I would try the 7806 as others have suggested.

Mount it on sheetmetal to serve as a heatsink. The tab is
electrically ground.

It's a low-risk proposition:

They only cost a buck or two at Radio Shack

They're self-protected against burnout. If they overheat they just
shut down

They'll deliver an amp or so until they overheat

If the Hobbs just draws short pulses, it's quite unlikely that the
7806 will overheat.