To triangulate your position when backpacking, hiking, sea kayaking, ocean kayaking or kayak fishing, use a handbearing compass, the kind with a mirror. Sight with the compass and mirror two landmarks you can positively identify on your chart or your topo map. Take bearings from both landmarks. Choose two landmarks that are obvious and unique: a radio tower, a water tower, the top of a lighthouse, a fire watchtower or mountain peak, etc.
Using your Nav-Aid if sea kayaking or ocean kayaking, the edge of the bezel of your compass if backpacking or hiking, and a straight edge, duplicate the two bearings on your chart or topo map. If on water, mark the bearings in grease pencil. If on land, use a mechanical pencil. Where the bearings cross is pretty much your position. More or less. Not exact. But much better than lost.
Why isn’t the technique more exact?
Most experts agree the best margin of error you can expect using triangulation while backpacking or navigating a kayak is to always be at least five degrees off. There might be ferrous metals in the area or in your kayak somewhere. It’s difficult to compensate for local variation and deviation with true precision.
And bouncing around in a drifting kayak, which is basically in motion even when at rest, also complicates taking accurate bearings. Taking bearings in the field or in the woods and mountains is tricky without a finely calibrated handheld compass.
In the above example, let’s say a lost kayaker took a bearing of 335 degrees off a lighthouse to the north, a radio tower 40 degrees to the east. Assuming this is one of her better days for triangulating ranges and duplicating them on her chart, her position is somewhere within a box about a two square miles in size; on a bad day, her position lies within a larger box.
It’s not rocket science, it’s not pinpoint accurate, and it’s not a cinch. But triangulation is all sea kayaking and ocean kayaking enthusiasts kayakers have outside of a single LOP and a measurement of distance off, and a whole lot better than having no clue whatsoever where we’re at. It’s also less distracting than gps.
And besides. Outside of GPS (in itself not simple work) there’s no other where are we? technique on the water or in the mountains that eliminates as much guesswork.
—Triangulation is more accurate if your bearing landmarks are at least 20 degrees but not more than 50 degrees apart.
— It helps much if you can prevent your kayak from drifting while you take your bearings and do your chart work. Tie up to a lobster pot. Raft to another paddler who holds your kayak in position as you do your work. Get out of current and wind.
One final tip for sea kayaking and ocean kayaking: Be careful your paddle doesn’t float off while you’re triangulating your position. Paddles have an uncanny tendency to drift away when dropped…
Keywords for this story are sea kayaking, ocean kayaking, backpacking and hiking, compass use, triangulation
About the writer: fishing guide Adam Bolonsky writes about fishing and the outdoors for Sea Kayaking Dot Net and NorthAmerican Kayak Fishing.
For my next post is a review about The PNW Ultralight Backpack. Will also be having a contest soon.