I think the nearest harbor (and ramp) to International Marine is Marina del
Rey. IM will give you directions. The Southern California Potter
association used to do most of their sailing from there. It's a short drive
from Inglewood. It's a giant marina with a channel that leads you outside a
breakwater to the ocean south of Santa Monica. The club used to hold races
from Marina del Rey to Santa Monica and back.
If you want to drive further (20-30 miles), Long Beach would be another
possibility. There's a ramp on a river that leads you into Los Angeles
(Long Beach/San Pedro) harbor. There are a number of harbors with ramps
along the coast to the south, in case you are going sightseeing on down
toward San Diego. I used to sail out of Huntington Harbor/Anaheim Bay, just
south of Los Angeles Harbor, but your P19 mast might be too tall to fit
under the bridge there.
Marina del Rey is probably your best choice.
Harry Gordon
P14 #234, Manatee
Mountain View, CA