Understanding Wind Conditions San Francisco Bay - Kayak Fishing

Exercise is half the reason I kayak fish. Sometimes when I've had enough lower body (legs) work out I paddle to get my upper body work out in.

I usually feel like I got hit by a freight train when I get home but I cannot deny the results. Been healthier than I have ever been in my life. I've lost 10+ lbs since last year doing what I love.

Combo or work out and monitor eating habits.

Thanks for the article, TLA, this is great stuff. The pattern of wind in the bay can be pretty intimidating for newer paddlers. I'd like to add a few notes of my own on wind and current, mostly a combination of my own experience trying to learn ARW and some excerpts from David Burch's Fundamentals of Kayak Navigation. I think they might help newer paddlers decide whether or not it's too hairy to go out.

One of the first things to remember is that the cruising speed of most kayaks is 3 to 4 knots. This means that on flat water, at a sustainable pace with moderate exertion, you can go somewhere between 3 to 4 miles per hour. This is dependent on your boat and mode of propulsion, mirage drives seem to land somewhere around 3.5 knots. The typical recreational kayak goes around 3 knots, an ocean touring kayak will be around 4. Your sprint speed will be somewhere just upwards of 5 knots.

Depending on your boat, it will take you 15 to 20 minutes in calm water to reach the gap in the rock wall, roughly 1 mile from launch:



It's a good idea to have a rough idea of how far you are from the ramp to decide whether or not you have enough gas in the tank to make it back in safely.

Factoring in Wind
The numbers above are based on perfectly calm conditions. When you add in wind, the calculus becomes trickier.

A 10kt wind will exert about 1 pound of force on a kayaker. The relationship of wind to force is not linear, as a 14kt wind will push with 2 pounds, and a 17kt wind pushes with 3 pounds. This doesn't sound like much, but it turns out that's about the same amount of force required to push you along at a speed of 3.5 knots. Sound familiar?

Actual circumstances vary, but this means a sustained 17 knot headwind can theoretically drop your speed to zero. In empirical observation, the actual drop is to about half your cruising speed but that's nothing to sneeze at. Remember our rock wall gap? That's now a 30 to 40 minute paddle.

Factoring in current
You can take current as a more or less additive force when you are moving directly with or against it. Fighting a 1kt current will drop your speed by one knot. Paddling with a 1kt current will increase your speed by the same.

In many spots in SF bay, including the ARW, the currents are harmonic with the tides. Slack current coincides with the top or bottom of the tide (give or take half an hour). Max current happens about 3 hours later. As far as direction, a high tide means current flows inwards from the ocean (read: the Golden Gate Bridge). Low pushes water out. Either way, it will generally hug the shoreline. Going back to the ARW example, the current should head west->east on a flood tide (low to high) and vice versa.



Checking NOAA predictions, we can see that this more or less tracks with the official Alameda current prediction station:



This means if you are fighting a 17 kt wind and a 1 kt current, your speed has now dropped to 0.5-1 kt. The gap is somewhere between one to two hours away from the ramp.

A Real World Example
I went out July 4th, on the water around 11AM, caught my butt, then tried to paddle back in around 1240PM from the flagpole. That's a little under a third of a mile, or a 6 minute paddle on flat water.



The wind was blowing almost directly from the west at ~10kt. Being so close to shore, I kept having to turn directly into the wind to stay on course. Let's say I lost half a knot to it.



I was on the tail end of a flood tide of 0.7kt. One hour after peak current, the actual current will be 90% of the peak. Two hours after, 50%. At 1230PM, current would have been around ~0.5kt.



Because I'm a dummy and didn't have a plan for bringing in the fish, I dragged it behind me on a stringer. Keeping our estimates round, the spinning flatfish brings me to maybe 1kt of speed loss even, down from 3kt to 2kt. A 6 minute paddle has turned into a 9 minute paddle. In reality, it took me a little over 10 minutes because I kept course correcting, and any time I stopped to catch my breath I just lost progress. I was tired but safe when I landed, but if I was trying to paddle in from Bay Farm? That's a recipe for a bad time.

