Lazy jacks sailing system is a method of containing a main sail when its lowered. By having a set of lazy jack lines either side of the main attached high up in the mast and down to the boom, the main can be dropped without falling on the deck. This method along with a Dutchman system helps single handed or shorthanded sailors.

The difference between Lazy Jacks and the Dutchman system is the lines of a Lazy Jack system are positioned either side of the mainsail.

The Lazy Jacks lines capture or cradle the mainsail as it drops. Lazy Jacks will not flake the sail neatly as the Dutchman system does but it will hold the sail on the boom.

The Lazy Jack system is much cheaper than a Dutchman system. No modification of the sail is required (although full battens work better), and the lazy jacks are attached to the mast with pop rivets or screws and the bottom end attached to the boom. This process is relatively cheap and fast.

The image above shows Roxy finishing the Vendee Globe race and you can see the lazy jacks attached to a white cover along the length of the boom. These guys chose Lazy jack systems over Dutchman due to the extreme conditions they sail in. When you are reefing or dropping the mainsail in extreme conditions, with a Dutchman system, the filament lines can drag on the discs that the filament line goes through the sail.

I have noticed this as the main is flapping about violently the main drags on the discs and is slow to come down if not getting hung up. You may need to drag the sail down manually.

If you combine the Lazy Jack system with a mainsail luff track and slide system, the front of the sail may flake itself somewhat, and then you can tidy up later.

In the case of the vendee Globe boats the lazy jacks are attached not directly to the boom but to canvas which is in turn attached to the boom. This picture of PRB, shows how the canvas captures the huge mainsail on these boats.

A variation of this is the stack pack, initially developed by Doyle Sails.

 

Basic System

The Harken lazy jack Diagram shows the main components of a lazy jack system.


This is the simplest system with just one top leg and one bottom leg. You can ad more bottom legs as required for larger mainsails.

First the top leg of the Lazy Jack is riveted to the mast. the top leg consists of a single strop and a block at its lower end.

Second the bottom legs are attached to the boom and fed through the block of the top leg.

The bottom legs have a cleat to adjust line tension.













This diagram shows multiple lazy jack legs for larger sails. You can ad as many legs as you like, but I would follow the manufacturers recomendation.