Aftmast rigs???

Discussion in 'Sailboats' started by jdardozzi, May 28, 2002.

  1. Yobarnacle
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    Yobarnacle Senior Member holding true course

    I have so many modifications on my boat, it needs it's own thread.
    I'll post that thread in November.
    I didn't want an argument why I shouldn't do some of the things I have, so, publish "fait accompli" is my strategy.

    I'll post succeed or failure. :D
    With excuses in case of the latter.
     
  2. CT249
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    CT249 Senior Member

    It would be interesting to hear his answer.

    However, to repeat - the point is that surely we should not be hypocrites. If we are negative about conventional rigs (as is so often the case here) then only a hypocrite would say we can't be negative about unusual rigs too. If we have to be positive about mast-aft rigs, then we also have to be positive about conventional rigs and the rules. Supporters of "unusual" rigs can't have it both ways. They can't just imply that many thousands of sailors are ****** who choose less efficient rigs, and then get defensive when their own claims are examined.

    * as noted earlier, I own two wingmasted boats so I know they work in many craft - it's just that there also equally good reasons why they don't work as well in other types.
     
  3. hoytedow
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    hoytedow Fly on the Wall - Miss ddt yet?

    Negative and positive would best be discussed in the electrolysis of battery thread. Rigging is a matter of personal style and aesthetic values mixed with known best methods for setting up for sailing. Hypocrisy is a word not usually seen in a thread about sails. What purpose can it possibly serve here?
     
  4. CT249
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    CT249 Senior Member

    Hoyte, you're dead right that rigging is a matter of personal style and values. But people here have made some fairly sweeping claims about this rig (and sneered at those who prefer other rigs) and in that case, surely in a forum like this they should engage in discussion about the testing that underlies those claims, instead of saying that "negative' comments should be ignored.
     
  5. Barra
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    Barra Junior Member

    CT249, You are such a patient man.

    I enjoy reading your articulate and considered posts.
     
  6. whitepointer23

    whitepointer23 Previous Member

    2nd that. He is like an encyclopedia of sail.
     
  7. hoytedow
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    hoytedow Fly on the Wall - Miss ddt yet?

    Being neither negative nor positive, I shall remain neutral.



    Two atoms are walking down the street one day, and one of them says to the other:

    "Hey, wait up a second. I think I lost an electron"

    The first atom replied, "Are you sure?"

    The second atom exclaimed, "Yes, I'm positive!"

    First atom negatively replied, "I think I found it."

    Being on the street and not in the swimming pool, I suspect their bond was more likely a covalent one than an ionic one.

    http://www.chemistrygeek.com/g8.htm
     
  8. brian eiland
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    brian eiland Senior Member

    Hi CT249, Might I suggest that you go back and look thru that test results paper that I posted, It appears as though the all-headsail rigs did rather well in that testing. And it was some pretty thorough testing involving VPP and RANS





    And please note that I am not trying to make the case that my mast-aft design is going to be that much better than the convention rigs. I'm just claiming that it is not going to be significantly less in performance than a 'conventional rig', and concurrently more user friendly to the aging cruiser than a big full battened mainsail rig,...... all 3 sails roller furl, and it provides for the balance and lower CE of a ketch rig,....a single-masted ketch
     
  9. Barra
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    Barra Junior Member

    Brian. I am an ageing cruiser. I find my large fully battened mainsail very useful and easy to handle.
    Its great when motorsailing as it stabilizers the boat and still provides useful drive when pointing very high ( much higher than one can sail only) when negotiating narrow channels or following leads as an examples. A headsail would be useless in this situation.

    It still provides some drive when the wind dies and the slop remains that shakes the stuffing out of the headsails rendering them next to useless.

    Roller reefing the headsails is a pain in strong wind, with the flogging sheets beating the crap out of the boat and anyone in the way.
    The main is easily controlled and reefed with a sensible set up.

    Have you done much offshore sailing?

    I would have thought you attentions would be better directed to ridding yourself of those pesky headsails.
     
  10. markstrimaran
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    markstrimaran Senior Member

    The simplistic head sail.

