Flight in severe Sink/Wave

About 18 months ago there was a couple week period with many shark sightings
off the Southern Califonia coast. During this time I was flying a helicopter
south along the Coast line just North of Santa Barbara. I was on the lee side
of the coastal mountain range, which at this time was an off shore flow. I
encountered sink, which was to be expected, but the sink band was much wider
than I expected. I thought the sink was due to wave action, however I could
not find teh lift band. I was losing alt @ between 200-400 fpm depending on
position. Both my passenger and I thought we could see several sharks in the
water! I moved closer to the mountains hoping to contact the "up" part of the
wave, but I only found rotor. So I moved out further until I was over the water
and still going down. I went out over the water as far as half mile and still
could not get out of the sink. Looking at large "fish" in the water I decided
to move back over land and if I was forced to the earth at least it was dry
land. I was down to about 150 feet AGL before the sink quit! Yes, I tried max
TQ and putting the nose down to get through the sink band faster. For teh
reasons listed above I was limited flying parallel to the sink band, but I had
never encountered a sink band about 3/4 mile wide in the lee of a mountain
before.

I am an experienced glider pilot who has much wave flying experience in
gliders. I have about 800 hours in helicopters. To this day I am not sure what
other decision I could have made but was hoping an experienced helicopter pilot
could give me his/her thoughs. I was concerned about getting too far out to sea
with many reports of shark sightings and no sea survial gear. The rotor was not
much fun either.

Any comments. Has anyone been forced tot he ground by sink and what did you do?

Thanks much