hi all

what is the rules if i want to have gas to cook with in the cabin

1st thing to remember is that lpg is heavy - you can pour it from cup to cup if you try. you can walk into a cabin, have it pooling below your knees, not know its there and as soon as you provide ignition source its boom.
keeping it simple:
bottle in a vented compartment outside of cabin
surge arrester required
isolation on all appliances
gas decection device / alarm in cabin
certain clearances above and around burners.
ventilation requirements
never use the cooktop or oven for heating
gas system to be inspected and certified prior to selling to new owner
NEVER diy gas.
a lot of gas fitters wont touch boats or caravans due to the liability.
id strongly advise not to use a camp stove inside the cabin without the adequate safety stuff, AND ventilation. carbon monoxide, co2 and a few other nasties as well.
also keep in mind the added dangers of petrol storage and fumes on board.