The Offshore Voyaging Reference Site

In-Mast, In-Boom, or Slab Reefing —Performance, Cost and Safety

Part 2

In Part 1 we compared the convenience and reliability of the three most common mainsail-handling systems.

Now let’s look at:

  • Good sailing performance
  • Reasonable cost
  • Low risk and safe to use

And then I will wind this part up by sharing a spreadsheet each of us can use to weight each criterion to arrive at the system that meets our own needs and wants best.

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More Articles From Online Book: Sail Handling and Rigging Made Easy:

  1. Six Reasons To Leave The Cockpit Often
  2. Don’t Forget About The Sails
  3. Your Mainsail Is Your Friend
  4. Hoisting the Mainsail Made Easy—Simplicity in Action
  5. Reefs: How Many and How Deep
  6. Reefing Made Easy
  7. Reefing From The Cockpit 2.0—Thinking Things Through
  8. Reefing Questions and Answers
  9. A Dangerous Myth about Reefing
  10. Mainsail Handling Made Easy with Lazyjacks
  11. Topping Lift Tips and a Hack
  12. 12 Reasons The Cutter Is A Great Offshore Voyaging Rig
  13. Cutter Rig—Should You Buy or Convert?
  14. Cutter Rig—Optimizing and/or Converting
  15. Cruising Rigs—Sloop, Cutter, or Solent?
  16. Sailboat Deck Layouts
  17. The Case For Roller-Furling Headsails
  18. UV Protection For Roller Furling Sails
  19. In-Mast, In-Boom, or Slab Reefing—Convenience and Reliability
  20. In-Mast, In-Boom, or Slab Reefing —Performance, Cost and Safety
  21. The Case For Hank On Headsails
  22. Making Life Easier—Roller Reefing/Furling
  23. Making Life Easier—Storm Jib
  24. Gennaker Furlers Come Of Age
  25. Swept-Back Spreaders—We Just Don’t Get It!
  26. Q&A: Staysail Stay: Roller Furling And Fixed Vs Hanks And Removable
  27. Rigid Vangs
  28. Rigging a Proper Preventer, Part 1
  29. Rigging a Proper Preventer—Part 2
  30. Amidships “Preventers”—A Bad Idea That Can Kill
  31. Keeping The Boom Under Control—Boom Brakes
  32. Downwind Sailing, Tips and Tricks
  33. Downwind Sailing—Poling Out The Jib
  34. Setting and Striking a Spinnaker Made Easy and Safe
  35. Ten Tips To Fix Weather Helm
  36. Running Rigging Recommendations—Part 1
  37. Running Rigging Recommendations—Part 2
  38. Two Dangerous Rigging Mistakes
  39. Rig Tuning, Part 1—Preparation
  40. Rig Tuning, Part 2—Understanding Rake and Bend
  41. Rig Tuning, Part 3—6 Steps to a Great Tune
  42. Rig Tuning, Part 4—Mast Blocking, Stay Tension, and Spreaders
  43. Rig Tuning, Part 5—Sailing Tune
  44. 12 Great Rigging Hacks
  45. 9 Tips To Make Unstepping a Sailboat Mast Easier
  46. Cruising Sailboat Spar Inspection
  47. Cruising Sailboat Standing Rigging Inspection
  48. Cruising Sailboat Running Rigging Inspection
  49. Cruising Sailboat Rig Wiring and Lighting Inspection
  50. Cruising Sailboat Roller Furler and Track Inspection
  51. Download Cruising Sailboat Rig Checklist
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Peter Carrie

Great article John (along with Part 1)! Unfortunately your spreadsheet came a few months too late for me. I have a Gulfstar 50 ketch which came with a retrofitted in-mast furling setup. (Two extrusions riveted to the mast to enclose the roller and sail.)

When I bought the boat I had a close look at the in-mast system, played with it a bit, and simply couldn’t stomach the dog’s breakfast of friction, inability to downwind reef, high probability of gear failure, and a horribly-shaped roachless, battenless sail. Slab me,
Baby! Even singlehanding in my late 60’s I gladly forego the notional convenience of that particular in-mast system.

Plus, I was then forced to buy a nice new Hydranet triradial – a guilty indulgence indeed!

SV Diddikai

Peter Carrie

Yes, we were able to save the mast. My rigger inserted rivets into all the old mounting holes, fashioned a new masthead fitting & crane for a spin halyard, tangs for new runners for new staysl, moved the halyards to internal, etc. The yard quoted $7,000 to repaint the mast… so I will delay my sailing plans somewhat this winter and do it myself. We condemned the old roller furling (round) boom which looked like a telephone pole and weighed about as much. (Its roller furling feature not having been used for many years.) Fortunately, my rigger located a hurricane salvage boom, which eased the pain somewhat. All-in, the conversion to slab reefing and boom replacement will cost about $US15,000. Not bad for the progress in turning a floating condo back into a sailboat.

Peter Secor

Very good overview of the pros and cons of each system. I have 10 years of experience with slab reefing (1 boat 33′) and 12 years with in-mast (2 boats 35′ and 45′). I haven’t had a jam or issue yet with the in-masts.

One comment I would make is that the performance tradeoff of in-mast is most pronounced in lighter airs where you need a full shape. Once you start to flatten and de-power a traditional main it begins to loose its performance edge. A high quality in-mast sail is already designed to operate as the best foil possible with a flatter shape and smaller size.

To the comment that “many in-mast boats have short rigs to compensate for the added weight aloft, and so are really motor-sailors, particularly if called on to go to windward.” I do agree. But I would also submit that there are also many in-mast boats that were designed for them that are certainly not motor sailors and sail very well upwind. You just need to understand these design considerations and take them into account.

In summary, I think a well designed boat with in-mast furling and quality sails performs very well – except in lighter airs. For me, this has been an acceptable tradeoff given the convenience factors. Just my two cents…

Rob Gill

Hi John, a few comments.

From memory, in 2014 we spent about 7,000 USD on our Leisurefurl boom, including a new Forespar solid vang, and rigging work. We needed a new mainsail, so that wasn’t a factor. For some this will add to the project cost as a new sail needs to be designed for in-boom furling.

