To Tether, or Not to Tether: That Is the Question

Going overboard is a coin toss with a 47% chance of death. The safety harness is designed to keep you attached to the boat. The problem is, sometimes staying attached is exactly what costs you your life.

Two Philosophies, One Ocean

Walk through any marina before an offshore passage and you’ll find two distinct camps of sailors preparing their boats. One group is meticulously rigging jacklines, testing tether clips, and checking harness webbing for wear. The other group stows their harnesses in a locker and relies on handholds, experience, and what they call “sea sense.”

Both groups think the other is reckless.

The tethered philosophy is straightforward: stay attached to the boat at all costs. If you go over the side, you’re still connected. The boat drags you, but at least you haven’t disappeared into the night. Recovery is possible because you’re still there to recover.

The untethered philosophy is equally logical: better to fall cleanly into the water than to be dragged alongside a moving hull. An untethered MOB is a recovery problem. A tethered sailor being dragged at 7 knots is a trauma victim—if they survive at all.

Here’s the uncomfortable truth: both philosophies have claimed experienced sailors. The tethered camp has lost people who drowned while attached. The untethered camp has lost people who simply vanished.

When Tethers Become Traps

A tether is not a guarantee of survival. It’s a guarantee of staying with the boat—which isn’t the same thing.

Consider what happens when a tethered sailor goes overboard while the boat is moving at speed. The tether goes taut. The sailor is now in the water, being dragged alongside or behind a vessel making 6-8 knots. The force of water at that speed makes it nearly impossible to:

• Keep your head above water
• Reach the release mechanism on your harness
• Signal to crew (if there is crew)
• Do anything except fight for breath

The industry response has been quick-release mechanisms—buckles and hooks designed to let you disconnect from the tether under load. In theory, you pull a handle, the tether releases, and you float free.

In practice, according to multiple studies and incident reports, quick-release systems are “very difficult to impossible to operate under load.” When you’re being dragged through the water, when your arms are fighting against hydrodynamic forces, when panic is setting in and cold water is stealing your dexterity—finding a small handle and pulling it with the required force becomes theoretical.

The Tarzan Method: A Blade of False Security

Some sailors carry a knife specifically to cut themselves free if their tether becomes a death trap. The logic seems sound: if the quick-release fails, cut the webbing and swim free.

This is what some call the “Tarzan method”—always ready with a blade, prepared to slash your way to freedom. The problems with this approach are numerous:

• Finding the knife: Under water, being dragged, cold, panicked—locating and opening a knife requires fine motor control you may no longer have
• Cutting position: Modern tether webbing is designed to be strong. Cutting it requires leverage and angle. Being dragged through water provides neither
• The decision point: When do you cut? Too early and you’ve untethered yourself needlessly. Too late and you’re unconscious
• Unintended consequences: A knife accessible in an emergency is a knife accessible during normal operations. Sailors have cut themselves, cut lines they didn’t intend to, or lost the knife entirely when they needed it

The knife as backup plan is better than no backup plan. But it’s not the solution the sailing community sometimes pretends it is.

The Jackline Problem: Where Safety Meets Reality

Jacklines—the lines running fore and aft that tethers clip to—present their own dilemma. Their placement determines whether you stay on the boat when you slip, or go over the side and hang.

Central vs. Peripheral Mounting

Safety experts, including those who advise major offshore rallies like the ARC, strongly recommend central jacklines—lines running down the centerline of the deck. The logic is geometrically sound: if you fall while clipped to a central jackline, you fall onto the deck, not over the side. The tether physically cannot reach the rail.

The problem appears the moment you try to actually work on a boat rigged this way.

With a central jackline and a standard 1-meter short tether (recommended for heavy weather), your range of movement becomes severely limited:

The Helm Nightmare

The cockpit—where sailors spend most of their time—presents its own tether frustrations. On boats with twin wheels (increasingly common on modern cruisers), a tethered helmsperson faces an immediate problem: you cannot move from one helm to the other while clipped in. The tether wraps around the wheel, catches on pedestals, or simply isn’t long enough to reach across.

Even at a single helm, the tether constantly interferes. It snags on the wheel as you turn. It catches under your feet during maneuvers. It tangles with other lines in the cockpit. The result is that many sailors unclip the moment they reach the helm—precisely the location where a wave, a sudden lurch, or a moment’s inattention can send them over the pushpit and into the water.

Some boats install dedicated cockpit attachment points near each helm. This helps, but requires clipping and unclipping every time you move—and in an emergency, those extra seconds of fumbling with carabiners can mean the difference between catching a problem early and watching it escalate.

