The Tide, Weather and Routing tabs have a time scroll bar or adjuster. This will appear once a pin is dropped or, on the Routing tab, once a route is calculated.
On the Tide and Weather tabs, you can drop a pin to set the location for checking tide or weather, and move the slider to evaluate different Departure times.
Once you move to the Routing tab, the Departure Time will stay at the time you chose on the Tide or Weather tabs.
When a route has plotted, the Departure Time adjuster will also appear on the Routing tab. Its appearance may vary depending on whether you are using savvy navvy on a mobile, laptop or desktop device.