Which O'DAY do you have? The Day Sailer (16'9") mast would be best searched for on the Day Sailer Class Association web forum on their site,
www.daysailer.org The DS was sold with either a hinged mast (hinge at or just above deck level) or solid, "keel" stepped mast at various times in the production run.
The Mariner or RHODES 19 (19'2") would be the Mariner Association or the Rhodes 19 Association, Cape Cod Shipbuilding and Stuart Marine both sell spars for the Rhodes 19. Used ones may be available from Stuart. I think most, if not all R19s had deck-stepped masts.
O'DAY 19 mast, maybe someone here is parting out a boat? These were only deck-stepped.
To: Sail sfbay: I doubt he will find any RHODES
18 masts from Stuart, they only have the one for the RHODES 19
<GRIN!> The RHODES 18 was never built by O'DAY, the only supplier I know of is Cape Cod Shipbuilding in Wareham, MA, although they are actively raced out of a couple of Maine harbors. Easy typographical error
<GRIN!> I knew you meant R19!