Post-nap addendum, 2019-07-11
After sleeping on it, one thing that bothered me was that I remember really struggling during the paddle back, but I couldn't justify that with the recorded numbers. However, I do distinctly remember glancing at Navionics when I stopped paddling and seeing a backwards drift of up to 2.2 knots, so what gives? Where did the extra 1.2 come from? At that point, the wind was probably a 4 on the Beaufort and hadn't quite kicked up to 5. (Beaufort is less reliable when wind and current are in line with each other so perhaps that was part of it.)

There's a few possibilities. One is that current hugging the shoreline will be stronger than current further out as the volume of moving water stays roughly the same but the space to move it through decreases as the bottom rises. Another possibility is that the shoreline around Ballena shows a sounding of ~2ft. For reasons I don't quite understand, paddling is harder in shallow water. https://paddlemonster.com/2018/07/is-shallow-water-slower-than-deep-water-a-forum-discussion/. That may have made things worse. Lastly, the current prediction station from the NOAA is a subordinate station, meaning it's not measured but derived from another station located at the mouth of the bay. Not only that, the measurement is predicted further offshore and as I've said before, current is highly localized (how many times have you paddled around a corner just to get to calmer waters?). Perhaps the extra knot came blasting out of a back-eddy from the channel around Ballena. The takeaway here is that you should use these numbers to help establish a baseline for your paddling/pedaling skills, but take the time to study your waters for local phenomenon. Be extra diligent if you're entering water at the top end of what you're comfortable with.

Post-shower addendum, one hour later
I'm still not happy with the above explanation, but I think I have it. The wind was going ~10kt from the west, or pushing with 1 pound of force. Per the chart from the book, this wind would have been pushing me east somewhere just shy of 2kt which puts us back in the correct ballpark range.



Due to the non-linear relationship here, you'd have to be very close to sprinting just to maintain an average speed. If you were just 'pressing hard', you would still be moving slow. SCIENCE!

Using these numbers
The main thing to note here is that you should plan your trip such that you won't be fighting both the wind and current at the same time on your return trip. Since this is a fishing forum and not a math forum, here are some rules of thumb for paddling in the bay:

• Check the current prediction before going out! This might be more important from a safety perspective than just straight tide predictions. It's a little hard to find, but https://tidesandcurrents.noaa.gov/map/index.html can give you current estimates if you select Advanced and choose 'Current Predictions' under 'Data Type'. If you're somehow too lazy to do that, at least remember that the current increases with the tidal coefficient. A delta of 6 feet will give you a strong current, 2 feet will be a weak current. Current is also very much a localized phenomenon and can change from area to area so you should check it in multiple spots. It will almost always be strongest halfway between the tide changes.
• Check the wind before going out, but know how to read the water.  The Beaufort scale gives you a way of estimating current wind speed based on the appearance of the water. https://simple.wikipedia.org/wiki/Beaufort_scale. A 4 shouldn't be too much of a problem for strong paddlers, but a 5 will probably ruin your day. During the summer, wind in the bay is primarily driven by a persistent offshore high pressure system. As the central valley warms up and drops in pressure, wind sweeps in directly from the west. This predictably happens around noon on most days.
• Verify predicted data. There is a difference on the NOAA site between stations that have actual recorded data vs numbers deduced from tidal harmonics. Know how to tell which is which. Use webcam data where it exists. The Cal Sailing Club has a webcam trained on a windsock in Berkeley's south sailing basin. http://cal-sailing.appspot.com/wind
• Doubling down on TLA's statement, Berkeley is unpredictable nonsense. It's fully open to wind and current from the Golden Gate and it feels like it kinda sucks all day long. The wind seems to pick up earlier there than other places, but then it also seems to die around 1pm before coming back with a vengeance. If someone else can diagnose Berkeley's patterns, I'd be glad to hear it.

No, that's still too complicated, make it simpler
Fine. Get on the water 3 hours before high or low tide. If you're fishing north of where you launch, go out on an ebb (high to low) tide. South, go on a flood tide. Try to get back to launch within two hours after the tide change. Get off the water before noon.

