Rule of Twelfths?

[BoMan]

With El Nino in effect, my local break is receiving a lot more water this year. I drive 1 1/2 hours to the coast and used to plan my sessions to begin an hour before high tide because it created many fun peaks across the area and thinned out the crowd. Now there is just too much water at high tide and I'm always watchful about getting slammed into the sea wall.

Water logged BO!

I read a about a Rule of Twelfths which could guide my session times based on the water level rather than simply going at high tide. What do you think? Sorry for being such a geek...but I am a tech guy!

Wikipedia explanation....
The rule of twelfths[1] is a rule of thumb for estimating the height of the tide at any time, given only the time and height of high and low water. The rule assumes that the rate of flow of a tide increases smoothly to a maximum halfway between high and low tide before smoothly decreasing to zero again and that the interval between low and high tides is approximately six hours. For the six hours, the rule says that in the first hour after low tide the water level rises by one twelfth of the range, in the second hour two twelfths, and so on according to the sequence - 1:2:3:3:2:1.
Example Calculation
If a tide table gave us the information that tomorrow's low water would be at noon and that the water level at this time would be two metres above chart datum and further, that at the following high tide the water level would be 14 metres. We could work out the height of water at 3:00 p.m. as follows:

*The total increase in water level between low and high tide would be: 14 - 2 = 12 metres.
*In the first hour the water level would rise by 1 twelfth of the total (12 m) or: 1 m
* In the second hour the water level would rise by another 2 twelfths of the total (12 m) or: 2 m
* In the third hour the water level would rise by another 3 twelfths of the total (12 m) or: 3 m
*This gives us the increase in the water level by 3:00 p.m. as 6 metres.

This represents only the increase - the total depth of the water (relative to chart datum) will include the 2 m depth at low tide: 6 m + 2 m = 8 metres.

[Big H]

How about the rules of a surf report? I use several, and data from one will give the current tide level and forecast that over the next days in 10 min brackets. One break I go to works on a min 1.8m swell when the tide is between .7m and 1.6m going or coming. I keep notes on all breaks I frequent and together with the site data can figure out when it's firing or not.

[Big H]

BTW I have no idea about the rule of 12ths.....seems like an interesting thing but in terms of accuracy and practicality, I go with data from Surfline, Magicseaweed & Wisuki apps on my phone....Wisuki pro does the 10min breakdown of tide heights....you just slide your finger along and will give you the exact water depths for your planned session time.

[billie_morini]

How about the rule of simply knowIng your surf break? Less thinking. More surfing.

[BoMan]

How about the rule of simply knowIng your surf break? Less thinking. More surfing.

Of course you are right about this. I live far away and can't get in the water more than once a month, so I spend too much time geeking out!

[BoMan]

Wisuki pro does the 10min breakdown of tide heights....you just slide your finger along and will give you the exact water depths for your planned session time.

Thanks for sharing! I really like the Wisuki app and I'm glad not to be the only data guy

[oldmansurfer]

You are all more fortunate than me to worry about tides and swells and such. I just go surfing during the time I have available and deal with whatever is there. No picking of tides or swells for me. It's about when I can free up the time

[billie_morini]

BoMan,

I recognize the location your photo was made! It’s Bolinas! I not only know what it is like to drive 1.5 to 2 hours to surf, I know your geographic region very well. I used to live in Vaca Valley (Vacaville, specifically). I’d drive 1 to 1.5 hours to surf at Bolinas, Salmon Creek, Point Reyes (rarely because it was too big for me), Doran Beach, and Dillon Beach (learned to surf here and went 100’s of times). I’d drive about 2 hours to surf in Santa Cruz at Pleasure Point, 138th Street, and a few other places good for long board. I surfed 4 times per month. I surfed only on weekends because of the distances. Consequently, when I surfed, I surfed all day. This, I believe, was better for a beginner than surfing an hour or two daily because it acclimated me to cold water, built strong muscles, and learned more about currents and ocean behavior. A few times, I’d surf after work at Pacifica. But, this required meetings in San Francisco to place me close enough. I did not surf but once or twice at San Francisco’s Ocean Beach. That water is rough!

Once I achieved intermediate level surfing ability, I alternated weekends between Pleasure Point and Bolinas. The surfing is much better at Pleasure Point, but I like the remote vibe in Bolinas. If you have never been to the 2 Mile Surf Shop in Bolinas, I recommend you go. Address is 22 Brighton Ave (behind the post office). You will see wonderful totem poles and related artwork similar to the Native American’s artwork in the Pac NW.

I recommend you take four days and camp and surf at Caspar Cove in Mendocino. The waves are beautiful, gentle peeling waves offering long rides. The water color is magnificent turquois. The locals that surf here are mellow. During my trips, I’d frequently encounter an old guy (>65) and a couple of young women. The RV and camp ground across the street from this break has wifi. My wife, dog, and I spent one Christmas camping and surfing there. With the wifi, it was possible some evenings to prepare e-documents with my colleagues in Germany during this trip. This address will dial you in: 14441 Point Cabrillo Dr, Mendocino, CA.

I used to rely on Magic Seaweed for surf forecasts. It is pretty accurate for the area I used to surf when I lived in NorCAL. In contrast, it is no good for SoCAL. I only got skunked once or twice. It helped that I went to surfing nearly every weekend. This helped me “calibrate” the surf reports.

