Route constraints and preferences

The default route uses the boat's polar, its certificate draft, and the available environmental data. Advanced options lets you state what this boat and crew will actually accept.

Some controls are hard constraints. The search may not cross them. Others are preferences: the route may accept a cost when the alternative is worse.

Boat performance and manoeuvres

Tacks & gybes can use boat-scaled time costs, be treated as free, or take custom penalties in seconds. These costs discourage a theoretical route from collecting tiny gains through repeated manoeuvres.

Performance scale multiplies the polar from 50 to 150 %. Use it for a known, sustained difference from the model—not as a forecast confidence control. Route stability can test nearby performance values without changing the primary run.

Depth

Draft override replaces the certificate draft for this run. Blank uses the certificate value. Safety margin adds water below that draft.

Depth is a hard constraint where coverage exists. It remains planning data, not pilotage data: generalisation, survey age, tide, and local hazards still belong on the navigational chart.

Waves

Wave avoidance adds a cost to rougher water. Maximum wave height refuses water over the chosen ceiling. These settings alter route choice; waves do not directly slow the modeled boat because the polar is assumed to represent its attainable speed.

Wave controls only act when the plan and course have a wave field. The result names when waves were absent.

Sailing angles and wind limits

No closer than and No deeper than limit the headings the crew is willing or able to sail. They may be measured against true or apparent wind.

Least true wind refuses conditions below a floor. Most wind sets a ceiling measured against true or apparent wind. These are hard limits, so an impossible corridor may return no finish rather than quietly violating one.

Water to avoid

Stand off land keeps the route a chosen distance from shore where the depth chart supports the calculation. The standoff relaxes near the start and finish, where leaving a harbour necessarily becomes a pilotage problem.

Keep-out areas are polygons drawn directly on the chart. Place at least three corners; the final edge closes automatically. Use them for traffic schemes, exclusion zones, local hazards, or water the sailing instructions prohibit. The route will not cross the polygon.

Read the refusal

A hard constraint can make a route impossible. When that happens, remove controls one at a time: first keep-out and shoreline clearance, then wind and angle limits, then depth. The point is not to make the solver return a line at any cost. It is to find which requirement made the requested race unsailable in the modeled conditions.