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Single vs Double Spreader

22K views 30 replies 17 participants last post by  SchockT 
#1 ·
I am considering a new(to me) boat and partway through it's production(still being made) it went from a single spreader rig to a double spreader rig. The location of the chainplates and genoa tracks remained the same. It was explained to me that they simply changed spar manufacturers and that size happened to be a double spreader rig with the new builder.

What are the pro/cons of either rig?

BTW, the boat is a Caliber 40lrc.
 
#2 ·
The usage of a double spreader rig allows the mast to be "less weight" or "less weigh aloft" a definite advantage over the usually heavier single spreader rig.

The disadvantage of a lighter weight mast is the propensity to vibrate (mast pumping) at certain 'induced frequencies' in comparison to a single spreader (usually less flexible / heavier) rig. However, that is easily taken care of by proper 'prebending' (forward bow) of the mast ... and/or the application of running backstays, etc. Each mast mfgr. recommends such 'pre-bending' for both single and double (multiple) spreader rigs.

The double spreader rig is usually lighter in weight/mass - thats a distinct ADVANTAGE over a heavier single spreader configuration. For each lb. 'extra' weight aloft requires (typically) an extra 5 - 10 lbs. of added ballast in the keel .... and ultimately adding unnecessary WEIGHT adds 'nothing' to a boats sailing and safety characteristics. The minor downside is that the adjustment of the rig tensions is a bit more complicated.
 
#3 ·
Thanks Rich. So you are saying the mast cross section is beefier.

The one boat I looked at with the single spreader has a convention full batten main. All the ones with double spreaders have in mast furling.

So add the weight for the in mast furling and the extra spreader and intermediate shroud and you might be getting close to the weight of the single spreader rig.
 
#4 ·
I'd cross the in-mast sailing boats off your list. In this case, the double spreaders are there not as a weight saver but because in-mast furlers need much stiffer rigs to operate properly. The stiffer rig is another reason they don't sail as well and the heavier and stiffer rig is the reason that the need to reef earlier when they have the same sail area.

Jeff
 
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#6 · (Edited)
Id agree about ditching the in mast furler.

Better to set up a 'traditional' mainsail that you can 'slab reef' ... and then add a STRONGTRACK, etc. system, etc.

Only time an in-mast furler is beneficial is when you do a lot of 'short sails' when constant raising / lowering, removing/putting on a sail cover, etc. becomes a PITA - IMHO
 
#7 · (Edited)
So, you can't bend the mast for the Nth degree of tweaking. Most people don't even sail their boats more than a handful of times per year. Maybe, if dealing with the main could be handled solo and easily by the average owner, they'd sail more often. I often see boats sailing on (furling) headsail ony, with the (non-furling) main neatly tucked under cover on light air days when they could really use the extra go from the main, but it's not worth the trouble. To the dedicated sailor, raising and lowering the main is all part of it, but some older, more experienced ones just want to get out there, and are tired of some of the more physically demanding aspects. I took lessons on a Catalina 310 with in-mast furling. It definitely would not be a deal killer. The boat moved well in light air despite 10,000 lb displacement, the sail was easily tweaked when the wind picked up and gusting induced some nasty weather helm. Look at the popularity of furling head sails. The cost is relatively low compared to in-mast furling. I fully believe if a mainsail furler system could be as inexpensive as a headsail furler, it'd be easily as popular, and non-furlers would be relegated mostly to purists' boats and racing craft. I have no problem with full manual operation, but I wouldn't pass on a good deal because of the in-mast setup. Not by a longshot.
 
#9 ·
So, you can't bend the mast for the Nth degree of tweaking. Most people don't even sail their boats more than a handful of times per year. Maybe, if dealing with the main could be handled solo and easily by the average owner, they'd sail more often. I often see boats sailing on (furling) headsail ony, with the (non-furling) main neatly tucked under cover on light air days when they could really use the extra go from the main, but it's not worth the trouble. To the dedicated sailor, raising and lowering the main is all part of it, but some older, more experience ones just want to get out there, and are tires of some of the more physically demanding aspects. I took lessons on a Catalina 310 with in-mast furling. It definitely would not be a deal killer. The boat moved well in light air despite 10,000 lb displacement, the sail was easily tweaked when the wind picked up and gusting induced some nasty weather helm. Look at the popularity of furling head sails. The cost is relatively low compared to in-mast furling. I fully believe if a mainsail furler system could be as inexpensive as a headsail furler, it'd be easily as popular, and non-furlers would be relegated mostly to purists' boats and racing craft. I have no problem with full manual operation, but I wouldn't pass on a good deal because of the in-mast setup. Not by a longshot.
I'm with Jeff on this one... and in mast furling on a 31' boat? There's no main on a 31' boat that couldn't easily be handled with a mast track and car system, full battens, and a home made set of lazy jacks. Simplicity is good.
 
