Roughly 80 percent of world trade by volume moves by sea, and a small number of narrow passages decide where most of it can go. Cut the Panama Canal out of an Asia-to-US-East-Coast rotation and the ship faces the Suez route or a rail land bridge across North America. Close the Suez Canal and a Rotterdam-to-Singapore voyage stretches from about 8,440 nautical miles to about 11,720 around the Cape of Good Hope, an extra 3,280 nautical miles and 10 to 14 days of steaming. These passages are called chokepoints because the global fleet has to thread through them, and the dimensions of each one (how wide, how deep, how high a ship can be) set the size classes that the world’s ships are built to. This article is the hub for those chokepoints and for the inland waterways that feed them. The voyage estimation framework turns a routing choice into a cost; the voyage fuel and CO2 calculator does the arithmetic on a diversion.
A chokepoint is worth understanding on two axes at once: the physical constraint that caps ship size, and the commercial geography that makes the passage worth a fee, a queue, or a risk premium. The four deep-dive articles one level down each sit at a different point on those axes. The Panama Canal is a lock canal whose chamber geometry created the Panamax and Neopanamax classes. The Suez Canal is a sea-level cut whose dredged depth defines the Suezmax tanker. The Strait of Malacca is a natural strait whose charted depth fixes the Malaccamax draft and whose narrowness drives a security regime. The Danube River basin is the inland-waterway case, where locks, river class, and a treaty regime govern barge convoys rather than ocean ships.
What makes a chokepoint
A chokepoint is a passage that concentrates a large share of traffic into a narrow corridor that has no easy substitute. The concentration comes from geography: the alternative route is so much longer, or so much more dangerous, that almost everyone uses the chokepoint despite the fee, the queue, or the risk. The strategic weight follows from the lack of a substitute. A passage that everyone can avoid cheaply is not a chokepoint; a passage that forces a 3,000-nautical-mile detour when it closes is.
Canal versus strait
The first distinction is whether the passage is artificial or natural. A canal is cut through land by people, owned and run by an authority that sets the transit fee, the booking system, and the maximum ship size: the Panama Canal Authority and the Suez Canal Authority are the two large examples. A strait is a natural narrowing of the sea between two coasts, owned by no commercial party, used without a transit fee, and governed by the littoral states under the United Nations Convention on the Law of the Sea (UNCLOS), which guarantees transit passage through straits used for international navigation. So the Panama and Suez canals charge dues and ration slots, while the Strait of Malacca, the Strait of Hormuz, and the Bab-el-Mandeb charge nothing and cannot refuse a lawful transit.
That ownership difference drives almost everything else. A canal authority can raise a toll, cut the daily slot count in a drought, or close for maintenance, and the market has to respond. A strait has no toll to raise, but it carries a different vulnerability: it can be made unsafe by conflict, piracy, or a single grounded ship, and the law of the sea gives the littoral states limited power to keep traffic moving through it. The 2021 grounding of the Ever Given closed the Suez Canal for six days, from 23 to 29 March, and left more than 400 ships waiting at the two ends and in the Bitter Lakes before the backlog cleared on 3 April; a closure of the Strait of Hormuz would have no canal authority to manage it at all.
The Panama, Suez, Malacca, and Hormuz passages are the four that set the global size classes, but they are not the only chokepoints that govern routing. The Kiel Canal, the 98 km lock canal across the base of the Jutland peninsula, cuts the North-Sea-to-Baltic run by about 250 nautical miles against the route around the Danish Straits and limits ships to 235 m length and a draft of 7 m at that length (up to 9.5 m only for ships under 160 m), a cap well below Panamax. The Turkish Straits, the Bosphorus and the Dardanelles, are the natural outlet of the Black Sea and the route for Russian, Kazakh, and Romanian crude and grain; passage there is governed not by UNCLOS alone but by the 1936 Montreux Convention, which gives Turkey the authority to regulate transit and warship movements. Both fit the chokepoint test of this article: a concentrated traffic flow with a costly or contested alternative, which is why a queue at either one moves freight rates the same way a Suez or Panama disruption does.
Lock canal versus sea-level canal
The second distinction applies only to canals, and it decides both the ship-size limit and the operating cost. A sea-level canal is a single open cut joining two seas of near-equal mean level, with no lift; the Suez Canal is the case, opened in 1869 across the Isthmus of Suez where the Mediterranean and the Red Sea sit at almost the same level. A sea-level canal has no lock chambers, so no chamber geometry caps the ship’s beam or length; the only hard limit is how deep the channel is dredged, which fixes the maximum draft, and the air draft under any fixed bridge. The Suez Canal carries no width limit comparable to a lock chamber, which is why ships up to about 400 m long transit it.
