How to compromise junk to trimaran?

More bloviation from the ignorant and prejudiced

You're not too bashful with your opinions, eh? Too bad you don't seem to know any actual relevant facts. After I sailed Batwing on a nice cruise across the Pacific, I sold it to a guy who sailed it around the world. He sold it to a couple that has cruised the boat to Venezuela from near Seattle. They're in Panama--with the original unstayed masts and rig, 35 years later - A Hasler designed junk schooner, still registered under the name Batwing.

Don't blame the rig for what Wharram did with it. You can put a junk rig in a tri if you want, but the through stepped mast will be rather in the way plunked down in the middle of a narrow hull.

As far as the Balestron rig goes, those who have tried it loved it, except for one set of folks whose boat was made tender by Aerorig's incompetence - their mast was way over its designed weight. None of these cruising rigs are meant for boats full of foredeck gorillas and coffee grinders. Unless you are extremely driven, you will cruise faster with an easily handled rig, because you don't have to do precautionary reefing, as you don't get too tired to get the best out of your rig. The Marconi rig is difficult to handle and fragile, compared to balanced unstayed cruising rigs such as the junk rig or the Balestron rig. Hundreds of little bits of stainless steel to come unscrewed or fail due to crevice corrosion - no thanks - any one of them failing will wreck your mast.

 

Hi Big Cat

Yo seem to have some strong ideas, opinions and experience. I've been playing with the idea of a 70' odd trimaran for cruising and I'd appreciate your thoughts on some of my ideas.

With 70' LOA equal hulls each with a beam of about 8', there would be ample room both inside and out. Sure mooring would be a complete nightmare!!!! That aside...

Now regarding the rigging. Conventional rigging (Sloop or cutter) would be a lot of hard work and therefore I feel a junk schooner with 3 or even 4 masts would be the way forward with cambered battened sails and positioned along the center hull (ama).

If cost weren't a factor, could it, would it sail? How well to wind? Obviously there many factors to consider but for the sake of the conversation let's stick to a trimaran with 3 junk sails on the ama.

Thanks

 

"A man convinced against his will, is of the same opinion still." (Old saying).

IMHO junk rigs are fine for Chinese junks, fat, slow, commercial boats sailing mostly in protected waters.

The laws of natural selection apply. Thats why the vast majortiy of sailboats today have marconi rigs.

The fully battened fathead mainsail on a rotating mast is exceptionally efficient and is a snip to slab reef. Roller furling jibs are here to stay.

 

I would totally disagree.....the vast majority of sailboats today have marconi (sloop) rigs because a) That's all the production builder offers, and b) someone (sales) has told the buyer who doesn't know any better that it's the best......The builders only offer marconi sloops because the rigs are all pervasive, thus cheap to buy in quantity, they're quick (cheap) to install, and generally boats will sail to weather well under them (in moderate winds, 10-18 knots).........in anything else forget it.....

The problems for the average sailor start when there's more or less wind......the summer cruising crew that come into our bay are two older folks out for a couple of weeks in a Benhuntalina.......the stock boat comes with a mainsail (often in mast or boom roller reefing) and roller furling 130 Genoa......In spring and into the summer here it blows NW 15-25 often every day for weeks.....These old folks only want to sail a reach or a run, never upwind, that's what the engine is for, and they can't deal with high heel angles........so I see them, trying to control the boat with the main totally rolled up and about 1/2 the Genoa rolled up, they've got this bag hanging off the headstay and are too scared to set anything else.......these folks would be far better off with a junk sail.....but no one will sell them one because......?

 

Sorry Tad.

Your argument doesn't hold water.

shortcomings of the junk rig compared to the Bermuda rig

The shape of the sail depends on the flex of the battens, and the battens do the opposite of what would be most desirable: they bend only a little when the wind is light, and they bend a lot when the wind is strong. Consequently the airfoil developed in light wind doesn't have enough chord length to develop much lift at low wind speeds. Perhaps the chief shortcoming of the junk rig is that it typically produces poor drive to windward in light winds.
The sail may remain almost entirely flat in light winds and develop unacceptable drive to windward
The fully battened sail is heavier than a sail made entirely of sailcloth with only short battens at the leech.
Also the Junk rig depends on an unstayed mast, which may be a problem in some boats and almost all catamarans.

 

This is true for battens (or anything) loaded by distributed pressure, and supported at the very ends.
Junk sail battens are supported NOT at the ends. Forward, where biggest aerodynamic pressure act, they stick forward of the mast. And this dramatically reduce the bend, caused by pressure. So junk sail battens tend to remain almost straight in any wind, by definition. And as far as I know, flexible battens, as used in bermuda sails, are poor choice for junk rig. Stiff wooden ones are much better.
I am yet to find a photo of junk sail with obvious bend in the battens. What I see in photos of junk sail in strong winds is cloth hanging in deep bags between basically straight battens. And because battens are more or less horizontal i.e parallel to airflow, to airflow the sail appears as flat.
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Totally agree with previous post on superior handling of junk sail for physically challenged people. All the loads to lines or cloth are designed out of the system from the outset.
In comparing to modern full batten fat head main, in strong winds, similar (at first sight) easiness of reefing comes from completely different sources:

Junk rig reef easily, because internal and handling loads are designed out of the system, independently of what kind of material is used for cloth and line;
if anything goes wrong, let go the halyard, and all the control lines are unloaded, and easy haul in.

Modern fat head main reef easily because it is made from low stretch cloth, battens are flexible yet very strong and durable, batten cars of excellent quality materials, made very precisely, perfectly fit equally precisely made mast tracks, resulting in low friction, reefing is done by low-stretch line, pulled trough low-friction blocs by powerful winches. If anything goes wrong, let go the halyard and jump to the mast to pull the main sail down by hand.

