined value or greater.   
     
     
         14 . The method according to  claim 8 , wherein the drive source includes an engine, and the method further comprises:
 obtaining an engine rotational speed and an operating amount of a throttle operator that controls an output of the engine as the load data; and   determining that the water landing of the watercraft has occurred with reference to the water landing decision logic when the engine rotational speed has increased by a predetermined value or greater even though the operating amount of the throttle operator has been kept constant.   
     
     
         15 . A watercraft comprising:
 the control system according to  claim 1 .