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  1. #31
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    Simon,

    I woul probably recommend getting used to the fixed length bleeter first over a few sails. Then finesse it by making it adjustable to see if it makes sense. If you don't use the standard fixed bleeter for a bit you might not know if the adjustable bleeter has an advantage.

    I think there is some risk in making boats tooo adjustable. There's always someone who has ropes everywhere to do every conceivable job at a regatta and in the end they often don't do as well as boats with simpler setups who just keep their heads up out of the boat a bit more.

    Not saying no ... but just progress slowly. The big advantage of the non adjustable bleeter is that it is EXACTLY the same rope and fittings that I envisioned back in '93. But with much nicer function!

    MIK

    MIK

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  3. #32
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    Totally agree with keeping it simple. I'm loving the one string to pull and a stick to steer simplicity of the Goat. I'm also pretty happy with the amount of twist control I have with the stock location of the downhaul. What is driving me to experiment further is the possibility of settling the boat down a bit on a fast run by having the ability to shove the boom forward a lot. The death roll has taken me by surprise more often than I'd like and that prevents me from pushing as hard as I want 'cause bailing sucks.

    It's certainly my lack of skill driving the boat hard off the wind that is the cause of my wipeouts but being technically minded I'm always looking for an engineering solution

    Assuming moving the sail forward with an adjustable bleater helps significantly then I envision a setup where most of the time the boat is sailed the way I have it set up now. The bleater, while adjustable, is a set and forget control for most sailing conditions. But when I want to push it with full sail and a good breeze I could take advantage of the adjustability.

    It's easy enough to set this up with a spare vang from the other boat so trying it costs nothing and no new holes need to be drilled in the boat.
    Simon
    My building and messing about blog:
    http://planingaround.blogspot.com/
    The folks I sail with:
    West Coast Trailer Sailing Squadron

  4. #33
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    I guess you saw this when I put it up Simon. It's on the other side of things.

    Rig playing too is great, but also with this experience I got on top of some of the other things that have been changing in the racing environment in the last ... eeeeek ... decades!!!!

    Sailing unstayed Cat Ketches and Cat Yawls safely and efficiently downwind in strong winds | Michael Storer Wooden Boat Plans

  5. #34
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    What we need is a way to adjust the downhaul along the boom. Then either the square lashing or the bleeter would work.

    For instance, FRANKENBoom has a shortened stave on the bottom, this provides a perfect hook to keep the the boom from sliding forward, and my rig looks much like Woodeneye's does in his upwind position. The problem is that downwind the boom end goes way up, and it is very difficult to get the downhaul to slide back on the boom since it's cinched tight and against the stave.

    So my bleater experiments these past few sails have been nice, a but the downhaul has been further back on the boom, which has calmed the sail down on runs, but adversely affected my upwind performance.

    We can either do an adjustable bleeter and tighten/loosen the downhaul accordingly, or we can figure out how to easily slide the downhaul positions forward or aft along the boom depending on runs or upwind legs.

    Bruce, nice piece on Romily, I was waiting for someone with the credibility to say it.

    Ian, I think you're in the wrong thread. Laser rigs are over in the Eureka section.

  6. #35
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    Quote Originally Posted by woodeneye View Post
    Hi Simon

    Well, we all know that Irens is wrong. The performance hit on the "bad tack" as he calls it is minimal and so insignificant that it doesn't matter. The performance hit of not having a boom is so much more! Just a bit of misguided thinking which he could correct by reading up here!

    One of the other things we have found is that full length battens don't work. I suspect that the battens on Romily would have caused severe distortion on the starboard tack which skewed his thinking.

    However, the high aspect rig does look nice, but really only possible if the spars are low weight and carbon fibre.

    I wonder if a lightweight boom similar to that used on the modern catamaran rigs would work with the Romily rig?

    Attachment 222627
    Yes, the performance hit on the bad tack seems to be minimal on my boat as well. What boggles my mind is that we go on and on about relatively subtle sail shape tweaks looking for those last few percent improvements, changing draft or twist and then a massive sail distortion on the bad tack seems to be no big deal. I believe it but only because I've experienced it. Still it just seems so wrong


    Wonder if the bad tack is worse on a much bigger boat. The wind loads on the sails are much higher due to higher righting moment so could there be some aerodynamic phenomenon happening on the big boat that is insignificant on a Goat sized boat?


    An airplane analogy I can think of is that an airplane with a light wing loading (empty of cargo) is much more tolerant of lift degradation due to ice buildup on the wings than an airplane with a heavy wing loading (fully of cargo). The heavy plane is flying closer to stall (the wings are working harder) than the light plane so it can't tolerate much loss of lift. Maybe the bigger boat's sail is flying "closer to stall" for lack of a better term and the bad tack is more badder than what we experience?
    Simon
    My building and messing about blog:
    http://planingaround.blogspot.com/
    The folks I sail with:
    West Coast Trailer Sailing Squadron

  7. #36
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    Interesting one Simon,

    It forced me to think about wing loading and how it fits in with sails.

    The thing that loads up the sails is stability. The more stable the boat the stronger winds it can go out in and stay upright.

    Stability is the limiter.

    One example I could think of is that take a goat in a strong wind.

    You can be sailing at the same angle of heel in a reefed boat or an unreefed boat.

    The reefed boat has a higher wing loading. Smaller sail area proving equal heeling moment.

    But two very different boats that are sailing equally upright - Say a Goat and Romilly - will have the same wing loading if he sails are not being feathered. Might have a different angle of incidence but the pressures per square metre will be approximately the same.

    I think?!

