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sfbaysailing 12-18-2012 04:16 PM

SF Bay Sailors - Transiting the Bonita Channel?
Hey everyone

I am considering heading north from SF bay tomorrow, towards muir beach. The NOAA forecast is calling for:


I have transited the Bonita channel before, but it was calmer than tomorrow's forecast, and I'm leery of getting in the Channel if there's too much swell running.
Does anyone have experience with how much swell is too much for the Channel?
Thanks for your advice! The boat is a Catalina 30.

MarkSF 12-18-2012 04:36 PM

Re: SF Bay Sailors - Transiting the Bonita Channel?
Another consideration is that little or no wind is forecast, so if your engine cuts out there you're going where the tide is taking you.

I like to use this spot forecast. It calls for light winds, 5 kts or less, in that area.

Marine Point Forecast for Latitude 37.8°N and Longitude 122.53°W

GeorgeB 12-18-2012 05:12 PM

Re: SF Bay Sailors - Transiting the Bonita Channel?
I concur with MarkSF, If the NOAA prediction holds true, this is going to be one big, lumpy, left-over sea that you will be transiting. You might not be able to hold a close haul course in the Northerly wind and tacking to Stb will put you over the Potato Patch, which will be real lumpy if we’re talking a general forecast 10 ft and 13 seconds. What time is your return trip? The next storm will roll through on Thursday, and a southerly wind shift could make the return trip a bit more dangerous than normal. Double check the current predictions for under the Gate as an ebb will cause the 13’ waves to stack up even higher. Let us know what you see out there if you go. This Picture is running the Bointa Channel in 10-15’+ waves at around 10 seconds. They were breaking clear across the ‘Patch. We saw one break continuously from the Patch and across Bonita at which point we bailed and went around to the main ship channel. Only to encounter a big one breaking clear across the channel. Be good, be brave.

dabnis 12-18-2012 06:19 PM

Re: SF Bay Sailors - Transiting the Bonita Channel?
Over the years, many, many trips in and out of the Bonita Channel, some of which I wish I had never started. 8 to 10 foot swells at 13 seconds, depending on currents, can be a pretty bumpy ride. Like George B, I have seen very nasty seas break out of nowhere. "Brave" won't help you if you lose power, the rocks are very close by. Just curious as why you want to do that this time of year with that big of sea forecast?

Paul T

sfbaysailing 12-18-2012 06:26 PM

Re: SF Bay Sailors - Transiting the Bonita Channel?
Hey everyone

thanks for the replies. I'm still up in the air - we are going to spend the night in aquatic park, so we still have some time to decide. And now the forecast is moderating a bit to:


George -
The plan is to return the same day, and ride the flood back in under the gate.

Paul -
We are hoping to drop some crab pots up at muir :) The currents shouldnt be too bad - max ebb at the gate is only 1.4 at 845am, and we are planning to exit the gate at 9, which puts us entering the channel right around 930 or so....

Is it feasible to sail out the shipping channel and check it out? Are their any good visual indicators (like breaking waves or not on the patch etc) that could help us make the go/no-go decision based on actual observed conditions?

Thanks guys! I really appreciate it

GeorgeB 12-18-2012 07:06 PM

Re: SF Bay Sailors - Transiting the Bonita Channel?
If the winds hold as predicted, you will be able to run up the channel on a Stb reach. You can even fly a kite if you go out to the light bucket. I’m not sure how good your crab production will be if you are only doing a couple hour soak (We drop off the pots on the way to Drakes and recover the next morning.) If the forecasts hold, your biggest problem will be keeping your sails full and the boat not stalling as you pitch and roll up and down in the swell. Think about rigging a preventer to keep the main from slating. You will be able to tell from a distance if Bonita (or the ship channel for that matter) is a bit much for you (listen to that inner voice). The shallow part of the patch is only 24-28’ deep and you will see the waves build (and possibly break) on the shoal way before they break in either channel. The Bonita mid channel buoy guards a 36’ submerged rock and expect to see the waves build up in that area before the rest of the channel. All of this is easily seen as you round Pt. Bonita. The tides are also in your favor.

The trip to the light bucket is another classic SF sail. Just sail 253* (or so) for 10nm and look for it. The bar pilot boat will be in the vicinity.

Not all days are challenging outside the gate. This shot is from one of them (2009 BAMA DHF). Sometimes the hardest thing is to keep your boat moving. On the other hand, twelve hours after this shot was taken, the winds were in the 20’s-30’s and the boat Heatwave, turtled and her crew were struggling for their lives. Be safe.

sfbaysailing 12-18-2012 07:15 PM

Re: SF Bay Sailors - Transiting the Bonita Channel?

Thanks for such great info!

So it sounds like I can go up around Bonita and check things out, which makes me feel better. I did a lightship sail last season, and it was much like your picture (though waaaay foggier).....and with less wind :(.....Also did an amazing Drake's Bay trip with perfect wind in both directions, so I can't complain :)

If we end up transiting the channel I'll be sure to post back on Thursday and let you all know how it looked, as well as give you the crab tally :)

Fair winds!

dabnis 12-18-2012 07:22 PM

Re: SF Bay Sailors - Transiting the Bonita Channel?
George B covered it well, but be careful, it is just a boat ride. Short time to put pots out, but nothing to lose unless you set in a rocky area.

Paul T

dabnis 12-19-2012 10:27 AM

Re: SF Bay Sailors - Transiting the Bonita Channel?

If you haven't left yet you might want to check out this real time site:

Northern California NOAA/CDIP Buoy Data

Looks like it may be a bit lumpy. Safeway has crabs for sale.

Paul T

sfbaysailing 12-21-2012 02:18 AM

Re: SF Bay Sailors - Transiting the Bonita Channel?
Hey everyone

So we ended up going up and down the channel on wednesday, and soaking the pots off muir beach for a few hours.
The channel was fine, no problems at all. It was, however, a bit intimidating to be inside of those large swells as they stood up on the potato patch....and then backed down again in the channel. I'd say that was probably as much swell as Id feel comfortable with in the channel, though I think it would be safe with more swell.
And we caught about 30 crabs and 6 sand dabs and had a big feast!
Thanks everyone for the was really helpful in making the decision.
All the best,

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