The result? Sailors faced with a genuine emergency—a sail flogging, a line wrapped around something, a situation requiring immediate action at the rail—must choose between:

• Staying clipped and being unable to reach the problem
• Unclipping to do the job and hoping they don’t fall
• Switching to a longer 2-meter tether that now allows them to go overboard

This is the fundamental tension: the safest jackline placement makes normal sailing operations difficult or impossible. And when operations become difficult, sailors take shortcuts. They unclip “just for a second.” They switch to longer tethers. They stop using the system entirely.

Tether Length: The Numbers

ISO 12401 specifies safety harness tethers should not exceed 2 meters. Most systems offer:

• Short tether (1m): Keeps you close to attachment point, limits movement severely
• Long tether (1.8-2m): Allows work at most deck positions, but permits going overboard on many boats
• Cow hitch/adjustable: Theoretically allows length adjustment, practically adds complexity in emergencies

The mathematics are unforgiving. A typical cruising yacht has a beam of 3.5-4.5 meters. With a central jackline, a 2-meter tether from the centerline reaches… the rail. Exactly the place you fall from.

The Legends Who Vanished

The untethered philosophy has its own sobering lessons.

Eric Tabarly, the legendary French sailor who won the 1964 OSTAR and transformed French ocean racing, went overboard on the night of June 12, 1998, while crossing the Irish Sea aboard his beloved Pen Duick. He was 66 years old, an icon of the sport, with more ocean miles than most sailors accumulate in a lifetime.

He was not wearing a harness.

His body was recovered three weeks later by a fishing vessel. The exact circumstances remain unknown—he was alone on deck at night, his crew below. One moment he was there; the next, he wasn’t.

Alain Colas, another French ocean racing legend and winner of the 1973 OSTAR aboard the trimaran Manureva, vanished during the 1978 Route du Rhum. His boat was found weeks later, damaged, empty. No body was ever recovered. No distress signal was sent. He simply disappeared into the Atlantic, leaving behind only questions.

These weren’t novices caught out by inexperience. They were the best sailors of their generation, lost to the sea in circumstances that remain uncertain decades later.

Survival Against the Odds: When Tethers Work

On October 17, 2025, Eric Marsh—at 72, the oldest competitor in the Mini Globe Race—was swept overboard by a wave while stowing his spinnaker at night. He was tethered. His auto-inflating lifejacket deployed.

What followed was a brutal test of endurance.

“I honestly thought it was all over for me,” Marsh reported afterward. “After many attempts, I finally dragged myself back on board.”

The tether kept him with the boat. But the inflated lifejacket—designed to keep him afloat—made climbing back aboard nearly impossible. The bulk prevented him from hauling himself up. Each failed attempt drained strength and body heat. Yet he refused to give up.

Marsh’s survival depended on several factors aligning: he was tethered (stayed with the boat), he had an inflatable lifejacket (stayed afloat), he was physically capable of self-rescue (despite being 72), and he had the mental determination to keep trying after repeated failures.

Remove any one factor, and the outcome changes entirely.

The Mathematics of Disappearing: Drift Analysis

When someone goes overboard and isn’t immediately recovered, the search area expands with terrifying speed. Understanding drift isn’t just academic—it’s the difference between a focused search and a hopeless one.

How People Drift

A person in the water moves due to two forces: current (the water itself moving) and leeway (wind pushing the exposed portion of the body). Search and rescue organizations use established models:

• Leeway component: Typically 2-4% of wind speed. In 20 knots of wind, a person in a lifejacket drifts approximately 0.4-0.8 knots downwind
• Current component: Varies dramatically by location (see table below)
• Combined drift: Vector sum of both, typically 0.5-3 knots depending on conditions

Regional Current Speeds

Search Area: It’s the Uncertainty That Matters

Here’s what many people misunderstand about drift: the search area isn’t the distance the person drifts—it’s the uncertainty in predicting where they drifted to.

If we knew the exact current speed, exact wind speed, and exact direction, we could calculate precisely where someone would be 12 hours later. The person might have drifted 17 nautical miles, but we’d know exactly which point to search. The search area would be tiny.

The problem is we never know exactly. Currents vary. Wind shifts. Leeway coefficients differ between individuals. These uncertainties compound over time, creating an expanding zone of probability around the predicted position:

• Speed uncertainty: If current is 1.0 ±0.2 knots, after 12 hours that’s ±2.4nm along the drift axis
• Direction uncertainty: If drift direction is ±15°, at 17nm distance that creates a lateral spread of ~9nm
• Combined effect: An elliptical search zone centered on the predicted position

To put 630 square nautical miles in perspective: that’s an area roughly 25 nautical miles × 25 nautical miles. Finding a human head—the only part visible above waves—in that area, in Southern Ocean conditions, is extraordinarily difficult without electronic aids.

