I found LD1A-12F headlight/horn relays for six bucks at the auto
store and available here for less:

http://www.jameco.com/Jameco/catalogs/c252/P138.pdf

where I've ordered sockets with coil suppression diodes. The relays
are completely sealed and appear to be as watertight and ignition safe
as any marine unit. 30 Amp, 220 watts. It'll be a simple matter to
carry a spare and they can serve as the shut off switches if the pump
jambs.

I got the parts for the snubbers. Does the presence of the diode in
the socket change anything?

Many thanks for your help on this. It's what this group should be for
instead of worrying about who's pretending to be Peggie.

--

Roger Long