A lock canal crosses high ground by lifting ships into a summit reach and lowering them at the far end. The Panama Canal lifts ships 26 m into Gatun Lake and lowers them back to sea level on the other side, because the Isthmus of Panama could not be cut at sea level through the Continental Divide. Locks buy the ability to cross a watershed, but at two costs. Each lock chamber is a fixed box, so its width, length, and sill depth cap the largest ship that can fit, and that cap is what created the Panamax and Neopanamax classes. And every lockage spends fresh water: per the Panama Canal Authority, the original locks release about 197,000 m3 of fresh water (around 52 million US gallons) from Gatun Lake to the sea on each transit, which is why a drought in the canal watershed forces draft cuts and slot reductions, as it did across 2023 and 2024.
How wide is the Panama Canal? The answer depends on which set of locks. The original 1914 locks have chambers 33.53 m (110 ft) wide and 304.8 m (1,000 ft) long, which fixed the Panamax beam at 32.31 m, leaving under 60 cm of clearance a side. The 2016 Neopanamax locks have chambers 55 m wide and 427 m long, raising the maximum vessel beam to 49 m at opening and to 51.25 m after a 2018 revision. So the navigable lock width is 33.53 m on the old locks and 55 m on the new, and the largest ship is always a touch narrower than the chamber it threads.
The constraints that define a size class
A ship that wants to use a given chokepoint has to clear three or four physical limits, and the binding one differs by passage. Beam is the side-to-side limit, set by a lock chamber width on a lock canal and by the dredged channel and traffic-lane width on a strait or sea-level canal. Length overall is capped by lock-chamber length on a lock canal and by maneuvering room elsewhere. Draught (the depth of the hull below the waterline) is limited by sill depth in a lock, by dredged depth in a sea-level canal, and by charted depth in a strait. Air draft, the height from the waterline to the highest fixed point, is limited by any bridge spanning the passage: the Bridge of the Americas over the Pacific approach to the Panama Canal caps the air draft there.
Air draft is the constraint that catches the ships the depth and beam limits miss. A vessel can clear every lock chamber and still be turned back by a fixed bridge: the Bridge of the Americas over the Pacific approach to the Panama Canal sets the limit there at about 61.3 m above the water at high tide, which excludes some passenger ships and certain heavy-lift vessels that ride tall above the waterline. A sea-level canal has the same exposure where a bridge crosses it. Air draft rarely binds a loaded bulker or tanker, which sits low, but it is the first wall a cruise ship or a car carrier meets, and it is the one limit a ship cannot reduce by discharging cargo.
The size class is named for the passage that sets the binding limit. Panamax is the largest ship the original Panama locks accept: 294 m length overall, 32.31 m beam, and 12.04 m draft in tropical fresh water, with the beam clearing the 33.53 m chamber wall by less than 60 cm a side. Neopanamax is set by the 2016 Panama locks, whose chambers measure 427 m long, 55 m wide, and 18.3 m deep, taking a ship up to 366 m long, 49 m in beam, and 15.2 m draft. Suezmax is the largest tanker that transits the Suez Canal fully laden, about 50 m in beam and around 16 m laden draft against the canal’s dredged depth. The 16 m figure is the working draft of a fully loaded Suezmax tanker, not the canal’s hard limit: the Suez Canal Authority publishes a beam-versus-draft envelope under which a narrower ship can sit deeper, up to about 20.1 m permissible draft at a reduced beam, so the typical Suezmax laden draft and the canal’s maximum permissible draft are two distinct numbers, not a contradiction. Malaccamax is the deepest-draft ship the Strait of Malacca can take at its roughly 25 m minimum charted depth, about 21 m draft, which corresponds to a part-laden very large crude carrier. A naval architect designing a ship for a trade that crosses one of these passages builds to the class limit, because a single centimeter over the cap turns the chokepoint into a wall.
| Class | Length overall | Beam | Draft | Typical ship |
|---|---|---|---|---|
| Panamax | 294 m | 32.31 m | 12.04 m TFW | Panamax bulker, mid-size box ship |
| Neopanamax | 366 m | 49 m | 15.2 m TFW | 13,000 to 14,000 TEU box ship, most LNG carriers |
| Suezmax | about 400 m | about 50 m | about 16 m laden | 120,000 to 200,000 DWT crude tanker |
| Malaccamax | not lock-limited | not lock-limited | about 21 m | part-laden VLCC, 250,000 to 280,000 DWT |
The table reads as a hierarchy of constraint, not a single ranking. A Neopanamax ship is longer and beamier than a Panamax but shallower-drafted than a Suezmax or a Malaccamax, because the binding limit is different in each case: chamber width at Panama, dredged or charted depth at Suez and Malacca. The Malaccamax draft is the highest of the four, since a sea strait can be far deeper than a lock sill, and it is the one that admits the largest deadweight.