This is fantastic. I especially like the wind current impact on speed from the mathematical angle but also empirical evidence. I recently peddled in to a 15kt headwind (based on windy forecast and now corroborated w the Beaufort scale) returning from Rocky Pt to Brighton Rd launch in Bolinas bay. I had to cover about 2.5 miles. I was surprised at my relative velocity, it was higher than I expected and was impressed w the torque of the mirage drive.  But also recognized that any kind of mechanical or physical issue and I would’ve been in deep doo doo. I guess my point is, it’s important to know the numbers and then test yourself in varying conditions, gradually approaching one’s comfort barriers.

Thanks Chriszsf.

Dont forget that if you are headed back to the launch from the opening in the wall and fighting an outgoing tide you could stay inside the wall which would have minimal if any current. Go all the way to the beach and land there, just inside from the launch. Some times if I am coming back along the second wall I will tuck inside it (greatly reduced current) till I get to the opening.

wow, chriszf that post deserves it's own dedicated thread. LOL. Very detailed.
Thanks for sharing your thoughts. 

wow, chriszf that post deserves it's own dedicated thread. LOL. Very detailed.
Thanks for sharing your thoughts. 

Totally agree! I think this should be a sticky. very detailed and informative. Thank you chriszf!!

The combined wealth of knowledge in this post is amazing thanks TLA and chriszf!!

This will make my first trip to ARW much easier appriciate it.

Thank you Chriszf and Lost Anchovie this info is shine gold it answer a lot of the questions I’ve been making in my head before adventure at any place in the Bay Area.
Thank you and now I feel more safe since I can take good decisions with the info you generously post, Namaste.
JC

Dude, Fantastic thread.  thanks so much for sharing it!

 I've had my 3d worst scary conditions experience on the SF Bay.  And, my 4, 5, 6 and 7th.

Bushy

Exercise is half the reason I kayak fish. Sometimes when I've had enough lower body (legs) work out I paddle to get my upper body work out in.

I usually feel like I got hit by a freight train when I get home but I cannot deny the results. Been healthier than I have ever been in my life. I've lost 10+ lbs since last year doing what I love.

Combo or work out and monitor eating habits.

Same here TLA! I just gotta get out more than once a month! Lol

This post is rad and really useful for SF Bay Area. I wanted to chime in on wind conditions yesterday and how unsafe they became.

Forecast read 3' S swell @ 18sec (which is not bad for us divers... maybe a little water movement/surge but nothing at all to shy away from. Wind was supposed to be 15-20kt SW w gusts of up to 30kt. That is not ideal at all, last time I was out in a kayak in 30kt winds, the dud I was with was screaming each time a wind wave white capped on him and almost flipped him (we were in pebble in an area that didn't have any shore access so we had to paddle far). Yesterday however, we were launching a small 14' whaler to dive from. The wind did not seem bad at all so we decided to go for it. Once we were out of the harbor in Monterey, we were blown away with how significant the wind waves were. Some were as high as 7'. When rounding Pt Pinos to head south, it was a washer machine but still doable. we went to a sheltered area, anchored and dove from 2:30p-5p. When we got back in the boat, pulled the anchor and left the sheltered area, there was a random, out of nowhere set of 8' short point wind swells (about 4 of them) that were very close to rolling and crashing over our small bow. This is the only time in my history of being on boats that I thought for sure we might be sinking it. I kept my whole wetsuit on, including gloves and a PFD. We even considered running with the swell down to SWS and ubering to go get our cars and trailer.

My lesson learned was, respect the wind report. That was super sketchy but thankfully the boat owner got us out and home to safety.

Thanks guys for all the nice writing and story sharing.

    There's a reason they put the Olympic Sailing Circle between Berkeley and Albany ... sailors call the area between the Golden Gate and Berkeley "The Slot".  Watch the fog roll in right from the Gate in a thin (at first) straight line toward Berkeley/Albany.   In the Bay, it's said that the wind doesn't blow, it sucks!   (Central Valley heats up, pressure drops there relative to the Coast, and the wind tries to equalize things.)   But if you get caught in high wind there, it's because you haven't been paying attention, because it starts off slow and builds gradually (usual conditions), unlike the west side off the south bay, where the wind gets sheltered by the ridge until it bursts through a gap - like at Candlestick.