Draft Limits Update at Amazon’s North Bar
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The maritime authority has updated regulations for vessels departing Amazon ports via the North Bar, establishing new seasonal draft limits and pilotage requirements
Background
The Barra Norte (North Bar)
Vessels calling at the Amazonian riverports, including Santana, Santarém, Itacoatiara, Novo Remanso, and Manaus, among others, enter and exit the region through the North Bar of the Amazon River. Incoming vessels are cleared at the Fazendinha Pilot Station off Macapá, where compulsory pilotage upriver begins.
Amazon’s Muddy Arc
The so-called Arco Lamoso (Muddy Arc) is a critical nautical stretch at the northern mouth of the Amazon River, located roughly 146 nautical miles from Macapá. It features a seabed composed of fluid mud. The Muddy Arc’s shallow depths and shifting sediments dictate the maximum operational draft for all large vessels entering or leaving the Amazon inland waterways. The area is defined by the following geographical coordinates:
- Point 1: LAT. 01°21.77’ N – LONG. 049°18.65’ W
- Point 2: LAT. 01°30.09’ N – LONG. 049°02.42’ W
- Point 3: LAT. 01°30.70’ N – LONG. 048°58.75’ W
- Point 4: LAT. 01°29.36’ N – LONG. 048°58.77’ W
- Point 5: LAT. 01°28.68’ N – LONG. 049°02.42’ W
- Point 6: LAT. 01°20.32’ N – LONG. 049°18.65’ W
- Point 7: LAT. 01°18.31’ N – LONG. 049°21.09’ W
- Point 8: LAT. 01°19.87’ N – LONG. 049°21.09’ W
Gradual Increases
Since 2020, the Brazilian Navy’s 4th Naval District (regional maritime authority) has authorised, on a precarious and experimental basis, vessels sailing out through the North Bar with increased drafts. According to studies conducted by grain traders and the local pilot association, an increase of 20 centimetres in the draft of a Panamax bulk carrier allows for approximately 1,800 metric tons of additional cargo on board.
New Regulation
Draft limits and pilotage
On 24 April 2026, the maritime authority issued Ordinance 223/Com4ºDN authorising new navigation conditions and maximum drafts for merchant ships sailing through the Grande do Curuá Channel and the Muddy Arc. This revokes previous regulations and comes into effect immediately.
Specific seasonal requirements
To account for the hydrological cycle of the Amazon Basin and its impact on navigation in the North Bar, Ordinance 223/Com4ºDN implements maximum sailing drafts and specific pilotage conditions in the region, divided into two seasonal periods:
From 1 February to 15 August (Flood Season):
- Merchant ships (excluding tankers and vessels carrying dangerous goods): the maximum draft limitation is 11.85 metres.
- Tankers and vessels carrying dangerous goods: the maximum draft is 11.65 m.
- Pilotage: engagement of river pilots is optional for vessels sailing with a draft up to 11.55 m. Pilotage is compulsory for outbound vessels with a draft of 11.56 m or deeper.
From 16 August to 31 January (Dry Season):
- Merchant ships (excluding tankers and vessels carrying dangerous goods): the maximum draft limitation is 11.70 m.
- Tankers and vessels carrying dangerous goods: the maximum draft is limited to 11.50 m.
- Pilotage: hiring a pilot is facultative (and not customary) for vessels sailing with a draft up to 11.50 m. Pilotage is compulsory for vessels with a draft over 11.51 m.
Restrictions and Recommendations
Regardless of the time of the year, outbound vessels passing through the designated coordinates of the North Bar must adopt the following measures:
- Under-keel clearance: the master must consider the prevailing tide to maintain a minimum net under-keel clearance (UKC) of 0.50 m for merchant vessels.
- Hazardous cargoes: tankers and ships carrying dangerous goods must maintain a net UKC of at least 0.80 m.
- Tidal window: All deep-draught crossings through the North Bar must be timed to coincide with high tide.
- Squat effect: maintain adequate speed to minimise squatting, ensuring the statutory 0.5 m to 0.8 m safety gap between the keel and the mud is not compromised.
- No anchorage: it is strictly forbidden to anchor within or near the defined navigable stretch of the Muddy Arc while awaiting a tidal window.
- Pilot experience: the coordinating pilot station must assign pilots with more than five years of experience navigating the Grande do Curuá Channel and the Muddy Arc.
Owners fixing vessels to operate at the Amazon riverports are strongly advised to closely liaise with their local agents and designated port facilities to confirm the prevailing draft restrictions before entering the waterways.
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