#sailing

Marine and surf forecasts as an API, powered by Open-Meteo — clean JSON, no key. Get the current sea state and the hourly and daily wave forecast for any coastline by latitude/longitude or simply by place name: significant wave height, period and direction, plus the swell and wind-wave components broken out separately, and daily maxima and dominant directions. A built-in geocoding helper turns a place name into coordinates. Forecasts run up to ten days ahead. Live forecast data straight from Open-Meteo's marine model. Ideal for surf-report apps, sailing and boating tools, coastal and marine-operations dashboards and beach widgets. 4 data endpoints. Authenticated with an x-oanor-key; fair-use rate limits per plan.

api.oanor.com/marine-api

Current-sailing (set and drift) navigation maths as an API, computed locally and deterministically — the course-over-ground, course-to-steer and current numbers a mariner, navigator or marine app plots a passage with. The course-made-good endpoint adds the boat's velocity through the water to the current vector to give the real track: the course over ground (COG) and speed over ground (SOG), with the drift angle the current pushes you off your nose — steering 090° through the water at 10 knots with a 2-knot current setting north comes out around 079° over the ground at 10.2 knots. The course-to-steer endpoint solves the other way: the heading to steer to make good a desired ground track, steering up-current to cancel the across-track set (sin(H−T) = −drift·sin(set−track) ÷ speed), and the resulting SOG — usually slower into a current, faster with it astern, and impossible if the current across the track beats your speed. The current endpoint finds the set and drift from the offset between a dead-reckoning position and an observed fix: the set is the bearing DR-to-fix and the drift is that distance ÷ the elapsed time, ready to carry forward. Everything is computed locally and deterministically, so it is instant and private. Ideal for marine-navigation and chartplotter apps, sailing and boating tools, and maritime-training utilities. Pure local computation — no key, no third-party service, instant. Degrees true. 3 compute endpoints. For great-circle distance use a geo-distance API; for tide times a tides API.

api.oanor.com/setanddrift-api

Boat-anchoring maths as an API, computed locally and deterministically — the scope, swing and load numbers a sailor or boater sets the hook by. The scope endpoint gives the rode to let out: scope = rode ÷ the vertical from the seabed to the bow roller (water depth + bow height), measured at high tide, so anchoring in 20 feet with a 4-foot bow at the classic 7:1 means paying out 168 feet of rode — let out more in a blow, and never less than 5:1 on all chain. The swing endpoint gives the circle the boat swings on: radius = the horizontal reach of the rode (√(rode² − vertical²)) plus the boat length, so that 168-foot rode on a 30-foot boat sweeps a 196-foot radius — the room you must leave every other boat, which swings too. The load endpoint gives the wind load the ground tackle has to hold, 0.00256 × drag coefficient × frontal windage area × wind speed², which quadruples every time the wind doubles — 50 square feet of windage takes 138 lb at 30 mph but 553 lb at 60. Everything is computed locally and deterministically, so it is instant and private. Ideal for sailing and boating apps, anchoring and cruising tools, ground-tackle sizing calculators, and seamanship study aids. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 compute endpoints. Estimates — add current, waves and a safety margin.

api.oanor.com/anchor-api

Sailing and naval-architecture maths as an API, computed locally and deterministically — the hull-speed and design-ratio numbers a sailor, boat-shopper or yacht designer sizes a boat with. The hullspeed endpoint gives the theoretical displacement speed limit from the waterline: hull speed = 1.34 × √LWL (feet) in knots, so a 25-foot waterline tops out around 6.7 knots (7.7 mph, 12.4 km/h) — with a tunable coefficient up to about 1.5 for light, easily-driven hulls, since planing boats leave the formula behind entirely. The ratios endpoint computes the two classic performance numbers: the Sail Area/Displacement ratio, SA/D = sail area ÷ (displaced volume in ft³)^⅔ using displaced volume = displacement ÷ 64 lb/ft³ for seawater — around 16–18 is a typical cruiser and 20-plus is sporty — and the Displacement/Length ratio, DLR = (displacement in long tons) ÷ (0.01 × LWL)³, where under 200 is light and over 300 is heavy, each returned with a class label. The ballast endpoint gives the ballast ratio = ballast ÷ displacement × 100, a rough proxy for stiffness and sail-carrying power that most cruisers hit near 35–45 %. Everything is computed locally and deterministically, so it is instant and private. Ideal for sailing, boating, marine, yacht-brokerage and boat-design app developers, boat-comparison and rig-sizing tools, and naval-architecture calculators. Pure local computation — no key, no third-party service, instant. Imperial units. Live, nothing stored. 3 compute endpoints. Design-ratio estimates, not a velocity prediction program.

api.oanor.com/sailing-api

The Beaufort wind scale as an API, computed locally and deterministically. The classify endpoint turns a measured wind speed — in metres per second, kilometres per hour, knots, miles per hour or feet per second — into its Beaufort force (0 calm to 12 hurricane), with the descriptive name (light breeze, gale, storm …), the corresponding sea state and the mean open-sea wave height, plus the speed expressed in every unit. The force endpoint looks up a Beaufort number and returns its wind-speed range in all units, its description, sea condition and wave height. The convert endpoint converts a wind speed across metres per second, kilometres per hour, knots, miles per hour and feet per second and reports the matching Beaufort force (1 knot = 0.514444 m/s). Speeds use the standard 10-metre reference height and wave heights are open-sea means. Everything is computed locally and deterministically, so it is instant and private. Ideal for sailing, marine, aviation, drone, weather and outdoor app developers, wind-warning and sea-state tools, and meteorology education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is the Beaufort wind scale; for the feels-like wind chill use a feels-like API and for live wind observations a weather data API.

api.oanor.com/beaufort-api