The Cuauhtémoc 

A detailed analysis of the events and decisions that led to the fatal collision.

As a sailor myself, I have experienced similar situations. This article is not about the storied history of the proud Mexican tall ship Cuauhtémoc, but rather a factual, comprehensible, and nautical analysis of a tragic accident.

The Known Facts

The Cuauhtémoc is a 90.5-meter-long, approximately 1,800-ton steel vessel. It is powered by a diesel engine rated at around 1,125 horsepower (827 kW), used primarily for harbor maneuvering and calm wind conditions. In contrast to the identically built German ship Gorch Fock, the vessel was not equipped with a bow thruster, based on the information available to us. ship features three steel masts and a full rig that can carry up to 2,368 square meters of sail. At the time of the accident, many crew members were secured in the rigging, preparing to set sail. Why this matters will become clear shortly.

The Location and Current Conditions EAST RIVER near Pier 17 NY

The accident occurred on May 17, 2025, at 8:26 PM at the Brooklyn Bridge in New York City. The bridge spans the East River — a waterway that, despite its name, is not a river in the traditional sense but rather a tidal strait between Long Island and Manhattan, heavily influenced by Atlantic tides.

That evening, a flood tide was in effect, meaning water was flowing northward (upriver) with a documented current speed of up to 5 knots (approximately 2.57 m/s). The geographic constriction at the Brooklyn Bridge can amplify these currents even further.

Speaking from personal experience, I’ve seen firsthand how powerful the current can be in a river delta. I once tried to take a 50-horsepower motorboat upriver on the Guadalquivir near Sanlúcar de Barrameda — and even at full throttle, I couldn’t make any headway against the current.

Interestingly, Christopher Columbus did manage that same stretch, but of course, he didn’t have a motor. He sailed up the Guadalquivir — well, he was Columbus, after all.

For a modern parallel, just look at sailor and YouTuber Sam Holmes. In one of his videos, he attempted to sail to Portsmouth, but the tidal current was so strong that he was pushed back and had to divert to Cowes instead. He couldn’t make it into the harbor against the current with his sailboat and had to wait it out. Currents like these aren’t just theoretical — they define what’s possible on the water. Sam Holmes Video watch here.

According to the available tidal data, the vessel’s departure time was relatively well timed. Had it departed just an hour later, it would have encountered a significantly stronger flood tide current.

The Wind Conditions

According to weather records, a southeasterly wind of about 10 mph (16 km/h) was blowing. While this might seem moderate, one must not underestimate its effect on a fully rigged sailing vessel — especially when many crew members are aloft in the rigging. Each person in the rigging presents surface area to the wind, significantly increasing aerodynamic drag — comparable to a set mizzen sail.

Sail Effect Without Sails

One might argue: “But the sails weren’t set — so it doesn’t matter.” However, anyone who has ever tried to raise a mast on a sailboat in 16 km/h wind without a crane knows just how much resistance even a bare mast can offer. Three fully rigged steel masts with shrouds, yards, lines, and people aloft create significant windage — even without sails.

Was the Engine Powerful Enough?

To answer that, let’s examine the forces involved and compare them to the engine’s capabilities:

Technical Analysis: Was Cuauhtémoc’s engine sufficient?

Cuauhtémoc — Data Summary

Parameter Value Displacement approx. 1,800 t Hull type Sleek, classic barque Length overall 90.5 m Engine power 1,125 HP (827 kW) Propeller 1 screw (est. diameter ~1.8 m)

Scenario: Drifting Astern Against Current (East River)

Factor Assumption Current 5 knots (2.57 m/s) against the vessel Wind 16 knots (8.2 m/s) from astern Rudder effect Severely reduced due to backward drift

Step 1: Hydrodynamic Resistance (Current)

We use the classical drag formula:

Step 2: Aerodynamic Drag (Rigging & Crew)

Even without sails, the three steel masts, rigging, and crew members aloft generate significant wind resistance.

• Estimated surface area: 200 m²
• Air density: 1.225 kg/m³
• Drag coefficient: 1.2
• Wind speed: 8.2 m/s

Step 3: Available Propulsion Force

With 827,000 W engine power and 55% propeller efficiency:

Summary of Forces:

Resistance Source Force (N)

Water current drag ~32,500 N

Wind on rigging & crew ~9,900 N

Total resistance ~42,400 N

Engine thrust available ~177,000 N

Preliminary analysis indicates that the Cuauhtémoc had sufficient engine power to maintain its position against both the current and the moderate wind. However, this assumption only holds true under one condition: that the vessel was moving forward — not astern.

