Swept spreaders?

[Skipper John]

Why are swept spreaders being used on so many production boats? They really limit mainsail trim down wind. I can see them for fast light weight boats that never sail dead down wind but most production boats are medium displacement or heavier so dead down wind sailing or close to it is often the best course, particularly offshore.
I don't see any structural advantage as most production boat masts are pretty stiff sections anyway and have been fine with conventional spreaders for many years. The only mast buckling failure I've heard of recently was on a Hansa 43 with swept spreaders and no forward lowers like the Jeanneau has with the same rig. So I don't see that the mast is stabilized any better with swept spreaders than than athwartship ones.
Can some rigging guru explain the advantage, if any?

[s/v Jedi]

For us, we have aft swept spreaders because we don’t have backstays

[tkeithlu]

Our friendly neighborhood Jedi has it, but add the increase in size of the headsail versus the main in modern boats. Not only no backstay, but more pull on the forestay. It's all geometry in wire, with my wondering how modern boats avoid pulling themselves apart from the necessary added tension in the standing rigging.

[wingssail]

Originally Posted by Skipper John

Why are swept spreaders being used on so many production boats? They really limit mainsail trim down wind. I can see them for fast light weight boats that never sail dead down wind but most production boats are medium displacement or heavier so dead down wind sailing or close to it is often the best course, particularly offshore.
I don't see any structural advantage as most production boat masts are pretty stiff sections anyway and have been fine with conventional spreaders for many years. The only mast buckling failure I've heard of recently was on a Hansa 43 with swept spreaders and no forward lowers like the Jeanneau has with the same rig. So I don't see that the mast is stabilized any better with swept spreaders than than athwartship ones.
Can some rigging guru explain the advantage, if any?

There are probably several reasons why a rig designer would use swept back spreaders.

But the main reason on fractionally rigged boats is so the shrouds can oppose the forestay load without the need for running backstays (Assuming the upper shrouds terminate at the hounds).

This type of arrangment also reduces the cost of the rig since you eliminate two sets of chainplates (the separate chain plates for the fore and aft lowers) and two diagonal shrouds (no foreward lower shrouds)

[Pizzazz]

Swept back spreaders is a better rig in my opinion. You can trim the genoa in to sail closer to the wind. You do not need a backstay. Less cluttered on deck and also a single rod below. You don't really sacrifice downwind speed. Most boats sail faster on a broad reach, less rolling... if you really wanted to go downwind, get a symmetrical spinnaker.

[thinwater]

The main reason is that you can use a lot more roach on the main, and example of which is the square top main. This is one of the reasons most multihulls have long been rigged without backstays. Of course, on a multihull you can due this with aft swept cap shrouds. And yes, they limit winging the main out, but that's not as bad as it seems:
* They are faster on a reach anyway.
* With a wide traveler it is easier to control main twist.
* If you are going dead down wind, it is easier to go wing-and-wing with a multihull--you don't need a whisker pole. It is also FASTER to go wing-and wing with the main in a bit, as the sail is full batten, it develops attached flow in the reverse direction, and that flow dumps int ht he genoa, increasing thrust.


Wing and wing in >20 knots, but not on the spreaders and no whisker pole. Easy and fast.

[Zzmeyer]

The swept back spreader restricts the amount you can ease the main. I have them because of a fractional rig with a square top main which increases my main sail area by 40% which eliminates the backstay and I don't want running backs. Simply a trade off.

[Skipper John]

Originally Posted by Pizzazz

Swept back spreaders is a better rig in my opinion. You can trim the genoa in to sail closer to the wind. You do not need a backstay. Less cluttered on deck and also a single rod below. You don't really sacrifice downwind speed. Most boats sail faster on a broad reach, less rolling... if you really wanted to go downwind, get a symmetrical spinnaker.

Most newer boats carry the beam well aft and tend roll viciously in quartering seas on broad reaches. Autopilots don't handle this in large waves very well at all.

Also, with swept spreaders the main can only let out to about 45deg before hitting the spreaders. Any further and you risk damaging the sails and/or the spreaders. This really limits good downwind sail trim.

So if you are a flat water sailor then maybe swept spreaders are OK. They are fine for high performance boats that use asymmetrical spinnakers.