We do envisage recouping our boom investment through the longevity of our mainsail vs slab reefing. Not through any use of the cover, but through the absence of stresses put on the leech, clew and tack areas in setting slab reefs, which can be considerable, especially in strong winds. Also factor in that our mainsail almost never flogs, even in strong winds which is hard to eliminate with slab or in-mast systems. Our sail is coming up 9 years and there are zero signs of wear or stretch. And we almost never motor anywhere, even for short hops – the mainsail is always up unless there is NO wind.

And not sure why slab reefing enables a bigger roach than in-boom reefing? The roach on our current mainsail was made bigger than on the slab reefed main it replaced. It now extends beyond our backstay by between 10 -> 30 cm at each of the upper battens, for light airs performance. We have a fairly short masthead rig, so the big roach gives a nice boost (see picture).

Once we roll the first reef in (between 15 -> 20 knots TWS), the roach clears the backstay to eliminate sail chafe. We use Harken chafe protectors on the back stay to enable the fully hoisted sail to tack and gybe smoothly even in very light wind (see photo) and see:

IMG_3614 Large.jpeg
Chris SD

Hi Rob,

My main could flog easily on my old Leisure Furl Offshore. Maybe it flogged less than slab in lighter winds, but I haven’t been able to compare.

Chris SD

I meant to put that photo in my profile. 🙂 I can’t remove it now.

Gino Del Guercio

Hi John,
My wife and I disagree with your statement that in-boom furling is “harder to use and higher risk.” Based on Hans’ video his in-boom system does look complicated and prone to issues. However, we installed a Leisurefurl system on our Brewer 44 four years ago and have done a lot of bluewater sailing since. Raising, dousing and reefing is dead simple with this system and we’ve never had a problem dousing the sail while running. My wife does not hesitate to reef the sail while off shore on her night watch without waking the captain. That alone is worth the extra cost, in my opinion 😂. Bottom line, not all in-boom systems are created equal.

Dick Stevenson

Hi all,
I have heard a variety of the reasons given by responders for their roller furl systems and I feel it is worth re-iterating some thoughts and observations. This is in no way done to challenge their decisions, but rather to suggest to readers who might be contemplating RF systems for their main that there are alternatives.
A number have said that a reason for purchasing roller furling for their mainsail allows for the least strong and experienced member of the crew to reef single-handed; unsaid, but implied is the suggestion RF is the solution rather than a solution. I would want to suggest that most boats can be massaged to allow slab reefing single handed.* My wife, Ginger, can set a reef from the cockpit in just a few minutes following our protocol below (for those who like to read details).
Then there is physical ease: this also does not, to my mind, have to be a challenge when slab reefing. Our raising/ reefing is not in any way a physical challenge for these two never-seeing- 70 yo-again sailors.
So, it is clear that I believe the benefits of RF mainsails are often an artifact of poor equipment/design or are exaggerated and/or illusory. Add the above to the many downsides of RF mainsails, actual and potential, and I suggest working to make slab reefing work: even going so far as to hiring a creative and trusted rigger/sailmaker/ deck designer to provide input.
My best, Dick Stevenson, s/v Alchemy
Hi all,             (awkward elements below may  reflect that it was written for a different venue)
At the risk of being presumptuous, I will include, in detail, how I do slab reefing on Alchemy. I know it took me years to work out the details, but even stumbling through, I never had a problem that was not easily fixed nor did I ever cause damage.
My only caveat is that, coming out of the factory, few boats, perhaps none, are equipped, or designed, to ensure that slab reefing is quick, easy, safe, and largely mistake-proof. To that end, 15-20 years ago, I junked all my Lewmar turning blocks as not slippery enough and bought the slipperiest Garhauer blocks (I think I might be happier now again with a new set, perhaps Harken, but I have yet to research this,). I was also very fortunate to have had the PO install Antal slippery track which has proved an extremely valuable, perhaps essential, piece of kit.
The other thing to keep in mind is that my mainsail has 5 full battens and a 2-fall lazy jacks system which allows me to reef the sail without the need to secure the loose sail.
It is hard to think that reefing could be much easier and safer (for boat and crew) than what I describe below: this on a 40-foot cutter rigged, mast amidships, heavy displacement boat). Presently, my boat is set up for the first 2 reefs, designed deep, to be accomplished from the cockpit under the dodger.
Preparation: Early in the season, either at the dock or when sailing: black “Sharpie” in hand, mark the main halyard to full hoist. Then set each of the 3 reefs in turn and mark the halyard and outhaul and downhaul reef lines with that handy sharpie. You are now set to get pretty close to a good set on the sail and get back to sailing without much fuss.
This is a crucial step basically allowing you to skip re-inventing the wheel every time you reef and allowing for a very quick initial set and a more leisurely fine tuning.
1.    First, decide: if I am putting in one reef, do I want to consider that conditions will dictate 2 reefs shortly and I should just do two now??
2.    Setting a reef going up wind, roughing it out,
a.    Get onto a close reach or there-abouts.
b.    Set the side decks boom vang to prevent the boom from jumping about
c.    Let the main sheet go till the sail softens and is back-winded a little.
d.    Lower the halyard to about 12 inches below the anticipated reef mark (the sail might not fall, with slippery track it might fall or fall some)
e.    Use the down haul, probably needing the winch a little, to get the tack in the correct position according to the Sharpie line previously made.
f.     Crank the halyard up the 12 inches or so to its first reef Sharpie line. The halyard tension should be close to set now. The mainsheet and or boom vang may need to be loosened to accommodate the boom end rising with each reef, see below)
g.    Winch in the outhaul line to its previously set Sharpie mark
h.    Relax, most work is done…
3.    Fine tuning:
a.    You now have a sail set to be sail-able: a rest can be taken.
b.    Then, take a good look for problems and sail set and let the boat settle into this reef.
c.    While jogging along, perhaps with the sail still a bit soft, assess sail shape and tension or loose the halyard, outhaul and/or downhaul accordingly.
d.    This is likely just a couple of inches, if that, of line adjustment
e.    Then handle the mainsheet and set course and enjoy what is likely a more comfortable ride.

