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The final moments before two vessels collide are a dichotomous mix of shockingly deep denial and frantically futile efforts to prevent the crash. The skipper’s mind is racing between “How can this be happening?” and “What can I do to prevent it?”

Any boater who has been involved in a collision would love to be able to turn back time to see how the accident could have been avoided. Fortunately, in post-accident investigations, we have the opportunity to do just that.

Examining what went wrong, and focusing on the lessons to be learned, can teach us all kinds of things about how to keep ourselves and our guests safe on the water.


A Case-Study Collision

It was 12:50 a.m. when the guided-missile destroyer USS Porter was navigating through the Strait of Hormuz, a major oil and gas shipping route leading into the Persian Gulf. Steaming along at 20 knots, the Porter attempted to pass ahead of an oil tanker approaching from the starboard bow. At the Porter’s speed, it was possible to make it, but it would have been safer to reduce speed, turn to starboard and pass behind the tanker.

As the Porter was passing the ship, the officer of the deck spotted the port light of a second oil tanker, blocked from view by the first tanker. It remains under investigation how the second vessel was undetected by sailors monitoring the Porter’s advanced radar system.

A recording of the bridge communication reveals the officer of the deck sounding concerned and telling the captain: “Sir, I have another merchant here on the starboard bow.” Having just barely cleared the bow of the first tanker, it was quickly becoming apparent that the Porter likely would not clear the bow of the second tanker. The officer of the deck requested permission to turn to starboard and pass behind the second vessel.

The ship’s captain dismisses the recommendation, and instead asks, “Why don’t we just go straight this way?” suggesting that the Porter should once again pass in front of an approaching ship. The officer of the deck hesistates before saying, “Aye, sir.”

Moments later, he again raises caution and says: “Sir, I would like to slow down.” The captain relents, and the officer gives the order to slow from 20 knots to 5 knots.

None of this would matter. The Porter’s fate was sealed. The ships would collide, with the tanker’s bow striking the Porter’s starboard side. While there was significant damage to both ships, no one was seriously injured.

The communication and confusion between the officers on deck is chilling to hear, and should be a lesson for all boaters. Even more alarming is that all of this took place on a ship with highly trained professional mariners, using the most sophisticated equipment.

If this could happen to them, then imagine how easily it could happen to us recreational boaters.

Learning the Rules of the Road

Many collisions, whether they involve commercial or recreational vessels, occur as a result of passing dangerously close to another vessel. In any approaching, crossing or passing situation, you may be able to squeeze by, but why try? The slightest miscalculation is too often met with disaster. Is the risk really worth the few moments you save by not slowing down and going around?

All vessels, from supertankers to rowboats, are required to follow internationally agreed upon navigation rules when encountering other vessels. Learning all the rules takes years of study, even by professional mariners. It is unlikely that recreational boaters will commit all of the rules to memory, but it’s critical for all boaters to learn the basic rules.

Collisions sometimes occur as the result of a common misunderstanding that in certain situations, one vessel has the “absolute” right-of-way over other vessels. The reality is that no vessel ever has complete right-of-way over another. Navigation rules provide for a “give-way” and “stand-on” vessel, or there may be two give-way vessels and no stand-on vessel. For example, two power-driven vessels approaching head-to-head are both considered to be give-way. Both are required to alter their course to avoid a collision.

Under no circumstances does a stand-on vessel have unconditional right-of-way over a give-way vessel. The rules say that the stand-on vessel has an “obligation” to keep a constant course and speed, so the give-way vessel can, in the prescribed manner, safely alter its course. So, “stand-on” only has an obligation, not a right. It is not privileged, nor is it free of the responsibility to prevent a collision.

The guided-missile destroyer USS Porter suffered significant damage after colliding with an oil tanker in the Strait of Hormuz. Facing page: Following an investigation of the incident, the commanding officer was relieved of command. Forunately, no one was seriously injured on either ship.

The guided-missile destroyer USS Porter suffered significant damage after colliding with an oil tanker in the Strait of Hormuz. Facing page: Following an investigation of the incident, the commanding officer was relieved of command. Forunately, no one was seriously injured on either ship.

And, the stand-on vessel may still be obliged to give way itself, particularly when a collision can no longer be avoided by actions of the give-way vessel alone. Too frequently, a boater will allow a situation to come too close to a collision, insisting on the right-of-way.

In almost all instances, more communication can prevent a tragedy. The rules state that the give-way vessel shall initiate early and obvious maneuvers to avoid a collision. The “obvious” part of that is a form of communication. If you swing your bow wide to starboard in an approaching or crossing situation, you’re communicating your intention to the other vessel. However, even in this case, the stand-on vessel has to monitor the give-way vessel’s actions and be prepared to take evasive maneuvers.

It doesn’t take much of an imagination to see how problems arise in this scenario. If the stand-on vessel takes those evasive maneuvers too soon, the skipper has violated his obligation to hold course and speed. If he waits too long, he could allow a situation to come too close to a collision. The keys are early awareness of the other vessel and communication.

Tips For a Safe Day on the Water

Be willing to get on the VHF radio and ask the other boater’s intentions. Commercial vessels agree upon a passing arrangement over VHF channel 13. When you’re navigating around commercial traffic, monitor VHF channels 16 and 13. All vessels over 65 feet are required to monitor both channels, but few recreational vessels do.

Along the Intracoastal Waterway, recreational vessels are in the habit of communicating their passing intentions over channel 16. Technically, this shouldn’t be taking place on channel 16, but the U.S. Coast Guard appears to be overlooking it. We would all do well to communicate passing arrangements on channel 13.

Whenever possible, stay out of navigation channels where larger, deep-draft commercial boats need to operate. Uncertainty reigns in the mind of a professional mariner when encountering a recreational boater. You can help eliminate that uncertainty. Initiate contact on channel 13 and ask how the larger vessel would like you to safely maneuver around it.

The modern commercial captain’s lingo for agreeing on a passing arrangement hearkens back to the days of steamships. Before VHF radio, a ship would signal its intention to turn to starboard with one short blast of the ship’s whistle. The intersecting ship would acknowledge with a single short blast of its own. If the ships were turning to port to pass each other, they would sound two short blasts of their whistles.

Today, when two approaching ships are calling each other on the VHF radio, they will typically ask, “See you on one whistle captain?” and the other will respond, “Yes, sir, see you on one,” meaning they will pass port to port.

Watch-keeping is a critically important, dedicated role on the bridge of a commercial vessel. It is no less important on recreational vessels. Everyone on board can lend a hand. As the captain of your boat, invite everyone aboard to assist you. Let them know their observations are welcome and appreciated. More than once, my wife or a guest has alerted me to another boat I hadn’t seen.

Early awareness and communication are key to avoiding collisions at sea. Let’s not need a time machine to learn this.

This article was originally published in the April 2022 issue.