Route notes · Secondary straits

Turkish Straits, Panama Canal, and Danish Straits: why they appear on an oil map

Three boxes that are not Hormuz, not Malacca, and not Suez. Black Sea’s only wet exit. A water-limited Atlantic–Pacific shortcut. The Baltic exit envelope. Each integer is AIS hulls in a rectangle — not barrels per day.

Published 7 September 2026 Glossary · box language on the chokepoints note

International Space Station view of the Panama Canal’s Gaillard Cut and Centennial Bridge, Pacific-side lock canal through tropical terrain
Panama Canal, Gaillard Cut and Centennial Bridge, September 2004. NASA / ISS Expedition 9 (ISS009-E-24099), public domain. Landscape crop of the Commons original. Geography only — no AIS pins, no invented draft annotations. Wikimedia Commons

Direct answer

Why does OilRoutes keep these three on an oil map? Because they are three of the eight named oil-transit boxes. They are secondary to Hormuz, Malacca, Suez/SUMED, and Bab el-Mandeb by EIA World Oil Transit Chokepoints volume rank — not optional geography. Turkish Straits: Black Sea’s only wet exit. Panama: a water-limited Atlantic–Pacific lock shortcut, mostly products and some LNG. Danish Straits: the Baltic exit envelope. Each live integer is tracked AIS hulls in a drawn rectangle — not barrels per day.

Eight rectangles sit on the header strip. Four of them already have hubs. This page is the glossary for the other three — not three mini-Hormuz notes and not a volume dump. Box definitions live on the maritime oil chokepoints page. This note quotes that language and tells you how to fly the camera when the headline is Bosphorus, Gatún, or Great Belt.

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Secondary is not unimportant

EIA’s 3 March 2026 World Oil Transit Chokepoints file still lists all seven waterways plus the Cape. Volume leadership is Malacca, then Hormuz. The Turkish Straits, Panama Canal, and Danish Straits sit lower on that table. Lower is not “ignore.” A Black Sea loading that cannot clear the Bosphorus has no other wet door. A U.S. Gulf product or LNG cargo that cannot use Panama still has Magellan, the Cape, or Suez — those are longer cameras. A Baltic export that cannot use the Danish envelope still has only a partial Kiel cut. Secondary means: different job, smaller EIA print, same AIS honesty.

Do not promote a quieter pin into “this door does not matter.” Do not promote a busy pin into EIA’s table. The Hormuz evergreen is the Gulf lock. Malacca is the Asia lane. Suez/SUMED and Bab el-Mandeb are the Red Sea pair. The Cape 2026 note is the Africa rounding. This glossary does not restate those hubs.

Direct answer

What is each one, and what does the box count? Quote the chokepoints note, which owns the definitions. Turkish Straits: “The Bosphorus and Dardanelles, which connect the Black Sea to the Sea of Marmara and then the Aegean. The box spans both straits rather than drawing two tiny rectangles.” Panama Canal: “The lock canal between the Caribbean / Atlantic and the Pacific. The box is tight around the canal prism. It is on the map because some product and crude cargoes use it; it is not a substitute for a canal-authority transit table.” Danish Straits: “The passages (including the Great Belt and related waters) that connect the Baltic Sea to the North Sea / Kattegat. The box is a regional envelope, not a single named cut.” A hull is “in zone” when its latest AIS position falls inside that rectangle. Dated flow belongs to EIA WOTC — never to a panel string.

Turkish Straits: one box, two cuts, Black Sea’s only wet exit

The chokepoints note is the definition: the Bosphorus and Dardanelles, Black Sea to Marmara to the Aegean; the box spans both rather than drawing two tiny rectangles. In js/chokepoints.js that envelope runs roughly 39.5–41.5°N, 25.5–29.5°E, camera center near 41.1°N, 29.0°E. A pin in Marmara or in either cut is in-zone. A pin in the Black Sea basin that has not entered the box is not.

EIA WOTC, 3 March 2026, is the geography desk: Bosporus about 17 nautical miles (Black Sea to Marmara); Dardanelles about 37 nautical miles (Marmara to the Aegean and Mediterranean); less than half a nautical mile at the narrowest; oil from Russia and the Caspian region toward Asia and Europe.1 EIA’s 1H25 print for the Dardanelles series is 3.7 million barrels a day — about 5 percent of global maritime oil trade, roughly 60 percent crude.1 That is EIA on Vortexa, not this map. The panel string dailyAvgFlow still reads “2.4M bbl/day.” That is not EIA’s 3.7 and not a citeable OilRoutes series.

