Sea Kayak Navigation: Plotting Your Position With A Compass

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In an earlier post, we discussed how to use a chart and compass to find a compass bearing we could follow to a desired destination. But all those techniques for heading somewhere new require us to know where we are now. As any kayaker who’s ever done a longer crossing or paddled along a featureless shoreline can confirm, it’s easy to lose track of your precise location. How do we find it again? 

First, a quick detour into a concept called a Line Of Position (LOP). You’ve almost certainly used LOPs before, even if you didn’t call them LOPs. If you were wandering around a city (for example, Vancouver, British Columbia) with a paper street map, you might have known you were somewhere on Granville Street, but not sure where along Granville. So you walked down to the next corner and checked the signs for the cross street. Finding it was Broadway, you now knew your exact location: the intersection of Granville and Broadway. Each of those streets served as one LOP for you. Where the two LOPs intersected was your location.

A section of roadmap showing the intersection of Broadway and Granville in Vancouver, British Columbia. Demonstrating the concept of Lines Of Position.
Granville Street is one Line Of Position. Broadway is a second Line Of Position. Where they intersect is your location. See, you’re already a navigator!

To determine our location when sea kayaking, we do exactly the same thing: we find the intersection of two or more LOPs. The only difference is that we use lines other than streets as our LOPs.

Even for novice kayak navigators, there’s one Line Of Position that’s so obvious you’ve probably used it without even thinking about it: the shoreline. (Yes, most shorelines are curvy and crinkly rather than straight. But there’s no requirement that every Line Of Position be a straight line. In my hometown of Vancouver for example, Kingsway Road has lots of jinks and bends, but I can still use it to clearly define a position such as “the intersection of Kingsway and Broadway.”)

Bendy LOPs? No problem: where they intersect is still your position.

So, if we only ever intend to navigate along shorelines, why would we ever need a second LOP?

Imagine you and I and several friends are kayaking close alongside the southwest shore of North Pender Island, admiring the undersea flora on the rock wall and petting the passing Orca. Distracted by all this merriment, we’ve lost track of how much time we’ve spent paddling vs drifting. Plus, the tricky currents on this coast have sped us up or slowed us down unpredictably. So now all we’re sure of is that we’re somewhere between Boat Nook and Smuggler’s Nook. We need a second LOP to show us exactly where between those points.

A section of marine chart, showing the lines of magnetic North drawn in with red, to allow plotting Lines Of Position without adding or subtracting for compass variation.
A section from CHS Chart #3441. Look for Canoe Rock (below the purple compass rose) and Pelorus Pt (on the right/East side of Moresby Island). The red lines I’ve drawn in point to magnetic North, 16° East of truth North. (Why 16° East? The purple compass rose shows true North, magnetic North as of 2005, and a predicted change in the magnetic variation of 8’ Westward annually. So in in the 18 years since 2005, the variation is predicted to have reduced by 2° 24’ (18 years x 8’ = 144’ or 2° 24’). The variation in 2005 was 18 1/2° or 18° 30’. Subtracting 2° 24’ from that gives us 16° 6’ East. This matches pretty closely with the 15° 46’ East predicted for this area by the online declination calculator. We can round either figure to 16° East for practical purposes.)

To lay out a second LOP, we need to take a compass sighting (AKA a bearing) from any clearly identifiable location shown on the chart and visible from where we are in the real world. A lighthouse, the tip of a cape, one side of a known island, or a distinctive mountain peak would all be excellent options. 

Looking out to sea from Pender Island, we find a highly distinctive landmark to take a bearing from: the red-and-white marker on Canoe Rock. Even better, it’s at roughly a right angle to the shoreline. (It’s a good habit to pick your landmarks so that your LOPs meet at as near to right angles as possible; this creates a much clearer intersection point than sharp acute angles or almost parallel obtuse angles.)

Taking a bearing from a real-world object (in this case, the orange thingie representing the marker on Canoe Rock) using a hiker’s/orienteering compass. Step 1. Holding the compass as level as possible, aim the Direction Of Travel arrow towards the landmark. Pro tip: this is much easier and more accurate if your body is facing the landmark. Which means your boat should also be pointing in at least the general direction of the landmark. Notice that at this time, the compass bezel dial is in a random direction relative to the magnetic compass needle, with the N (for North) on the bezel not aligned with the red needle tip. 
Taking a bearing from a real-world object using a hiker’s/orienteering compass, Step 2. While keeping the Direction Of Travel arrow aimed at the landmark, twist the bezel dial until the meridian lines in the bottom have put “Fred in the shed” — that is, the red box on the bottom of the bezel is enclosing the red half of the magnetic needle, and the N on the bezel is directly in front of the red needle tip. Read off the degrees at the Read Bearing Here indicator. In this case, the bearing to Canoe Rock is 224°. (BTY, if this whole process feels exactly the same as taking a bearing to a visible landmark you want to paddle to following a compass course, that’s because…it is!)

Great. We have our bearing off Canoe Rock. So now what? So now, we’re going to transfer that bearing into an LOP on our chart.

