In-Mast Furling on Cats - Pros & Cons . . .

[emcmia]

I ran with the conventional (Privilege) factory designed/fitted main for more than 12 years (and 12k NM), including new main replacement midway during that period. I replaced that rig with a LeasureFurl system three years ago this month.

Learning curve aside, I wouldn't go back. Performance is as good - if not better than with the original batt-car rig. Plus, being over 60 and shorthanded more often than not, the big sail gets deployed sooner and more often. With a canted mast, the key to hoisting and down hauling is a rigid boom vang (by Garhauer), which easily and consistently facilitates the right angle. Even without electric winches, I have yet to experience any of the problems cited herein.

[Cotemar]

emcmia,

That is great news on your boom furler. Can you share some pictures with us.

Mark

[colemj]

Yes, I see a lot of cats with in-boom furling that works well. Most of the problems cited here are with in-mast furling, which is what the original post was about.

Mark

[ParadiseDreams]

Originally Posted by capngeo

Other than a Hobie Cat, I have all my time on Monos...... My current boat has a Stow Boom and I love it. I could care less if I'm missing a knot because my sail is not PERFECT, and that knot is well offset by convenience. I guess you cat sailors like to go FAST!

I should start off saying I have no practical experience, however from everything I read, I believe you severely underestimate how many compromises are already being put into cruising cats and how much they are loaded for convenience. They need all the sail area they can get and some. And no, not for racing.

I think a knot is a lot to lose when you're already slow and I would rather have an IBF instead of an IMF. Same convenience and we don't have as many drawbacks. I would definitely look for an IBF in a future cat, I don't think I would ever consider an IMF on the type of cruising cat I'm looking for.

So now you have at least one opinion from an inexperienced future buyer

[muskoka]

Absolutely correct PD. The modern cruising cat can't afford to lose sail area gratuitously as they're typically undercanvassed. In fact, the new Lagoons are carrying about 30% sail relative to their displacement - a quick glance at the older 380 versus the new 400 gives an idea of how weight has ballooned without any commensurate increase in sail area.

In defense of this trend you often hear "My cat managed 12 knots in 20 knots of wind". So what. Most sailing isn't done in high winds and the real litmus test is how it sails in light airs. To me the most compelling argument for more sail is that I'm still sailing in 8 knots of breeze whilst all the larger cats are motoring.

[emcmia]

Originally Posted by Cotemar

emcmia,

That is great news on your boom furler. Can you share some pictures with us.

Mark

Mark, this LeasureFurl IBF system was retrofitted on my 1993 43' Privilege about three years ago. Masthead height above WL is 68ft. F/g battened mainsail is about 660 sf; P is 54ft and E is 18ft. Although not needed during normal ops, topping lift has been retained to reduce compression fatigue on vang spring. With canted mast, vang retracts to set fixed 90 degree angle to facilitate sail hoisting and furling. Manual drive spool (via snatch block at foot of mast and winch) is used to furl sail onto mandrel; if furling line were to break, the spool can be manually rotated with winch handle. U-joint (not shown) at mast end of mandrel allows for reefing when mast/boom are at an acute angle. Original mast bracket allowed raising gooseneck fitting to upper slot to accomodate hardtop and setting the spar at a right angle to the mast. Sail track and guide are clamped onto existing mast track - very smooth with little friction. Total DYI installaton time was about 10 hours. Sail cover retracts on endless loop to cavity under sail compartment - very convenient when rigging for hurricanes in south Florida.

[Cotemar]

emcmia,

Very nice set up. You did a great job.
Nice photos also.

Mark

[Lexam]

Hi guys. I emailed Ted Clements head of Antares Design and asked him about the in mast furling system vs the regular mast. He gave me permission to repost his response and has put it on his blog.
Mast Height & Performance « Catamaran Concepts
(Blog has pictures)

"Question: Hi Ted, for us Antares fans out there, could you do a contrast and comparison of the various masts available to the Antares 44i? As far as I know there are 2 different masts available. The ICW and the In mast furling. Could you give the pros and cons of these and performance?

Answer: There is one mast and standing rigging configuration (height & geometry) available for the Antares that was initially engineered by Selden Spar and has been used successfully since inception. Some options in sail handling have been added to accommodate different owners cruising preferences.

When the design was first being developed, a stability study was undertaken to establish some parameters to apply. The company always had a very close relationship with its customers and the prevailing philosophy demanded that the new boat could be handed over with confidence to its trusting owners.

The sailplan / stability design exercise pre-dated the establishment of any benchmarks such as the ISO Standards now offered for offshore Category A vessels so we used experience with the company’s other existing designs and charted the sailplan/hull parameters/wind speeds to establish a threshold that we knew would be safe and forgiving to the maximum degree that could be practical. This was, in effect, full size model testing.

