Built for the people who plan and price voyages: charterers, owners, operators and brokers deciding whether a ship fits a route and what the transit will cost. The canal transit limits that matter — beam, draft and air draft — and the tolls live scattered across canal-authority circulars that change with drought and tariff seasons. We assembled the current limits, the "which ‑max fits" map and indicative tolls into one place.
The rynda voyage-economics calculator applies canal tolls and restrictions by vessel class when it builds a route, so you can price a Suez-vs-Cape decision directly.
📖 See also: Ship types & sizes · Freight rates & the market · ECA / SECA zones reference
Contents
- At a glance
- Canal transit limits by waterway
- Panama Canal
- Suez Canal
- Kiel Canal
- Turkish Straits — Bosphorus & Dardanelles
- Strait of Malacca and the St Lawrence Seaway
- Which ‑max fits which canal
- What a transit costs
- For developers and modellers
- FAQ
- References
At a glance
The short version, if you read nothing else:
- A canal limit is usually one of four numbers: length overall (LOA), beam (width), draft (depth below the waterline), or air draft (height above the water). The tightest one for your ship decides whether you fit.
- Panama has two sets of locks. The old locks cap beam at 32.31 m (Panamax); the new Neopanamax locks (2016) allow beam 51.25 m, LOA 366 m — but draft is drought-sensitive (nominally 15.2 m, stepped down to 15.09 m in early July 2026 and further toward ~14.8 m by mid-August).
- Suez has no locks — it's limited by draft (~20.1 m) and air draft (~68 m under the Suez Canal Bridge), so it passes fully-laden Suezmax tankers and the largest container ships; VLCCs (Very Large Crude Carriers, ~2m-barrel tankers) transit part-laden.
- Kiel and the Seaway are the small ones: Kiel caps LOA ~235 m / draft ~9.5 m / air draft 40 m; the St Lawrence Seaway caps LOA ~225.5 m / draft ~8.08 m (Seawaymax).
- Capesize is too big for the Panama Canal laden (its draft exceeds the ~15 m Neopanamax limit) — the "Cape" name is historical, from before Suez was deepened; the modern Suez can in fact pass a laden standard Capesize, and only the very largest VLOC/Valemax are Suez-excluded on draft. Many Capesize routes still go via the Cape of Good Hope, but for distance, not size.
- Tolls are large and structured differently per canal (Suez in SDR — the IMF Special Drawing Right, ≈ US$1.37 — per net tonne; Panama by type/tonnage/booking slot). Budget them into TCE (Time Charter Equivalent — the voyage's net daily earnings), not as an afterthought.
Limits and tolls change with drought measures and annual tariffs. Always confirm the current canal-authority circular before fixing; the figures here are the 2026 baseline.
Canal transit limits by waterway
Maximum vessel dimensions by waterway (2026 baseline):
"TFW" = Tropical Fresh Water — the draft reference used at Panama, where fresh water and climate shift the safe draft.
| Waterway | Max LOA | Max beam | Max draft | Max air draft | Locks? |
|---|---|---|---|---|---|
| Panama — old (Panamax) locks | 294.13 m | 32.31 m | 12.04 m TFW | 57.91 m | Yes |
| Panama — Neopanamax locks | 366.14 m | 51.25 m | 15.2 m TFW nominal (drought-cut: 15.09 m early Jul, ~14.8 m mid-Aug 2026) | 57.91 m | Yes |
| Suez Canal | no fixed limit | ~77.5 m (draft-dependent) | ~20.1 m (66 ft) | ~68 m | No |
| Kiel Canal | 235 m | 32.5 m | 9.5 m (7.0 m full-length) | 40 m | Yes |
| Turkish Straits (Bosphorus/Dardanelles) | no fixed limit | — | practical ~17–20 m | ~58 m (bridges) | No |
| Strait of Malacca | — | — | ~20 m laden (≈25 m channel) | — | No |
| St Lawrence Seaway | 225.5 m | 23.8 m | 8.08 m (26.5 ft) | 35.5 m | Yes |
| Magellan Strait | no fixed limit | — | natural deep water | — | No |
Panama Canal
Two lock systems run in parallel, and the class you can send depends on which one you need:
- Old (Panamax) locks — beam 32.31 m, LOA 294.13 m, draft 12.04 m TFW. This is the classic Panamax envelope (and the container "Panamax" ~5 100 TEU — twenty-foot container-equivalent units).
- Neopanamax locks (opened 2016) — beam 51.25 m, LOA 366.14 m, draft nominally 15.2 m TFW. These take Neopanamax boxships (~14 000 TEU) and larger bulkers/tankers.