#8 · (Edited)
Its not about bending the mast to the Nth degree, its about having a reliable offshore rig since the OP says that he is buying a Calber 40LRC. The long range cruising models were optimized for offshore and long range cruising where the convenience of not having to raise a mainsail seems pretty trivial when you consider the need for fast, accurate and reliable reefing, (per RichH), shortened sail life implicit with in-mast furling, and that as a long range cruiser the mainsail will be up for weeks at a time without having to raise or lower it.

The spar stiffness issue is one of safety. Most rigs, even the comparatively stiff rigs of the 1960's and 70's, will sag to leeward in a abig gust and with the head of the mast curved off off to leeward in a really big gust. Even a small amount of sag and flex will help depower the boat noticably in big gusts and the added stiffness that is often designed into rigs with in-mast furling takes away that flex.

I would also suggest that in-mast furling is a poor choice for a single-handed sailor going offshore. If the in-mast furler jambs, as they tend to do more frequently after long periods reefed under high load, a single-hander does not have the crew to assist in freeing it through the various methods recommended which often involves sending someone up the mast to clear the jambs.

I can understand that to the current generation of arm chair sailor, weekend warriors, in-mast furling may seem appealing, but for the Original Poster, who is buying a boat that is heavily biased for offshore work and long distance voyaging (to the point that they make lousey daysailers and coastal cruisers) in mast-furling should be a deal breaker.

For what it is worth, many boat builders who had previously been making in-mast furling standard (charging an up charge for a normal mainsail) on smaller and smaller boats have begun to move away from in-mast furlers as standard equipment. I asked about this at the last boat show and was told that the service calls were killing them and besides they were feeling a real push back on this issue.

Then again, I should have known that you would defend anything that hurt sailing ability, seaworthiness and performance. ;)

Jeff
 
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#10 · (Edited by Moderator)
[EDIT-JRP] What percentage of boats actually go out regularly? Forget serious bluewater action. Many will sacrifice 1/2 to 3/4 knot just for an extra blade on a prop for the rare moments when the extra thrust would help, maybe reduce prop walk too. Now, just how much do you back under power in a sailboat? What about that loss of performance? My point is, if I were outfitting a world cruiser, no I wouldn't use an in-mast furler, but you're ASSuming, because a boat has an LRC nameplate, the OP must want to ply points unknown in very blue water. Get real.
You say boat makers are moving away from in-mast as standard equipment for service call issues. Fine. More moving parts, more complicated mechanism. It's gonna cost more when something goes wrong. Also, it costs more up front. Is it possible the boat makers might be trying to induce buyers by reducing the price with a standard rig? Duh! You did say they were moving away from standard equipment offerings, but apparantly, they're still optional.
Also, as for ocean cruisers, they are just as often as not at full sail. Often, they're somewhere in between, not just hoist and forget, so be careful with uninformed generalizations.
 
#11 · (Edited by Moderator)
[EDIT-JRP]What percentage of boats actually go out regularly? Forget serious bluewater action. Many will sacrifice 1/2 to 3/4 knot just for an extra blade on a prop for the rare moments when the extra thrust would help, maybe reduce prop walk too. Now, just how much do you back under power in a sailboat? What about that loss of performance? My point is, if I were outfitting a world cruiser, no I wouldn't use an in-mast furler, but you're ASSuming, because a boat has an LRC nameplate, the OP must want to ply points unknown in very blue water. Get real.
You say boat makers are moving away from in-mast as standard equipment for service call issues. Fine. More moving parts, more complicated mechanism. It's gonna cost more when something goes wrong. Also, it costs more up front. Is it possible the boat makers might be trying to induce buyers by reducing the price with a standard rig? Duh! You did say they were moving away from standard equipment offerings, but apparantly, they're still optional.
Also, as for ocean cruisers, they are just as often as not at full sail. Often, they're somewhere in between, not just hoist and forget, so be careful with uninformed generalizations.
Oh my... tell us, just what do you really think? :laugher
 
