CastScience

Terms, privacy and credits

Use of the app

Not for navigation. Use official charts and your chartplotter.

CastScience gives estimates to help plan a fishing trip. It does not judge whether conditions are safe, and regulation summaries are not the official regulations.

Wave height estimates: accuracy and your responsibility

CastScience estimates wave height from the forecast wind over the water, the distance of open water upwind (fetch) and the water depth, using the U.S. Army Corps of Engineers Shore Protection Manual (1984) method. The figure shown is the significant wave height: the average of the highest third of the waves. The largest wave in about an hour is typically 1.86 times that figure.

These are estimates, and they have not yet been checked against measured waves on this lake. Known sources of error:

  • Forecast wind: a wind 3 mph stronger than forecast raises wave height 13 to 20%.
  • Wind over water: the over-water wind is estimated from land forecasts with a factor that is still an assumption. Using 1.3 instead of 1.2 raises wave height about 8%.
  • Method: two standard methods give heights 6 to 16% apart at these depths and distances.
  • Not modeled: gusts, sudden wind shifts, boat and ship wakes, waves reflected from breakwalls and seawalls, and steeper waves where current runs against the wind, such as at river mouths and in shipping channels.

Combined, actual waves can be 25% or more higher than shown.

Before and during every trip:

  • Read the current National Weather Service marine forecast for your area and check for a small craft advisory.
  • Check recent buoy or shore observations where they exist.
  • Look at the water at the launch, and keep watching it. Conditions can change within an hour, especially when a front passes.
  • Know your boat, its load and your experience.

The decision to go out, where to go and when to come back is the boat operator's. CastScience provides estimates to help plan, not a judgment that conditions are safe.

Privacy

  • Without an account, your settings and your last plan are kept only on this device, in the browser's storage.
  • With an account, CastScience stores the sign-in provider's user id, your saved setups, your plans and your logbook. It does not store your email address.
  • Sign-in is run by Clerk (clerk.com), which keeps your email address to send sign-in codes, and a sign-in cookie on this device. If you sign in with Google, Google gives Clerk your name, email address and profile picture.
  • Logbook positions are private: only you can see them.
  • Your position on the map (location button) is shown on this device only; it is not sent to CastScience.
  • You can download everything stored for you, free, on the Account page. Deleting your account there removes your data from CastScience and your sign-in account from Clerk.
  • No tracking or advertising scripts run while advertising is switched off. Before any ads run, a consent notice will ask where the law requires it.

Credits

  • NOAA: Great Lakes Environmental Research Laboratory (GLSEA lake temperature), National Data Buoy Center, National Weather Service, Climate Prediction Center, Office of Coast Survey (charts), National Centers for Environmental Information (climate normals)
  • Iowa Environmental Mesonet (airport weather history)
  • OpenStreetMap contributors (launch positions, base map)
  • Protomaps (base map tiles)
  • Natural Earth (lake outline and border)