The ocean is very deep indeed! The Pacific Ocean (the one you will visit to go whale watching) is at its deepest point 36 *thousand* feet deep.
That's about the height of Mount Everest, the tallest mountain in the world. In the Santa Barbara Channel, the ocean is not nearly so deep --
only about four to five thousand feet. The Sea Center on Stearns Wharf is a great place to learn more about the ocean.

The ocean's depth varies. For instance, there is a continental shelf that makes the ocean adjacent to the land on the east coast shallow compared to the west coast (where the continental shelf is much shorter), so what people consider to be the ocean when they look out from the beach is
actually quite shallow on the east coast. But the ocean can also be quite deep, for instance, did you know that the depth of the Santa Barbara Channel can be as deep as 613 feet? Along the Santa Barbara coast the depth goes to about 200 feet deep (which extends about 5-10 miles out from shore), then falls to a depth of about 613 feet in the channel, going to about 900 feet deep past the islands a few miles and then to 2000-3500 feet deep past that area. So the ocean can get quite deep!