What Is A Jackline?

A jackline is an essential safety feature for sailors, especially when working on the deck in rough conditions. It is a rope, wire, or webbing that stretches from the bow to the stern of a sailboat, providing a secure attachment point for the crew’s safety harness. 

By connecting their harness to the jackline, sailors can move about the deck while remaining tethered to the boat, reducing the risk of falling or being swept overboard.

In addition to using a jackline, consider incorporating other safety measures like man overboard location alert systems to further enhance your safety while at sea.

Remember, taking the time to learn the proper techniques for installing and using a jackline on your sailboat helps ensure your and your crew’s safety, even in the most challenging conditions.

Understanding Jacklines

Three primary materials are used for making jacklines: rope, webbing, and wire. 

Rope jacklines, typically made of high-strength nylon or dyneema, are easy to grip and comfortable to use. 

Webbing jacklines, made of flat nylon or spectra webbing, are less prone to rolling underfoot and thus, less likely to cause slips or trips. 

Wire jacklines, usually made of stainless steel, are strong and durable but can be slippery and challenging to handle.

When choosing between these materials, consider the working environment and the specific requirements of your vessel. For instance, the tension, stretch, and resistance to abrasion of the jackline material must be appropriate for your boat size and working conditions.

Spectra webbing is popular for its high strength and low stretch characteristics but may not be ideal for short spans due to higher impact loading on the person falling.

In addition to the material, the placement and tension of the jacklines are crucial for their effectiveness.

Ideally, jacklines should be located along the deck, allowing a harnessed and tethered crew to reach the rail but not beyond. This reduces the risk of going over the side and improves the chances of recovery.

Ensure the tension is just right – not too tight, which can cause a tripping hazard, and not too loose, which can cause the line to twist or catch.

When installing jacklines, measuring the required length is critical. One method to measure accurately is to use a bungee cord or an internal bungee in the jackline. The bungee ensures consistent tension while allowing some stretch and better movement on deck.

Installation and Positioning of Jacklines

Once you know where to put the safety line, begin by securing pad eyes to the bow, stern, and any other necessary points on the deck, ensuring a secure connection for your jacklines.

You can use cleats as alternative attachment points, but pad eyes provide a lower profile and reduce tripping hazards.

Once they are in place, run the jacklines from the bow to the stern along the port and starboard sides of the deck.

Position them inside the shrouds and try to keep them as close to the centerline as possible. This will allow you to move freely between the stern and bow while reducing the risk of falling overboard.

In addition to the port and starboard jacklines, installing another on the foredeck is beneficial. This provides a secure tether point when working on the bow, especially in windy or rough conditions.

Ensure the jacklines are rigged under sheets and over deck-routed control lines to prevent tangling or damaging your equipment.

For multihulls, consider installing them closer to the windward hulls. This positioning grants easier access to the trampoline and creates a shorter tether distance, reducing potential fall hazards. Additionally, you can add short jacklines or safety lines near critical workstations, such as the mast or helm.

When selecting a harness system, choose one that is comfortable, sturdy, and suited for your sailing conditions. Double-check the compatibility of your harness with the jacklines and pad eyes to ensure proper functionality.

Remember that periodic inspection of your jackline installation is crucial for maintaining safety. Check for wear, corrosion, or any other signs of damage and replace the components as necessary. 

Jacklines for Different Boats

Whether you’re sailing a multihull or a monohull, having jacklines installed on your boat is essential for safety in rough weather. 

Ideally, jacklines should be located halfway between the toerail and the mast/boom. This placement ensures they are easily reachable but not obstructive to other running rigging. 

When installing pad eyes, it’s essential to position them so that you can move from the cockpit to the jackline and from one jackline to another without ever unhooking your safety tether.

The materials used to make jacklines have evolved over the years, with modern options such as braided Dyneema offering strength and durability comparable to steel.

It’s important to choose strong materials that provide a good grip for your tether’s hook. Also, remember that different boats may require unique tether and jackline lengths, so account for your boat’s size when planning your system.

Along with jacklines, safety tethers (or lanyards) are a key element. If you’re interested in the concept, have a look at the benefits of tethering to your boat to learn more about why it may be a good idea under certain circumstances.

Key Characteristics of Jacklines

Choose easily distinguishable jackline colors to prevent confusion while clipping in, especially in low light. Opt for contrasting hues and consider reflective webbing for better nighttime visibility.

Wichard fittings are often used as strong anchor points. They are designed to withstand heavy loads and are available in various sizes to suit your needs.

Ensure the anchor points you select have sufficient safe working load capacities, such as the Harken small round pad eye with a safe working load of 4300 lbs (1950 kgs).

The elasticity is an important factor to consider. Ideally, they should be made of high-strength, low-stretch materials, as significant elongation can increase the risk of falling overboard. Webbing material, for instance, offers a good balance of strength and minimal stretch.

Complying with the ISAF standards is crucial for your safety gear. These regulations provide guidelines for the appropriate use of jacklines and other safety equipment.

UV resistance is another critical characteristic to consider, as jacklines are exposed to sunlight and harsh weather conditions. Materials with high UV resistance, like polyester webbing, help maintain strength and durability over time.

Adequate safety factor is necessary to account for wear, corrosion, and unexpected loads. Select materials with a high breaking strength to maximize safety and ensure that the safety factor exceeds the expected working load.

Tensioning is key to their effectiveness. Proper tension ensures that the jackline remains taut and reduces the chances of a crew member being dragged overboard. Tensioning devices like turnbuckles can help adjust and maintain the desired tension.

Advanced Usage of Jacklines

In advanced usage, you may consider employing a “Y” tether, which provides additional support and stability when navigating the sailboat. 

This system offers two attachment points – one long and one short – to secure your harness when crossing the boat or working in tricky situations.

The short side of the tether limits your range of motion but can significantly reduce drag, while the long side allows for greater freedom of movement during passages where stress on the tether is less likely.

The Y-tether can act as a “third hand,” offering a hands-free system to facilitate your tasks on deck.

While working on the cabin top or near the sailboat’s edge, maintain your body’s balance and avoid tripping hazards, such as lines and other equipment.

“Secure your jackline along the boat’s centerline, either on a cabintop handrail or a continuous line system, to minimize tripping hazards while maximizing the area covered.”

Captain Donald Quackenbush, USCG Master Yacht Delivery Captain

To improve the functionality, consider these points:

  • Always use safety harnesses with jacklines to ensure maximum protection.
  • Inspect your jacklines regularly for wear and tear, and replace any damaged parts immediately.
  • Be mindful of the maximum stress points during heavy weather and adjust your tether length accordingly.

Following these guidelines allows you to leverage the advanced usage of jacklines, providing increased safety and stability during your sailing adventures.

I’m the founder and chief editor here at Sailing Savvy. I spent a decade working as a professional mariner and currently, I mix those experiences with digital publishing. Welcome, and I hope that we can be the hub you need for safe passage.