The Sea Stallion’s maximum speed

The task here is to find out how fast The Sea Stallion can actually sail. Download, unzip and open the navigation data from the voyage. Go through the table and find the absolute maximum speed measured during the whole voyage or on a particular stage.

  • Source criticism: What can be said of the recorded maximum speed? Is it a momentary record, which was perhaps due to the error inherent in the GPS, or due to the ship, and the GPS antenna with it, being thrown forwards by a wave? Analyse the speed in the seconds and minutes prior and subsequent to the point of maximum speed and see if it is a realistic reflection of the ship’s speed.
  • Try averaging the speed over the course of, for example, 15 seconds. What is the maximum speed now?
  • At which wind speed and sail setting does the ship sail fastest?
  • Or conversely: What is the maximum speed with various wind speeds and various sail settings?


As a rule of thumb it is normally said that a displacement vessel (i.e. one that does not plane on top of the water) has a theoretical top speed(Vmax) in knots which is dependant on its length at the waterline (Lv1) in feet according to the formula:

Vmax = 1.34*√Lv1

  • What is The Sea Stallion’s theoretical maximum speed?
  • How does this correspond to the recorded top speed on the voyage?