Skip to content Skip to navigation menu

Safety Harnesses, Tethers & Jacklines


What they do

Safety Harnesses

Safety harnesses are webbing assemblies that physically connect you to the boat to prevent you from falling overboard or, failing in that role, are intended to keep you from being separated from the boat. Harnesses are either stand-alone items or are integrated with offshore type inflatable life vests. Tethers clip you to a fixed-location padeye or to jacklines (also called trolley lines or jack stays) that are lengths of rope, webbing or wire running fore and aft or athwartships. Jacklines can be run on the boat’s centerline, along each side deck or secured inside the cockpit.

For years, customers bought foam life jackets, safety harnesses, and tethers when they equipped their boats to go offshore. This has changed dramatically with the introduction of the combination safety harness and inflatable life jacket. In virtually all conditions where you’d elect to wear a safety harness, you’d also elect to wear a life jacket, and vice versa, so in our opinion, the buying of separate items is not warranted.

There’s another reason to wear harnesses integrated with inflatables: it’s very difficult to find a combination of separate life jackets and harnesses that don’t interfere with one another. And it’s time consuming to prepare to come on deck when you have to juggle foul weather gear, gloves, a hat, life jacket, etc. We greatly prefer the simplicity of putting on one piece of safety gear with all of the components built-in.

ISAF Requirements

The International Sailing Federation (ISAF) includes the following warning in Section 5.02 of their 2010-2011 Offshore Special Regulations for sailboat racing: “Warning: it is possible for a plain snaphook to disengage from a U-bolt if the hook is rotated under load at right-angles to the axis of the U-bolt. For this reason the use of snaphooks with positive locking devices is strongly recommended.” Our ISAF-Specification Tethers meet these requirements with snaphooks that cannot accidentally release, but are simple to manually disengage.

Safety Harnesses

Snap Shackle: Easy to release under load, but can be released accidentally if the lanyard is pulled. Best for the harness end of the tether.

Safety Harnesses

Snap Hook: Easy to attach, difficult to detach under load. The new snap hooks are designed to reduce accidental release from padeyes and deck attachments.

Safety Harnesses

Double-Action Safety Hook: Easy to attach and detach. Lightweight aluminum hook locks closed automatically and will not come undone accidentally. Easy to release with one ergonomic hand movement.

ISAF-Spec tethers also include indicator flags stitched into their webbing that show if the tether has been overloaded, compromising its strength. These function like the little green dot in the inflators of some inflatable PFDs that show when the device is armed and ready, and are a simple visual indicator. The regulations state: “a safety line purchased in January 2001 or later shall have a colored flag embedded in the stitching, to indicate an overload. A line which has been overloaded shall be replaced as a matter of urgency.” We also recommend a Personal Gear Pouch, the ideal place for small flares, a strobe light and PLB. Slide the pouch onto the waist belt of your safety harness or life jacket.

Jackline Considerations

Jacklines should be as strong as the safety harness, since the strain on them is greater. They are commonly made from nylon webbing treated to resist UV degradation, but nylon stretches too much, allowing too much range of motion when crewmembers are clipped to it.

Therefore, we recommend either using low-stretch braid like V-12 or Amsteel, or polyester webbing jacklines from West Marine (which are easier on your feet than stepping on round line, and won’t roll under your feet and knock you off balance). Any of those alternatives will dramatically reduce the distance that the jacklines can be pulled off-center, which can contribute to keeping your crew on deck where they belong. It is also critical to tether yourself on a short leash, so when a wave bashes you, you only get knocked down, and not overboard. A double tether (with both a 3' and a 6' leash) is great for this purpose. Use the short section when in a stationary location.

We sail in coastal and offshore races regularly on an Antrim 27 sportboat, and our jacklines are polyester webbing. Because this stuff is stretchy, we tie in an extra purchase with a loop near the back end (a bowline) that we cinch up tight with a couple of half hitches. This system has worked well for keeping us onboard. ISAF’s rules include this warning: “A safety harness is not designed to tow a person in the water and it is important that a harness is used to minimize or eliminate the risk of a person’s torso becoming immersed in water outside the boat. The diligent use of a properly adjusted safety harness is regarded as by far the most effective way of preventing man overboard incidents.”