#12 ·
Interesting discussion - a little heated, but interesting..
My take: The difference in ease of use between a well setup slab-reefing and in-mast furling system is so small that the added complexity and cost is just not worth the additional loss in comfort and performance. The only real difference is the time it takes to remove (or unzip if you have a stackpack) the sail cover, while reefing takes more or less the same time, however might be a little less granular with slab-reefing (only of theoretical value IMHO)
While it's just how I feel, a lot of sail makers feel the same (although they will try to sell you in-mast too, because of the extra $$$ they earn).
While I also see a lot of people only using the headsail, I think that's true for boats with in-mast too, but I also see a lot of boats with in-mast motoring, where "simpler" boats just sail in both ends of the wind-scale. Problem is neither your, nor my observations are statistically significant.
Some of the IOR boats with large headsails sometimes are sailed without the main, because some people (wrongly if you ask me) feel that it is just not needed for cruising.
 
#13 ·
Folks-

I looked at all of the posts on this thread and I don't see that the orignal question was directly answered.

The question posed was the pros/cons of single spreader rigs vs. double (multiple) spreader rigs. On that question I too am curious.

I have a '88 C&C 30 MKII with a double spreader rig. I have owned her for just over 3 years. When the surveyor did his thing, he looked at the rig and said something like "Double spreaders....good rig". I was too love-struck with the boat to ask him to elaborate.

It seems that most of the boats I see that are over 35ft with single spreaders are more "production-line" boats like Catalilnas. I'm not dissin Catalinas, it's just my observation.

My understaning from tidbits in the various posts is that a double-spreader provides stabilty and stiffness to a lighter, more flexible mast. Anyone care to elaborate on that?

Also, IMHO, in-mast furling, no. For a new boat that is still on the production line, i'd definitely look at in-boom furling. I think you'd get a better sail shape and ease of reefing. Although no expert, I'm guessing that it woud jam less, or if it does, it's not so difficult to fix as it's all open and accessible.

My Saturday morning 2 cents!

Peace,

Doug
S/V Totoro
Seattle.
 
#14 ·
Could it be that twin spreader rigs allow closer sheeting of the genoa as the spreaders do not extend as far outboard as single spreaders do? Also very tall rigs lend themselves more to multiple spreaders while shorter rigs can get by fine with single spreaders.
 

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#15 · (Edited)
Doug, I think there were some pretty direct and well directed answers concerning the OP's question. The boat he mentions (after his initial post) has in mast furling, which needs the additional structure offered by double spreaders for stiffness. Let's take a step back. Let's assume a boat has a very standard slab reefing system, so there's no furling system variables. I'm not a voice of any authority, but here's my take assuming an aluminum mast:

