Understanding how to read nautical charts is one of the most important skills for safe sailing. These special maps are packed with information about water depth, hazards, landmarks, and routes. In this guide, we’ll break down the essentials so you can confidently plan and navigate your sailing trips. What Is a Nautical Chart? A nautical chart is a map designed for marine navigation. Unlike road maps, charts show: • Water depth (in metres or feet) • Underwater hazards (like rocks or wrecks) • Buoys and markers • Tides and currents • Navigation routes • Shorelines and land features You can get nautical charts in two main formats: • Paper Charts: Good backup for electronic failures • Electronic Charts (ENCs): Used with chartplotters or navigation apps Key Features on a Nautical Chart 1. Depth Contours and Soundings • Numbers on the chart show how deep the water is at low tide • Depths may be in metres (UK) or feet/fathoms (USA) • Shaded areas often indicate shallow zones 2. Navigational Aids • Buoys: Floating markers that guide you through safe water • Lighthouses: Mark coastlines and hazards • Daymarks: Fixed signs used during daylight Learn the IALA buoyage systems (Region A for UK/Europe, Region B for USA/Canada) to understand what each marker means.
5. Compass Rose • Shows true and magnetic north • Helps you set and follow courses How to Use a Nautical Chart Step 1: Identify Your Starting Point and Destination • Use known landmarks, marina names, or GPS coordinates Step 2: Plot Your Course • Draw lines between waypoints • Avoid hazards and shallow areas • Plan alternate routes in case of weather or tide changes Step 3: Check Tides and Currents • Use a tide table or app • Tidal height can affect where you can safely sail Step 4: Use a Parallel Ruler and Dividers (for paper charts) • Measure angles and distances • Compare with the compass rose Some Electronic Charting Tools Many sailors today use apps or chartplotters with GPS: • Navionics (available in UK/USA) • iNavX • Savvy Navvy • OpenCPN These apps provide live tracking, tide data, and automatic route planning. But don’t rely solely on tech—always carry a paper chart and compass as backup. Tips for Reading Charts Safely
• Always know where you are: Check your position often • Understand chart symbols: Use a legend to decode icons • Watch scale and zoom: A small detail may be missed when zoomed out • Stay updated: Charts can go out of date—check for updates • Practice regularly: Get comfortable plotting on paper even if you use electronics ⸻ Helpful Chart Resources • UKHO (UK Hydrographic Office) • NOAA Nautical Charts (USA) • Navionics App • OpenCPN Free Navigation Software • IALA Buoyage Explained ⸻ Learning to read nautical charts gives you greater freedom and safety on the water. With a bit of practice, you’ll be able to navigate confidently, plan better routes, and avoid trouble spots with ease. Stay sharp, and happy sailing! Step 1: Learn the Parts of a Sailboat Before you start sailing, it's important to know your boat. Which 'pieces of string do I pul and what is the pointy end called?" That sort of thing. Here are some key parts:
Knowing these parts will help you when you finally get on the water. A great and easy to read book for pre-sailing (and one you can take with you) is the RYA Competent Crew Handbook.