My third reef outhaul is accomplished under the dodger: the downhaul is attached at the gooseneck. Attempts to handle the downhaul line from the cockpit always lead to going to the gooseneck to check things out anyway: there was just too much sailcloth bunched together under the third reef tack so that doing the downhaul from the distance of the cockpit could lead to damage to the sail or to the track cars. As a third reef for us is a once every 2 years job, this has not been a hardship.
Some people note age as a factor in roller furling mains: We are both in our 70s and have no trouble reefing the main alone from the cockpit. Note also that either of us can reef/douse alone and not disturb the off-watch person.
A safety element of slab reefing is that end of boom height is increased with every reef (work with your sailmaker to determine the height change wished for) to where it is no longer at head-sweeping height in these boisterous conditions where the boom could be jumping around
From the time that a reef is decided upon till the reef is set (but perhaps not fine-tuned) can be as short as a couple of minutes with all work done under the protection of the dodger and no need to zip up the foul weather gear or to clip and unclip the harness to get to the mast.
The worst mishap in all the slab-reefing we have done is to drag a little sail cloth into the grommet, once leading to a small abrasion hole, easily ignored and later fixed.
Dropping the halyard below its mark and then increasing halyard tension after the tack position is set ensures that sail will not get dragged into the grommet as can and does happen when the downhaul reef line is used to tension the halyard and when the tack is dragged into place. Using the halyard in this way allows the downhaul to position the tack when there is little or no tension on the line.
*This is nice for the off-watch crew, but far from necessary or, to my way of thinking, a reason to tolerate the down sides of roller-furling mains. Many reef at night anyway and being awakened for 5 or 10 minutes if things are heating up is not a bad thing. 

George L

Hello Dick,

it couldn’t be designed and said any better.

2 Minutes to put in a reef reliably from the cockpit.
No stress for a couple in their 70ies.

your experience shows again, that in mast or roller furling is a not-so-brilliant solution for a non-existing problem.

Kudos to John for presenting all this material and trying to keep his biases out, but it is a bit of a foregone conclusion

Tim Zimmermann

Hi Gino: I inherited a Leisureboom system and am still learning the nuances. I’d be very grateful if you could share any details of your procedure for reefing or dousing your main while off the wind or running. Thanks,

Chris SD

Hi Gino,

My Catalina 42 had a Leisure furl boom furler and I also found it easy to use overall. That said, the 3 things I did not like about it was:

1) Always having to pay attention to the boom angle when furling so it rolled up properly

2) I didn’t have much success furling it downwind and always had to go into the wind to reef

3) The boom is heavy and it would give the mainsheet a workout even when motoring into port in rough weather. I made the mistake of a loose mainsheet while jibing once and am glad I didn’t break anything. I felt the margin for error is lower just due to the weight of the boom.

Taras Kalapun

Great article!
How is your J/109 reefing setup?
I would lime to see more comparison between reefing near mast, single line reefing and double line reefing (separate leech and luff lines led to cockpit).

Frode Rognstad

I have zero experience with, and had near-zero knowledge of in-boom furling systems until these articles, and a recent encounter with another boat. That boat is a 50-odd foot, steel-hulled, 73,000 lbs motorsailor.

Following the owner telling me how he tore the main twice, in the last year, I’ve watched him make modifications to try making the system work better. He first cut off the bottom two feet of track, to avoid the sharp entry angle off the mandrel onto the track. He then installed a green/red LED indicator, showing when the vang is correctly extended, thereby having the correct (only) angle for operating the system. Further, he’s installed a mast-mounted camera, looking into the boom, to visually confirm the (un)furling goes without visible binding.

I asked how his two-way furling motor and electric winch were synchronized, to avoid too much or too little tension on the halyard. He showed me the two toggles, one for each motor, that he alternates, based on attempting to hear when one motor or the other is struggling more than expected. I asked him how he felt this system could be operated by additional crew, and he shrugged, indicating that until he could design a synchronization controller, that was probably a no-go.

It’s quite possible his boat has an especially poorly designed system, and that far better solutions exist. I felt, and he agreed, that neither simplification nor ease-of-use had been accomplished.

Dick Stevenson

Hi John and all,
In addition to admiration for a series of balanced, thoughtful and well researched articles on a complex subject. I would wish to point out that yours is about the only venue where this could have occurred.
I have noticed, over the decades, how few articles of any sort there are in the usual sailing publications touching on this subject. I also know that none of the letters to the editor where I mentioned RF in mainsail managing got published where letters on other subjects occasionally did.
So, skippers have had, prior to your series, a wide array of often questionable input in making this important decision (anecdotal, manufacturers, advertising, those who have bought into one of the systems, etc.)
The maritime industry would be well served to have light shown in other areas and kudos to AAC for its example.
My best, Dick Stevenson, s/v Alchemy

Matt Marsh

My C&C 35-II might not be able to keep up with a J/109, but even so, we have found the most important sailing performance criteria in our area to be VMG to windward and tacking angle to windward. Both of these are highly dependent on mainsail shape and set.
On the Great Lakes, half or more of all your sailing will be with the wind coming from very nearly dead ahead. The main (whether full, flattened, or on the 1st reef) and headsail will both be sheeted in tight. Anything that compromises the ability of the mainsail to provide efficient lift when close-hauled is a huge detriment to the boat’s ability to do its job. If you give up 10° of tacking angle in these waters, you may as well give up the rig entirely and just buy a motorboat.
In-mast furlers are — while not unheard-of — certainly quite rare around these parts. This is probably why.