A section of marine chart with a hiker's compass, bezel parallel to the lines of magnetic North. Showing how to draw a Line Of Position on a chart.
Using a hiker’s compass to transfer a bearing onto a chart as an LOP. We keep the bezel dialed to 224°, from when we “shot” our bearing to Canoe Rock. Keeping the meridian lines on the bottom of the compass bezel as parallel as possible to the red magnetic North lines on the chart, we put one edge of the compass baseplate on the Canoe Rock landmark on the chart. That baseplate edge is now a Line Of Position. Where that LOP intersects the shoreline is our location. In this case, the baseplate doesn’t quite reach to Pender Island, so we extend the LOP by eye and pencil it in. (Notice that we don’t care about where the compass needle is pointing now: we’re just using the compass bezel and baseplate as a protractor.)

Woot! We are unlost! We are right where the shoreline (the first LOP) and the bearing from Canoe Rock (the second LOP) meet. High fives everyone! 

BUT…

We took that compass bearing with a hand-held land compass from the cockpit of a kayak rocking in the waves (landing to take the bearing wasn’t an option on the cliffy shores). And we extended that LOP by eye from where we ran out of compass baseplate. So there have been lots of opportunities for errors to creep in. How can we cross-check our apparent position? By determining a third LOP.

Happily, our pod of paddlers includes the excellently-equipped Greta Geerweenie, so we can not only shoot an entirely separate landmark, we can do so using a more accurate instrument. Because Greta’s kayak boasts a deck compass, aligned with the keel line of her kayak. So to take a bearing, she simply aims the bow of her boat toward her chosen landmark (Pelorus Point on the east side of Moresby Island), and reads the bearing in degrees at the lubber line.

A model kayaker with a real, full-sized marine compass pointing towards a marker. Showing how to take a bearing on a landmark with a deck-mounted kayak compass.
Taking a bearing with a deck-mounted marine compass. With the kayak pointing towards the real-world landmark (the orange thingie now representing Pelorus Point), we read the bearing directly from the black “lubber line.” In this case, it’s 172°. (No bezel twisting required. Because instead of the needle on a hiking/orienteering compass, a marine compass has a floating, degree-marked dial that rotates to line up with local magnetic North.)

But Greta’s opportunities to flaunt her superior gear don’t end with the deck compass. Now it’s time to transfer the bearing she shot onto the chart as that third LOP. Rather than roughing it with the hiker’s compass, she whips out her modified Davis Protractor, complete with String™ that extends much further than the baseplate on a hiker’s compass.

A chart with string-added Davis Protractor. Showing how to use the string as a Line Of Position to determine your location based on a compass bearing to a known landmark.
Using a string-equipped Davis Protractor to transfer a bearing onto a chart as an LOP. Position the protractor’s centre point over the landmark we took the bearing on (Pelorus Point). Pivot the protractor until its North-South grid lines are parallel to the red magnetic North lines on the chart. Pull the string taut across the degree reading we got with the compass (172°) on the outside edge of the protractor. Where the string intersects the shoreline is our location. Reassuringly, it’s pretty much the same place as the LOP from the first landmark showed us. (And remember how we said we don’t care about where the compass needle is pointing for this step? The Davis Protractor doesn’t even have a compass needle to distract us!)

We won’t always be paddling with a Greta Geerweenie. But we still can (and should) cross-check our plotted position wherever possible by shooting at least two landmarks as bearings and bringing them down onto our chart as LOPs, even if we’re only using a humble hiker’s compass for everything. It’s also true that in the real world, our multiple LOPs won’t usually intersect with the suspiciously perfect agreement they have in this story: typically they’ll form a triangle. You’ll know you’re somewhere inside that triangle, and as long as it’s small enough, it will be good enough for navigation purposes.

A PLOT TWIST!

Clever readers (which is all of you, of course) will have realized something: once we’ve intersected two or more LOPs based on compass bearings, we don’t need the shoreline LOP anymore to know where we are. That’s exactly how bigger, deeper boats, who need to stay further from the shore than kayaks, do it. And exactly how you can do it as you graduate from simple shoreline paddling to longer crossings. There are even other compass-free LOPs you can use when away from the shore. But we’ll save those for another post.

Freshwater Get-away

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September 30, 2022

Wanting a trip that was low in cost and complications, we’d opted for a fresh water adventure on Alouette Lake in Golden Ears Park. This avoided the time and deadlines of ferry trips, and let three of us revisit a campsite we hadn’t been to in many years. The expedition consisted of myself, my friend Rhian, and Paul and Nessa, two longtime friends I hadn’t seen in person since before the pandemic.

Rhian and I met the other two expeditioneers at the boat launch on Alouette Lake about noonish. As anticipated, with all the faffing about, we didn’t launch until about 1:30 – just in time for the afternoon wind to have ramped up in our favour.