Now, if you are really serious, then you will do what I did. I moved from the Vaca Valley to a surfing location on the coast. When I decided this would be my course of action, I looked for new employment in only 3 places: San Diego, Santa Barbara, and Santa Cruz. For my profession, there wasn’t much opportunity in Santa Cruz, but I tried. Ultimately, employment was offered in Santa Barbara. The surf is not as good as in San Diego or Santa Cruz, but the close breaks require 12 minute drives.

Billie

[billie_morini]

BoMan,
just got an idea. Let's share some of the totem poles and artwork at 2 Mile Surf Shop with our forum braddahs. It may interest some to know the man in the gray cap without sunglasses is 7 feet tall. He provides scale for one of the totems. He was visiting from Germany and one of my very best friends. There are many additional large-scale Native-inspired artworks at the shop.

[billie_morini]

BoMan, you reminded me how much I enjoyed surfing at Bolinas. Here are some murals that you may have seen. They are located around the corner and down the beach from the location your photo was made. There are/were many more. These photos were made in April 2014. Ditto with the totem photos.

[RinkyDink]

I think your calculation is useful and is probably a good way to estimate the tide. If you're familiar with the spot, then I'd throw the depth part of your calculation out, unless the depth of your spot changes significantly on a regular basis. It seems to me that all you really need to estimate is the increase in meters in order to know if the tide is in the range of your sweet spot or not.

[jaffa1949]

With El Nino in effect, my local break is receiving a lot more water this year.

El Nino doesn't effect the tides, there are changes to oceanic volumes due to thermal expansion and increased storm activity will create storm surges the extra water will be the flooding rains El Nino brings to the US west coast.
There will be bigger surf from the increased storm activity.
Here in Australia we have the opposite droughts, bushfires and a full continental high parked over us generating 45C temperatures for days on end. Double underhead swell conditions from non storm activity.

Tides however continue to do their thing according to the moon and sun relationships.
Knowing your beaches at all tides probably is the best way to consider and then lay your swell forecasts and directions on top.
Understand about the drive costs in time and petrol. Knowledge will get you through.
Billy's advice fits the Bill go surfing not over geeking older guys can sniff the wind view the clouds and be on it for the little unpredicted surfs before the phone a friemnd crew get on it!

[BoMan]

I just go surfing during the time I have available and deal with whatever is there. No picking of tides or swells for me. It's about when I can free up the time

Dealing with what's there is a great way to learn and build skills! In September I will retire and start doing more of that too.

[billie_morini]

Holy days of relaxation, BoMan! Retirement in 9 months! The first thing to do upon retirement is ma me a week long surn trip to San Onofre State Beach near Oceanside, CA. Three outstanding breaks for beginners and intermediates, MELLOW vibe, warm water, big fat & slow swells. On good days, rides are close to 1 minute.

[oldmansurfer]

Yeah I learn a lot from surfing whatever is there but really it is my only choice since I am on call 24/7. If I were retired..... now then I could go surfing whenever and wherever I wanted and for longer periods of time. Then paying attention to swells and tides and such would be more important.

[BoMan]

Sorry for going off topic but there’s so much good stuff here!

billie_morini wrote: I recognize the location your photo was made! It’s Bolinas.

You are right. My grandfather owned a house on the Little Mesa at the top of Altura Road. When I was five, he taught me to bounce into shore on a canvas mat and I’ve been going ever since!

billie_morini wrote: If you have never been to the 2 Mile Surf Shop in Bolinas, I recommend you go.

It’s one of my favorite spots along with the Coast Café and the “Super Market” where you can hear the floor creak as you walk!

billie_morini wrote: I recommend you take four days and camp and surf at Caspar Cove in Mendocino. The waves are beautiful, gentle peeling waves offering long rides.

This sounds fantastic. We sometimes visit my cousin in Anchor Bay a few miles south and I’ve never found a break that’s a good match for my skills. The paddle out is too far at Point Area and Black Point is usually closed out. Thanks!

billie_morini wrote: Santa Barbara. The surf is not as good as in San Diego or Santa Cruz, but the close breaks require 12 minute drives.

You are living the good life and it’s truly a small world. In 1969, I was a freshman at UC Santa Barbara living in Anacapa Hall and borrowing my roommate’s log to cruise the tiny breaks at Goleta and Isla Vista.

[billie_morini]

Gosh, BoMan! It is a small world full of confluences. I would have never imagined your grandfather owned property in Bolinas or that you were a resident student at UCSB. When you were five years old, Bolinas must have been 100x the heaven it is today. I'd have loved it. If you were at UCSB in 1969, then maybe you witnessed the '69 oil spill, CSN&Y playing on campus for a $4.25 door ticket, Blind Faith performing at the Earl Warren Showgrounds, and Gov. Reagan's State of Emergency after Bank of America was stormed. It's amazing there was so much unrest at little ol' UCSB back then. It was pretty well undeveloped country out there back then, for sure. The wildlife and nature must have been even more accessible than today.

Don't worry about following me off-topic. My forum braddahs know it is not easy to contain my contributions.
P.S. I like the Eliot quote in your tagline. That's me.

[Big H]

We like following along Billie.....riding the conversation like a wave letting it tell you which direction to go!

[billie_morini]

Big H,
Mahalo, brah!
shoots den,
billie