50's-early 70's, single spreaders were the standard. The load analysis tools that were available in the day to the average spar maker, even aerospace, were pretty crude by today's standards. Milling and extrusion tech was good, but there was significant costs to engineering thin wall sectioned structures if the project wasn't intended to literally fly. So there we go, thick mast sections and a single spreader where pretty bomb proof and relatively easily manufactured. We're also talking about wire vs. rod rigging, so there's a bit more movement to consider as well. I'm still blown away when I see an old Nautor rig; a tree trunk section w/ check stays, baby stays, the whole thing.
The downside? For cruising, not much, but for racing, it was weight aloft and the inability to change foil (sail) shapes, and much wider genoa sheeting angles. Next came the inline double spreader rigs. Mast sections got much smaller and lighter. Add running backs and check stays, even lighter and smaller as rig designers squeezed the section higher up the rig. The rigs were relatively unforgiving, but for the owners of race yachts, it was worth the performance gains even if measured in inches and boat lengths. Eventually this stuff becomes refined enough that it gets adopted for cruising applications, in this case sans the more extreme mast sections. Smaller sections, less weight aloft, changes in what goes under the boat (think back to how 'radical' the Valiant 40 was thought to be in the age of Westsails ) At this point, race boats are now into triple spreader rigs and even smaller sections. Now the masts are very bendy (rod rigging and low stretch mylar/kevlar laminate sails start appear... loads increase while rig weight continues to decrease ) giving the added benefit of more sail shape control. This coincides with the arrival and acceptance of ULDB boats (Ballenger Spars inlineljjkAll this rig & sail technology continues to make it's way into the cruising world, just not to the extremes of what we see on race boats. So now, many cruising boats come equipped with swept back double spreader rigs (eliminates the need for checks & runners, but has one disadvantage of wear and tear on the main as there's more contact with the spreaders at deeper sailing angles)... etc, etc.... In the mid 90's, carbon rigs/hulls make regular appearances on race boats. Mast sections continue to get smaller/bendier, and sail technology begins to move from paneled sails to a single surfaced shaped sail a la something like North 3DL and UK Tape drive... this is also now widely accepted in the cruising community for those with the desire and budget... Yesterday's blue water bombproof boat is still a great boat in it's simplicity, ease of repair and maintenance, but much slower and heavier than a more current off shore design. Are there trade offs? Sure. One that particularly sticks in my mind is an older S&S Swan that had a new double spreader rig installed... the weight aloft was greatly reduced and the boat sailed much better at the top end of a given wind range before having to reef or change/shorten headsails.... anyway, out of time, etc....

Mitiempo, is that "Heart of Gold"? Your first image looks like the rig from one of my regular race rides.
 
#21 ·
There seem to be several themes running through this thread. In mast furling makes for easier deployment and "dousing" the mainsail. But it's a mechanical system subject to mechanical failures, and sail limitations ... no horizontal battens etc.
An alternative is to use a traditional main and a motorized halyard winch... or drill w/ winch bit to raise the main from the cockpit. Lowering still requires some deck work.

Shrouds and spreaders are there to stiffen the mast... and keep it "in column". More spreaders and shrouds means a smaller profile and lighter mast... which has aerodynamic / sailing advantages as well as less weight aloft... Without extra ballast the boat will be a but more tender with lighter rig I would think. More shrouds means a more complex tuning process to balance the forces of the shrouds to keep the mast straight.. and again more elements subject to failure. More spreaders means they can be shorter and allow slightly closer sheeting as well.

The decision about the number of spreaders and sail configuration is driven by the type of sailing... cruising and long sails, racing or day sails and so forth. Simple tends to fail less and be easier to maintain.
 
#22 · (Edited)
This year the boat went from Barrington R.I. to Oriental NC to Antigua. Then cruised over the season to Grenada. Discounting multi hulls the MAJORITY of boats had in mast furlers . The windwards in season see an average of high teens low twenties. Compression zones are higher. Reefing and unreefing is common as you go from wind shadows to compression zones.
Amels, HRs, Hylas’, and so many RTW blue water boats come from manufacturers with them. So many of the French aluminum LRCs I see are rigged that way.
Think what you want theoretically but the reality is on boats “out there “ not being daysailed or coastal cruising. Boats flying ARC, SDR and OCC burgees you frequently see in mast and in boom with more in mast when under 60’ and more in boom when over 60’.
I don’t like either and spec’d slab brought aft to a powered winch.
I had in mast jam on a passage home from Bermuda. It was a Hinckley so built right. It had vertical battens to increase the roach. Was run on hydraulics. Crew some how folded a batten around the sail so there was a layer of sail,then batten inside two layers of sail, then a layer of sail. Occurred during a night time squall. Ended up cutting it and listening to the remaining fragments for hours.
In boom requires heading into the wind. Too scary for me as I sail mom and pop. Have no interest in doing that in 3 meters. Worry about that moment you’re beam to. Worry about fact if halyard breaks the main is in the water.
No I’m quite happy with slab brought aft and a Dutchman or stack pack. Still it’s obvious in mast works for many transoceanic cruisers.
 
