That 13 amps is at 220 Volts. Not quite 3kw but close. The round blue plugs that I have are rated at 16 amps. The standard UK power plugs are 13 amps and they have an internal fuse. We used the 16 amp power to drive our heaters. At that time in St. Catherine's the electricity was not metered. We paid a fixed (high) price so I didn't care about how much power we used.

I repowered Storm Along at Foxes Marina at Ipswitch. If Ipswich Haven marina is the one that has locks we stayed there for a week too. Nice people at that marina. Foxes was a bit snooty.

Yes, humidity was a problem - we lived with it in England but ended up buying a dehumidifier in NZ. BTW dehumidifiers do draw a bit of power.

I've been reading your blogs. Reminds me of many fine times in England.

Enjoy.