Anyone who has ever maneuvered a boat in reverse knows that rudder effectiveness is significantly reduced. Ships operating in reverse are far more difficult to control. (A brief technical note: this is exactly why so-called pod drives — where the entire propeller unit can rotate — are so advantageous; they offer excellent maneuverability even when going astern.)

What is Pier 17?

Pier 17, located on the East River in Lower Manhattan, is not part of New York’s official port infrastructure. It is:

• Not a public commercial harbor
• Not under the jurisdiction of the Port Authority of NY & NJ
• Not a “free docking point” for vessels

Instead, Pier 17 is municipally owned, managed by the New York City Economic Development Corporation (NYCEDC) and operated by the Howard Hughes Corporation.
Anyone wishing to dock here does not need a port clearance — but rather a private agreement with the operator.

What applies on the East River — Pilot requirement? Tug requirement?

The East River is not a traditional river route but rather a tidal strait, with its current reversing direction several times a day. For this reason, under U.S. law, it is classified as a “navigable water of the United States” — meaning it is a federally regulated waterway.

The following regulations apply here:

• Pilotage requirement under 46 U.S.C. § 8501 ff.:
  Vessels over 100 gross register tons or flying a foreign flag are required to have a state-licensed pilot on board.
• Reporting requirement under 33 CFR § 161 (U.S. Coast Guard):
  Large vessels must notify Vessel Traffic Service (VTS) New York of their arrival or departure via VHF radio.
• New York Navigation Law § 89 complements these federal rules at the state level.

Pilot was on board. But: What does a pilot do?

Based on the information available to us, a state-licensed pilot was on board the vessel at the time of the incident. These pilots are local experts — often born in the region or trained through many years of hands-on experience. They are intimately familiar with the unique conditions of the East River: every current, every bridge clearance, every shoal or sandbank.

❗ Importantly: A pilot never physically steers the vessel.
The pilot does not assume command, but rather provides the captain and helmsman with navigational guidance — such as course corrections, speed adjustments, or responses to current and traffic conditions. The crew continues to operate the vessel, and the ultimate responsibility remains with the captain.

This division of responsibility is defined by law: 46 U.S. Code § 8501(c):
“This chapter does not affect the master’s responsibility for the safe navigation ofthe vessel.”

In other words, even when a pilot is on board, the captain (master) retains full legal responsibility for all decisions — including whether to follow the pilot’s advice in critical situations.

In practice: The pilot is the local expert. The captain remains the commanding authority.

Was the U.S. Coast Guard under a legal obligation to deny passage under the prevailing conditions?

On the evening of May 17, 2025, conditions on the East River appeared calm at first glance: mild winds of around 10 miles per hour and clear visibility. But beneath the surface, nature was already shifting. The tide was turning, and the notorious tidal current of the East River was gaining strength — a silent force reaching up to 4 knots.

In precisely such moments, a key authority comes into play:
the Captain of the Port (COTP) of the United States Coast Guard (USCG) — in this case, COTP New York.

This official is empowered under federal law (see 33 CFR § 160.111, § 161.11, and 46 U.S.C. § 70051) with the authority — and in hazardous conditions, even the obligation — to regulate or prohibit vessel movements.

The powers of the COTP include:

• Issuing navigation restrictions or closures for specific waterways,
• Detaining individual vessels in port,
• Imposing mandatory pilotage or tug assistance, even on short notice,
• Enforcing no-anchoring zones or temporary traffic suspensions.

Typical reasons for such actions include:

• Strong currents that make safe maneuvering difficult,
• Limited vessel maneuverability (e.g., no bow thruster),
• Or navigational choke points, such as the area beneath the Brooklyn Bridge.

Enforcement can occur through:

• VHF radio contact with Vessel Traffic Service (VTS) New York,
• Direct orders from a Coast Guard patrol vessel,
• Or preemptive safety advisories, such as a Marine Safety Information Bulletin (MSIB).

Is there a legal obligation to secure the vessel to a tug (tow assist) near the Brooklyn Bridge on the East River?

Short answer: No general legal obligation — but conditional authority exists.

There is no automatic, federally mandated legal obligation under U.S. law for a vessel to be physically secured to a tugboat (i.e. “made fast”) while transiting the East River — even near the Brooklyn Bridge, where navigation is narrow and tidal currents strong.

