All,

Thanks for the replies. It should mention that just about all the wire I
am working on at the moment is internal to the boat.

I think I will continue to use the untinned wire (bargains on marine
cable are not common in NZ) but seal the ends as suggested. I am aware
of the issue with fatigue if the copper is too thick and so will use
something with lots of thin strands. I also solder all the small crimp
connectors as well as crimp them which I believe will offer some protection.

For the nav lights (front, back and mast) I an leaving the existing wire
in place as it is tinned and in excellent condition.

Thanks again,

Steve