How about, :- float switch operating a warning lamp, then bilge pump on 3
way switch, ie off, to float switch or direct to supply. I fitted this for a
customer and also fitted a alarm,( but he found the alarm too annoying!) You
could fit a large warning light or even a strobe type, ( float switch are
rated at several amps), which would be difficult to ignore. All circuits
fused of course! The normal 'rule' type switches only illuminate the light
when the pump is running but it seems to make sense that even if bilge
pumping is 'anti-social' there should still be some warning of excess bilge
levels.
Regards Dave