Crossing Current

Guiding Principle – Most kayakers can paddle around 3 knots. Currents can be much faster than that on the sea, throw in some wind and some swell, and they can change a paddle from a leisurely cruise to a white knuckle experience. Adjusting for current through dead reckoning and piloting are critical to good seamanship.

Performance Objectives –

Paddlers should plot a course adjusting for current.
Paddlers should use piloting to cross current
Paddlers should determine ETA when crossing current.
Paddlers should demonstrate where to find tide and current information.

Materials:

Props for ranges/transits
Eldridge/Reed’s
Scratch paper and Pencil
Orienteering compass/parallel rules/Nav-Aid
Photocopy of Charts
Varying difficulty of problems depending on knowledge and skills of paddlers.
Moving water

Content:

Crossing current using piloting:

Ranges/Transits:

Line up two fixed points and keep them stationary in relation to one another.
Requires constantly adjusting heading in relation to current and destination

3. Monitor progress using auxiliary ranges/transits.

Crossing current using dead reckoning:

Draw a line from departure point to intended arrival point (rum line)
Find distance and determine estimated crossing time w/o current
Determine direction and speed of current at intended time of departure (Coastal Pilot such as Eldridge/Reeds).
Draw the direction of current from departure point (set)
Determine the distance set and mark on set line
Draw line from distance set to arrival point. Bearing of this line will be heading. Length of this line will be ‘real’ distance traveled and time for crossing can be estimated.

Crossing current in the real world, the art of navigation:

The reason navigation is an art. In reality, we often use a combination of piloting and dead reckoning when crossing a current. We consult tide and current tables and have an idea what the water will be doing when we intend to cross. We may plot a course ahead of time if the currents and/or the crossing are significant. When we get to the crossing, we look for cues like:

Current flowing past lobster/navigation bouys. Near and far away.
Path of boats working or traveling across crossing
Direction and velocity of the wind especially in relation to the current.
Distinct or indistinct eddy lines, swirls, boils, foam, and general water texture.
Direction and size of swell, especially breaking waves

Once we start the crossing, we find the intended course, determine whether to paddle upstream and use the current, or to cross right there. We keep track of ranges/transits to monitor our progress. We also look at other kayaks in our group/shoreline behind us to monitor progress.

AND we are constantly thinking: Where will we go if the shit hits the fan.

Practice, practice, practice – even when you don’t need to b/c someday you will.

Where to find current information:

Information on tides and currents is published in a number of different locations in print, online, and on computer software. It takes practice to interpret this information from printed tables. Paddlers should be aware that what happens in the real world can vary considerably from published information.

Computer software:

Tasks/Activities:

Assign a crossing current problem to students. Be sure that they have plotting a course down before they attempt this exercise. The difficulty of the problem should depend on the ability and experience of the students.
Start with hypothetical situation with current at right angle to desired course and nice even numbers.
Move to current at differing angles but keep crossing relatively short.
Finally, crossings of multiple hours, solving the problem for each hour.

Assessment Tools:

Paddlers should know what a range/transit is and how to apply them to crossing a current.
Paddlers should know how to plot a course.

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