We have developed a data logger to record the speed, course, and wind speed/direction simultaneously for the “Transitioning to Low Carbon Sea Transport” project in the Marshall Islands implemented by GIZ. The recorded parameters can be used to create polar plots to compare the performance of different sailing vessels. The device is open source, arduino based and works off-grid:

Data logger mounted on the kubaak of a traditional Marshallese canoe (Photo: E. Kokmeijer)

The logger can be mounted to any vessel. One of the first tests were done on Proasis:

Unfortunately, the conditions were not favorable with off-shore winds and lots of shifts in strength and direction (the wind shifts can be seen as the wavy course lines on the upwind tacks).

Due to the bad conditions and the limited number of data sets recorded, the polar plot can only be seen as rough estimate of Proasis performance:

The top speed was recorded at 11.7 knots so far. This video shows sailing at 8-9 kn:

The upwind performance, especially the tacking angle, is something we are not happy with yet. There are two main reasons for the upwind issue:

  • The sail we use right now is a 30€ second hand polytarp sail with lots of wrinkles, and a shape far from ideal. Its to small too. We will make a better one for the 2022 season.
  • The leeboard was built 30% smaller than designed as we found out recently. Due to unknown reasons we have made it smaller, maybe we should check the drawings more often. A larger one requires a larger mount too, so its a lot of work. We will most likely do it spring 2023.