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When to Reef … and How

Note:  Although this article is primarily for the W17 trimaran, the layout and procedure suggested will apply equally to the W22 and other similar boats.

Just because a W17 is very stable, it does not mean that you’ll never need to reef.  In fact, reefing will often pay dividends in overall performance and can certainly add an important safety factor in strong or gusty conditions.   Particularly when selecting the larger race rig, you will definitely need to reef more often, so getting your boat properly rigged to make this an easy task is a priority.   As soon as the bow of a W17 ama starts to often get pressed within about 40mm of the water surface, I know the time has come and on some trimarans, you might need to consider reefing even earlier.

One very important thing to ALWAYS remember is this:   It’s FAR easier to shake OUT a reef in easing weather, than it is to take IN a reef in conditions that are getting worse by the minute.

There are many advantages in sailing with a properly reefed sail that still retains an efficient shape.

1: Less leeway and higher speed potential in rough conditions.

2: Boat will sail more level, improving efficiency for both the sails and the hulls.

3: Significantly lowers the load off sails & rigging and makes sailing the boat more pleasurable with less stress for all aboard.

Sadly though, most boats are poorly set up to be reefed and that’s typically the biggest obstacle to reefs being taken in.   It’s really not that difficult so let’s see what’s needed and understand why.

Other than the halyard, there are just TWO main lines that will hold the sail in its lowered position … the CLEW line and something forward at the TACK to hold the luff tension.

The aft CLEW line has a critical-location attachment to the boom. You need to get this right when you first rig the boat.   Pull the sail right up and then lower it so that the aft cringle for the main reef (1st one) is just at the boom when held up to the right height for sailing (temporarily use the topping lift for this).   Now, with the sail gently pulled aft away from the mast, note the cringle position and make a mark on the boom, just 75mm (3”) farther aft than the cringle (eyelet).   This is where you want to attach a strong eye-strap on the PORT side and then a small pulley to the boom on the STARBOARD side, so that a rope passing around the rear of the sheave will be in roughly the same alignment as the fixed end will be when hitched to the eye-strap on the PORT side  (see photo & sketch below).  Once installed, the CLEW LINE will therefore run from the strap on the port side of the boom, up alongside the rear of the sail, through the reef cringle, down to the aft side of the pulley you’ve installed on the STARB’D side of the boom and forward to a cleat on the boom; one that’s easily accessible from the cockpit, even when the boom is swung outboard.     Obviously, when the sail IS actually reefed, this line will be tight with the sail held down to within say 40-50mm of the boom top and after cleating, you will need to get rid of about 1.5 meters of rope tail.     You can either wrap this around the boom (as the boom will be accessible since the sail is loose-footed) or even Velcro a small cloth pocket to either the boom or the sail adjacent to the reef cringle, to stow it in.     The other critical line is one to hold the TACK (or fwd corner) of the sail.   While some like to attach this with a line to the main tack location that’s used when the sail is fully up, I personally find that the sail has very low horizontal tension at this location, while the REAL load is down the luff to keep the sail flat and under tension.  This is best done with a readily adjustable DOWNHAUL, commonly called ‘a Cunningham’ after the fellow who first got serious about adding this  adjustment to the luff of a mainsail:  Briggs Cunningham (skipper of the winning America’s Cup boat in 1958).   So personally, I do not bother with a TACK attachment itself as it’s redundant once the Cunningham is installed.   This is ‘most convenient’ as you will already have an adjustable 3 or 4 part Cunningham rigged and attached to the mast below the boom, for use when the sail is fully up (see photo).   So when lowering the mainsail down to the first reef, the Cunningham will ‘fall away’ from its normal position and the hook will become available to be placed in another cringle, located 8-12” (200-300mm) above the line of the actual reef.     IF your sail does not have cringles for a Cunningham (always 6-12” above the normal TACK cringle at the mainsail luff … then return your sail to the sailmaker and have them added as they are really essential for efficient sailing.   (I specify that ALL mainsails for my boat designs made by HYDE have them.


The height that the mainsail is set when planning to use any reef, should be set so that the AFT cringle and CLEW line are holding the boom at the right height for adequate crew clearance and to also suit the mainsheet.  This will typically mean that the Cunningham cringle will be about 300mm above the boom at the gooseneck … a position that will be ‘just’ reachable by the Cunningham tackle.   I would mark this position on the Mast with a small arrow of Duct-tape so that when lowering the main to take a reef, you know EXACTLY where to stop and belay (cleat) the Main Halyard.