Paul Browning

My thanks once again to John for this series of articles which enables people with strongly held views to communicate respectfully and the rest of us to figure out a thought process to make the best decision for us. As Dick Stevenson says, that opportunity isn’t afforded us much elsewhere.
I particularly applaud John calling out the bullshit so prevalent amongst salesmen.
I have sailed several thousand miles on a boat with in-boom roller reefing and whilst it didn’t give too many problems, I thought it was an added complication that was all good while ever it was all good, but I never trusted it to be ever thus. Especially when the brown smelly stuff hits the fast moving air.
My experience with in-mast furling is limited to assisting various cruising yachties fix their IMF systems, which I’ve now done 4 times. I’ve never once had to fix my own or anyone else’s slab reefing set up. But that could be just me.
I suspect George L is close to the mark with his comment that both IMF or IBF are “not-so-brilliant solutions for a non-existing problem.”
Simplicity and reliability are greatly underrated qualities on blue water cruising boats. Best wishes to all grappling with their reefing solution. There’s a lot of money and angst to be saved by keeping it simple.

Chris SD

Hi John, I just joined your most excellent membership site. in a nutshell, my wife, 8 year old daughter and I are sailing the west coast of Mexico this winter and heading to Tahiti this spring.

This is our second boat and we are aboard a 2012 Beneteau Sense 50 with in-mast furling. I share your opinions and feelings about this and have plans to change to a conventional mast since we have some extensive offshore sailing plans. An expensive prospect but we are so happy with our boat we intend to keep it for at least 10 years, likely longer.

I was wondering if you had any tips as I start down this road:

1) I am planning to sail back to San Diego to have this done only due to the fact I haven’t found an easy way to do this in Mexico. Do you happen to know a good outfit on the west coast of Mexico capable of the job?

2) I would like to set up an ideal rig for offshore sailing and plan to replace all my sails at the same time. It was suggested to me to go with hydranet for longevity, a 110% jib and a code 0. I already have an assym.

3) Knowing very little about the details of sail cuts and shapes, do you have any recommendation as a good compromise between performance and long term cruising?

4) Apparently our Sense 50 is subject to drifting at anchor more than usual in high winds. I haven’t experienced this yet but think it might be wise to get a riding sail. I also don’t like topping lifts much and was wondering if you had a suggestion for a riding sail type yo like that doesn’t require one to raise.


Chris SD

Thanks John,

Good suggestion about just sailing it as it is, but over the longterm I personally wouldn’t be able to live with in-mast furling.

I did put it out there on a few forums in case someone wanted to swap masts, but no bites.

Looking for a different boat is also another interesting suggestion and one that I didn’t even consider. We basically live on ours and I think the effort and time to go through the buying process, fitting the new one with what we want, and moving our all our things potentially overseas to a new location is still a higher price to pay than the $30k to replace the mast.

It would be hard as well parting with all the work we’ve put into Nizhoni so far with a new stainless arch, close to 2k watts in solar, upgraded instruments and radar, washer, custom mattresses, bow sprit, sound system and the list goes on.

I feel if I get the rigging and sails where I want it, my happiness will eclipse the money I am missing. 🙂

Jeff Totman

After always sailing with slab reefing I considered myself a purist. You just can’t beat the sail shape of a slab reefed main and with a good lazy jack and reefing setup I found it pretty easy to reef whenever I needed to. But 10 years ago I wanted a bigger cruising boat and found a Tayana 48 in good condition that has a discontinued Profurl behind the mast system with an almost new laminated sail. This system has 5 C-shaped things on hinges with delrin rollers along the outer edges, that are evenly spaced and held in place along the mast track to prevent the luff from sagging to leeward. I thought it looked ugly and that I’d hate it and planned to remove it and replace it ASAP. But as I’ve become accustomed to it I’m no longer in such a hurry. The rig is about 72’ tall so slightly taller than some to make up for lack of roach. It’s jammed, but only when I’m unfurling it, never when furling. I’ve never had to go up the mast to clear a jam, just furl it back in and tighten it a bit as I do and then unfurl it with no problems. As for additional weight aloft, that’s pretty minimal since there is no heavy hardware in or at the top of the mast and the extrusion is aluminum similar to a jib furler. The C shaped things on the mast are made of aluminum and I don’t know what they weigh, but I can’t imagine them being more than about 5 pounds each. I can reef off the wind just as easily as any other point of sail and without leaving the cockpit since the furling and outhaul lines are led there to a single electric winch. There was definitely a learning curve (must be on starboard tack to unfurl and keep the leach tight) but sort of against my will I’ve become a fan due to the simplicity of the system and ease with which I can reef on any point of sail. One thing I didn’t see mentioned is that with all the roller systems you can easily have the just right amount of mainsail up for conditions right then and if conditions change in 10 minutes you can easily adjust and probably will because it’s so easy, but with slab reefing you are limited to where your reef points are. No argument here regarding sail shape but I find that for me that trade off is well worth the convenience. IF this system ever fails I’ll happily go back to slab reefing but for now I’m happy with what I have.

Charlie Wright

Hello all, I own Paradigm the only Ron Holland designed Trintella 55, a British built twin headstay sloop. John, you might remember, I posted on your article concerning cuddys. Paradigm’s mainsheet and traveler, as in the picture on the posting, is on top of the cuddy keeping it and the mainsheet away from crew. Great Trintella/Holland design. Paradigm was built in 2004 and then sailed in the August from England to Annapolis for the US Boat Show. Not the optimum time to make an Atlantic crossing however “the show must go on”. Paradigm was ordered and commissioned by a collegiate racing friend and fitted with the earlier Leisure Furl boom furling system which had an electric motor aft in the boom. In 2014 I purchased Paradigm. During a subsequent complete refit Paradigm now has the Leisure Furl Offshore(tm) System. Knowing on the Atlantic crossing there had been a knockdown and subsequent downwind reefing, I asked my friend to write about the event. You will also read that Paradigm can be sailed comfortably on a broad reach in 20-30 knot winds gusts to 40, with a full hoist main and Solent. The crew onboard were experienced with the exception of Katie. The crew had schedules to meet back in the UK and Paradigm was therefore sailed aggressively, much like a racing boat. Here is his summary:

“Paradigm had waited for two days in Bermuda for Hurricane Alex to pass through. We headed out on a windy morning and were broad reaching towards the Chesapeake in 20-30 knot winds. The winds held steady throughout the day but picked up to an occasional puff of 40 knots late in the evening. We had had rain off and on that night, and there was thunder and lightning to both starboard and port. I should have reefed the main before I went off watch but thought that things were relatively stable with Adam and Louis in charge.  