The live variable is draft: Gatún Lake is rainfall-fed, so drought forces the Authority to publish reduced maximum drafts. The Neopanamax maximum was cut to 15.09 m (49.5 ft) from early July 2026. A ship loaded to the nominal 15.2 m can be forced to lighten or trans-ship. Air draft is capped at 57.91 m by the Bridge of the Americas.
Too big for either Panama lock — the giants (ULCV ultra-large container vessels, ULCC ultra-large crude carriers, Valemax ore carriers) — route via Cape Horn or the Cape of Good Hope. (The widest of these also exceed Suez; a standard laden Capesize, however, fits Suez.)
Suez Canal
Suez is a sea-level canal with no locks, so it isn't limited by lock chambers — it's limited by depth and bridge height:
- Draft ~20.1 m (66 ft) at the standard beam; a published draft/beam table trades one against the other, so a narrower ship can go deeper and a very wide ship must be shallower (beam up to ~77.5 m at reduced draft).
- Air draft ~68 m under the Suez Canal Bridge.
- No practical length limit.
Consequence: Suez passes fully-laden Suezmax tankers (~1 m barrels) and the largest container ships, while VLCCs transit part-laden or in ballast to stay within the draft. This is why the historical "Suezmax" class is a draft/beam envelope, not a lock size — and why the canal, unlike Panama, isn't drought-limited.
Kiel Canal
The Kiel Canal is the short-cut from the North Sea to the Baltic (avoiding the run around Denmark). It's a small-ship canal:
- LOA 235 m, beam 32.5 m, draft 9.5 m (reduced to ~7.0 m for maximum length/beam), air draft 40 m under the fixed bridges.
It handles feeder boxships, Handysize/Supramax bulkers and small tankers — anything Panamax-beam or under with modest draft. Larger ships take the longer Skagen route around the top of Denmark (which also crosses the North Sea and Baltic SECAs).
Turkish Straits — Bosphorus & Dardanelles
The Bosphorus and Dardanelles connect the Mediterranean/Aegean to the Black Sea. They are natural straits, not built canals, governed by the Montreux Convention:
- No fixed lock, but large ships need pilotage, tug escort and traffic scheduling through a narrow, winding, current-swept channel that runs through Istanbul.
- Air draft ~58 m is the practical bridge limit; deep-draft ships are managed by traffic separation and daylight/one-way rules rather than a hard draft cap.
For voyage planning the Straits rarely exclude a ship on size, but they add waiting time and pilotage cost, and Montreux dues apply.
Strait of Malacca and the St Lawrence Seaway
- Strait of Malacca — the Asia–Middle East artery. Limited by the strait's ~25 m controlling depth, giving a laden-draft ceiling of ~20 m — the Malaccamax class (~300 000 DWT). Don't confuse the channel depth (25 m) with the ship's draft (20 m).
- St Lawrence Seaway — into the North American Great Lakes. A tight lock system: LOA 225.5 m, beam 23.8 m, draft 8.08 m (26.5 ft), air draft 35.5 m (116 ft) — the Seawaymax class. Anything Panamax-sized is already too big.
Which ‑max fits which canal
The "‑max" ship classes are literally named for these limits (full glossary in Ship types & sizes):
| Class | Binding waterway | Fits |
|---|---|---|
| Seawaymax | St Lawrence Seaway | Seaway + everything larger downstream |
| Panamax | Old Panama locks (beam 32.31 m) | Old + new Panama, Suez, Kiel-ish |
| Kamsarmax | Port Kamsar (LOA ~229 m) | As Panamax for canals |
| Neopanamax | New Panama locks (beam 51.25 m) | New Panama, Suez |
| Suezmax | Suez draft envelope (~20.1 m) | Suez laden; too wide/deep for old Panama |
| Newcastlemax / Capesize | (port/route, not a canal) | Too big for Panama laden → Cape route, though the modern Suez can take a laden standard Capesize |
| Malaccamax | Malacca depth (~25 m) | Malacca; too big for Panama, and at ~20 m draft borderline for Suez |
The rule of thumb: a Capesize or bigger cannot use the Panama Canal laden — it routes via the Cape of Good Hope or Cape Horn. That's usually a distance choice as much as a size one; a laden standard Capesize does fit the deepened Suez, and only VLOC/Valemax-scale giants are Suez-excluded on draft.
What a transit costs
Canal tolls are material — often tens to hundreds of thousands of dollars — and each authority prices differently:
- Suez Canal — charged in SDR per Suez Canal Net Tonne (SCNT), with surcharges and vessel-type coefficients; the SCA revises tariffs regularly. As a very rough order of magnitude for a large ship, on the order of $8–12 per GT (gross tonnage) laden — but the real bill is driven by the SCNT tariff and coefficients, so use it only as a placeholder and confirm the current tariff.
- Panama Canal — priced by vessel type, tonnage/TEU and lock system, plus a booking-slot fee that spikes when the canal auctions scarce slots in drought. Indicatively ~$10–14 per GT laden.
