Gear: PredictWind automatic wave routing

The app has added an automatic wave-routing feature that will factor in the boat’s beam, waterline length, draft and displacement and calculate the most comfortable route in a head or following sea.

“Experienced sailors instinctively know that wave conditions can have a dramatic effect on the boat’s performance,” PredictWind said.

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“How the waves affect your performance is now auto-calculated in the routing algorithm so you can benefit from a more accurate, safe and comfortable route.”

PredictWind’s routing software can then calculate the roll, vertical acceleration and “boat slamming” incidence – how often it will hit or fall off a wave – and display the results on the weather table alongside wind, swell and wave data.

PredictWind’s route planner already can account for prevailing weather to help skippers steer around bad weather. 

Roll is the side-to-side movement of a boat, with a comfortable roll – one where gear on a deck is not likely to move around – limited to around 4.0 degrees.

Vertical acceleration – the common cause of seasickness – is related to the G forces acting on someone as the boat moves up and down. Things start to become uncomfortable on a boat at around 0.2G.

Slamming relates to the bow of a boat rising out of the water and then slamming back down on the water with a fair bit of heat as it comes off the wave. A slamming rate of around once every 30 seconds is considered uncomfortable for the crew and potentially dangerous for a boat.

Annual subscriptions for cruising packages for PredictWind start from $5.99 a month or $44.99 a year for a basic plan, up to $159 a month for a professional account. A standard plan, best suited to cruising, costs $77.99 a month.