What they do
Safety harnesses are webbed belt–based assemblies that physically connect you to the boat and which should prevent you from falling overboard or, failing that role, should keep you from being separated from the boat.
Jacklines (also called trolley lines or jack stays) are lengths of rope, webbing or wire running fore and aft, or athwartships, to which safety harness tethers are attached. They can be run on the centerline of the vessel, along each side deck, or secured inside the cockpit.
What people are really wearing…
For years, customers bought foam life jackets, safety harnesses, and tethers when they equipped their boats to go offshore. This has changed pretty 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.
The International Sailing Federation (ISAF) includes the following warning in Section 5.02 of their 2006–2007 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.” The ISAF–Specification Tethers on the opposite page meet these requirements with Italian–made Kong Spa snaphooks that cannot accidentally release, but are simple to manually disengage.
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 1/01 or later shall have a coloured flag embedded in the stitching, to indicate an overload. A line which has been overloaded shall be replaced as a matter of urgency.”
Another item that we’re great fans of is the Personal Gear Pouch, which is slid onto the safety harness or life jacket waist belt. These little pouches are the ideal place to put small flares, a strobe light, a signalling mirror, and the like.
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 are clipped to it.Therefore, we recommend either using low–stretch braid like V–12, Endura 12 or Amsteel, or Polyester Jacklines from West Marine. Any of those choices 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.
Explanation of Tether Components
A. 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.
C. 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.