Why ocean currents belong in every sea-kayak expedition conversation

A straight line is not necessarily the travelled route

Wind, waves, current, drift and paddling decisions can make the actual track very different from the shortest line between two points. NASA’s account of the Crossing the Ditch expedition describes how the team used satellite sea-surface temperature and altimetric-current information alongside Google Earth waypoints. It also records that the journey took 62 days rather than fitting the original hoped-for timing.

The lesson for any paddler is to distinguish a map distance from the time, effort and uncertainty involved on the water. Forecast and observed conditions can change what is achievable and whether continuing remains appropriate.

Turn information into decisions with expert help

Ocean products have resolution, timing and interpretation limits. A satellite image or app does not tell an inexperienced user exactly what will happen at a launch, headland or landing. Seek current marine forecasts and local professional knowledge, and learn how to interpret relevant information through appropriate training.

Expedition planning should include alternatives, cutoff decisions and contingencies for delay. If the only acceptable outcome is reaching a fixed destination on a fixed day, the plan has removed room for safety-driven decisions.

• Compare the planned line with possible drift and actual track.
• Use current official marine forecasts and credible ocean data.
• Ask experienced local professionals about interpretation.
• Allow extra time and supplies for credible delays.
• Set decision points for changing, waiting or abandoning the plan.