It was a bright but chilly Saturday morning when twelve club members rolled up at Red Point, Jervis Bay to attend Stuart Trueman’s annual navigation weekend.
Right on 8am, just like in the army, Stuart commenced. We were given a chart of Jervis Bay. You will notice that I didn’t write “map” of Jervis Bay. A map is land-focused whereas a chart has a water or ocean-based orientation. We brought our own protractors, compasses and rulers. A member pulled out a flash new GPS, recently won at Rock ‘n’ Roll and asked, “Why do we need to know all this? Hasn’t the GPS made navigation skills redundant?”
Stuart’s reply was swift. He delivered a sermon on one of his worst paddling days in western Tasmania when he relied on his GPS for his position. He suddenly realised he was dangerously off course. He was struggling in strong head winds and he decided to return to his starting point, exhausted. You can read his harrowing account in the March 2007 issue of the magazine. Stuart says that he no longer relies on GPS on long trips. Like anything electronic, it breaks down or runs out of battery just when you need it or on Stuart’s trip he could not get a fix. Proper chart navigation and compass skills must be learned irrespective of your use of the GPS.
What is the difference between deviation and variation? Stuart showed us that deviation is the movement of the compass needle when affected by metal. To test this, we lined up our kayaks on the beach facing north. As we passed a can of beans around, the needle moved. We learned to keep metal objects well way from the compass when packing a kayak. In the process we noticed that some compasses did not show north accurately. It’s worth buying a good compass.
Variation is just a little more complicated. The acronym CMA, meaning Compass to Map Add, certainly helped. The variation is the difference between magnetic north on a compass and true north found on charts. You use true north readings when plotting a course on a chart and you need to adjust to a compass reading when paddling. For example, Sydney charts have a magnetic variation of +12 degrees. Therefore, assuming you have taken a reading of 80 degrees from the chart or True North then you must deduct the variation of 12 degrees and follow 68 degrees Magnetic North when using the compass. Stuart advised us to convert all the readings for our trips to magnetic readings before we get into the kayak.
Stuart recommended two books on navigation: “Sea Kayak Navigation Simplified” by Lee Meyer and “Fundamentals of Kayak Navigation” by David Burch.
After Stuart’s lecture he handed out an assignment. One question was to find two points on the Jervis Bay chart. It looked easy until the concept of a “bearing” appeared. When you have lost your whereabouts on the water you need to take a bearing. This requires learning to recognise land-based markers such as mountains or other fixed land markers where you can take a compass reading. For this purpose it is useful to carry a second handheld compass in your PFD. You take compass readings from the two or three fixed markers on land, translate the compass readings to take into account the variation, then draw intersecting lines to find where you are on the chart.
You need to know how long it will take to paddle a certain distance. Assuming on average you paddle 3 knots or 5.5 km per hour then you can plot where you should be after each hour, or work out how long it should take to get to a particular point. This is all very dependent on the wind and current. Your chart should give you an idea of the current and the coastal waters forecast should give you the wind speed, favourable or otherwise to your paddling time.
We jumped into our kayaks and tried to locate the plotted points. It was difficult for some of us to distinguish one headland from another and match them up with the chart. Stuart turned up with a GPS which he used to confirm that our point was out by a couple of hundred metres.
This navigation day was a great learning experience. Navigation skills are essential for kayakers.
On Sunday, we all went out for a paddle. I ended up in Stuart’s group. Our proposed route was kayaking around Beecroft Peninsula, into Currurong, then after a short portage across the road to the creek in Jervis Bay and back to Red Point. But where was that portage point? Stuart relied on good old memory and so at Currurong, after a number of surf entries and re-entries, the sun going down in the west, a swearing, bedraggled Stuart found the point on the beach leading to the road which had been marked by a big pole but was hard to see in the fading light.
We all gave Stuart a “not yet competent” marking for his navigation skills and told him to come back next year for retesting. In all, it was a fantastic paddle.
A big thanks to Stuart and his assistants, Sharon, Rob and Andrew for the weekend.