However, based on federal regulations, the U.S. Coast Guard — specifically the Captain of the Port (COTP) New York — has broad discretionary authority to require tug assistance, including making fast, depending on the situation.

Application near the Brooklyn Bridge (East River):

The area near the Brooklyn Bridge is:

• A tidal choke point with narrow clearances and frequent ferry and commercial traffic,
• Subject to strong, reversing tidal currents (often 3–4 knots),
• Under the active monitoring of Vessel Traffic Service (VTS) New York.

In such zones, the Captain of the Port may require:

• One or more tugboats,
• That the vessel be made fast to a tug (secured),
• Or that tug assist be on standby for safety.

This is often determined by:

• Vessel size and type (e.g., length over 65 ft / ~20 m),
• Maneuverability (e.g., lack of bow thruster),
• Traffic density and current strength.

A tug was not legally required, yet one was either requested or assigned. However, when analyzing the footage of the vessel’s departure, it is questionable what role the tug at the bow actually played. Given the tidal current at that hour, the vessel would have naturally drifted away from the pier.

The only plausible function of the tug positioned at the bow was likely to prevent the ship from being pressed sideways against Pier 17 by the incoming current — and to assist in gently pushing it toward the center of the East River’s navigational channel, where the vessel could then gain headway under its own engine power.

Why did investigators board only three days later?

I can only speculate here — but the timeline raises legitimate questions.
Under normal circumstances, all ships within the waters surrounding New York fall under the territorial jurisdiction of the United States.

This means that U.S. authorities — such as the Coast Guard or local police — are generally permitted to board a vessel, especially in the case of an incident involving public infrastructure, such as a collision.

The legal basis for such action includes:

• 46 U.S.C. § 70051 — Authority to control vessel movement in hazardous conditions
• 33 CFR § 160.111 — Captain of the Port: Restrictions and orders
• UNCLOS Article 27 — which permits a coastal state to exercise jurisdiction over foreign vessels that voluntarily enter its territorial waters, particularly when public safety is at stake.

However, in this case, the situation is different.

ARM Cuauhtémoc is not a civilian vessel, but an officially commissioned warship of the Mexican Navy.
The abbreviation “ARM” stands for Armada de la República Mexicana.

And under international law, warships are subject to special legal protections.

According to UNCLOS Article 32, warships enjoy complete immunity from the jurisdiction of any foreign state, even while docked in a foreign port.

It is reasonable to assume that the Mexican government withheld immediate permission for U.S. investigators to board the ship.
Mexican military and naval police personnel — perhaps representing the Navy or other state institutions — may have insisted on conducting their own internal investigation first.

Summary:

Based on the current analysis, the following conclusions can be drawn:

Weather conditions were normal at the time of departure. The chosen departure time was reasonably aligned with the tidal cycle. All applicable legal requirements for navigating the waterway were observed. A licensed pilot was on board. Although tug assistance is not mandatory by law, a tug was present to support the vessel during departure.

Assuming the captain was an experienced seaman, two plausible scenarios emerge:

1. Either he was unable to apply forward thrust to the propeller when the tug released the vessel, or
2. he did so too late.

It is highly likely that the captain was well aware of the thrust capacity of his ship. For that reason, he likely saw no need to request an additional tug or to remain secured to the assisting vessel. Furthermore, as seasoned sailors, we can reasonably assume that the captain correctly assessed the wind and current conditions, as well as the distance to the bridge. This was almost certainly not his first time commanding this ship — especially considering he planned to sail on to Iceland afterward, where wind and currents often dictate what ships can or cannot do. Those who succeed in such waters must have a deep understanding of their ship’s limits and capabilities.

In the end, the most likely explanation remains: the captain was either unable to engage the engine in time or was unable to generate sufficient forward thrust to stabilize the ship once it had already begun drifting astern.

Upon reviewing the footage, I would cautiously suggest that the vessel did not have its engine engaged while drifting in the center of the East River’s navigational channel. It appears the ship was caught by the current, which accelerated it to approximately 6 knots.

Only after the vessel struck the Brooklyn Bridge did the crew seemingly manage to bring the engine online — just in time to prevent a full collision with the shoreline.

This observation raises critical questions about the timing of engine activation, situational awareness on the bridge, and the vessel’s readiness to maneuver under its own power in a fast-flowing tidal strait.

We now await the details to be provided by the official investigation report.