Suddenly, I was roused from sleep by a lap full of sea water. Paradigm had sustained a knockdown and water had come in through a galley port that Katie had left open. I immediately went on deck and crawled to the cockpit. I immediately furled the working jib to reduce at least some sail. The main was full hoist with the boom angle setting probably not changed since the morning hoist. We headed the boat up slightly, but we were still on a broad reach as I did not want to increase the boat’s angle of heel in a 60-knot breeze. I activated the boom motor and fortunately was able to reef the main down to the equivalent of a second to third reef.”

Charlie Wright

Hello John, Well true to the text in your article above that was a robust push back on an actual well documented experience by some also very experienced sailors. My friend that commissioned Paradigm grew up racing “R” boats one design on Lake Michigan with his parents. Definitely a vessel that takes a lot of talent to be sailed and raced well. Additionally he has raced in over twenty-five Chicago Mackinac races including first overall IOR. Many rough nights pushing the limits including flying large symmetrical spinnakers. His home is full of other sailing trophies. Thinking he is a qualified judge of conditions. The crew observed higher than 60 knots on the wind instrument however my friend went with what he observed when he got on deck for his initial recount of the event.

Here is an update from him at my request:

The puff that caused the initial knockdown was at 80 knots. The wind then settled down a bit to 60 knots and we reefed under those conditions. The boat sailed well with the reef and no jib. The waves were 20 to 30 ft. high but we had no trouble on a beam reach in those conditions.”

Charlie continues: Sorry the hatch has become a distraction. That hatch is in the galley just forward of the aft cabin where my friend was sleeping off watch. The hatch was not in his cabin. The spray did as he recounted get to him. When it was opened, who should have closed it or even the hatch is not the focus of my post. The cuddy does offer great protection for the companionway when crew are headed on and off deck. It is possible to clip on inside the cuddy then exit aft. As we know many issues happen around the companionway.

Paradigm had been sailing all that day under control in 20-30 knots with gusts to 40. Yes we all agree Paradigm was over canvased that night when the wind line hit. As John K. has written and said many times sailing to a schedule leads to taking risks.

Another design feature on Paradigm that we are seeing more of now is an inside self tacking Solent with tight sheeting angles for great and convenient upwind sailing in over 15 knots true 20+ apparent. However off the wind there is a lot of twist in the upper half of the sail. This depowers the Solent considerably. There is also a storm jib that hanks onto an attachable shorter inner stay opposed by running backstays. These stays can also reduce rig pumping. With the boom at the furling angle there is twist at the top of the main full hoist, again depowering the sail to some degree. I generally drop the aft end of the boom with the vang on a reach to tighten the leach.

One of the benefits of a boom furling system is that during furling or dropping the main there is downward force capability on the luff bolt rope. Additionally by snubbing the main halyard, the luff of the sail is kept tight and not bunched. Both factors enhance the process. As with any powered system this needs to be managed to avoid injury, damage to the equipment and the sail involved.

There was a featured article in the March 2005 issue of “Cruising World” about Paradigm. The article by Dieter Loibner is titled “Waltzing Trintella”. In the article Dieter relays his experience sailing Paradigm on the Chesapeake Bay. Quoting him “On that October day, the Chesapeake was snorty, coldish and choppy”. He then goes on to say “While other crews on small boats in the vicinity held on for dear life, here I was, casually ambling forward on the high side without worrying about getting tossed overboard.” “What fascinated me most was the smooth motion. Leaning on the headstay with my eyes closed, the rhythm of the heaving bow transported me to the scene of a baroque Viennese ballroom where a crowd of elegant dancers parlayed a champagne mood into the 3/4 measure of “The Blue Danube” waltz”. Hence the origin of the article’s title. More importantly the Atlantic crossing reefing is documented in the article. John perhaps you have access to that issue of “Cruising World”. Unfortunately this is not available on the Cruising World website. I would be happy to scan you a copy.

The reason for the August departure were delays building Paradigm due to Trintella’s financial issues. Paradigm actually went under the English channel on the train twice. After the hull was completed in England she was transported to the Trintella yard in the Netherlands then back to England to be completed.

At an Annapolis ISAF Offshore Personal Survival Training Course I was able to talk with John K. about reefing a boom furling main downwind. I made a point of having that discussion as it is a topic with many dimensions and opinions. John has a very interesting technique. I will leave that for John to discuss.

One of the crew on the Atlantic passage was Peter Dorman the British navigator for the late Prince Phillip during the Cowes Week races prior to this trip. This was his fifth crossing of the Atlantic. At the time he worked for Hamble Yacht Services. Hamble completed Paradigm. At the conclusion of the trip Peter was heard to say this was the first crossing that he made in which there was no serious argument among the crew. John perhaps you know Peter and can get his remembrance of the trip.

Rob Gill

Hi Charlie,

Two comments full of interesting detail thank you – especially as we explore downwind reefing with our Leisurefurl system.

I am pretty convinced that with the sail rolled around the mandrel when well reefed (which requires mast clearance to roll further) and for efficiency of the universal joint, that broad reaching is the optimum point of sail to reef on downwind, with the boom out about 50 degrees from the centreline.

Broad reaching is also our quickest point of sail, which reduces the apparent wind dramatically. In 30 knots of breeze, we are surfing continually around 15 knots, with finger tip helm control, bolt upright and tracking as if on railways lines. So apparent wind around 20 knots.

It is such enormously fun sailing, that the temptation would be to hold on too long as the wind rises, and as your friend discovered in dramatic circumstances. I believe from sister-ship accounts, in 40 knots TWS, we will be approaching 20 knots and surfing, still with finger tip helm control. I don’t intend to ever find out, unless perhaps we have a “race crew” aboard.

Since we have only reefed on a broad reach in 20 knots so far, I would be really interested to know if you regularly reef downwind yourself with Paradigm, and what are the biggest wind and sea conditions you have had success with?