[Jim Cate]

Most newer boats carry the beam well aft and tend roll viciously in quartering seas on broad reaches. Autopilots don't handle this in large waves very well at all.

What has this questionable statement got to do with swept back spreaders? Not trimming the mainsail out all the way would in general help dampen out rolling, not increase it.

And our experience with swept back spreaders is that there is not so much loss of speed due to the mainsail trim when sailing deep angles. We've done a lot of miles wing and wing with the genoa poled out and the main just touching the spreaders. Reasonably fast and quite stable... autopilot handling it just fine.

Jim

[s/v Jedi]

Originally Posted by Skipper John

Most newer boats carry the beam well aft and tend roll viciously in quartering seas on broad reaches. Autopilots don't handle this in large waves very well at all.

Also, with swept spreaders the main can only let out to about 45deg before hitting the spreaders. Any further and you risk damaging the sails and/or the spreaders. This really limits good downwind sail trim.

So if you are a flat water sailor then maybe swept spreaders are OK. They are fine for high performance boats that use asymmetrical spinnakers.

Come out meet us out there in the 20’ waves and 40kts wind and we’ll see if your straight spreaders and backstays can stand up to our rig

[wingssail]

Originally Posted by Skipper John

Most newer boats carry the beam well aft and tend roll viciously in quartering seas on broad reaches. Autopilots don't handle this in large waves very well at all.

Also, with swept spreaders the main can only let out to about 45deg before hitting the spreaders. Any further and you risk damaging the sails and/or the spreaders. This really limits good downwind sail trim.

So if you are a flat water sailor then maybe swept spreaders are OK. They are fine for high performance boats that use asymmetrical spinnakers.

"roll viciously"? Hmm, never notice that when I sail those types of boats. Do you have experiences you can cite?

"45deg before hitting the spreaders. Any further and you risk damaging sails and/or spreaders"

We find that spreader patches protect the sails and the loads on the spreaders is not much. This is not really a problem.

I personally prefer athwartship shrouds, not swept back spreaders, and no fore and aft lowers, because I have more control over mast bend, but most modern racing boats have swept back spreaders.

[wingssail]

Originally Posted by s/v Jedi

Come out meet us out there in the 20’ waves and 40kts wind and we’ll see if your straight spreaders and backstays can stand up to our rig

Do you have running backstays to the top of the rig?

[sailorboy1]

Since i have a B&R rigged boat with 30 degrees aft spreaders i will say

Yes it does limited sail trim some. But it is rarely an issue except to those who try to sail it like an older design and go deep downwind. In the meantoime ot is a rig that never needs any adjustment while sailing.

[s/v Jedi]

Originally Posted by wingssail

Do you have running backstays to the top of the rig?

Yes, we have Dyneema masthead running backstays.

[Skipper John]

Originally Posted by wingssail

"roll viciously"? Hmm, never notice that when I sail those types of boats. Do you have experiences you can cite?

"45deg before hitting the spreaders. Any further and you risk damaging sails and/or spreaders"

We find that spreader patches protect the sails and the loads on the spreaders is not much. This is not really a problem.

I personally prefer athwartship shrouds, not swept back spreaders, and no fore and aft lowers, because I have more control over mast bend, but most modern racing boats have swept back spreaders.

My comments are based on sailing an '05 Junneau 39 from Spain to the Bahamas 2 yrs ago. We had 4 experienced crew with many years of experience.
We found that in winds over 15 kts the waves built to 2 m and up to 4 m over 20 kts. Since the course was essentially downwind we sailed wing and wing. We would not sail in those winds with the main on the spreaders so the boom was only out about 45 degrees. With the boom like that sailing dead down wind in big seas is risking an involuntary jibe even if reefed so we steered 70 to 80 degrees apparent. This puts the waves on the aft quarter causing the boat to round up 'viciously if no correction action is taken. The autopilot can't anticipate and then it over corrects making matters worse. So it's manual steering in those conditions.

That boat has TWIN backstays. Very comforting in 30 kts downwind! Why do you think. Junneau/Sheldon put backstays on this swept spreaders rig?

My own boat has a conventional rig with a backstay of course. It has stood up to jibing a full main in 50 kts. I wouldn't do that in a swept spreaders boat with no backstay.