I have lived in the Bay Area and sailed on SF Bay for 45 years. Your statement demonstrates my concern about folks placing unwarranted trust in AIS. As you note, fog on SF Bay can come up quickly and envelope your boat in a matter minutes. However, many recreational boats do not have AIS capability and the 20T USCG navigation buoys (that are not always exactly where they are charted) do not broadcast an AIS signal. So trusting your boat and your life to AIS displays in the fog is, IMHO, very dangerous. The ships and ferries have the right of way in all the narrow channels on the Bay and while they will do their best to avoid you when they are elsewhere, they frequently have a very limited ability to do so. AIS is one source of helpful information, but it is only one. And one that should not be relied upon for vessel separation in dense fog. I fear too many folks are not developing their skills with radar and general watch keeping because they are relying on AIS and chartplotter technology instead of taking personal responsibility to use all means to see and be seen in poor visibility situations.
Four days into a 21 day passage from Kauai to San Francisco, my wife and I were having breakfast in our cockpit when we encountered our first ship. I had set a five mile alarm ring on our AIS and it dutifully announced a 700 foot bulk carrier approaching our position. The CPA (Closest Point of Approach) was over a mile. We watched as the ship came into view.
Our ride that year was a 45 foot steel sailboat named Kaien. As most of us know, one of the advantages of a steel boat is that it has an excellent radar signature compared to fibreglass.
I hailed the skipper to let him know our position, course and speed. In a heavy Slavic accent and broken English the captain said that he was bound for Japan with a load of ore. I wanted to get a sense of how clearly he could see my radar signature, so I asked him:
“Captain, do you have me on radar?”
After a longer than necessary pause, the captain seemed a little irritated when responding almost as if I had insulted him.
“Of course I have radar,” he said.
“Yes, I understand, sir. Do you see me on your radar?”
Another pregnant pause and then:
“Wait a minute, I will go turn it on. I will call you back when I see you.”
Later we discovered some commercial crew compensation schemes provide incentives for keeping equipment in working order. The tests are done at the end of a long journey. Apparently, one way to keep mechanical equipment like radar arrays in working order is to use them as little as possible.
On another occasion, I was returning from sea singlehanded on a Tartan 3500 about to enter the San Francisco shipping channel. It was just after midnight and visibility was marginal with intermittent areas of fog and wind blown spray. Breaking waves on either side of the channel meant that I had few options to maneuver outside the channel to avoid traffic. I called VTS (Vessel Traffic Service) to announce my position and to ask about any traffic I might encounter. VTS said there was a tug towing a barge exiting the bay about to enter the ship channel. I did not have AIS on board.
Once I could see the two masthead white lights of the tug, I got on the VHF to arrange passing him in the channel. Given the conditions, it was difficult to judge his distance, but I could clearly see his running lights. I asked the captain if he could see me.
“No. I can’t see your running lights and you don’t come up on my radar. You should get one of those radar reflectors and put it up in your rigging,” he suggested.
Standing at the wheel, I looked up my mast and hanging off the port lower spreader was a metal octahedral radar reflector obviously failing to do its job.
There was no collision that night, but my faith in radar was shaken once again.
