Raspberry Pi navigation on the open seas

Difficulties

After I had demonstrated that the map navigation worked on a tablet with a Rasp Pi web application, unforeseen problems arose. I had to find a way to tie down a smartphone or tablet on board in the event of rough seas. Also, whatever device was used had to be protected from water damage caused by splashing and waves.

I used an iPad Air 2 as the navigational device. A short search using the keywords "iPad" and "boat" quickly brought a solution to light. Armor-X [10] offers water repellent iPad covers and suitable brackets. One of the brackets was even originally designed for mounting on the handrails of a boat.

The end result of the search efforts was an iPad Air 2 that had been packed into a water-repellent cover and mounted on the control column, making it impervious to rough seas and wind (Figure 7).

Figure 7: A bracket secures the iPad in place while it carries out its duties.

Outlook

One positive indicator for the future is that Vogel does not consider avNav complete. When asked about the feature wish list in a sailing forum, he regularly requests additional input from users. A good example of his approach is found on the topic of wind measurement. Modern plotters can use wind information for navigation when it is captured by a wind measuring device.

Wind data indicates current wind direction, which is of course important for maneuvers such as turning and jibing. It can also indicate how a captain should navigate to reach a target location in the most efficient manner possible. When sailing, the issue is to find the route currently permitted by prevailing winds instead of choosing a route simply because it is the one desired.

The topic of wind measurement and display is still not part of avNav. However, Vogel has explained that the feature has been placed on the wish list and he needs help from users who have a wind measuring device on board. Therefore, as soon as he finds a good test candidate, he will address the topic more thoroughly. Further development of avNav is ongoing in other areas, too. As I submitted this article for print, Vogel had announced to the sailing forum that he had recently reworked the visual interface for avNav and was looking for feedback.

In closing, avNav offers a perfect example of the possibilities that open source software has created. Hopefully, Vogel will want to work on his program for a long time to come.