Why routing and freight economics hinge on chokepoints
A chokepoint sets three numbers that drive the cost of a voyage: the distance of the route, the fee to use the passage, and the time lost waiting for or transiting it. Each one feeds the voyage estimate that owners and charterers run before they fix a cargo. The voyage estimation article walks the full calculation; the short version is that distance times speed gives steaming days, steaming days times the daily bunker burn gives the fuel bill, and the canal dues sit on top as a direct voyage cost.
The route distance and the alternative
The commercial value of a chokepoint is the distance it saves against the next-best route. The Suez Canal saves a Europe-to-Asia voyage roughly 7,000 nautical miles and 9 to 12 days against rounding the Cape of Good Hope; the Panama Canal saves an Asia-to-US-East-Coast voyage the long detour around Cape Horn or the Suez routing the other way round the planet. The size of that saving is what a transit fee is priced against. When a canal toll rises or a slot becomes scarce, an operator compares the higher canal cost against the cost of the longer route, and at some break-even the longer route wins.
The Cape of Good Hope is the standing alternative to Suez, and the arithmetic shows why the canal is normally worth its fee. Rotterdam to Singapore runs about 8,440 nautical miles through Suez and about 11,720 nautical miles around the Cape, an extra 3,280 nautical miles that adds 10 to 14 days at a typical liner speed and the fuel to match. The Cape route carries no toll and no draft limit, which is its compensating advantage: the largest crude tankers, the ULCCs that cannot transit Suez even in ballast, use the Cape by design. For a laden box ship, the Suez toll is far cheaper than two weeks of extra bunkers and an extra rotation of charter hire, so the canal wins until it is closed or unsafe. The voyage fuel and CO2 calculator sizes the fuel and emissions gap between a canal transit and the diversion.
The transit fee as a voyage cost
Canal dues are a real line in the voyage estimate, and which party pays depends on the charter. Under a voyage charter party the owner carries the canal dues out of the freight, alongside the bunkers and port charges; under a time charter party the charterer pays the dues along with the other voyage-variable costs. So a toll increase lands on whichever party holds the voyage cost under the fixture, and a severe rise can turn a marginal voyage unprofitable. The two large canals price the toll on a tonnage measure, not on cargo weight: Panama uses the Panama Canal Universal Measurement System (PC/UMS), a volumetric figure close to gross tonnage, while Suez uses Suez Canal Net Tonnage (SCNT), a deduction-based number systematically below gross tonnage. The two systems give different numbers for the same ship, which is why a route comparison has to price each canal on its own basis. The Panama Canal PC/UMS toll calculator and the Suez Canal SCNT dues calculator compute each one from the ship’s measured tonnage.
The tonnage basis matters because the two canals can give a different toll for ships of identical size. PC/UMS at Panama measures total enclosed volume in units of 100 cubic feet, so one PC/UMS net ton equals 100 cubic feet (about 2.83 m3) of enclosed space, and the figure runs close to the gross tonnage of the 1969 International Convention on Tonnage Measurement of Ships. SCNT at Suez starts from a similar volumetric base but deducts machinery, crew, and certain other spaces, so it lands systematically below gross tonnage. A single hull therefore carries one PC/UMS net-tonnage number at Panama and a lower SCNT number at Suez, and the toll rate per ton differs again by ship type at each canal. A clean route comparison cannot apply one toll figure to both passages; it has to measure the ship on each canal’s own basis and apply each canal’s own published rate, which is why the two toll calculators are separate tools rather than one.