    Another reason I love an aft mast stay sail rig. Is the ability to easily modify any sail with a simple Kenmore sewing machine.
    In a pinch for cash. Simply find any cheap main sail. Put some hanks on it. Then recut the foot.
    Believe it of not. I can sail upwind with a main sail from a Santana 21. That has hanks wipped too the bolt rope. On my inner stay sail.

    I would hate to be in the middle of the Pacific on my budget with a sail that can not be easily repaired or tailor made from what's locally available.
     
  11. markstrimaran
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    markstrimaran Senior Member

    25 mph gust

    Santana 21 bolt rope main sail. Rigged on the inner stay.
     

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  12. CT249
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    CT249 Senior Member

    WARNING - LONG POST

    Thanks Barra and WP! :)

    Mark, Yo and others - can I just point out that nothing I have written is intended to dismiss the mast-aft rig, which obviously works well for some people. My intentions are not to attack any rig or sailor, but to defend other rigs and sailors from attacks upon them.

    Brian; I'm not an aerodynamics expert and therefore not qualified to comment on the technical merits of the Milan study. However, since I'm stuck at home with a cough, I may as well make some remarks;

    1 - the authors do not seem to be balanced in their assessment of each rig in some ways. For example they say that in the conventional rig"the tuning techniques required on the mast, the boom, the stays and the sails, need, to be effective, expensive equipment like additional tracks, sheets, vangs and the correspondent purchases;"

    This seems to be biased. The two-jib setup also has a boom, it has as many sheets as a conventional mast. There seems to be no reason why their boomed staysail would not need a vang (all else being equal) and their genoa would have to be barber-hauled out or have its excess twist controlled in some other way when sheets are eased. IMHO their low-clew genoa would be fairly ineffective downwind because of twist, but that seems to be ignored. Their single-headsail rig has a long boom that would require some sort of vang and pose other problems - again these seem to be ignored in an effort to praise one rig and damn the other. They do more of the same, but I won't go into detail.

    * They show the conventional rig as being tested when it is trimmed incorrectly, with a straight mast and mainsail reefed down to the same height as the #3 jib, which was not flattened as it really would be. Therefore the conventional rig was not being tested at its optimum performance.

    * They ignore the important effects of headstay sag (which makes headsails harder to depower) and the ease of using mast bend to depower a main, which appears to be unfair to the conventional rig.

    * There was no report on testing at wider apparent wind angles.

    For these reasons, there is probably reason to doubt whether the study was fair.


    2 - Tests are great, but the real world has shown many tests have been shown to be wrong in the past (see AstroSail for example, or the huge fracas about the 3/4 aft measurement under IMS).

    These tests results appear to say that speed will increase around half a knot under the twin headsail rig, which is an ENORMOUS speed jump. If I recall correctly, this is a performance advantage roughly in the order of adding a canting keel. It's the equivalent of making the whole boat bigger by about 7 feet.

    It beggars belief that the many, many thousands of sailors who have been involved in the sport over the years would have missed what would have been the biggest jump in mono performance in many decades. When races are won by a fraction of one percent, no one can miss an increase of about 7%. That's like having a Farr Mumm 30 that can just about beat the world's best Farr 40 OD around the course each week, or a J/24 beating a top Etchell or J/29 across the line every time they race.

    For about a century, sailors have been REDUCING the number of headsails they use in many yacht classes. They have also spent decades testing sails and pulling them up and down while racing and experimenting. Thousands of people have lots of experience with staysails and cutter rigs, and (all else being equal) just about all of them have thrown them away because they have found them slower in reality. People note what happens to boatspeed when they set and drop sails!

    If this study was correct, all the pros who have designed rigs and played with them are ****** who have not been smart enough to look at their speedo while they are out there testing sails and racing. Apparently this amazing stupidity has been existing since, for example, the J Class and 23 Metres went from three headsails to one.