AND I would be very, very interested to read what John K had to say on reefing a furling boom off the wind, though looking on-line he appears to have conventional slab reefing on his own sail training yacht.

And lastly, your Paradigm looks a beaut Charlie (from a brief look on-line), very much a classic Ron Holland …!

Stein Varjord

Hi Charlie, Rob and John,
Although I’ll pick slab reefing any day of the week, this is interesting accounts telling me that I might prefer in boom to in mast reefing.

On wind strength, I also have some experiences from >45 years of racing and cruising. Worth mentioning: A near hurricane around 60 knots plus gusts far stronger, in the Atlantic with waves “as big as mountains”. We were on a fast 12m, (40 ft) catamaran carrying a 5,5 square meter (60 sq ft) storm jib only. A comically small sail for the boat, but almost too much in the gusts. We were on a broad reach at speeds from 10 to 25 knots.

Another time, a short attack in very protected waters. The official statement by the national institute of meteorology in Oslo, located nearby, was sustained winds at 10 m above ground (33 ft) of at least 250 km/h, 125 knots. Gusts at 50 meters altitude (150 ft) perhaps double that. It was deemed, from the extreme temperature drop, to be a rare turbulence from high altitude jet streams. Came from completely clear skies.

This was while racing in the inner end of the Oslo Fjord autumn -83 on a 33 foot Bianca Afrodite 101, which is a slender boat, has a tall but very light and low windage rig and 60% of its total displacement in its deep fin lead keel. Designed in cooperation with Paul Elvstrøm. Beautiful low flush decked fast boat, for the time… During the hardest gusts we had only the bare rig. The mast was slapped into the water repeatedly. Absolutely insane.

These experiences mainly showed me that when it pipes up enough, the actual quantity becomes kinda irrelevant, or at least impossible to judge in any meaningful way. We just have to engage maximum of what we got of hunkering down methods, and then hold on. It doesn’t really matter if it’s far too much or way way too much. We can’t do anything more.

We can’t really judge visually how tall a specific wave is with any reliability. There’s no useful reference. Same with really strong winds. It breaks our scale of reference, comparison. We can only judge it from the increase in effect on our environment. That effect scales a lot faster than the linear wind speed increase. Our judgement will scale accordingly, probably amplified by our emotions. In a storm, a gust may seem to double the power and effect, while the actual wind speed increase might be 10%.

The boat wind instruments are also not suitable for verification. For starters, they are very far from calibrated precision instruments. Their job is to show us changes, not measure actual values. They may be precise enough for our needs in medium wind, but in high winds there are aerodynamic and other problems with most designs rendering their numbers VERY inaccurate.

The conclusion from all this is that I must support what John says about the wind speed numbers mentioned. As explained, I totally get where the numbers come from, and I’d never question the experience, competence and skills of those presenting them. Still, 60 and 80 knots true wind speed means really brutal forces are at play. Forces that can be calculated. They are big enough to say if something is possible or perhaps flat out not. I’m not an engineer who can do that calculation, but I’ve felt those forces lots of times and can witness that in 60 knots of wind, on any boat, all sails must be down, except perhaps one heavy duty tiny storm sail. If it was realistically possible, I might even have wanted to take down the mast.

Charlie Wright

Hello Rob, thank you again for your kind comments concerning Paradigm. With the Trintella 55, Ron Holland designed another amazing sailing yacht as many before and some since. He wrote an extensive memoir published a few years ago. The title of the book is “All the Oceans”.  
My friend Art and his wife Mary Jo made a few modifications to the deck design. Not necessarily to Ron’s part of the design. They raised the deck area forward on the Cuddy slightly to eliminate a single step down going forward from the main cabin. Steps can cause injuries especially at night. There is an unavoidable step going aft starboard side to the galley. It has a red LED light mounted on the side of the step. Many hand holds. On deck a double rail system was added to the passageway, which was lowered removing one step, from the Cuddy to the twin helm station. This allows being clipped in from the protected Cuddy companionway all the way to the helm stations with guard rails both sides.  Art, being a top dinghy sailor, also had the single mainsheet attachment on top of the Cuddy changed to a short traveler. This allows the boom to be centered close hauled in light air without adding too much twist and tension to the leach of the main. Obviously it can be used to some degree set to leeward.
Rob, you have a very quick vessel judging from your post. Definitely a plus to decreasing the apparent wind speed downwind. I sail a DN iceboat. Conversely gybing is easier and safer than tacking. With the efficiency of the iceboat, you gybe in seconds with most of the wind across the bow not the stern. American Magic in Auckland definitely experienced the significant effect of a high-speed tack, the resulting apparent wind and speed through the water decrease, while experiencing a significant true wind increase during the bear away. They tactically decided not to do the bear away and gybe in the puff. Costly. I was able to discuss this with Terry Hutcheson. It was not an issue with the running backstay preventing the main from being trimmed out. It was the effects of the rapidly changing true wind. A dimension to be considered when reefing. In gybing with dinghies letting the boat accelerate then at the end of a puff ideally while surfing reduces apparent wind gybe. Reefing downwind in limited increments as the apparent wind changes makes sense once you are caught out.  
To your question of reefing experience downwind with the Leisure Furl system I generally always reef into the wind. I have lowered the sail downwind when heading in and used the engine to take pressure off the main by decreasing the apparent wind angle. After reading John’s article and the comments to downwind furling this spring I plan to primarily reef and lower downwind to get more personal data to various wind ranges. Thank you for the perspective on boom angle, AWA, AWS and TWS.  
Again, I would encourage you to contact John Kretschmer directly on expanding his process. He did say in Annapolis as I am remembering it, was to over sheet the main on a deeper downwind reef with a Leisure Furl system. That over sheeting effectively reduces sail area presented and increases the stalling effect taking pressure off. If it was more of a broad reach thinking John K. would head up slightly and take pressure off the main slightly as Art did during his event. John K. did make a video for Forespar. In it on reefing he does not address doing it only into the wind. The video understandably shows the process basically into the wind. The Forespar YouTube video is “Forespar Leisure Furl Handling”. In the video he does show how you can reduce camber (flatten) the mainsail with tension from the boom furling mandrel.  
After some testing this spring, I will post more. Please add anything you experience or refine. Cheers

Rob Gill

Hi Charlie,

It is becoming clearer to me that many of us with in-boom furling were habitually reefing upwind, simply because that was the instruction in the manual.

