Young captain steering a boat

Why you should have an automatic main switch

Do you know where to find and how to shut off the main power switch onboard your boat in case of an emergency?

Many boat owners don't spend time reading manuals and instructions on their boating equipment. One of the essential safety devices used on thruster systems onboard a boat is a circuit breaker. Electric thrusters must always have a fuse and a circuit breaker in the main power feed circuit. 

Locating the main switch

In case of an abnormal current consumption in the course, the fuse should blow. However, situations can occur where it doesn't, making it necessary for the safety of the people on board, the boat itself, and those around to shut down the main power to the thruster manually. 

Shutting it down can be problematic, however. A boat's main switch is, in most cases, located either in the bilge, technical room, or engine room. That means you'll have to leave the helm to be able to shut it off. 

Even boats with remote-controlled main breakers might be problematic to handle. These breakers often support more than just the thruster, resulting in shutting down other systems you might need to operate the boat when shutting it down. 

The logical solution

Boat owners don't always take the time to read manuals and learn about their boating equipment, making it difficult to know what to shut off in case of a problem. That is when an automatic main switch comes in handy. You can quickly close the circuit without leaving the steering position by merely pushing the 'off' button on the control panel. An obvious reaction in case of trouble, even for those unfamiliar with the boat and the equipment on board.

Automatic main switch and fuse for thruster

Auto-off function

You can probably relate when I say people forget to shut off the main switches when leaving their boats. The Sleipner control panel has an auto-off function, making this problem disappear entirely. 

To comply with regulations, the automatic main switch has an additional mechanical shut-off feature on the main switch itself. This is a backup in case there is a failure on the switch. However, the practical usage doesn't change as you leave the mechanical override on the 'on' position. The override should only be used in emergencies if the automatic main switch doesn't work as it should (which is virtually impossible as the default is 'off'), but rules are rules. 

Another advantage of the Sleipner's automatic main switch is that it's the same for each voltage. It doesn't matter if it's a 30 kg or 210 kg thruster that you're fitting – you only have to make sure to get the correct thruster voltage version and use the right-sized fuse in the switch. 

Benefits with an automatic main switch 

  • You turn the main switch on and off using the thruster control panel 
  • There is no power at the thrusters' electric motor and relays until the control panel is activated. It will be shut off automatically with the auto-off function of the control panel in case you forget
  • Automatic shut-down of the main switch in case of an overheat situation in the thruster system
  • Easy to install. You only have to fit one item instead of a separate main switch and fuse with interconnecting power cables
  • Cable connections are prepared for double cables if required
  • Plug-and-go control cable wiring (see diagram below)
Wiring diagram intelligent power control

For an optimal, safe, and user-friendly thruster installation, we always advise installing Sleipner thrusters with Intelligent Power Control, a control panel with an auto-off function (standard on all control panels), and an automatic main switch.