The Time Factor

Search area grows exponentially with time, not linearly. This is because:

• Uncertainty compounds: The longer the drift, the more the errors in current/wind estimation multiply
• Conditions change: Wind shifts, currents meander, weather systems move through
• Position uncertainty increases: A 5% error at 10nm is 0.5nm; at 40nm it’s 2nm

What These Numbers Mean

In practical terms:

• Within 1 hour: A single yacht can conduct a reasonable visual search
• Within 4 hours: Multiple vessels required for systematic coverage
• After 12 hours: Without electronic locating device, survival depends on luck more than search
• After 24 hours: Visual-only search is essentially hopeless

This is why MOB beacons exist. An AIS transmitter or PLB with GPS doesn’t eliminate the search—but it can reduce a 1,000 nm² uncertainty zone to a pinpoint.

The Lifejacket-Tether Paradox

A recurring theme in MOB incidents is the separation of safety equipment. The tether is attached to the harness. The MOB beacon is attached to the lifejacket. The knife is on the belt. The strobe is… somewhere.

In the 2024 ARC incident, the sailor had an AIS MOB beacon on his lifejacket. The beacon transmitted. The search knew approximately where to look. Nineteen hours of searching found nothing. We may never know if the lifejacket separated from the sailor, if the beacon failed after initial transmission, or if conditions simply made recovery impossible.

The lesson is clear: redundancy matters. A single MOB beacon can fail. A lifejacket can separate from its wearer. A tether can trap rather than save.

The question for every sailor becomes: how do you guarantee that when you need your safety equipment, all the pieces are actually with you?

Toward a Solution

The ideal MOB safety system would:

• Detect the MOB event automatically—not requiring the person in the water to activate anything
• Alert the crew immediately—not waiting for someone to notice an absence
• Mark the position precisely—GPS accuracy, not “somewhere astern”
• Transmit location continuously—because drift begins immediately
• Alert remote rescue services—because the yacht may not be able to recover the person
• Integrate with lifejacket—guaranteeing all components are present together

Current technology addresses some of these requirements. AIS MOB beacons provide position. PLBs alert rescue services. Lifejackets keep you afloat. But the integration remains imperfect—multiple devices from multiple manufacturers with multiple failure modes.

The realistic answer is probably a combination of technologies, not reliance on any single one. AIS has limited range. PLBs depend on satellite coverage and battery life. Lifejackets can separate. Every technology has limits—and in the ocean, limits get tested. Tethers aren’t on this list because they can’t be enforced—anyone can unclip “just for a second,” and that second is often when disaster strikes.

The next generation of MOB systems will need to acknowledge this reality: not one perfect solution, but multiple overlapping layers of protection. Unified equipment that detects, locates, and alerts automatically, with redundancy built in rather than added aftermarket.

The Answer to the Dilemma

So: tethered or untethered?

Here’s a position that may be controversial: untethered, with reliable relocalization, is probably safer—provided one non-negotiable condition is met.

The logic is straightforward. An untethered MOB who falls cleanly into the water faces a recovery problem. A tethered sailor dragged at speed faces immediate physical trauma, drowning risk, and the near-impossibility of releasing under load. The untethered sailor has time—not much, but some. The tethered sailor being dragged has none.

But this calculus only works if you can stay afloat long enough to be found. Which brings us to the one piece of equipment that changes everything:

The lifejacket has priority over everything else.

A lifejacket keeps you floating. Floating keeps you alive. Alive means you can be found. Without a lifejacket, even the best MOB beacon is just marking where your body sank. With a lifejacket, you have hours instead of minutes—enough time for drift calculations, for search patterns, for rescue.

The lifejacket is the foundation technology that makes untethered sailing survivable. Every other piece of equipment—beacons, strobes, dye markers—is secondary. They help you be found. The lifejacket keeps you findable.

This shifts the question from “tethered or untethered?” to something more practical: how do we ensure the lifejacket is always worn, always functional, and always integrated with location technology?

The dilemma isn’t really about tethers. It’s about flotation first, then detection, then location. Get those right, and the tether becomes optional rather than essential.

But the lifejacket, while necessary, is not sufficient. Floating alone in the ocean, even for hours, means nothing if no one knows you’re there. The complete solution requires multiple layers working together:

• Active MOB beacons—devices that transmit your position when activated or upon water immersion
• Passive MOB detection—systems that alert when a signal that should be there suddenly isn’t (you don’t need to do anything; your absence triggers the alarm)
• Remote alert generation—automatic notification to rescue services and shore contacts, not just the boat you fell from
• Crew training—knowing how to execute recovery maneuvers, operate equipment, and respond in the critical first minutes

We keep losing sailors—experts with decades of experience and novices on their first passage alike. The ocean doesn’t discriminate. The solution isn’t a single device or a single philosophy. It’s a system: flotation to survive, detection to be noticed, location to be found, and trained people ready to act.