So now we can quickly run through The STEPS of REEFING  .. and as you’ll see, it’s now all pretty straight-forward once you’ve set the rigging up correctly.

SUMMARY – Steps of Reefing:

First, assuming you are already sailing upwind, totally ease off the mainsheet and pull the jib to windward, so that the front half of the foot of the jib is parallel to the centerline of the boat.   This is a fast way to stall the boat and put her HOVE TO, so that you can work on the sail without speed, or running into someone.    You may need to slightly adjust the tiller to keep her straight as she’ll still advance at 0.5 to 1kt.

  1. Take up the slack on your topping lift, so that the boom does not fall when you lower the sail.
  2. Lower the Mainsail until the Cunningham cringle is at least 300mm above the main boom – or at the mark you placed on your mast.Secure the main halyard.
  3. Haul on the TACK Reef line (std side) to take up all the slack and cleat securely with the sail now being about 50mm (2”) above the boom.
  4. Return to the forward end and place the Cunningham into the cringle 300mm above the boom and haul down to apply good tension to the luff.(IF you have a really stretchy luff-rope you may need to release the Cunningham and slightly raise the main halyard to give yourself more stretch space, before resetting the Cunningham)
  5. Ease off the topping lift slightly so that the boom now hangs on the Clew Reef Line.

Some sailors would just start sailing again, but as I’m someone who likes to keep things neat, I’ve not quite finished yet.  Old traditional sails typically have BUNT Lines hanging down on each side of the sail so that they can tie them around the unused sail using the traditional REEF knot (so where DID you think that name came from ;).   But I want to suggest something faster that I’ve used on all my boats for the last 25 years.   If there are eyelets with BUNT Lines tied in, I first remove the lines.   Then I reeve a 4mm black-covered (more UV resistant) shock cord through the eyelets, in and out through the eyelets from the luff, running one from each side.   I thread in a small nylon hook (see sketch) so that there’s one between each eyelet … preferably all on the STARB’d Side that you are working from.  

Now you can slab fold or roll in the lower, unused part of the sail and by stretching above the boom but under the sail, you can grab the shock-cord on the port side and pull it under the sail, to drop it over the hook on the starb’d side.  (It takes far less time to do than it does to explain this).    Here is how it looks on my own boat Magic.   Your sail is now neat & compact and when shaking out a reef, this shock-cord is the first thing to unhook.

Then, in reverse for SHAKING OUT a Reef

  1. Get HOVE TO, with the Mainsheet paid out & jib partly backed.
  2. Take up the slack on the topping lift
  3. Unhook the shockcord
  4. Remove the Cunningham
  5. Release the CLEW Reef line/outhaul
  6. Haul up the Mainsail
  7. Re-install the Cunningham and add tension
  8. Ease off the topping lift …. and go sailing

Practice Makes Perfect …. so, after setting up your rigging & sail correctly, start to reef far more often.  You will be surprised at how well your boat will perform in rough conditions … and you’ll feel a lot more relaxed about the conditions too.

Enjoy!                                                                                                                                                          Mike, 2018

PS:  IF your boat is not a W17 and needs a Boom Vang ... that will need to be removed first when reefing, and re-installed last.

Also, some have asked, ‘why not use the rotating boom to reef the sail?’.  The main reason is that you need the boom totally free and accessible to attach the mast tiller line that controls mast rotation.  Same applies when setting the Storm Mainsail.  On the W22, the mast tiller goes forward over the Cuddy, so rolling up the reefed portion of the sail on the boom IS then possible, but you would not want to take the sail load on this roll.  The CLEW reef-line and Cunningham are still needed to take the sailing loads, especially in high wind conditions as when reefed.

In really high winds conditions, I strongly recommend the safety, comfort and use of a small but efficient Storm Mainsail …. see this link Sailing with a Storm Mainsail

This works so well behind a rotating wing mast, that you can still hit speeds over 10kts. with the W17. (Correction ... just hit 12.6kts (!) with the storm sail and jib, July 2018. ;-)  ... mostly due to the efficiency of the wingmast when combined with this small high-aspect sail.

Copyright Mike Waters:  2018
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