Process of elimination, electrical fault

[Laundryman]

Sitting on my boat in the marina, only 2 of the switches on the main switch panel were switched on, cabin lights and water pump. Meaning that power was going to both lights and pump, though neither were in use at the time. Then all the lights on the switch panel came on on their own.. Soon as I pressed one of the buttons, they all went out again, except the 2 that were already switched on. Mains was connected at the time as was the battery charger.
Where do I start please or should I not be concerned? Thank you Alan

 

[savageseadog]

Sitting on my boat in the marina, only 2 of the switches on the main switch panel were switched on, cabin lights and water pump. Meaning that power was going to both lights and pump, though neither were in use at the time. Then all the lights on the switch panel came on on their own.. Soon as I pressed one of the buttons, they all went out again, except the 2 that were already switched on. Mains was connected at the time as was the battery charger.
Where do I start please or should I not be concerned? Thank you Alan

Always be concerned at anything out of the ordinary. There will be a loose connection to the common connecting all the lights.

 

[pampas]

Pay particular attention to all negatve connections, as a poor earth is the usual cause of this type of fault.

 

[MudShipper]

Loose wire

Sounds like a loose wire floating about behind the switch panel as from your description it is an intermittent fault and cleared when a bit of vibration from operating another switch moved it. Turn off power to the panel before attempting to investigate further as it might move the loose end back into contact with something else.