A worked contrast makes the basis difference concrete. Take a Suezmax crude tanker of about 157,000 DWT that measures roughly 81,000 GT. At Panama the PC/UMS net tonnage sits near the gross figure, so the ship presents on the order of 80,000 PC/UMS net tons to the toll table. At Suez the same ship measures lower, because SCNT strips out the engine room, crew spaces, and other deductible volumes; a Suezmax commonly comes in around 80 to 85 percent of GT on the SCNT basis, so the same hull presents closer to 67,000 to 69,000 SCNT to the Suez table. The number the toll is charged on is therefore some 12,000 to 13,000 tons lower at Suez than at Panama for the identical ship, before either canal’s per-ton rate is applied. The rates then diverge again: the Suez Canal Authority’s January 2024 laden crude-tanker tariff is a tapered scale starting at 11.04 SDR per SCNT for the first 5,000 tons and falling to about 2.13 SDR per ton on the topmost band, while Panama prices crude tankers on its own per-net-ton rate that steps with vessel size and loaded condition. The practitioner lesson is that quoting one canal’s tonnage or one canal’s rate against the other overstates or understates the dues, which is why the Panama Canal PC/UMS toll calculator and the Suez Canal SCNT dues calculator measure the ship on each canal’s own basis rather than sharing one number.
The fee is not always the toll alone. The Panama Canal runs a fast-track auction for vessels that need a transit at short notice, and during the 2023 drought, with daily slots cut from the normal 36 toward the low 20s, auction slots cleared at multiples of the standard toll. The Panama Canal Authority confirmed a record single-slot price of US4.5 million once the regular toll was added. For a liner box ship on a tight schedule that cost can be justified; for a bulk carrier it tips the balance toward the longer route. The auction price is a clean market reading of what the chokepoint is worth on a given day.
The waiting time
Time at anchor waiting for a slot is a cost even when no fee is paid. A ship queuing at a canal anchorage burns fuel, accrues charter hire, and consumes its schedule, and during the 2023 Panama drought wait times for vessels without reserved slots reached 20 days or more. Waiting time also raises a regulatory cost: a ship idling at anchor for weeks burns fuel that worsens its annual Carbon Intensity Indicator rating under the IMO framework, an effect that did not exist as a planning factor before the CII took effect in 2023. Voyage planners now weigh queue length as part of the routing decision, not only the toll and the distance, which is one more reason the voyage estimation calculation has grown more involved.
The security and transit-fee dimension
Chokepoints concentrate not only trade but risk. A narrow passage that every ship must use is the natural place for piracy, for a naval blockade, or for a state to exert pressure, and the security regime around a chokepoint is a standing part of its operating cost.
Security on the straits
The Strait of Malacca is the case study in chokepoint security. Through the 1990s and early 2000s the strait carried one of the highest piracy and armed-robbery counts in the world, concentrated at the narrow eastern approaches near the Phillip Channel, where the navigable water is about 2.7 km wide. The littoral states (Indonesia, Malaysia, and Singapore) answered with coordinated MALSINDO sea patrols, the Eyes in the Sky air patrols, and a mandatory ship-reporting system, STRAITREP, run through Singapore vessel traffic services, and incidents fell sharply. The Regional Cooperation Agreement on Combating Piracy and Armed Robbery against Ships in Asia (ReCAAP), with its information-sharing center in Singapore, built the reporting backbone. The lesson is that a strait’s security is a function of the littoral states’ cooperation, because no canal authority exists to run it.
The Bab-el-Mandeb shows the same risk in a harsher form. The strait is about 18 miles wide at its narrowest, with traffic split into two 2-mile channels, and it is the southern gate of the Red Sea, the link between the Suez route and the Indian Ocean. Per the US Energy Information Administration, oil flow through the Bab-el-Mandeb averaged about 8.7 million barrels a day in 2023, but attacks on shipping from late 2023 onward pushed many operators to route around the Cape of Good Hope instead, cutting the flow to roughly 4.1 million barrels a day in 2024, and liquefied natural gas flows through both the Bab-el-Mandeb and the Suez Canal fell sharply through 2024 as ships avoided the area and insurance premiums rose. The cost of a chokepoint here is not a toll but a war-risk premium and the alternative-route distance, the same Cape detour that a Suez closure forces.
The Strait of Hormuz
The Strait of Hormuz is the most concentrated oil chokepoint on earth and the clearest example of a passage with no substitute. Per the US Energy Information Administration, oil flow through Hormuz averaged about 21 million barrels a day in 2022, equal to roughly 21 percent of world petroleum liquids consumption, along with about a fifth of seaborne liquefied natural gas, most of it Qatari. At its narrowest the strait is 21 miles (about 33 km) wide, with shipping confined to two 2-mile-wide lanes separated by a 2-mile buffer. The Gulf exporters have almost no way around it: a few pipelines bypass a fraction of the volume to the Red Sea or the Gulf of Oman, but the bulk of Saudi, Kuwaiti, Emirati, Qatari, and Iraqi seaborne energy has to pass through Hormuz. That lack of an alternative is exactly what gives the strait its strategic weight, and why any threat to close it moves oil and freight markets within hours. The transit itself is free; the cost is the insurance premium and the geopolitical risk that ride on every cargo.
