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Recently (March 2002) I have seen and heard some very misleading comments about the best way of crossing Banks Strait in a kayak, allowing for the tidal currents. The map shown is not drawn to scale, but just to give a rough illustration of what is involved in my thinking. The blue lines (labelled A,B,C,D) show the general direction of the current flow, running from east to west when flooding, and west to east when ebbing. The green line is magnetic north/south.

Assume there is little wind to speak of.

If I am starting at Little Musselroe and want to go to Rebecca Bay (Clark Island) I would measure the straight line distance (about 12 nautical miles) and say that would take me between 3 and 4 hours (a group more likely 4). This route is along the green line. Now it depends on which direction I want to go from Rebecca Bay as to when I would leave Little Musselroe.

If I want to go on to Preservation Island, and round the western side of Cape Barren Island, I would leave Little Musselroe Bay 2 hours before low water and steer Magnetic north. The first 2 hours the current would take me out to the east of the green line, the next 2 hours would bring me back to it, and as I approach the shoreline of Clarke Island the current will be taking me sideways (A) towards Preservation Island. If on the other hand I was proposing to go up into Kent Bay and round the eastern end of Cape Barren Island, I would leave 2 hours before high water. Then as I approach Clarke Island, the current will be sweeping me sideways round Moriarty Point in the direction I wish to go.

In either case you are basically paddling at right angles to the current, so it has no effect on the time you take to cross to Clark Island. This is basically the shortest distance across Banks Strait, although it is slightly shorter if you start from Swan Island. This plan takes you almost into Rebecca Bay where you can land easily should you have any emergency on the way over.

If there is a wind, then this may alter my plans. A fresh westerly wind would allow me to sail, but I would make leeway to the east - therefore I would probably leave at low water and let the leeway and the west flowing current cancel each other out, and my course then hopefully would be straight along the green line, and as I neared Clark Island I would head alongside the island towards Preservation Island. Keep in mind that when the weather forecasters talk about westerly wind they are talking about due west, not magnetic west (14 degrees difference).

However, if I was on Swan Island, and wanting to go to Preservation Island, and on up to Trousers Point on Flinders Island I would use a different plan. If I was on Preservation Island and wanting to cross to Little Musselroe Bay I would use a different plan.

To go from Swan to Preservation I would probably leave an hour before low water and still paddle magnetic north. After an hour I should be past line C and getting towards B as the tide starts to sweep me to the west. Keep paddling magnetic north and keep cutting across the line of the current at right angles till you are swept sideways to the west side of Clarke Island. By this time you should be into line A which is now helping you go in the required direction.

Recently I paddled from Preservation Island to Little Musselroe Bay, the last 2 hours after the sun had gone down. We left Preservation about an hour before high water, and kept a course magnetic south. After 2 hours (as the sun went down) we were approx magnetic south of Preservation Island about line B - the first 2 hours cancelling each other out as far as drift sideways goes. Then we would have been starting to be swept sideways faster and faster in an easterly direction, still paddling magnetic south. Eventually we were close to the shoreline and found that Little Musselroe Bay was directly in front of us (see trip report ).

Of course, some days the tides just aren't at the right time to do all the above in daylight hours, and you will have to go on the 'wrong' tide, and arrive at the other side with the tide flowing in the opposite direction that you would have wished for - as in the trip report above, on the first day. We arrived at Spike Bay with the current starting to run against us - but the forecast for later on in the day, on the correct tide, was bad. If we hadn't paddled early in the morning when we did, we would not have crossed Banks Strait that day at all, or for the next couple of days.

The point I am trying to get across is not to just blindly allow 2 or 3 hours of tide in each direction - it depends on where you are starting from, and where you want to finish up - and roughly what your speed is. For instance a double would probably take less than 3 hours to cross from Swan Island to Rebecca Bay, so would only allow one and a half hours of current flow in each direction. So think about the blue current lines, and work it out for yourself, always keeping in mind what the current is going to be doing as you arrive at the other side, when you may well be starting to tire.
Laurie Ford.