I'm to lazy to go look at a chart right now, heading to Victoria BC for the boat show in Sidney this weekend. But the area I'm referring to is about 900 feet deep so you can imagine how startled I'd be to discover I am about to plow into something a hundred feet from me, sight unseen, out in the middle of the pond, so to speak.
In fact, one area between Vancouver Island and Denman Island I was transiting with friends, first time out in the new old boat. I told my friend my boats draft is 6 feet (in reality more like 3 feet), we were transiting a very deep area when the depth sonar started registering 3 and 4 feet in the middle of the channel. We panicked a wee bit but when I look into the ocean all I could see was the dark green one associates with deep seas. I talked to a chap in the marina parking lot about two weeks latter about these false hits and he told me he had some friends experience the same false reading I had. The only thing that makes any sense was whales transiting.