Montreux is a named-explainer topic, not an OilRoutes holding. Türkiye’s Ministry of Foreign Affairs dates the convention to 20 July 1936 and says it maintains freedom of passage for merchant vessels while setting a separate regime for warships.2 Wikipedia’s convention page repeats the peacetime merchant-vessel “complete freedom” clause.3 This page will not invent a wartime legal conclusion, a tanker exception, or a “Montreux closed the strait” finding from an empty rectangle. Quote the explainer. Fly the box. Count what is broadcasting.

Fly the Turkish Straits box on the live map →

Panama Canal: lock prism, products and LNG, drought via ACP

Again the chokepoints note: lock canal, Caribbean / Atlantic to Pacific; box tight around the canal prism; on the map because some product and crude cargoes use it; not a canal-authority transit table. In js/chokepoints.js the rectangle is small — roughly 8.8–9.5°N, 80.0–79.3°W, camera center near 9.15°N, 79.7°W. A hull in the Caribbean approaches or in the Gulf of Panama that is not inside that prism is not in-zone.

EIA, using Panama Canal Authority statistics plus Vortexa, is why desks still care: more than 2.3 million barrels a day of petroleum and other liquids in FY 2025 (1 October 2024–30 September 2025), most of it refined products (about 2.2 million barrels a day). EIA calls the waterway about 3 percent of global maritime petroleum flows that fiscal year — and an important products and LNG lane from the U.S. Gulf Coast toward western South America and Asia.1 The panel’s “0.9M bbl/day” is not that print.

The constraint is water, not a Hormuz-style pinch. EIA’s October 2023 Today in Energy note — “Drought at the Panama Canal delays energy shipments, increasing shipping costs” — and the 2026 WOTC update both point at Gatún Lake, which supplies the lock prism. WOTC says FY 2024 oil flows fell because of drought, then product flows recovered in FY 2025 after water levels returned toward average.41 Quote ACP or those EIA sentences for drought. This page will not invent draft feet, daily slot caps, or a new ACP table. Alternatives EIA names — Magellan / Cape Horn / Drake, the Cape of Good Hope, Suez, and the Trans-Panama Pipeline — are other cameras, not this prism.

Fly the Panama box on the live map →

Danish Straits: Baltic envelope, Kiel partial, shadow-fleet ≠ in-zone

The chokepoints note again: passages including the Great Belt and related waters; Baltic to North Sea / Kattegat; a regional envelope, not a single named cut. In js/chokepoints.js that envelope runs roughly 54.5–57.8°N, 10.0–13.5°E, camera center near 56.0°N, 11.8°E. A hull anywhere in that rectangle is in-zone. A hull in the Baltic that has not entered it is not. A hull in the Kiel Canal is a different cut.

EIA WOTC: “a series of channels that connect the Baltic Sea to the North Sea.” The 1H25 print is 4.9 million barrels a day — about 6 percent of global maritime oil trade. A footnote is load-bearing: “The Danish Straits do not include flows through the Kiel Canal.”1 Kiel, in that same file, is a partial alternative: small tankers, virtually only oil products, nearly 200,000 barrels a day in 1H25. Partial means smaller and product-heavy — not a spare Danish envelope. The panel’s “3.3M bbl/day” is not EIA’s 4.9.

A “shadow fleet” or Danish Maritime Authority headline is a desk or authority claim. This box is AIS in a regional envelope. It is not a DMA voyage count, not a sanctions census, and not a dark-fleet tracker. Silent hulls will not appear. That honesty is the dark-AIS undercount hub, not a new Baltic scrape. Do not paste a Hormuz dark-share onto the Great Belt.

Fly the Danish Straits box on the live map →

Three boxes, one honesty rule

Box What the chokepoints note says it is What the live integer is not
Turkish Straits Bosphorus + Dardanelles; Black Sea → Marmara → Aegean; one box spanning both Not EIA’s 3.7 million b/d; not a Montreux holding; not two cameras
Panama Canal Lock canal, Caribbean / Atlantic ↔ Pacific; tight to the canal prism Not an ACP transit table; not draft feet or slot caps; not Hormuz-scale crude
Danish Straits Great Belt and related waters; Baltic → North Sea / Kattegat; regional envelope Not Kiel; not a DMA / shadow-fleet census; not EIA’s 4.9 million b/d

Ship-class nicknames still do not filter the map. OilRoutes keeps AIS types 80–89 (and optional type 35). VLCC, Suezmax, and Aframax is the size-class note. How extra days become freight and a crude risk premium — without inventing a dollar — is the markets and freight note.