A hypothetical sailplan was frankly ‘eyeballed’ to start with, (my task being to adjust the drawing while the sailplan ‘committee’ leaned over my shoulder). This provided some sail areas and centres of effort to consider. The large sail areas caused some chin massaging but they were deemed to be acceptable, just. The stability numbers were checked against the chart we had developed, an exercise that engendered a lot of ‘ultimate case’ imagination, speculation and debate. Of course the potential for the drive power of the sailplan continually tugged things toward the adventurous side of the equation. Things were adjusted a little but at foundation, the ‘eyeballed’ rig stood, a testament to my colleagues sensibilities.

It wasn’t until this exercise had been run through that the height of the mast truck off the water was measured and fortuitously found to be acceptable for transiting the ICW. I suppose that if it had been with a foot or so we would have reduced it, but this just wasn’t necessary. There was certainly no compromise, the sailplan as it still stands was considered to be adventurous enough.

The standard mast carries a luff track for a fully battened mainsail. The boom is provided with extensive internal hardware and tackle for two ‘single line’ reefing systems. In common with all modern catamarans in its size range, the boom is fairly high above the deckhouse. Several years ago we developed of an optional MainTamer boom which consists of a set of light weight laminate ‘wings’ attached to the standard boom that in effect provide a platform to contain the mainsail folds so they don’t tumble about. The sail itself remains the same fully battened high roach cut and hidden away inside the MainTamer is the standard Selden single line reefing boom. If you were to break the MaintTamer in some remote location, the boom may still do its job and be readily serviced.

The optional ‘new’ element for Antares is the Selden in-mast furling system which primarily involves the mast extrusion itself. The external hardware, appearance and dimensions of the spar are essentially the same. The boom extrusion is in common with both configurations but the internal provisions for single line slab reefing are absent. The mainsail has been designed by North Sails specifically for the Antares and is well within the maximum capacity of the mast system. By necessity, sail battens in a furling main must be parallel to the mast rather than the boom, as is the case for the slab reefing sail. Although full length vertical battens could support a roach similar to that of the standard mainsail, practical issues preclude such awkward stuff on an ocean cruising vessel, (imagine a raising/lowering exercise with 40′+ battens to handle). The North Sails design therefore accepts the relatively limited roach that may be supported on a series of short vertical battens. This is a compromise to the total mainsail area of approximately 30%.

For many years, the Antares was not offered with a furling main option, despite the considerable interest expressed by customers. There were two primary reasons for this; the prototypical nature of the gear on offer and the compromise to the mainsail area. Recently, both of these reservations have undergone some re-thinking.

For over ten years, Selden spar and rigging engineering has been incorporated closely with our own production engineering, forming a kind of mutual investment structure. Over the years we discussed the furling main issue periodically and it was with some satisfaction that the announcement was made that Selden was ready to offer the equipment. This was critical to us as our boats are dispersed all over the world at any given time and the knowledge that the Selden network may be available for assistance to owners as well as ourselves is an essential. Simply put, we (and our customers) needed Selden level support for any venture into furling mainsails. We now have it.

The move to produce our boats in Argentina led to the development of a working relationship with North Sails Argentina. This provided access to some fresh and considered opinion from the world class sail loft. Turns out the perceived loss of push from the reduced roach may not be all that significant a factor for our cruising boat; in a set with large headsails the proportionate effect of the main is significantly reduced along with the compromise due to a reduced roach, the limited crew and sail trimming effort likely to be available very much reduces the potential for a maximized performance main, and the relative ease of furling means the sail will actually be used a lot more.

This last point is probably the most significant and is echoed by Selden experience. Faced with the necessity to remove its cover, release the gaskets, go through the hoisting process with a possibility of shortly having to drop or reef sail and reverse the process, owners are justifiably reluctant to use the main much of the time, especially when it involves excursions out into inclement conditions. The furling main with its electric deployment from the helm gets used a whole lot more. This means the contribution of the sail over a period of cruising is much greater, isn’t that really ’performance’?

In ideal conditions you may lose a little speed and that may be significant to your style of sailing. There is no meaningful way to quantify that loss as it will depend on the sails set, wind conditions, point of sailing, your motivation, etc.

Regardless of the theory which will be debated back and forth endlessly from different perspectives and by any number of us ‘experts’, the fact remains that the recent Antares boats equipped with furling mains delighted their owners, (despite our skepticism and reluctance). Acknowledging that they can’t instantly try different sail styles in succession they however report no apparent loss of perceived ‘performance’. I believe this is all that can be asked for, so we gracefully concede the field and say, “The furling main is a viable option for many if not most owners.”

Putting yourself in an owners shoes, and the rest of his weather gear">foul weather gear, and perhaps letting go of some things that you considered ‘de rigueur’, is the only tenable evaluation exercise. The definition of ‘performance’ for a cruising boat may acknowledge racing sail parameters but needs to encompass and be weighted toward the compete voyage experience.

The full roach, slab reefing, fully battened mainsail system is there for owners who can enjoy the advantage of it. The reduced roach furling main is there for a more practical approach. Which configuration will arrive at the next port first is debatable."

TC

[Cotemar]

Lexam,

Very well written. Glad you posted it. Always wondered what goes on behind the curtains in these design houses.

Mark