Draft increase at Amazon’s North Bar

Maritime authority renews permission for vessels leaving the Amazon ports through the North Bar with a draft of up to 11.90 metres

Following up on the trials started in April 2020, on 6 January 2022, the 4^th Naval District (4DN) issued Ordinance 7/Com4ºDN authorising, on an experimental basis, vessels sailing out of the North Bar of the Amazon River through the so-called Arco Lamoso (“Muddy Arc”), with a maximum operational draft of 11.90 metres. The Muddy Arc is a stretch of seabed composed of fluid mud at about 146 nautical miles off Macapá in the state of Amapá.

The temporary permission has immediate effect and does not apply for tankers and vessels of any size carrying dangerous goods.

Conditions and restrictions

Vessels sailing downstream the Amazon River through the North Bar with a draft limit between 11.75 m and 11.90 m must observe the following restrictions and guidelines:

• Inform the 4DN of the intention to sail with the experimental draft 24 hours in advance

• Consider the prevailing tide at the time of departure, observing a minimum under keel clearance (UKC) of 0.50 m, mindful of the characteristics of each vessel

• Observe the height of the tide in the Muddy Arc, which must be equal to or higher than 3.10 m, according to the tide table of the Navy Directorate of Hydrography and Navigation (DHN), to navigate in the high tide in the area within specific coordinates (Point 1: Lat 01° 39’ N – Lon 049° 01’ W; Point 2: Lat 01° 29’ N – Lon 048° 52’ W; Point 3: Lat 01° 20’ N – Lon 049° 37’ W; and Point 4: Lat 01° 11’ N – Lon 049° 28’ W)

• It is forbidden to wait at anchor for a sailing tide window within the above-mentioned geographic points

• Keep adequate speed to minimise squatting

• Observe full compliance with the draft limitations imposed

• Vessels sailing with a draft above 11.50 m must compulsorily take a pilot

To sail via the Grande do Curua Channel through the Muddy Arc, outbound vessels must, sequentially, meet the criteria below until they reach a maximum loaded draft of 11.90 metres:

• Two passages with a draft of 11.75 m;
• Two passages with a draft of 11.80 m;
• Five passages with a draft of 11.85 m; and
• Five passages with a draft of 11.90 m

The coordinating pilot station must assign a pilot with at least five years of experience with navigation in the area and coordinate the boarding of at least one representative of the maritime authority

Reporting requirements

Within a maximum of 10 days after each passage, the pilot must issue a standardised and conclusive report on the manoeuvre performed, informing i) whether it was safe or posed a risk to navigation, ii) the draft observed, iii) the plotting of vessel’s position every five minutes with the local depth, according to the tide height, and iv) the speed developed by the vessel considering the squat effect and the lowest under keel clearance (UKC) observed during the passage through the given coordinates.

After fourteen sequential passages with the increasing drafts mentioned above, and within thirty days, the maritime authority will review the pilot reports and assess the feasibility of maintaining the increase in the draft limit permanently. However, if the authority perceives any risk to vessels sailing with the increased draft, it may simply revoke the Ordinance at once.

Impact and repercussions

North Bar is the main gateway for vessels calling at the Northern Arc’s Amazon ports of Manaus, Itacoatiara, Santarém, Juruti, Trombetas and Santana (Macapá). In addition to containerships, ocean-going bulk carriers arrive with fertilisers for Brazilian agribusiness and depart with commodities such as soya beans, corn, wood chips and minerals (iron ore, bauxite, and manganese) originating from the Central-West and North regions of Brazil.

Increasing the draft limitation in the region is one of the measures defended by the Brazilian Association of Private Port Terminals (ATP). It recognises that the increment of just 20 centimetres means an extra payload of a few thousand tonnes, which significantly impacts the productivity and revenue of the terminals and optimisation of the use of bulk carriers.

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