Adjusting your sails based on the wind direction is called 'sail trim'. The better your trim, the faster you sail. Step 3: Safety First Of course, you are not going to go sailing on your own or without a competent companion. But even if it's just to make sure you bring the right clothing, always check the weather before you go out. Always wear a life jacket, and tell someone your sailing plans. Never go to sea without a VHF radio. Bring along useful gear like:
Step 4: Learn Basic Manoeuvres You can sail most sail boats in any direction except for into the wind or very close to that angle (say 30 - 40 degrees either side of the true wind direction). Basically then, you can sail from about 35 degrees 'off' the wind direction all the way down to the direction of the wind (known as a 'run'). You can do this with the wind on the right hand side (or 'starboard' side of the boat or with it on the left hand side ('port' side of the boat). When going from the wind being on one side of the boat to the other, we need to turn the boat through the wind. Turning the front of the boat (the 'bow') through the wind is called 'tacking'. Turning the back (or 'stern') of the boat through the wind is called 'gybing'. Tacking is safer and more common, especially in strong winds. Step 5: Practice Steering and Sail Control Use the tiller or wheel to steer. Push the tiller away from you to turn the bow toward the wind. Pull it toward you to turn away from the wind. If you have a wheel and not a tiller, then it works just like a car. Turn right and go right. Turn left and go left. Control your sails with sheets (ropes attached to the back corner of the sail - 'the clew' - that adjusts sail angle). Pull in the the sail to go upwind, loosen it to go downwind. Watch your tell-tales (small ribbons on the leading edge, belly and back edge of sails). If the tell tales on the leading edge flutter, adjust the sail angle. In very basic terms, when sailing on a beam reach (wind at 90 degrees to the boat) or 'higher' - i.e. closer to the wind direction - you want the tell tales on the leading edge (also called the 'luff') to be flying on both sides of the sail. If the tell tales on the 'leeward' side of the sail (the side facing away from the wind direction) flutter, ease the sheet to let the sail out until they start flying horizontally. If the tell tales on the 'windward' side (the side fronting the wind) are fluttering, pull in the sheet to trim the sail in more. When the tell tales are flying on both sides of the leading edge you have the beginnings of a well-trimmed sail. A good basic is to remember two things when trimming sails;
Step 6: Try Short Trips First Start with short sailing trips in calm water. Practice tacking, gybing, and trimming the sails. Keep out of the way of other boats and make sure you know the basics of the 'rules of the road' for sailors. Stay close to shore in water deep enough for your boat - remember tides! Get used to how the boat reacts to your movements. The more you practice, the more confident you’ll become. Make sure to have an instructor with you. Step 7: Take a Sailing Course
One of the best ways to learn is by taking a class. Sailing schools teach:
Step 8: Keep Learning and Exploring Once you know the basics, you can try:
Sailing is a lifelong skill. Every day on the water is a school day, so just get started! Many sailors will rarely do more than short day-sails throughout their sailing career. And that’s fine. For the more adventurous, the idea of longer voyages soon becomes appealing. In fact, many students consider their night sailing to be the highlight of their course.
Even then, many night sails don’t require a watch system. But if your voyage is going to be over 18 hours or more, it’s worth putting in place some sort of watch system, especially if conditions are challenging. This helps keep people safe from exposure on deck and allows for equal rest for all, even if that isn’t always sleep. In this video, we talk you through how to calculate and plot and Estimated Position (EP). We have no allowed for the application of variation and deviation, so as to keep this simple. There is a link in this video to a tutorial showing how to apply variation and deviation. In this short video, we bring it back to basics. Once you have appraised what you need in terms of charts, pilotage books and almanacs, etc it's simply a matter of working out how long the passage is likely to be (an estimate based on the distance divided by an estimated boat speed). Once you have that, work out the critical tidal windows and when you will meet them and then you will be able to plan the passage based on when you want to get there and/or when you want to leave. Remember; Appraise - Plan - Excecute - Monitor Of course, sometimes the forces of nature will not be kind and you might need to allow for a stop at some point to allow for weather, foul tide or other issues. But if you have planned well, you will know what to expect and if you brief your crew well, so will they. If you'd like to use my dynamic passage plan PDF | Click here. Tides are the regular rising and falling of the ocean surface, caused by the gravitational pull of the moon and the sun. The phenomenon of tides is a result of the gravitational interaction between the earth, moon, and sun, and is also influenced by the shape of the earth's surface and the rotation of the planet. Tides play a crucial role in shaping the coastal environment. In this post, we will explore how tides are caused around the world, the effects of the moon, sun, and geographical features on tidal flow. "I have always been fascinated by the ocean, to dip a limb beneath its surface and know that I'm touching eternity, that it goes on forever until it begins here again." - Lauren DeStefano |
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PDF DOWNLOADS![]() Build a rock-solid passage plan every time with my multi-page passage planning template. More Info.
![]() I always use a pilotage plan template when I'm entering a port I don't know well - or at night.
More Info ![]() I use this pre-departure checklist both as a memory-jogger and also as a delegation tool. Delegate the completion of this form to crew and be sure they've forgotten nothing important!
More Info. COMING SOON...Bite-sized, topic-specific micro-courses for sailors. Click here for more details.
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