#24 ·
The furling main may make reefing easier... but there is a cost for this convenience... in more complexity failure prone mechanical systems which are difficult to repair I presume offshore. Slab reefing seems to be pretty idiot proof and for this reason for a small crewed offshore voyager this may make more sense. If you are watching the weather. and it looks like you'll need a reef... do it while it's easier. No big deal to shake out a reef. The Dutchman has served me well offshore and for coastal cruising... easy and inexpensive to maintain and repair.... full batten and large roach main. Boat is fractional so the main is large and the head sail small. I find this a sensible rig for how and where I sail. Selden mast is stout and rigging diameter is 8mm which is very strong. Mast is easily bent with a block and tackle to flatten main. Love the fractional rig... and with a Milwaukee raising the sail is no problem. I discovered all the above after I got the boat...
 
#25 · (Edited)
Yup
See only down side to frac as more single pieces of the standing rig which when they go the stick comes down. Agree with Jeff needs to be done right then good to go. Still like the redundancy of the masthead/solent. With a reefed main my runners replace the backstay and if either forestay goes the other will keep the stick up. Have multiple unused halyards with one at level of highest spreaders, several at masthead and pole lift at second. All dyneema so can replace strouds until we sort things out.
This year saw two fracs that had troubles. One folded the mast. Saw it on the hard at Jolly. The other lost the stick and was being towed in when I saw it in Chatham, union island while at anchor. Both were common production boats not the kind of fracs JeffH talks about.
Also have learned to really like going downwind with the genny on one side and the solent on the other with no main. That’s safe, easily rigged and easy/ fast to strike. Have even been doing it without no pole as the pole scares my wife. Just don’t be ddw and that works fine with the genny on the more downwind side.
Thing people don’t stress enough imho is things fail, finding good riggers and supplies maybe difficult, ease of doing evolutions quickly, safely and by yourself is very important to the cruising couple.
 
#27 ·
With powered winches be it for halyards or sheets or any running rigging it’s key to listen. At the first change STOP and free the self tailor. Now avoid the self tailer in general when using power on the main or jib furlers.
Wife didn’t listen once for a jib furling line. Now they are pulled in by hand except in rare circumstances. Find if you add backstay so there’s little sag it’s not an issue except in very strong winds.
The main halyard is very long so using power is very convenient. Crew didn’t listen once and put a hole in the main from the tack reefing hook (which is now covered and clamped with a fairly rigid hose normally used for water). I also turn off all the power winches with crew aboard. I have them wake me if a reef is required. Even when I use it for a jib furler I don’t use the self tailor. Rather tail with one hand and button on the other. That way any hang up is felt even before the winch motor starts to labor.
From talking with others with in mast they don’t let anyone touch it. Getting the right amount of friction on the clew as you roll it up is key and a matter of acquired touch. So to avoid mishaps they always do it themselves. I’ll let a good sailor use power if I’m watching. They won’t even allow that and insist only they touch the reefing.
 
#28 ·
Most boats with powered winches have a track and car system and are not using slugs in a slot (probably because electric winches are more often found on larger boats). I would be very cautious using a powered halyard winch on a slot and slug main. While cars can get held up in tracks, it is unusual to stop dead to the point of damaging the sail.

Some electric winches have load sensing on them and will stop before most damage occurs. Otherwise, they do give sensory feedback, and one does get in tune with them after a while.

It is good practice to always be watching what you are winching with electric winches. Probably so with non-electric also, but more with electric. The good part is that one can simply lean back in any convenient position and operate the winch with their toe while watching the sail - no head down grinding.

Mark
 
#29 ·
When we were building our W32 in the mid '70s those supposedly in the know were advocating a double spreader rig on a telephone pole mast. Idea was you could lose a shroud and still have some mast left. Yes you might have had more mast left after a cap shroud parted than a single spreader in the same situation but you were still going to lose the upper part of the stick with the halyard sheaves and hardware as well. In retrospect it wasn't much of a benefit compared to the extra weight of the wire and cost to try and have a few foot taller jury rigged mast. Of course those pundits were also saying a shorter stick was better, forget about light air performance, and optimize for too much wind.

Think the move to multiple spreaders is really about shroud angles and being able to sheet headsails in tighter with inboard chain plates. Question how much weight savings there are when you have multiple wires in place of one or two. Last time I checked Stainless Steel weighs a bit more than aluminum. What you lose in stick weight with a thinner walled extrusion is going to be eaten into by the additional wires to support it. Once again believe it has more to do with sail trim from having a bendy tunable mast.
 
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