War, sanctions, and the charter
The legal machinery that allocates chokepoint risk between owner and charterer sits in the charter party, not in the canal tariff. The BIMCO war-risks clauses (CONWARTIME for time charters, VOYWAR for voyage charters) let an owner refuse an order that would send the ship into a listed war-risk area, and they pass the additional war-risk insurance premium for entering such an area to the charterer. When the Bab-el-Mandeb and the southern Red Sea became war-risk areas, those clauses decided who paid the premium and who carried the cost of the Cape diversion. The interaction of chokepoint risk and charter risk is treated in charter parties overview; the point here is that the chokepoint creates the risk and the charter party allocates it.
Inland waterways and the chokepoint idea
The chokepoint logic does not stop at the coast. Inland waterways carry their own version of every constraint that an ocean chokepoint imposes, scaled to barges and river-sea ships rather than to Suezmax tankers, and they connect the deep-sea network to inland production and consumption.
The Danube and the lock-and-class system
The Danube River basin is the European inland case. The river runs 2,857 km from the Black Forest in Germany to the Black Sea, draining 801,463 km2 across 19 countries, and it is made navigable by locks at the Iron Gates and elsewhere and graded by the UNECE waterway classes that cap the size of convoy a given reach can take. The lower Danube from Turnu Severin to Sulina carries the Class VII designation, the highest in the European network, taking large pushed convoys; the upper river drops to Class V or VI. Navigation is governed by the 1948 Belgrade Convention and the Danube Commission in Budapest, while water quality runs under the 1994 Danube River Protection Convention and the ICPDR. The river ties into the deep-sea network through the Rhine-Main-Danube Canal, completed in 1992, 171 km long with 16 locks, which joins the Rhine system at the North Sea to the Danube system at the Black Sea and makes a continuous inland route across the continent.
The Danube also shows the chokepoint as a strategic asset. After Russia blockaded Ukraine’s deep-sea Black Sea ports in 2022, the EU’s Danube Solidarity Lane routed Ukrainian grain through the lower Danube ports at Reni, Izmail, and Galati to the Black Sea port at Constanta, keeping the exports moving by inland water when the sea route was shut. The river became the alternative when the chokepoint closed, the same pattern as the Cape standing in for Suez, played out on an inland waterway.
Where inland waterways meet the deep-sea chain
Inland waterways feed the same trade chain as the canals and straits, and the handoff happens at the port. A grain cargo can move down the Danube by barge, transfer to a deep-sea bulker at Constanta, and then cross the Suez Canal to Asia, with the inland leg and the sea leg priced and contracted separately. That handoff, and the documentation that carries the cargo across the modal break, is the subject of freight forwarding and incoterms, where the Incoterms rule fixes where the cost and risk pass between seller and buyer along the route. The port where the modes meet is covered in ports and terminals overview; a chokepoint and a port are two ends of the same routing decision, the passage that gates the route and the place where cargo enters and leaves it.
The four deep-dive articles
Each of the four leaf articles below takes one chokepoint or waterway to depth. They are the place to go for the lock geometry, the toll mechanics, the security regime, and the governance of each passage; this hub maps how they relate.
Panama Canal
The Panama Canal is the 80 km lock canal across the Isthmus of Panama, lifting ships 26 m into Gatun Lake and lowering them on the far side, run by the Panama Canal Authority since the United States transferred sovereignty on 31 December 1999. Its original 1914 locks set the Panamax class at 32.31 m beam, and the 2016 expansion locks, with chambers 427 m by 55 m by 18.3 m, created the Neopanamax class at 49 m beam and 15.2 m draft, opening the canal to most LNG carriers and to box ships up to about 14,000 TEU. The 2023 to 2024 drought, which cut daily slots and forced draft restrictions, showed how a lock canal’s dependence on fresh water makes it vulnerable in a way a sea-level canal is not.
Suez Canal
The Suez Canal is the 193.3 km sea-level cut between the Mediterranean at Port Said and the Red Sea at the Gulf of Suez, opened in 1869, run by the Suez Canal Authority from Ismailia. It has no locks and no width limit comparable to a lock chamber, so it takes ships up to about 400 m long; its only hard limit is the dredged depth, around 24 m design with a published laden-draft limit near 20.1 m, which defines the Suezmax tanker. The 2015 New Suez Canal added a parallel channel for two-way traffic over part of the route, and the 2021 Ever Given grounding, which shut the canal for six days, is the standing example of how a single ship can close a chokepoint that carries a large share of world container trade.