Thanks to these articles, I hope that we will all practise reefing off the wind and perfecting our technique, so that downwind reefing in gale force winds will be entirely achievable and normal.

I will certainly post some updates as we go, and look forward to your experiences too.

Charlie Wright

Hello John, Thank you for your thoughts in your recent post. Agree some wind instruments can be inaccurate at higher velocities. More on that later. Let’s focus on conditions as Paradigm saw them. Paradigm was sailing stable and well in consistent winds into the 30s gust to 40 knots, large seas all that day out of Bermuda and into the night. Per your post the wind instruments would be accurate. The sail configuration was the Solent and a full hoist main. Things were stable enough that a crew member was able to, this was August, open the small below deck level hatch in the galley.  During the night a wind line hit Paradigm causing her to heel significantly creating an issue with the open hatch and being able to continue with that sail plan. The action of the vessel indicates a much stronger wind. My friend, Art, helped the on-watch crew reef completely the Solent and after heading up slightly to take pressure off the main, still broad reaching, furled the main to near a “triple” reef point. As we know the in-boom furling can be reefed to any full batten location. Paradigm regained stability and was sailed under that configuration until the winds decreased. We know by the actions of the vessel that the true wind was over 40 knots and to cause a change from full hoist with Solent to a significantly reefed main with no Solent the wind velocity had made a significant increase. As Rob Gill pointed out the apparent wind, as we know the wind the vessel sees, would be less on a broad reach in surfing conditions. Whether the true prevailing wind was 50, 60 or 70 knots is not material. Let’s just say Force 9 based on a documented and accurate reading of Force 8. So, we can say based on accurate wind instrument readings below 45 knots, your number, that the Paradigm crew reefed on a broad reach the Solent completely and the Leisure Furl mainsail significantly in Force 9 winds. Are Art and I recommending having to deal with this situation? No. The point of my original post was based on the accident earlier this year with the mainsheet and traveler issue while furling into the wind. There are other options. Art’s experience is the documented ability, when done correctly, that you can furl the Leisure Furl system on a broad reach in Force 9 winds and waves. Could he have had issues happen during that furling? Absolutely. Could a successful repeat of that furling be made if needed in the future? Seems it could. Are you better to furl by heading up to a close reach. Captains call, possibly no. Do you want to go head to wind to furl the main in heavy seas. Likely not, however, again captain’s call. 

To the question of sailing vessels in strong winds I can speak firsthand to some experience. On Paradigm, Art, Glenn Haman the professional captain and I sailed Paradigm to the BVIs. We had one passenger Mary. My second solo night watch was crossing the Gulf Stream just out of the Chesapeake Bay. Winds were out of the SW 40 Knots apparent on a close reach so with the Gulf Stream current. Sail plan was Solent and main furled to the top spreader. No issues. Glenn took over after my watch and kept the same sail plan. On the bay the strongest wind I have recorded was 43.9 knots with the same sail plan no issues. However close-hauled feathering in the puffs.  Those are the best examples I have with Paradigm.

More relevant to the discussion of sailing vessels in Force 10 to 12 I have the following experience. A good friend of Art is Skip Novak. Art put me in touch with Skip for the passage from Porto Williams, Chile in the Beagle Channel across the Drake to Antarctica and then back across the Drake around Cape Horn to Porto Williams.  The vessel was Pelagic Australis, Skip’s second expedition vessel. Serious high latitude 74 foot sloop triple headsails. Going into Antarctica our sail plan was double reefed main and working jib in Force 9 winds. Our first night out of the peninsula headed back the 9-12 PM watch recorded a 16 millibar drop in barometric pressure. They reefed to the working jib and double reef main in Force 8 winds.  We started our watch at midnight with three crew, one seasick. Anticipating higher winds, we completely reefed the working jib. With the coffee grinder behind the mast a fourth reef was attempted. We were not able on a broad reach to achieve the fourth reef. We settled for the third reef. We rolled in the seas from our port quarters using the autopilot under control. My watch captain Laura Parish estimated the waves by the end of our watch at 25 plus feet. Laura and I alternated watching the radar to try and spot growlers while the other watched out of the pilot house windows for growlers. It was snowing so Laura went on deck with a window scraper occasionally to remove the snow from the windows. Our third crew slept after helping to get the reefing done. The drill on the radar was to look at all the wave reflections and find a reflection that stayed in the same place. That might be a growler. The icebergs show up clearly on the radar. Winds built to a steady Force 10 with significant gusts to Laura’s estimate of low Force 12. Pelagic Australis continued to sail well under auto pilot and mainsail to the third reef point. Laura was the watch captain for the winning vessel on the BT 2000 round the world race. Also, this was her third year on Skip’s boats in the Southern Ocean. She has seen a lot. I observed while watching the radar steady 50 knots with much stronger gusts. Per John’s observation the wind instrument gave random low numbers after 55 knots. I will go with Laura’s perspective.  Paradigm, a vessel Skip knows, is closer to an expedition vessel than a production sailboat. However not to Pelagic Australis’s level. Two months later I helped sail Pelagic Australis from Porto Williams Chile to Cape Town via the Falklands and Tristan da Cunha. Many hard to see wind lines. Many quick sail configuration changes.

All that said this is my last post on Paradigm’s Atlantic crossing downwind reefing. My advice as we all hear often is reef early and avoid schedules. If caught out do your situational analysis, make the best decision available prioritizing crew safety.  Sails and systems can be repaired or replaced. 
Rob thank you for your comments. I will on another post address some thoughts on your questions. I look forward to your perspectives on future posts. Cheers, Charlie, Paradigm, Gibson Island, Maryland.

