I recently bought an O'day 27 and have come across a surprise in the wiring
of the battery switch.

This is the usual 1,2, both or off.

The two batteries are wired with their positives strapped together, and the
negatives disappear separately into the switch.
All positives are taken from the deep cycle battery, including the starter.


Tomorrow I intend to remove the switch with a view to rewiring in a more
conventional way.

Can anyone speculate on why the wiring should be as it is. Also, is there
anything I should know to prevent blowing the alternator?

Thanks in anticipation

Henry