100m Hookup cable

I'm going to Norway next year and have been advised to get a very long hookup cable - at least 50m. I have a couple of 25s and a 10 and could join them together. I'm not too keen on this though as the plugs/sockets where they join would be exposed to the wet, etc. A local dealer has offered me 100m 16A cable on a roll and I can put a plug & socket on. Would this length be likely to suffer serious voltage drop?