{"openapi":"3.1.0","info":{"title":"Winch Drum API","version":"1.0.0","description":"Winch and cable-drum maths as an API, computed locally and deterministically — the rope-capacity, line-pull and rope-out numbers a winch operator, rigger or recovery driver works a drum with. The capacity endpoint gives the rope a drum holds by exact layer geometry: the sum over every full layer of the turns per layer × π × that layer's mean wrap diameter, where turns per layer = drum width ÷ rope diameter and the number of layers = the flange-to-barrel depth ÷ rope diameter — a 10-inch barrel, 20-inch flange, 12-inch-wide drum on half-inch rope holds about 940 ft over 10 layers. The layer-pull endpoint shows why pull falls as the drum fills: the rated pull is for the bare-drum first layer, and as rope piles on, the growing lever arm cuts the line pull and raises the line speed in the same ratio — pull × (first-layer diameter ÷ this layer's diameter) — so the top layer of a deep drum can pull barely half the bottom-layer rating, which is why you spool off to bare drum for a hard pull or add a snatch block. The length-at-layer endpoint gives the rope wound after a number of full layers, for marking the rope or knowing how much line is out. Everything is computed locally and deterministically, so it is instant and private. Ideal for winch- and hoist-sizing tools, recovery and off-road apps, marine and industrial-rigging utilities, and engineering calculators. Pure local computation — no key, no third-party service, instant. Geometric estimate — allow for nesting and freeboard. 3 compute endpoints. For capstan friction use a capstan API; for block-and-tackle a pulley API.","contact":{"name":"PremiumApi","url":"https://www.oanor.com/by/premiumapi"}},"servers":[{"url":"https://api.oanor.com/winch-api","description":"oanor gateway"}],"tags":[{"name":"Winch"},{"name":"Meta"}],"components":{"securitySchemes":{"oanorKey":{"type":"apiKey","in":"header","name":"x-oanor-key","description":"Get your key at https://www.oanor.com/developer/keys"}}},"security":[{"oanorKey":[]}],"paths":{"/v1/capacity":{"get":{"operationId":"get_v1_capacity","tags":["Winch"],"summary":"Rope capacity, layers and turns","description":"","parameters":[{"name":"barrel_diameter_in","in":"query","required":true,"description":"Barrel (core) diameter (in)","schema":{"type":"string"},"example":"10"},{"name":"flange_diameter_in","in":"query","required":true,"description":"Flange diameter (in)","schema":{"type":"string"},"example":"20"},{"name":"drum_width_in","in":"query","required":true,"description":"Drum width between flanges (in)","schema":{"type":"string"},"example":"12"},{"name":"rope_diameter_in","in":"query","required":true,"description":"Rope diameter (in)","schema":{"type":"string"},"example":"0.5"}],"security":[{"oanorKey":[]}],"responses":{"200":{"description":"OK"},"401":{"description":"Missing or invalid x-oanor-key header"},"402":{"description":"Active subscription required"},"429":{"description":"Rate-limit or monthly quota reached"},"502":{"description":"Upstream did not respond"}}}},"/v1/layer-pull":{"get":{"operationId":"get_v1_layer_pull","tags":["Winch"],"summary":"Line pull and speed at a layer","description":"","parameters":[{"name":"bare_drum_pull_lb","in":"query","required":true,"description":"Bare-drum (rated) line pull (lb)","schema":{"type":"string"},"example":"10000"},{"name":"barrel_diameter_in","in":"query","required":true,"description":"Barrel diameter (in)","schema":{"type":"string"},"example":"10"},{"name":"rope_diameter_in","in":"query","required":true,"description":"Rope diameter (in)","schema":{"type":"string"},"example":"0.5"},{"name":"layer","in":"query","required":true,"description":"Wrap layer number","schema":{"type":"string"},"example":"5"}],"security":[{"oanorKey":[]}],"responses":{"200":{"description":"OK"},"401":{"description":"Missing or invalid x-oanor-key header"},"402":{"description":"Active subscription required"},"429":{"description":"Rate-limit or monthly quota reached"},"502":{"description":"Upstream did not respond"}}}},"/v1/length-at-layer":{"get":{"operationId":"get_v1_length_at_layer","tags":["Winch"],"summary":"Rope length at a number of layers","description":"","parameters":[{"name":"barrel_diameter_in","in":"query","required":true,"description":"Barrel diameter (in)","schema":{"type":"string"},"example":"10"},{"name":"drum_width_in","in":"query","required":true,"description":"Drum width (in)","schema":{"type":"string"},"example":"12"},{"name":"rope_diameter_in","in":"query","required":true,"description":"Rope diameter (in)","schema":{"type":"string"},"example":"0.5"},{"name":"layers_wound","in":"query","required":true,"description":"Full layers wound","schema":{"type":"string"},"example":"5"}],"security":[{"oanorKey":[]}],"responses":{"200":{"description":"OK"},"401":{"description":"Missing or invalid x-oanor-key header"},"402":{"description":"Active subscription required"},"429":{"description":"Rate-limit or monthly quota reached"},"502":{"description":"Upstream did not respond"}}}},"/v1/meta":{"get":{"operationId":"get_v1_meta","tags":["Meta"],"summary":"Spec","description":"","parameters":[],"security":[{"oanorKey":[]}],"responses":{"200":{"description":"OK"},"401":{"description":"Missing or invalid x-oanor-key header"},"402":{"description":"Active subscription required"},"429":{"description":"Rate-limit or monthly quota reached"},"502":{"description":"Upstream did not respond"}}}}},"x-oanor-pricing":[{"slug":"free","name":"Free","price_cents_month":0,"monthly_call_quota":4850,"rps_limit":2,"hard_limit":true},{"slug":"starter","name":"Starter","price_cents_month":1230,"monthly_call_quota":49000,"rps_limit":6,"hard_limit":true},{"slug":"pro","name":"Pro","price_cents_month":3960,"monthly_call_quota":205500,"rps_limit":15,"hard_limit":true},{"slug":"mega","name":"Mega","price_cents_month":12200,"monthly_call_quota":1108000,"rps_limit":40,"hard_limit":true}],"x-oanor-marketplace-url":"https://www.oanor.com/api/winch-api"}