Do not copy the “avg flow” strings from the Turkish, Panama, or Danish panels into a briefing as if OilRoutes measured them. Those labels are not EIA WOTC and not a citeable OilRoutes series. Quote EIA, ACP, or the named desk. Treat the live integer as tracked AIS in the rectangle now.

Direct answer

How do you use the map next to a secondary-strait headline? Open the live map. Name the waterway. Fly that one box. Read the claim — closed, drought, draft, shadow fleet, Montreux, Kiel — before the integer. Treat the number as tracked AIS oil tankers in the rectangle right now. Assume undercount: the dark-AIS hub. Box language: maritime oil chokepoints. Peacetime rank: EIA WOTC. Canal water: ACP or EIA’s drought note — no invented draft feet. A shadow-fleet headline is not a Danish in-zone census. Never copy the panel’s average-flow string as an OilRoutes measurement.

A practical sequence when the headline is not Hormuz

Demo Mode is labeled and is not live AIS. Do not use a demo fleet to invent a strait closure. Cite OilRoutes for what the map shows and for this glossary. Cite EIA WOTC for peacetime flow. Cite ACP / EIA for canal drought. Cite Türkiye MFA or the convention page for Montreux language. Never cite this article as a throughput series or a price.

What this page will not do

It will not replace the live map. Homepage / stays the product. It will not invent mb/d, ACP draft feet, slot caps, DMA or shadow-fleet voyage counts, Montreux legal conclusions beyond the attributed explainers, voyage days, insurance percents, or dollars per barrel. It will not present dailyAvgFlow — “2.4M,” “0.9M,” “3.3M” — as an OilRoutes measurement. It will not turn these three into mini-Hormuz hubs or reprint EIA’s full table as if this site tracked it.

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Sources & further reading

Box definitions belong to OilRoutes’ maritime oil chokepoints note and are quoted, not rewritten. Peacetime flow, share, and Kiel / products / drought mechanism language belong to EIA World Oil Transit Chokepoints (3 March 2026) and to EIA Today in Energy on the Panama drought. Montreux language belongs to Türkiye MFA and to the named convention explainer. This page does not add a new scrape and does not invent mb/d, draft feet, slot caps, or voyage counts.

  1. U.S. Energy Information Administration, “World Oil Transit Chokepoints,” last updated 3 March 2026. Vortexa-based except Panama Canal Authority statistics (fiscal year) with EIA conversions. Turkish Straits (Dardanelles) 3.7 million b/d in 1H25 (~5% of maritime oil trade; about 60% crude); Bosporus ~17 nm, Dardanelles ~37 nm, less than half a nautical mile at the narrowest. Panama Canal more than 2.3 million b/d in FY 2025, about 2.2 million b/d refined products; ~3% of maritime petroleum flows; Gatún Lake drought cut FY 2024 oil flows, recovery in FY 2025. Danish Straits 4.9 million b/d in 1H25 (~6% of maritime oil trade); footnote: Danish Straits do not include Kiel Canal; Kiel nearly 200,000 b/d in 1H25, small tankers, virtually only products. eia.gov
  2. Republic of Türkiye, Ministry of Foreign Affairs, “Note on the Turkish Straits.” Montreux Convention signed 20 July 1936; maintains freedom of passage for merchant vessels and a separate regime for warships. This page does not invent a wartime legal conclusion from that note. mfa.gov.tr
  3. Wikipedia, “Montreux Convention Regarding the Regime of the Straits.” Peacetime merchant-vessel “complete freedom” clause (Article 2) as commonly quoted. Explainer only — not an OilRoutes legal holding. wikipedia.org
  4. U.S. Energy Information Administration, “Drought at the Panama Canal delays energy shipments, increasing shipping costs,” Today in Energy, 31 October 2023. Gatún Lake / lock-water mechanism; delays and higher freight for energy cargoes. Draft feet and slot caps are not reprinted here. eia.gov