My guess is that first option would be more appealing for physically infirm person. And would cost way, way less in dollar terms. And, psychological pressure from "mainstream" aside, more encouraging to go out for occasional sail.

 

No development class with a maximum sail area rule uses junk rigs. They have some advantages, but speed is not one of them. Also, many of the performance claims are based on the "good side", where the battens are not laying against the mast.

 

Junk rig excels in "speed for $" terms, not in "speed for sail area" terms.
Junk rig excels in "speed for manpower" terms, not in "speed for sail area" terms.
And, if business of this thread is about "junk rig on trimaran", in my view, performance "per sail area" or "pure speed" are out of the question....
Reasonable speed for minimum $ and minimum manpower look like primary design objectives.
Or like objectives, naturally achieved by junk rig...

 

Can you justify your claims with any study? Seems to be you are making claims as if they were fact instead of personal preferences. Show me the price of a junk rig and sails compared to a standard masthead rig.

 

Here is attached approx price comparison between bermuda and junk rig of same area. It is based on X79 (sorry, it is not masthead, I simply had the data at hand). I do not say here if it is possible to put a junk rig on X79. Deck hardware is not included here.

On more information on junk rig properties, there is a lot of sources. Quite good one in department of easiness of handling is "Voyaging on a small income" by Anny Hill. If a small woman is able to reef or unreef the 35ft boat sails alone at will, at night, in heavy weather, than handling is certainly not so difficult or heavy.

As for efficiency, lets say (a guess) with junk rig you will have 20% less VMG to windward, as with properly handled bermuda. However, with improperly handled bermuda (from my experience: wrong headsail, old headsail, old main, incorrect tuning of masthead, and even more critical, of fractional rig) you can easily loose about the same. If not more. For much higher price. And with hard work for crew.

While I can imagine small woman tuning the fractional rig with bakstay, runners, chekstays, outhaul, Cunningham, boom vang, mainsheet and traveler, changing a headsail or taking/shaking a reef is a little more involved. And force to pull most lines is certainly more as that needed to operate junk rig.

 

oldsailor.......

When you use direct quotes from an outside source....it's usual to quote that source.......http://en.wikipedia.org/wiki/Junk_Rig

Do some research on cambered junk sails before putting all your faith in Wikipedia......

But you did not address my point...which was that most out-for-a-holiday summer cruisers don't sail in light wind because it doesn't meet the schedule.....and they don't sail in higher winds because it's too scary, and they certainly are not going out of the cockpit in those conditions......

In reality a well engineered unstayed rig will be about the same weight as a stayed sloop, but VCG will be lower because a lot of the weight is in the deck reinforcing and lower section of the mast.

 

Unstayed junk rig in a catamaran........

 

And another one.....somebody needs to work on that Wikipedia entry.......

 

Perm stress: Backrunners, check stays, etc. come on!. You are finding a really complicated rig that is not for cruising. A marconi rig has a much lighter, and cheaper mast. The standing rigging is two stays, two upper shrouds and two or for lowers. Changing headsails is a thing of the past. If you are comparing apples to apples, then compare changing a headsail to changins a junk sail. I think a headsail is easier. Then you are once more biasing the comparison. A badly set rig against a well set one. I am willing to discuss pros and cons of rigs, but that is ridiculous.

 

"Backrunners, check stays, etc. come on!. You are finding a really complicated rig that is not for cruising."
Rig with controls described is physically less demanding in changing weather conditions, as masthead rig: it is physically easier to pull some strings to flatten/deepen/change angle of attack of big main and small jib, as to run forward to change a big headsail or trim the sheet of big headsail (big being a relative term). Normal (not pushed for lightness as in Star class) fractional mast with runners and checkstays, as for example on X79, design wise is pretty able to tolerate an odd error with runners, during gybe or tack, unless really pushed with spinnaker up in Force 6, but this is certainly not done while cruising. After maneuver is completed, all this paraphernalia offer so much more control to force created by the rig, at so much less physical effort (in terms of muscle power exerted).
I understand perfectly well, that such a rig ask for more intelligent handling, as most of weekend sailors (without racing background in their youth) will ever dream about. It is too many gears to shift for person not really interested in process of doing it.

"A marconi rig has a much lighter, and cheaper mast."
If under marconi you mean masthead rig, think again. For same sail area and number of spreaders on the same boat, fractional rig has lighter and cheaper mast, smaller number of headsails for different weather conditions. With fractional vs masthead, mast length will bigger, but fore triangle will be lower, resulting in shorter unsupported panels of mast => lighter section of mast. If one like to go without runners at all, it is perfectly possible, than mast weight will be somewhat in between masthead and frac with runners.

"Changing headsails is a thing of the past."
#1 genoa, rolled down to storm jib size and still having remotely decent shape, is still to be invented, so headsails have to be changed, only not so often, as before rollers.

"If you are comparing apples to apples, then compare changing a headsail to changins a junk sail. I think a headsail is easier."
Than we should compare changing bermuda mainsail vs changing a junk sail.
How many cruising boats carry a spare mainsail?

"Then you are once more biasing the comparison. A badly set rig against a well set one. I am willing to discuss pros and cons of rigs, but that is ridiculous."
What I did try to point at, is that bermuda rig of any sort need very carefull and more-or less constant tweaking to work at its best (For average cruisers, about 20% lost is not that unusual, I have seen it more than once. And difference in settings is not that big to be noticed easily, if one do not look specifically for them); hence loss of performance due to basically less efficient, but less demanding and easier to handle rig is not that big in the end.