The tides are the breath of the ocean; understanding them is about more than just knowing when high water is; it’s about efficiency, safety, and making sure you always have water under your keel. For sailors used to the steady levels of Lake Zurich, Lake Zug or Lake Geneva, the massive tidal ranges of the Atlantic can be a shock. Understanding tides is one of the single biggest steps in converting your lake skills into offshore competence.

For those who want a refresher—or if you missed our recent talk on tides—here is a summary of the key concepts we covered.

Why Tides Matter

Tides affect us in two ways: vertically (height) and horizontally (stream/current).

• The Positive: They provide “free horsepower” when the stream is with you and allow access to shallow harbours at high water.
• The Negative: They can leave you high and dry if you miscalculate, slow you down if you fight the current, or create dangerous sea states like “wind-over-tide”.

What Causes Tides? (The Earth, Moon & Sun)

Tides are essentially a tug of war between the Earth, Moon, and Sun.

• The Primary Driver: The Moon has the biggest influence because it is closer to Earth. Gravity pulls the water into a “bulge” on the side facing the Moon, and then pulls the Earth into this bulge, leaving a corresponding high-tide bulge on the far side of the planet.
• The Sun’s Role: While less powerful than the Moon regarding tides, the Sun reinforces or counteracts the Moon’s pull depending on their alignment.

What is the difference between Spring and Neap Tides?

Understanding the phase of the moon is your first step in predicting the tidal range.

• Spring Tides (Big Range): Occur at New Moon & Full Moon. The Sun, Moon, and Earth line up, combining their gravity to create higher highs and lower lows.
• Neap Tides (Small Range): Occur at the Quarter Moons. The Sun and Moon are at 90° to each other, partially cancelling out their forces. This results in lower high tides and higher low tides.

Tide Tables

Tide Tables are published by most ports (or can be looked up online) and contain the information of High and Low Water and the tidal heights of both High and Low Water. Be careful with the times as they are usually in the local times and do not adjust for “summer time”. In the summertime, you may have to add an hour to get the correct time.

Navigation Essentials: Height & Depth

When planning a passage, remember that charts use Chart Datum (CD), which is usually the Lowest Astronomical Tide (LAT)—the lowest the tide is predicted to fall under average conditions.

• The Formula: Actual Depth = Charted Depth + Height of Tide.
• Drying Heights: Watch out for underlined numbers on the chart; these are rocks or banks that dry out at LAT.

Glossary of Essential Tidal Terms

• LAT: Lowest Astronomical Tide (lowest possible tide under normal meteorological conditions)
• Chart Datum: Depth of Water (or Drying Heights) at LAT.
• MHWS/MLWS: Mean High/Low Water Springs
• MHWN/MLWN: Mean High/Low Water Neaps
• Spring Range (average): Is the range between MHWS and MLWS
• Neap Range (average): Is the range between MHWN and MLWN
• Depth of Water: Tidal height + Depth Below Chart Datum or Tidal Height – Drying Height
• HAT: Highest Astronomical Tide (Highest tide possible under normal meteorological conditions. Clearing height under bridges are from HAT)
• Height of Light: Height of the light signal above MHWS

The Rule of Twelfths (How to calculate tidal heights?)

For semi-diurnal tides (like we have in Europe/Atlantic), the tide doesn’t rise at a constant speed. It follows a bell curve. To estimate the height at a specific hour, use the Rule of Twelfths:

1st Hour: Rises 1/12th of the range
2nd Hour: Rises 2/12ths of the range
3rd & 4th Hours: Rises 3/12ths (max flow)
5th Hour: Slows to 2/12ths
6th Hour: Finishes with 1/12th

Note: The Rule of Twelfths is an estimation for semi-diurnal tides and should not replace official tide tables for critical clearance

Rule of 12ths Calculator

Estimate tidal height between High and Low water.

Low Water (m)

High Water (m)

Total Tidal Range: 3.0m

Tide flows fastest during Hour 3 & 4

Tide vs. Current: Understanding Tidal Streams

Never ignore the current. Tidal streams can significantly alter your ETA and safety.

• Tidal Diamonds: Look for the magenta diamonds on your chart. These refer to a table giving you the “Set” (direction) and “Rate” (speed) of the current for each hour relative to High Water.
• Tidal Atlases: Visual guides with arrows. Thicker arrows mean stronger currents. Remember that numbers like “12, 23” on these charts often mean 1.2 knots at Neaps and 2.3 knots at Springs.

Meteorological Effects

Meteorology: Tide tables are based only on the movements of celestial bodies (astronomy). They cannot predict the weather. Real-time conditions can change the water level significantly:

• Air Pressure: High pressure pushes down on the sea surface, lowering the water level. Low pressure (depressions) allows the water to rise. A difference of 30 hectopascals can change the sea level by ~30cm (one foot).
• Wind: (Storm Surges): Strong, sustained winds blowing onshore can “pile up” water, creating higher-than-predicted tides. Conversely, offshore winds can push water away, resulting in unexpectedly low tides—a danger for shallow moorings.

Dangers to Watch For

1. Wind over Tide: When the wind blows against the tidal stream, it creates steep, choppy, and dangerous waves.
2. Tidal Races & Overfalls: Fast water squeezed around headlands or flowing over uneven seabeds can cause turbulence. Avoid these when the tide is running hard.

