Questions And Answers

What is Sailaway?
Sailaway is a sailing simulation game from Orbcreation B.V.. It can be obtained on their website https://sailaway.world/

What is a polar diagram?
A polar diagram describes the boat speed in nautical knots (kt, nautical miles per hour) a specific boat can sail at a specific wind speed and a specific wind angle (TWA, True Wind Angle).

What is a polar file?
A polar file is a text file in CSV format. It contains a table of a boat´s maximum speed at different wind speeds (columns) and different wind angles (TWA, lines).

Why do I need polars for Sailaway?
If you decide to compete in a (long distance) sailing race you should be able to anticipate the fastest route to your next destination. Tools like QTVLM do a great job here using weather gribs and the secific polars of your boat. The more precise the polars are, the more accurate is the predicted route. You can import and use the polar files from this site in QTVLM.

Where can I download QTVLM and how much does it cost?
QTVLM is free for download here: https://www.meltemus.com/index.php/en/download.

How exactly does routing in QTVLM work?
That can´t be explained in two sentences here. A good starting point are some Youtube videos explaining the use of QTVLM with Sailaway: https://www.youtube.com/results?search_query=sailaway+qtvlm - the official Sailaway Discord is another good resource: https://discord.gg/Cykyns

How can I load a polar file in QTVLM?
Open the menu `Boat` - `Boat(s) settings` - `Polar` - `Import Polar` and select the downloaded polar file.

How can I visualize a loaded polar file in QTVLM?
Open the menu `Boat` - `Wind Polar analysis` to see a visualisation of the boat´s polar. You can vary the wind conditions at the top right of the window.

How can I contribute to make specific polars better?
Find some people and organize a Sailaway race for a specific boat. Telemetry of all participating boats will automatically be tracked and enhance the quality of the polar files.

How exactly does this polar database thing work?
A script generates a list of racing (and moving) boats (updated daily). Every 60 minutes, each of these boat´s speed, TWA and wind speed is retrieved from Sailaway´s API server. These values are written to a database file. Another script generates the polar files (daily at 01:00 UTC)

How acurate are these polar files?
Good polar files should ba a) complete and b) reflect realistic values. For a) we have to collect each boat speed of each boat type under every possible wind condition (combination of TWA/wind speed). For b) we should collect as many data points as possible for every contition from a). "Database Statistics" (in the navigation bar on the top) should give you an overview over the state of this database.

How high is the resolution of the polar files?
Wind speed goes from 4 kt to 38 kt in steps of 2 kt. TWA goes from 30° to 180° in steps of 5°. So 558 data points are required for a complete polar file for a specific boat.

What about missing values, how does QTVLM handle them?
Whites are valid (value = 0.0) but discouraged. Source: https://wiki.v-l-m.org/index.php/QtVlm_Polar_Diagram

Why are the links in this list not clickable?
Because I have no idea how to embed a <a href=...> link in a dictionary handed to a Flask HTML template. Perhaps you can help me? Workaround: Mark the link text and open in new tab with a right click.