The fleet ready to launch. The Narrows is visible in the distance as the gap between the taller mountain on the left and the much lower hill on the right. Photo courtesy Paul Richards
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Different Angles On Sea Kayak Compass Navigation

If you’ve done any map/chart and compass navigation at all, you’ve wrestled with the inconvenient truth: with some very limited local exceptions, in most parts of the world, the needle on your compass does not point to the true North pole (the Northern tip of the axis around which the Earth revolves, also known as the geographic North pole); instead, that needle usually points to the magnetic North pole. Sort of. Because what that needle is actually doing is aligning itself with the local magnetic field of the Earth. And those local fields are heavily influenced by currents and counter-currents in the sea of molten iron that swirls far below the Earth’s outer crust.

kayak deck compass with sail reflection
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Shoulder season on the Sound: Hotham Sound

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September 30, 2021

During the drive to Earl’s Cove, heavy rain showers coated the winding road with sheets of water a centimeter deep at times. It was uninspiring, but by the time we arrived at the ferry terminal, it had cleared.

As we approached Saltery Bay on our second ferry ride of the day, we could see Freil Falls (AKA Harmony Falls) in the distance off the starboard side. Shortly afterward, the ferry crew announced whales cavorting off the port side. I snapped a couple of photos of the “you can’t quite make it out, but this black blur is a whale” variety.

The Falls in the distance
A humpback whale spyhops in the distance

By the time we’d landed it was late afternoon. Packing the boats for the first time on any trip always involves a couple of hours of faffing about, especially when you have to go park the car several hundred meters from the put-in after offloading. So we opted to car camp at Mermaid Cove that night, and make a single hop, all by daylight, to our intended destination at Elephant Point the next day.

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The Trip That Wasn’t (Part 2)

August 20, 2001

Though I had set my watch alarm for 6:30AM, when my bladder alarm went off at 3:30AM, the wind was howling fiercely through the trees and the barometer had continued to fall. I switched off the clock alarm and slept in until 8AM – which was fine: as it turns out the wind continues to blow against me and whitehorses gallop north through the passage as far as the eye can see.

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Sea kayak safety: the parallel rescue

Plenty of sea kayakers know the bow rescue – a technique where the rescuer presents the bow of their kayak to a capsizee, so the unfortunately inverted paddler can hip flick back up using the bow for support. There are many Youtube videos showing it, and it’s taught in Paddle Canada and other sea kayaking courses.

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The Trip That Wasn’t (Part 1)

August 13, 2001

Just getting to the put-in at Prince Rupert from Vancouver has proven to be an epic. I’d driven up from Vancouver to Port Hardy and camped at the Wildwood Campground. The Port Hardy to Prince Rupert ferry which was supposed to leave at 7:30AM on Sunday, August 12, had engine troubles. On the plus side, this meant I didn’t have to get up at 4:30AM to hike from the campground to the ferry terminal. Having driven over to the terminal at 7:30 and dropped my kayak and equipment, I drove back to the campground to park my car long term, and caught a lift back to the terminal in the RV of a friendly Dutch family I’d been chatting with the evening before. 

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Paddling The Past: A Fishy Tale

All fishers have tales about The Big One That Got Away; here’s mine about The Big One I Was Glad To Let Go.

One summer in the early oughts of this millennium, four of us took the MV Uchuck from Gold River into Nootka Sound, with our sea kayaks as deck cargo. My wife and I were in my double kayak; my buddy Mike had borrowed my single for the trip, and his partner was paddling another single.

Several days into the trip, we were camped on an idyllic beach with a view of the open Pacific. I borrowed back my single boat and set off in search of supper. Since I was after bottom fish, I was using a hand reel and lure, but had no gaff or net — a nearly tragic oversight, as we shall see.

a sea kayak breaks out through surf
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Valhalla Warrior: Solo Kayaking And Hiking On Slocan Lake, Part 1

July 9, 2003
The shuttle driver from Smiling Otter dropped me off with my boat and gear at the north end of Slocan Lake at about 13:00 hours. The weather was lovely and sunny.

The first few hundred yards of paddling was past beautiful summer cottages. Beneath the emerald water, I saw what I’m speculating might be Asian Milfoil growing on the bottom – a corkscrewed shape, like a drill or auger. The branches of an evergreen freshly toppled off the bank vanished into the ghostly green depths of the lake. The water was startlingly clear; in the shallower areas, I could see the shadow of my kayak flitting across the lake bottom. 

kayak from underneath rescan resized

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Predatory Rites: Finding one’s place in the Polar food chain

a tent wrecked by a bear attack

The tent post-attack. Sorry for the shaky picture; I was still pretty shaky myself.

There is nothing quite like the experience of nearly being eaten to make you appreciate how fleeting your position atop the food chain is. In the summer of 1993, I became one of the lucky few to acquire this sort of insight.

Backcountry tourists, as opposed to those who live in the wilderness, seem to fall into two equally simple-minded groups. Those of the old school are convinced that behind every bush, a predator lurks expressly for them. They are barely able to stagger down trails under the burden of rifles and grenade launchers. Late-night forays to answer the call of nature are made perilous by the razor wire and minefields they have used to “secure” the camp perimeter. These folks have delusions about their own importance in the scheme of things. Continue reading