A mainsail that drops into its cover without a fight gets used more, gets covered more, and lasts longer. It is worth a little effort to get right, and most of the problems have straightforward causes.
What a lazy cradle is
A cover permanently attached along the boom, held open by lazy jacks running to the mast. The sail drops into it and the cover zips shut over the top, so the sail is flaked and covered in one operation.
The alternative is lazy jacks alone, which guide the sail onto the boom without covering it, plus a separate cover put on afterwards.
The trade is the usual one. A lazy cradle means the mainsail is always covered, which is the single best thing you can do for it, and it costs a little windage, some weight on the boom, and the lazy jacks are in the way when you hoist.
Why a sail flakes badly
If your mainsail spills over the boom instead of folding into the cradle, it is usually one of these.
Not enough full battens. Full battens are what make a sail fold in the same place every time. A short-batten sail has nothing organising it and will always need help.
Cars that do not run freely. If the sail does not come down under its own weight, it does not come down evenly either. Clean the track, check the cars.
Lazy jacks in the wrong place. Too far forward and they do not hold the aft part of the sail; too far aft and they catch the battens on the way up. Their attachment points on the boom and on the mast both matter.
The cradle opening is too narrow for the bulk of the sail. A new sail in heavier cloth than the last one, or with more roach, may simply not fit in the old cover.
Coming down off the wind. A mainsail dropped with wind in it goes wherever the wind puts it. Head up, or at least close-hauled.
Reefing lines lying across the sail and stopping it folding.
Getting it right when the sail is new
The best time to solve this is before the sail is built.
If you have a cradle and the current sail does not flake cleanly, say so and photograph it — the cradle, its opening, where the lazy jacks attach, and the sail half dropped. Batten arrangement, roach and cloth can all be chosen with that in mind.
If you are fitting a cradle at the same time as a new sail, mention it, because the sail can be designed to suit.
Hoisting past lazy jacks
Full battens catch on lazy jacks on the way up. This is normal and there are three answers.
Head straight into wind so the sail goes up without pushing sideways.
Slack the lazy jacks off and pull them forward to the mast before hoisting — most systems are arranged for this and it is the reliable answer.
Adjust where they attach so the geometry is better.
Forcing a batten past a lazy jack is how batten pockets get torn.
Looking after the cover itself
Zip it fully. A partly closed cover lets sunlight onto a strip of the sail and lets water in.
Check the stitching at the ends of the zip and where the lazy jacks attach. Cover stitching is exposed and it is the first thing to fail.
Watch where the cover mouth rubs the sail. A stiff opening works against the sail every hoist and every roll at anchor, and it is a common chafe point.
Do not zip a wet sail in and leave it. A cradle is a very good place for mould to grow.
Covers for other sails
A furling headsail is protected by its UV strip, not by a cover. The strip is doing that job and it is consumable.
Flying sails live in bags. They have no protection of their own and should not be left hoisted at anchor.
A quick check every season
Lazy jack lines for chafe and stretch, the cover’s zip and stitching, the attachment points on the boom, and whether the sail still flakes as cleanly as it did.
If it has got worse, something has usually stretched or a car has stiffened — both easy fixes if found early.