    How could it be that people went to all the expense of developing single-headsail J Class rigs if the cutters they were racing against were basically faster? If twin headsails and no main make a boat 7% faster then why did the boats with one headsail beat the cutters? If these claims were correct, then decades ago the old 6 Metres with cutter rigs would have beaten the latest 8 Metres with sloop rigs - can anyone seriously claim that no one would have noticed such an bizarre reduction in speed from the newer and bigger boats? Was there some sort of mass delusion going from Keil to Cowes and all the way to Auckland, which stopped people noticing that their new rigs were dramatically slower than the old ones? Has this delusion continued to the present day, and stopped people who use cutter rigs in some classes from using them in other classes?

    Every scientist I know of (and I'm married to one) would probably say that in a situation like this, where there has been years of real-life experience, such reality trumps experiments - and for decades reality has shown that cutters are NOT faster (all else being roughly equal) and therefore this test must not be accurate.

    EDITED TO CONDENSE
     
  13. CT249
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    CT249 Senior Member

    It's great if you enjoy your rig. I don't think anyone has a problem believing you can modify a main and use it as a staysail that will take you upwind.

    But a bermudan sloop rig sail can be very easily repaired. Stickyback, some sail thread and a sailmaker's palm can work wonders.

    Bermudan rigs can also be extremely cheap, if you get one that allows you to use the sails from a popular racing class. If you ask at the right time (like when the owner's wife is within earshot and wants the garage cleaned out of beautifully-kept sails that have been used 30 times) you can get them for free! :D
     
  14. Yobarnacle
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    Yobarnacle Senior Member holding true course

    CT249.
    I only took exception to what appeared to be your opinion, that only racing would determine a rigs suitability/superiority amongst the techs. Hence, my egotistical remark, I only needed to convince myself. :D

    There have been many rigs tried and many abandoned, for various reasons.

    Legend says Columbus changed the rigs on the two smallest of his fleet of three, from caravel lateena to caravel redonda (square sails), because they ( Pinta and Nina) were out sailing the larger Santa Maria. Was it more feasible financially to square rig the two smaller lateen vessels than to improve the larger vessel with the lateen rig? Or was he concerned too much speed was dangerous? Or, were the square sails more self tending? Somebody please ask him his reasoning, when next they meet him. :D

    At any rate, the lateen rig all but disappeared from the seas, while square riggers dominated for centuries after Columbus. Why?
     

  15. brian eiland
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    brian eiland Senior Member

    There are pluses and minus for mainsails galore. But I would direct you to a couple of forum discussions where you might find a significant number of sailors that have 'abandoned' their mainsails for various reasons. I'm sure there are many other such threads, but I can't find them at the moment on short notice:

    Main-less Rig
    http://www.boatdesign.net/forums/multihulls/main-less-rig-21274.html

    Furling Mainsail or Not
    http://www.cruisersforum.com/forums/f116/furling-mainsail-or-not-63150.html

    Don't Use the Main
    http://www.cruisersforum.com/forums/f48/dont-use-the-main-115978.html

    Death of the Ketch
    http://www.cruisersforum.com/forums/f47/the-death-of-the-ketch-85028.html

    Square-top Mains
    http://www.boatdesign.net/forums/sailboats/square-top-mains-9668.html

    Loose-footed Mains
    http://www.boatdesign.net/forums/sailboats/loose-footed-mains-2595.html


    Most CRUISERS do not go out looking for windward sailing, but rather try to pick and choose reaching or downwind conditions. The full battened mainsail can often find itself pinned up against the spreaders or other rigging (ie, the shrouds on multihulls, the lazy jacks, etc)), making it more difficult to reef that sail down as the wind conditions gather strengh. And the skipper may delay his reefing as he hopes the wind will diminish and he won't have to wrestle with lowering and re-raising that mainsail (and turning upwind to do so).

    For safety reasons I might like to have a lower AR rig with its lower CE. Look at the difference in mast height (for the same sail area sloop) of my rig. And lower AR sails have proven their worth in reaching and downwind sailing.

    Those are a few of the reasons that I sought out a ketch-style rig, and I happen to have found a way to do it without the addition of a second mast & its associate rigging......a single-masted ketch.

    As far as motorsailing with your mainsail up I might well be able to do that with just my central mainstaysail up.
     

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