Strait of Malacca
The Strait of Malacca is the roughly 930 km natural strait between the Malay Peninsula and Sumatra, the principal sea route between the Indian Ocean and the South China Sea and the busiest international strait in the world, with 80,000 to 100,000 transits a year. Its roughly 25 m minimum charted depth fixes the Malaccamax draft at about 21 m, forcing the largest crude tankers to transit part-laden or to divert through the Lombok or Sunda straits, and its 2.7 km narrowest navigable width at the Phillip Channel concentrates traffic and risk. The littoral states run the security and traffic regime through STRAITREP, the MALSINDO patrols, and ReCAAP, the model for managing a chokepoint that no authority owns.
Danube River basin
The Danube River basin is the inland-waterway counterpart: a 2,857 km river draining 801,463 km2 across 19 countries, made navigable by locks and graded by UNECE waterway class, governed for navigation by the 1948 Belgrade Convention and the Danube Commission and for water quality by the 1994 ICPDR regime. Linked to the Rhine system through the Rhine-Main-Danube Canal, it carries the same constraint logic as an ocean chokepoint (a size cap from the lock and the river class, a governance regime, an alternative-route role when the sea route closes) scaled to barge convoys rather than deep-sea ships.
Limitations
This article maps the chokepoints and the size classes they set; it is not a transit manual or a substitute for the authority’s current notices. Canal dimensions, draft limits, and tolls change: the Panama Canal varies its maximum draft week by week with the Gatun Lake level, the Suez Canal Authority revises its tariff circulars most years and is deepening the southern channel, and a published size-class figure is a planning number, not a guarantee for a specific transit. Before fixing a voyage, confirm the current draft, air-draft, and beam limits and the live tariff against the Panama Canal Authority and the Suez Canal Authority directly.
The size-class limits stated here are the standard reference figures: Panamax at 294 m by 32.31 m by 12.04 m, Neopanamax at 366 m by 49 m by 15.2 m, Suezmax at about 50 m beam and around 16 m laden draft (against a Suez Canal maximum permissible draft near 20.1 m at reduced beam), and Malaccamax at about 21 m draft. The actual maximum for a given ship depends on its trim, its salt-water-to-fresh-water draft correction, and the day’s published limit, and a ship at the class edge can be refused on a low-water day. The oil-transit and trade-share figures come from the cited primary sources for the years stated and move with the market and with disruption; the Bab-el-Mandeb and Red Sea volumes in particular fell through 2024 as traffic rerouted, and a current figure should be read against the source’s latest release rather than against the number quoted here.
The strait security and law-of-the-sea description is a general summary; the rights of transit passage, the littoral states’ enforcement powers, and the applicable war-risk and sanctions regime turn on the specific passage, the flag, and the cargo, and a real routing decision through a contested strait needs current legal and war-risk advice, not a generic account. None of the linked calculators replaces a full voyage estimate built on the actual ship, the actual route, and the live tolls and bunker prices.
See also
- Panama Canal: the 80 km lock canal, the Panamax and Neopanamax classes, and the PC/UMS toll system.
- Suez Canal: the 193.3 km sea-level cut, the Suezmax tanker, and SCNT dues.
- Strait of Malacca: the busiest international strait, the Malaccamax draft, and the STRAITREP and ReCAAP security regime.
- Danube River basin: inland-waterway navigation, the UNECE waterway classes, and the Belgrade and ICPDR conventions.
- Voyage estimation: turning a routing choice into a cost of bunkers, days, and dues.
- Freight forwarding and incoterms: how cost and risk pass between seller and buyer across the modal break at a port.
- Ports and terminals overview: the place where the inland and deep-sea legs of a route meet.
- Charter parties overview: how canal dues and war risk are allocated between owner and charterer.
- Voyage charter party: the owner-carries-canal-dues family of charter.
- Time charter party: the charterer-carries-canal-dues family of charter.
- Panama Canal PC/UMS toll calculator: estimate Panama tolls by ship type and PC/NT.
- Suez Canal SCNT dues calculator: estimate Suez dues on the SCNT basis.
- Voyage fuel and CO2 calculator: size the fuel and emissions gap between a canal transit and the diversion.