Yara said..
If it is oil burning make sure you have plenty of ventilation. Designing a flue in a plastic boat is quite tricky.
No its the oil bar heater I used the one here at home that never gets used but my partner didn't like that so I bought a slightly smaller version.
Its like being in Townsville in the winter once it warms up

so Ill be wearing a singlet inside the boat today

sorry Donk
Last time I used one to help set off some epoxy when it was a little cold
some thing like this one its been tested and tagged