Neophytes call them “maps”. But any old salt can tell you a nautical chart is a different beast entirely. For starters, they’re huge, and covered with lots of weird symbols numbers. No, those aren’t the secret messages from the Illuminati for people who have read too many Dan Brown books. But those symbols mean stuff, and once you understand them you’ll never look at a body of water in the same way. Here’s why you should become a nautical chart nerd.
When I started hiking and mountaineering, I learned to read topographic maps, so I could navigate off-trail and learn to read the contours of the land to find good routes. When I started coastal sea kayaking, I needed to do the same thing: find good routes and landing spots through offshore rocks, coastal swell, and current. Unlike the land, the sea is always moving. The chart is the key to the mystery of how it moves.
The Top and the Bottom
Most of those symbols on a nautical chart describe the bottom of sea or river you’re in. They describe the depth, rocks lurking just below the surface, and channels that dry to mud when the tide is out. The shape of the bottom of the sea controls the surface behaves. Gentle wells turn into breaking waves when they hits shallows areas. Wind across deep water will cause ripples, but creates rough water when it pushes water across shallow subsurface rocks, Understanding the bottom helps you stay safe on the top of the sea.
Find the Nozzles
Nautical charts help you predict the water will do really strange things. Tide changes generate currents, and these currents will accelerate through narrow passages, form swirling eddies around headlands, and create surf waves where they pour over rock shelves. At its worst, you can end up fighting a strong current or swept into a bad spot. At it’s best, you can get a free ride and find great spots to play.
1571 nautical chart from Portuguese cartographer Fernão Vaz Dourado
Don’t Get Squashed
Nautical charts aren’t just topo maps of the sea. They’re also a road map. Giant ships ply our waterways. If you’re a kayak, sailboat, dingy, or anything smaller than an oil tanker, you don’t want to play in the middle of the interstate. Learn where the shipping channels are, and look both ways before you cross the street.
Fog
When fog rolls you’ll suddenly find yourself traveling blind. The ability to read a chart here becomes critical. Knowing directions, reading landmarks from quick glimpses through the pea soup, and knowing how to navigate by compass will keep you off the rocks.
Fish
My friend Jason, a kayak-fishing expert, always stresses that his most important piece of fishing gear is a nautical chart. It shows him the undersea rocks where fish gather, and how deep they are. There’s no point in dropping your lure twelve feet when the rock is twenty feet down.
Impress Your Friends
When the conditions get wacky, chart reading quickly goes from nerdiness to wisdom. I’ve helped groups find an offshore island in the fog, guided them through tiny passages protected from big ocean swell, and anticipated tidal rapids where none were marked.
It’s way cooler than GPS
On one long fogbound crossing off the west coast of British Columbia, I challenged a friend of mine with a GPS to see who could plot a more accurate course to an offshore island. We landed right next to each other. And a nautical chart won’t run out of batteries or short out when you accidentally drop it in the drink.
They’re Free
The government would rather not have to come get you in a bright orange Coast Guard helicopter. As a result, American charts are fee online. Now you can nerd out to your heart’s content for free. You can also download Chart #1, which tells you what all those funky symbols mean.