Robert Ashcroft

Hi all, I have a pro furl in boom system.
I did struggle with no electric winch for a few years, possible but yes hard work. With regards to reefing the correct boom angle is important to avoid bunching fwd or putting too much load on the leach. Approx 87 degrees to the mast is what I use. In this case I can reef while sailing on a close reach or even up wind. I de-power the main and with the headsail keeping me going I do not need to luff up into the wind at all or even A/C, It’s very easy to stick a reef in. Thanks for the article.

Terence Thatcher

Thought I would add another late comment. There is a guy called Captain Q that does superficial used boat reviews. A few months ago he reviewed a Bavaria 40 with inmast furling. Talked about how easy and wonderful it was. Said the vessel was ready for offshore. I tried posting comments urging him to correct his errors. I cited the magazine article you have mentioned about the Nova Scotia tragedy. (I subscribed to his videos to view the boats, what my spouse calls boat pornography.) He removed my posts 3 times and I gave up.

Stein Varjord

Hi Terence and John,
I’ve seen a couple of videos by that guy, and some others of the same type. Their purpose is to make boat ads and sell the boats, to get paid by the seller, and as a byproduct, get some YouTube revenue. They are sellers dressed up as entertainment or info.

They have no interest whatsoever in giving good knowledge or having an interaction. There can be opposing comments on their videos, but only after the boat has been sold, when they stopped caring. These people are good examples of why we need to totally distrust any youtube (and other) channel, until proven otherwise, and even then stay suspicious.

Rob Gill

Hi everyone,

Thought I would post an update after committing to give things a go and report back with the results.

Today we sailed to Great Barrier Island in a SW 25 knot gradient breeze and blue skies, from Auckland. We left with full main and jib – champagne sailing, on a deep broad reach, goose winged. Seas were steep, short and stroppy.

Clearing the land, the wind increased to 30 knots for a time, gusting to 35 knots. In the peak of those gusts, we tucked in the first reef using our manual Leisurefurl in-boom reefing system, down wind.

With the boom out at about 45 degrees to the centre line and the first mate on the helm, I rolled the mainsail to the bottom batten with vang eased, topping lift on, plenty of tension on the downhaul and the halyard eased, incrementally.

Very happy with the reef and result. I really can’t tell any difference from when we roll the sail upwind. It hasn’t bunched up at the tack as I feared it might. See the picture of the stowed sail – we didn’t shake out the first reef before stowing.

A quick thank you to John for raising the possibility in this series of posts, and challenging my thinking. Previously, we would have rounded into the wind, hove-to and then paid off again. This was easier and safer.

More experimenting needed before I can say it’s easy, but a good start.

Rob Gill

Hi John,

Thank you and good question – no we were deep broad reaching for speed.

At the time we tucked in the reef, our maximum apparent windspeed was around 27 knots. And we were surfing between eight and 11 knots. So not quite enough breeze to keep us surfing continually without our Code 0 up. Over sheeting the 103% jib would have had no effect, except to slightly slow us down and increase the apparent windspeed.

Using the jib to backwind the mainsail I now think would only work on a reach or even close reach no matter what wind strength, and being beam on to the wave train, then we may as well turn all the way up wind to close-hauled.

I perhaps should mention, since your articles we regularly reef downwind in lesser breeze. This was the first time attempting it in near gale force conditions.

A thought occurred to me after this experience -> whilst reefing, we were always reefed…! At anytime I could have locked off the halyard and downhaul clutches, if something else needed my urgent attention. And then returned to complete a first, second or even fifth reef later. As we have discussed, optimum sail shape is achieved with the batten held under the mandrel in lieu of an outhaul, but this is not really material downwind as the sail always has good shape.

Tim Zimmermann

Hi Rob: Your accounts of your downwind reefing experiments are very helpful as I learn the nuances of my Leisurefurl boom reefing setup. Two quick questions: 1) when you are reefing off the wind it sounds from your report that even though the boom is eased out to about 45% from centerline (which is how far out Forespar says it can go during furling) the mainsail remains loaded as you winch it down to reef it. Is that the case (asking because there is usually a lot of emphasis on unloading the main–which is why many people seem to come up to at least a reach)? And 2) if you are often reefing downwind with the main loaded at least somewhat, do you ever notice any chafe or wear on your luff tape (have you ever had to replace it and the boltrope in the nine years you have had the mainsail)? Thanks so much, Tim

(PS: the only modification to your boom setup I have been using while lowering or reefing the mainsail is to snug the vang back up once the topping lift has been set to bring the boom angle to about 87 degrees, which locks the boom angle in).

Rob Gill

Hi Tim,

Just got back from Great Barrier today. Awesome sail with the Code 0 up and full main. By the afternoon the wind increased ahead of a cold front approaching NZ, to about 25 knots so approaching the Tiritiri Matangi Channel (a renown wind funnel), we rolled the Code 0 away and tucked one reef in downwind.

Q1. Confirming the sail was fully loaded on a broad reach, this time I brought the boom in to 35->40 degrees off the centre line to keep the sail from pressing hard on our moderately swept-back spreaders. The reef wasn’t so good this way and the sail crept forward on the mandrel towards the mast. I need to work on adding trailing edge sail protection to the spreader and tip.

Anyone have a good solution for sail / spreader protection, something that will stay working in good condition, even when permanently exposed to the elements?

Q2. We have only been reefing downwind since John raised such a possibility as a necessity, in this series of posts..!

Our bolt rope is original and still appears in very good shape with no chafe. And we really use our mainsail – we average about 90 days a year aboard, and we only motor in flat calm or coming into / leaving anchorages. All other times we are sailing (some motor sailing). We also clocked one 6 month live-aboard SW Pacific circuit.

We do use Dry Lube to keep the track and luff tape lubricated. Also our full length battens are bolted through the sailcloth which supports the sail luff, and reduces chafe and wear offshore.

Our mainsail shape looks like it did new – I really think we will get another 9 years unless our NZ UV gets to the sail. Rolling the sail around a mandrel is really very kind on sail fabric.

Agree, snugging the vang is a good idea in waves, not so much for the boom angle which we set with the topping lift and lift from our solid vang – but more to minimise the load on the mandrel shaft and connection through the mast.