Fine-Tuning the Navigation Algorithm

The algorithm has become pretty complex and I use a visualization to simulate how the boat would behave at different locations on the ocean in different wind conditions. It helped me fix tons of small bugs which I couldn’t find by real testing. Here are some interesting points:

  • The boat can’t sail straight upwind or downwind. In unfavorable wind conditions, it will keep the heading at least 45 degrees to the wind.
  • If the wind conditions are unfavorable for some period of time, the boat will follow a zigzag pattern. This way, it can sail upwind as well as downwind.
  • If the boat deviates from the shortest path, it will get back to the path rather than going straight to the destination.
  • It’s most important to minimize the flap adjustments as we are limited by the actuator life-span.
  • The boat reacts to the change of the wind almost instantly if the change is confirmed in 3 seconds.
  • Most of the time, it will head to the destination plus/minus 7 degrees. There is some tolerance in order to avoid constant steering.

How the Sailwing Works

This video shows how the sailwing is being controlled by the flap just like an airplane wing.

A powerful fan is blowing air onto the sailwing. When the autopilot sends a wireless command to the actuator that moves the flap, the sailwing starts moving until the flap points in the same direction as the wind is blowing. This way, a relatively small force is required to move the massive sailwing. As Archimedes said: “Give me a lever and a place to stand and I will move the Earth.” Practically, only a 10-degree sailwing adjustment is needed to provide the maximum lift, but as you can see, even 45 degrees is possible. To me, it looks like magic.

Who invented it?

This invention dates back to World War II (Fin Utne’s boat Flaunder destroyed by the war) and was used on some manned yachts in 1990’s (Walker Wingsail). Today you don’t see yachts like this, because traditional sails seem to be more economical. However, an autonomous boat with a wing/tail system came to light in 2004 (the Atlantis project, University of California, Santa Cruz). It’s kind of resurrecting a decades-old technology. Now I’m relying on it to cross the Atlantic.

(Source: Catalyst, N16, 2004, Catalyst, N17, 2004, A.Y.R.S. No. 14, 1957)

The Boat Has Got Wheels!

This aluminum support makes the boat easy to transport from my warehouse into the van and then directly into the water. Maybe I will use it for the official launch from Newfoundland, just need to find a suitable launch ramp for small boats.

Successful Test

The boat got wet for the first time and it went awesome! Although the wind wasn’t high enough to make thorough tests, the boat was moving through the waypoints. Below is a link to the tracking map from testing on a lake.

When you hover your mouse over any green dot, you will see plenty of data. The same amount of data will be transmitted from the ocean. To see a short explanation, hover your mouse over any data displayed on the right.