What is Lazy Jacks?
Lazy jacks are lines that run from partway up the mast down to the boom, creating a cradle on both sides of the mainsail. They can be temporarily released to clear the sail for hoisting or stowed while sailing to prevent impacts on sail shape.
Answered by The Wrench — the boat maintenance platform trusted by boat owners and charter operators to track, schedule, and understand every system on the water.
Printing is disabled for this article.
Sign up for The Wrench to access our full library offline.
What it is
Lazy jacks are lines that run from partway up the mast down to the boom, creating a cradle on both sides of the mainsail. They can be temporarily released to clear the sail for hoisting or stowed while sailing to prevent impacts on sail shape.
What it does
Lazy jacks catch the mainsail as it's lowered, keeping it from falling on deck or into the cockpit. This makes flaking and covering the sail much easier and safer, especially for short-handed crews. Lazy jacks contain the sail in a neat pile on top of the boom. They're particularly valuable for cruising boats and make sail handling less physical and more manageable. When lowering the sail in rough conditions or at night, lazy jacks prevent the sail from going overboard or tangling.
Why it matters
For cruising sailors, lazy jacks make mainsail handling dramatically safer and easier. With lazy jacks, one person can easily lower, flake, and cover the mainsail. They prevent the sail from dragging in the water when lowered at anchor or in heavy weather. While racing boats rarely use them due to potential interference with battens, for cruising boats they're one of the most practical rigging additions possible.
General Maintenance
Inspect lazy jack lines seasonally for chafe and UV damage. Check all attachment points on the mast and boom for security. Adjust line lengths if the sail isn't dropping evenly into the cradle. Check that lines can be easily released if your system requires clearing them for sail hoisting. Verify lazy jacks don't interfere with full-length battens or other sail hardware during hoisting. Replace them every five years, or earlier if needed.
Common Issues
- UV damage to lines left up continuously
- Attachment points on boom working loose
- Lazy jacks catching on batten ends during hoisting
- Lines positioned incorrectly, creating uneven sail cradle
- Insufficient number of lines per side to contain sail
- Lines too tight, preventing proper sail shape
- Hardware corroding or seizing, making adjustment difficult
Free download
Buy a house or a boat?
Our free calculator runs the numbers side by side. Tell us where to send it.
Try The Wrench free
Stop tracking rigging & sails maintenance on napkins.
The Wrench tracks every task, expense, and inspection across your fleet. Schedule automatically, get reminded on time, and never wonder when you last serviced something again. Free plan available, no credit card needed.
Related articles
Blocks & Sheaves
Blocks are pulleys used throughout a sailboat's rigging system to redirect lines and provide mechanical advantage. They can be fixed, swi…
Read articleBoom Preventer
A boom preventer is a line or system that prevents the boom from an accidental gybe when sailing downwind. It typically consists of a str…
Read articleBoom Vang
The boom vang is a system used to control the vertical angle of the boom and the twist of the mainsail. It can range from a simple block-…
Read article