Lazy Jacks – A Practical Sail Handling Aid for Cruisers

Managing a large mainsail on a cruising yacht can be a challenge, particularly when short-handed. Lazy jacks are one of the simplest and most effective solutions for keeping a mainsail under control during hoisting, reefing, and lowering. For many sailors, they strike the perfect balance between cost, simplicity, and practicality. This article takes a technical look at how lazy jacks work, their advantages and limitations, and the options available for upgrading your sail-handling system.

What Are Lazy Jacks?

Lazy jacks are a network of light control lines that run from the mast to the boom, forming a cradle on either side of the mainsail. When the sail is dropped, the system guides the sail down onto the boom, preventing it from spilling across the deck.

A typical system has two or three legs per side:

• Upper termination – attached to the mast, usually at or just above the lower spreaders.

• Intermediate legs – running down to the boom, sometimes through small blocks or rings.

• Boom termination – secured forward of the clew, often with a cleat for adjustment.

The result is a rigging structure that contains the mainsail without significant mechanical complexity.

Why Fit Lazy Jacks?

For many cruising sailors, the mainsail is the hardest sail to manage, especially when it comes down in fresh conditions. Lazy jacks offer several advantages:

• Short-handed sail handling – keeps the sail tidy during hoists, drops, and reefs.

• Reduced deck work – less need for crew to be forward handling heavy canvas.

• Improved safety – fewer trips onto the cabin top in difficult conditions.

• Faster sail stowage – sail is already gathered on the boom, ready to be flaked and covered.

Design Considerations

Number of Legs

Two-leg systems per side are common on smaller boats, while larger yachts benefit from three or more legs for better sail control.

Line Materials

Polyester is widely used, but many modern kits incorporate Dyneema® or similar low-stretch lines for durability and reduced chafe.

Adjustability

Some systems include a control line allowing the lazy jacks to be retracted forward against the mast when sailing. This prevents battens snagging during hoists and reduces chafe on the sail.

Stack Pack Integration

Many sailmakers offer integrated sail covers (often called “stack packs” or “lazy bags”) that work in combination with lazy jacks. The lazy jacks support the bag, which encloses the sail and provides UV protection. A stand-alone lazy jack system, however, is lighter, less bulky, and often easier to retrofit.

Lazy jacks combined with a stack pack

Advantages and Limitations

Advantages:

• Low-cost compared to in-mast or in-boom furling systems.

• Straightforward retrofit with minimal deck hardware required.

• Reliable – very little to fail compared to mechanical furling.

Limitations:

• Can interfere with battens during hoists if not properly adjusted.

• Adds some windage and additional lines around the sail area.

• Does not eliminate the need to flake or reef the sail manually.

For many cruising yachts, these drawbacks are minor compared to the benefits, particularly for those sailing with reduced crew.

DIY Installation

Lazy jack kits are designed for straightforward installation by boat owners with basic rigging knowledge. Key steps include:

1. Choose the mast attachment point – usually at the spreaders or around 60% of mast height.

2. Fit small blocks or thimbles – at the mast and boom attachment points to guide the lines.

3. Run and tension the legs – ensuring symmetry and enough slack to allow sail movement.

4. Test with the sail – checking for battens catching during hoists, and adjusting accordingly.

Most sailors can fit a kit in a few hours with standard tools, and once set up, the system requires minimal maintenance.

Lazy Jacks vs Alternatives

Stack Packs – combine lazy jacks with an integrated sail bag. Great for UV protection but heavier and more expensive.

In-mast furling – convenient, but adds weight aloft, reduces mainsail area, and involves more moving parts.

In-boom furling – preserves sail shape but is mechanically complex and costly.

Lazy jacks sit in the middle ground: affordable, effective, and mechanically simple, making them a popular choice for cruising yachts of all sizes.

Lazy Jack Kits from Harken, Barton, and Pfeiffer Marine

At Upffront we stock complete lazy jack kits from three of the leading manufacturers:

• Harken Lazy Jacks – precision hardware and durable line kits designed for reliable performance.

• Barton Marine Lazy Jacks – cost-effective solutions well suited to cruising yachts.

• Pfeiffer Marine Lazy Jacks – German-engineered kits with robust fittings for long-term use.

Each kit is supplied with all the necessary components for installation and is available in sizes suitable for a wide range of yachts.

Conclusión on Lazy Jacks

Lazy jacks are one of the simplest upgrades you can make to improve sail handling and safety on board. They offer excellent value, are easy to install, and make mainsail management far less of a chore – particularly for shorthanded crews. If you are looking to make mainsail handling easier, browse our full range of Lazy Jacks kits clicking below:

LAZY JACKS