Not me. Me Father (77 with a 33' foot twin engined motorboat - kept on a drying mud berth).
This
winter he finally decided to fit
remote Battery Switches so he didn't have to
lift the
engine covers (x2 of the 4 and heavy feckers

) every time he came onboard. and every time he left. It's been on the list for a dozen years
Anyway, Aged Parent used to be an electrician - back when electrikery was all new and exciting (at least in Britain it was), so he is not as phased by bits of wire as I am.........so over the
winter he acquired the bits and pieces needed. and gradually installed them. The Starboard
engine connected up no problem a month back. The final connection (for the Port engine) was made last week.............absolutely feck all

Obviously a lot of checking went on, wiggling of wires and checking connections to no avail - not even a squeak.
Diagnosis was a duff
battery - getting on a bit, and hadn't been used for a few months. Obviously these are full sized
batteries. 4 foot down in the
bilge. But he got it out on his own. then decided it would be a good idea to nick one of my fairly new
batteries (in his garage on charge).......so he managed to carry that one accross the harbour (tide out

) up 5 foot of boarding ladder and down 4 foot of
bilge...........connected up and f#ck all

I will cut out the next bit of checking and wiggling of wires. and swearing........
.......but the answer I wish to share was 3 stage:-
a) put the kettle on and have a cuppa tea
b) think carefully
c) and then make sure you are turning the battery switch
fully to on

.......and not just within a fraction of an inch of making the connection

Afterwards he said it was always stiff to operate. I think he was still talking about the battery switch............