Summary

Safe navigation relies on understanding these cycles. Know your Moon phase (Springs vs. Neaps), check your stream (diamonds and atlases), and always ensure you have enough water under the keel (Rule of Twelfths).

Want to put this into practice or learn more? Join us on one of our activities this coming summer.

The post Sailing Tides Explained: A Guide to Springs, Neaps & Not Getting Stranded appeared first on All Winds Adventures.

Learning to Windsurf Foil has been something I’ve wanted to do for quite some time. I first discovered Windfoiling back in 2000 when I saw Rush Randle and Kevin Ozee foiling at Lower Kanaha in Maui. The rudimentary foils they were using then were often to be seen sitting in the then Neil Pryde Maui (now Adventure Sports Maui) store. But, at that time the foils were heavy and unrefined constructions far from the equipment that is available to any of us these days and not available for the general public to try at all.

Fast forward 20 years, and foiling has become available to the masses. There are a number of brands offering windsurf-specific or crossover foils, and there is more equipment coming on the market on almost a daily basis.

I first tried foiling myself in 2017 on one of the original Bic Foils. My first session was what I considered to be reasonably successful, as I managed to fly for about 200m with relative ease. A couple of months later, I tried again on an RRD Foil, which was a complete disaster with a lot of crashes and no sustained flight. Third time is the charm they say and on holidays in Cabarete, I rented a foil and got some tips from ex-PWA pro Andy Pusch which saw me getting some sustained flights by the end of the session.

Lately, with the delivery of my Smik Mongrel and Slingshot Hoverglide windsurf foil, I’ve been getting out on the water as much as possible and spending a lot of time learning to windsurf foil.

Setup

In general, you want the centre of lift of the front wing between your feet. If you are overpowered, then you can set the foil backwards (or your foot straps or mast foot forward). This reduces the lift on the foil and helps you set down if you need to. In lighter winds, setting the foil forwards (or the foot straps/mast base backwards) will help give you more lift. As a basic rule, I have found it easier to sustain height with the centre of lift of the front wing situated between my feet.

Most of the equipment on the market today has a deep Tuttle finbox, which does not allow much movement of the foil position unless your foil offers different fuselage positions (like the Slingshot). With these boards, any tuning will be down to moving the mast foot or footstraps. Some crossover boards, like the Smik Mongrel (which I am using) have tracks for a plate-mounted foil pedestal, which allows more fine-tuning possibilities.

For learning, using a shorter mast may make it less scary as you will not rise too high, and if you overfoil (go so high that the foil comes out of the water), the resulting drop when the foil loses lift is less harsh and easier to recover. Once you are comfortable, then you can move to a longer mast, which allows more room to correct if the foil starts rising too much.

A higher boom than when normal windsurfing will help you stand up a little straighter over the foil and offer more control.

Getting Going

At this point, very small movements in your body position affect the foil. Moving very slightly back will cause you to rise (and potentially overfoil), and moving forward will cause you to touch down.

Staying Up

Once on the foil initially, I found it easier to sail closer to the wind. This makes it easier to depower the sail and control speed. As the foil accelerates, it increases lift and thus turning downwind makes it feel like you will more easily overfoil and potentially get pulled over the front. Initially, practising closer to the wind than a beam reach seems to allow more control.

Once up, it’s possible to practice controlling the ride height by pushing forward gently and allowing a light touchdown, then shifting the weight back slightly to rise again. Repeat this again and again until you start to find the balance point where the foil will stay flying steadily at a reasonably constant height with only small corrections in body position.

Initially, I sailed with no back straps, which allowed me to move my back foot if necessary to help get the balance right. After successfully getting a few sustained flights under my belt, I put the back straps on and looked at tuning the foil to sit between the straps.

Downwind

I found that once I could get steady flights upwind, it was easier to unhook and keep the sail forward on extended hands as I turned downwind. Then I could push my knees and head forward if I needed to reduce lift.

With time and a bit more comfort, you can stay sheeted in, bear away and shift your hips a little further forward to help maintain ride height without over foiling.

Mistakes

One of my own most common faults I encountered was reverting to an overpowered windsurfing technique in the gusts. When I windsurf (on a wave board) as a gust hits, I tend to drop my hips, bend my knees and make myself compact to allow the board to float over the chop, accelerate and make it more difficult for the gust to pull me off my feet. With the foil doing this takes the weight off the wing, allowing it to lift and get out of control. When foiling, as the gust hits, you need to stay upright over the board and shift the weight forward to counteract the increased lift as the board accelerates in the gust. Almost like a slalom technique, but with even more pressure into the board through quite straight legs.

Foiling has given me a newfound love of windsurfing here in Switzerland. Instead of buying an 8m sail and 130l freeride board to make use of the light wind conditions we tend to get here, I replaced my wave SUP with a windSUP/Foilboard, and now I can sail in the same light winds with my existing wave sail quiver. The learning curve of foiling is becoming addictive, and I can’t wait to get back on the water again at the end of every session.

What’s next?

Now with stable flight ticked off, I’ve been working on foiling gybes and from there who knows… That’s the beauty of foiling. For someone who’s been windsurfing for more than 30 years, learning to windsurf foil is allowing me to experience my windsurfing firsts all over again. First time planning, first gybe, first jump… It’s like I’ve turned the clock back 30 years and am experiencing my youth all over again, and I can’t wait for what the future brings.

The post Learning to Windsurf Foil – First Steps appeared first on All Winds Adventures.