How to solve a tide height using the rule of twelves

The Rule of Twelves Tide Plot Curve

Here is a tide curve plot for any tides that follow the rule of twelves (note that none do exactly but it can be a decent rough approximation for some semi-diurnal locations).

Tap on the image and you can download a PDF that you can print out, laminate and keep on your boat with erasable markers.

A rule of twelves tide plot

A rule of twelves tide plot

NOTE:

If you are going to use this you had better make sure that the tide at the location of interest actually approximates this curve. Too many sailing instructors and sailing associations teach that tides follow the rule of twelves. They DO NOT. It can be a decent approximation in some circumstances. You are far better off to use an actual plot for that location using real data.

 

Below are some good example problems with solutions to follow so that you understand exactly how to use a tide curve. The QR scan code will lead you to these problems as well. Thus, if you forget and you are on your boat, just scan the QR code with your mobile phone and the example problem will show. A QR code scanner is being embedded into the new NauticEd Sailing App .

Solve this tidal problem

Another tide problem

Take our Coastal Navigation sailing course to REALLY understand tides

Author

  • Grant Headifen

    My vision for NauticEd is to ensure that families and friends get out on the water not only safely but with true COMPETENCE, confidently savoring every moment of their valuable time.

    Achieving this means being the pinnacle of sailing and boating education—offering comprehensive multi-media theoretical instruction coupled with hands-on, on-the-water training through our global network of American National Standards Instructors. We steadfastly avoid becoming a mere certification mill; our focus is on delivering genuine competence, ensuring our students are well-prepared for enjoyable, real-world boating experiences.

    View all posts
Search for a topic.
Last updated on February 3rd, 2023