Currents in the Bay

[kaiwahine]

I'm an intermediate sailor and I mainly windsurf at Crissy, I'd like to learn more about the tides, currents and overall patterns of the bay. I'm starting to go out further and further and want to make sure I know how to sail safely in the conditions there. Where's a good place to gather all this info? thanks.

[faradroka1]

under each site id, you'll see a tides link. many of the SF Bay sites depend upon specific tide conditions to sail. Third Ave needs somewhere around 2 feet of water and many sailors there prefer the ebb to the flood. Most people would never sail Treasure Island on the flood, yet at Berkeley the tide effect is ignored. You can sometimes find this info on each "local info" link, or troll the forums. Crissy has one of the strongest currents in the Bay, so ask around at the launch for the local experience.

[victor]

specifically for crissy you can click on "tides" and it not only gives high and low it also gives the current (max flood, slack, max ebb) 3 knots doesn't seem like much until you are trying to swim against it with your rig.

if the wind isn't cranking you want to avoid sailing on a strong flood no matter how flat the water looks because it is more difficult to get up on a plane and it's easy to get washed past the launch and end up under some pier along the embarcadero.

a strong ebb USUALLY means bigger swell and chop which you might not enjoy as an intermediate sailer. if the wind dies and you are far from shore you could end up outside the gate.

to further complicate the situation there are other factors that can mess the whole thing up. many times it can be flooding hard on one side and ebbing of the other. eddies develop with the water moving in the oposite direction from the tide. in the spring the extra water coming down the rivers can make it seem like it's ebbing all day.

unfortunately the water doesn't read the tide tables. the best thing to do is watch the other sailers. if you see everyone having a hard time keeping above anita rock and people are walking their rigs up the beach then it's flooding. if everyone is west of anita rock it's slack or ebbing. if no one is sailing then it's probably not a good idea to go out.

[diannesf]

You are really smart to look into this, as the currents, especially at Crissy, are tricky.

I recommend you always look at the currents, and not the high/low tide data on the charts. You can check those by looking at the Tides link for Crissy on this site. This gives you a much better idea of how things should go.

Also, here's a link that shows 'real time' currents and their strengths, and you can zoom in. It's not actually real time, so make sure to check the time stamp. And remember that all tide/current tables and models are estimates.

http://sfports.wr.usgs.gov/SFPORTS/vec_map/centbay.html

You may already know this, but just because it's 'ebbing' doesn't mean the tide is going out all across the bay. In fact, the water is moving in different directions and at different speeds (and can be quite strong) depending on exactly where you are (mid-bay, fishing pier, north tower, anita rock, etc.) at a certain time in the cycle.

Before we had all this info online, we used to use those little booklets published every year with the tides and currents. You can probably still get one at a fishing shop, or West Marine, and I recommend it because they have nice pictures that show the relative strength of current, as well as the direction, for every hour from slack to maximum strength (of flood and ebb). It's really interesting, (and it can save you a lot of time and frustration) to see the way the currents actually work.

Just as an example, at max flood, in the middle of the bay, you'll get pushed downwind pretty fast. But if you stay near shore (if it's windy there) you are actually in an ebb (an eddy, but it's still an ebb). That's how experienced sailors on small gear get upwind and are able to sail by the South Tower in a flood.

[MULLDE102f]

Be safe, carry a radio. I broke a a mast at Crissy years ago (20 kts, powerful flood tide, huge swell). No possibility of making it back to SF or Marin, I was headed for the East Bay when a Red & White tour boat spotted me and called in a Coast Guard rescue. It could have been really bad, Crissy can be serious stuff.

[kaiwahine]

thanks for everyone's posts. I just bought a radio, some towing line and a whistle. I'll also be studying the currents/tides model.

[spanker_jeep]

Yeah,

Serious stuff. I have been rescued a few times myself. Everytime it was due to a wind shut down/sailing into the wind shadow of ft. point and the current ultimately grabbing me. Always seemed to get sucked out. Getting back on a flood I have always made it to "last ditch beach". Been there yet? You will know what I am talking about when you get caught in a flood.
I dont sail with anything more than a line. I have been very, very lucky.

Good luck man. You certainly cannot eliminate all risk, but you can mitigate it.

[martyrosse]

Another minor thing to consider is that the tides for Crissy on iWindsurf are actually the tides for the Golden Gate entrance. Having sailed Crissy for years, my own personal rule of thumb is to do everything an hour earlier than you would think from looking at the tide tables. So if I want to sail during an ebb, I start sailing an hour before slack. To catch the biggest swell straight out in the middle from the beach at Crissy, I try to be out there at least an hour earlier than max ebb. And if I want to avoid getting caught in a flood, I get out an hour ahead of the time when the ebb ends (slack). The true difference may not be an hour, but I found that this rule of thumb is useful and simplifies things a lot, especially for avoiding getting pushed downwind when the wind drops off late in an ebb. Again, this is a personal rule of thumb that some people may find minor flaws with, but it's something I really would have liked to have known much earlier in my Crissy experiences.

[tomg]

You'll master the jibes before the tides.

[cherrywood182]

One other thing - If you do call for a coast guard rescue, don't tell Epenrose or we will all have to suffer