- Turkish Straits — Montreux dues (modest, per net tonne) plus pilotage/tug.
- Kiel Canal — a per-NT due (small, ~$0.5–0.6/GT-equivalent) plus pilotage and line-handling.
- Magellan Strait — free under Chilean rules (a natural passage).
These are estimation figures for fixture P&L, not the final disbursement — the real bill depends on the current tariff, the ship's exact tonnage certificates and booking. Fold them into TCE: the voyage-economics calculator charges the canals a route actually crosses.
For developers and modellers
- Route-aware tolls: the voyage-economics calculator detects which canals a route crosses and charges laden/ballast tolls per canal by GT, so a Suez-vs-Cape comparison shows up directly in TCE.
- Fit logic: gate a class against a waterway by its binding dimension — Panama old by beam ≤ 32.31 m, Neopanamax by beam ≤ 51.25 m + draft ≤ current TFW max, Suez by draft ≤ ~20.1 m + air draft ≤ 68 m, Seaway by LOA ≤ 225.5 m + draft ≤ 8.08 m.
- Drought is a variable, not a constant: treat the Panama Neopanamax max draft as an input (15.09 m from 1 Jul 2026, subject to change), not a hardcoded number.
FAQ and common confusions
Q: What's the difference between Panamax and Neopanamax?
A: Panamax fits the old Panama locks (beam ≤ 32.31 m, LOA ≤ 294 m). Neopanamax fits the new 2016 locks (beam ≤ 51.25 m, LOA ≤ 366 m). Both names are current because both lock sets still operate.
Q: Why can Suez take bigger ships than Panama if it's older?
A: Suez has no locks — it's a sea-level cut limited only by depth (~20.1 m draft) and bridge height, so it passes fully-laden Suezmax and the largest boxships. Panama's ships must fit inside a lock chamber.
Q: Why does the Panama draft keep changing?
A: The locks are fed from rainfall-dependent Gatún Lake. Drought forces the Authority to publish reduced maximum drafts (e.g. 15.09 m from early July 2026). Model it as a moving input.
Q: Can a VLCC transit the Suez Canal?
A: Yes, but usually part-laden or in ballast to stay within the ~20.1 m draft. Fully laden, a VLCC is too deep. (The SUMED pipeline exists partly to move crude past this constraint.)
Q: Air draft — when does it actually bite?
A: For tall ships (large container stacks, LNG carriers) under fixed bridges: 57.91 m at Panama, ~68 m at Suez, 40 m at Kiel, ~58 m in the Bosphorus, 35.5 m on the Seaway. A ship can fit every other limit and still be too tall.
Q: Can a laden Capesize transit the Suez Canal?
A: Yes — a standard laden Capesize (~18 m draft, ~47 m beam) fits the modern deepened Suez (20.1 m draft envelope). The "Cape" name is historical, from before Suez was deepened; Capesizes still often route via the Cape of Good Hope, but for distance, not because they don't fit. What's genuinely too big is a laden Panama transit (draft over the ~15 m Neopanamax limit) and, for Suez, only the largest VLOC/Valemax.
Q: What is TFW (Tropical Fresh Water)?
A: TFW is the draft reference the Panama Canal uses — the maximum draft a ship may have in the canal's warm fresh water. Fresh water is less dense than seawater (so a ship sits deeper) and Gatún Lake's level swings with rainfall, which is why the Panama TFW draft limit is published and cut during drought.
Q: Is the Kiel Canal worth it for a Panamax?
A: No — Kiel caps beam at 32.5 m and draft at ~9.5 m, so a laden Panamax bulker generally takes the longer Skagen route around Denmark instead.
Q: How much does a canal transit cost?
A: Enough to matter to TCE — roughly ~$8–14 per GT laden at Suez or Panama for a large ship, plus Panama's booking-slot fee in drought. Always price it from the current tariff and the ship's tonnage certificates.
References
- Panama Canal Authority (ACP) — Vessel Requirements notices and toll tariffs (Neopanamax/Panamax limits, draft advisories).
- Suez Canal Authority (SCA) — navigation rules, the draft/beam table and toll circulars (SDR per SCNT).
- Kiel Canal (Kiel-Canal.org / WSV) — dimensions and traffic rules.
- Montreux Convention — Turkish Straits regime and dues.
- St Lawrence Seaway Management Corporation — Seawaymax dimensions.
- rynda voyage-economics calculator and Ship types & sizes.
Document version
- 2026-07 — first public version. Panama (both lock sets, incl. the 1 Jul 2026 draft cut), Suez, Kiel, the Turkish Straits, Malacca and the Seaway, with the ‑max fit map and indicative tolls. Canal limits and tariffs change; confirm the current authority circular before fixing.