    MIK

  8. #37
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    Quote Originally Posted by Boatmik View Post
    But two very different boats that are sailing equally upright - Say a Goat and Romilly - will have the same wing loading if he sails are not being feathered. Might have a different angle of incidence but the pressures per square metre will be approximately the same.

    I think?!

    MIK
    You mentioning different angles of incidence got me thinking. The angle of incidence is critical to maximising performance. Too small and you have no lift (power), too high and you have too much drag ultimately leading to stall.

    Given identical wind and sail trim on a Goat and a Romilly, a different angle of incidence implies different boat speed. The slower heavier boat has the higher angle of incidence because it has to develop more power. The higher angle of incidence results in more drag. Soooo could it be more sensitive to further drag increase due to the bad tack?

    Here's an experiment that may shed some light on this. We know that on the Goat with full sail up in a decent breeze, say 12knots, the bad tack is not noticeably worse. Now reef down to the second reef in the same breeze and see if the tacking angle deteriorates on the bad tack.

    If the above proves to be the case then maybe what's going on is that high sail area to displacement boats like the Goat can tolerate the bad tack wheras much lower sail area to displacement boats like Romilly and countless other ballasted boats get more severely penalized on the bad tack. This could account for the different experiences folks have with balanced rigs and bad tacks.
    Simon
    My building and messing about blog:
    http://planingaround.blogspot.com/
    The folks I sail with:
    West Coast Trailer Sailing Squadron

  9. #38
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    The biggest boats I've sailed with balance lug are Bolger's 23ft Martha Jane.

    Graham Cheers built his using my scantlings (a lot of Bolger's stuff assumes fastenings and also uses USA stock sizes for bigger timber. Which might not be so relevant to bonded structures and other countries.

    When he launched it he was really happy reaching and downwind but upwind it wouldn't stay with conventional boats.

    He trailed it from Sydney to Adelaide the first year so I could go over it.

    We went sailing one afternoon... Hoop and it was pretty well what we do with the goat.

    Get corner lashings right, absurd amounts of downhaul (I think we put a trucker's hitch on the system), showed him not to bring the front sail tighter than 10 degrees and use the sheet to detwist and dial in the right weather helm with the mizzen.

    He said 'is this the same boat?".

    No difference on opposite tacks on that one that could be noticed either.

    There is of course the problem of super light winds (<2kn) where the air doesn't have enough momentum and can't develop enough force to get around the mast and reattach.

    Which is why sails should be flat and well twisted in such conditions. The bend around the mast can be a real problem.

    If sail is really well trimmed and boat is sailing well there's normally a separation bubble on one side of the jib luff and also on both sides of the mainsail just behind the mast..

    But with a properly trimmed daily the flow just wants to reattach.

    Google - Gentry tuft system - to see what the separation bubble might look like and how it can be exploited on jibbed boats to get a very fine indicator of trim. You should land on the arvilgentry.com website.

    MIK

  10. #39
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    On writing the above I now realise that part of the reason the balance lug is less bad than we think is because there is significant separation behind the masts of conventional masts.

    Another indicator is when you put trim tufts on the jib they should be somewhere between 1/4 and 1/3 back from the luff, but the mainsail ones have to be further back as they won't fly if they are too near the separation bubble behind a conventional mast.

    In the very early 1900s the balance lug was the pre-eminent small boat racing rig. Much more competitive than the gaff and Bermudan. But as the Bermudan receive more development I can imagine them clutching for why it was better. It's easier to say... Because the sail presses on one side than to say the Bermudan has a better mast/sailing combination or more attention is paid to the traveller or other bits aimed at correcting its relative losses made because of twist.

    I'd evidence that by arguing that when you apply all the same tweaks to the balance lug, or gunter lug or gaff, the performance difference is not that great.

    That's the problem for people who haven't experienced the minor nature of the real differences.

    Whereas I'd be pretty sure that theory of that time would not have recognised control of twist answer spar/sail bend/shape interaction as the main performance producing developments of the last century.

    MIK

  11. #40
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    Romiley!

    Maybe because of the extreme high aspect of the sail the separation bubble will be a much bigger proportion of the Lee side of the sail. Also the stability to hold up such a tall rig will mean an increased mast diameter.. Increasing the separation bubble size.

    Additionally the mast is much longer.making the separation bubble take up more span in absolute terms. Maybe tall narrow balance lugs are slightly flawed.

    Speculation. But it makes logical sense.

  12. #41
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    Simon, in how much wind are you experiencing round-up death rolls? Full sail? Do you have the sail flat or full bodied when this happens? Last weekend I was in enough wind for little whitecaps, and going downwind I had the downhaul and outhaul very tight, and I was very stable. When I eased both, I noticed less stability. Later I was reading about sail settings in different conditions, and it said that for higher winds downwind, with unattached flow, a tight flat sail is recommended. Mik, does the flat sail make the boat more stable, in those conditions, or is it a question of efficiency and performance?

  13. #42
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    Quote Originally Posted by Boatmik View Post
    On writing the above I now realise that part of the reason the balance lug is less bad than we think is because there is significant separation behind the masts of conventional masts.

    Another indicator is when you put trim tufts on the jib they should be somewhere between 1/4 and 1/3 back from the luff, but the mainsail ones have to be further back as they won't fly if they are too near the separation bubble behind a conventional mast.

    In the very early 1900s the balance lug was the pre-eminent small boat racing rig. Much more competitive than the gaff and Bermudan. But as the Bermudan receive more development I can imagine them clutching for why it was better. It's easier to say... Because the sail presses on one side than to say the Bermudan has a better mast/sailing combination or more attention is paid to the traveller or other bits aimed at correcting its relative losses made because of twist.

    I'd evidence that by arguing that when you apply all the same tweaks to the balance lug, or gunter lug or gaff, the performance difference is not that great.

    That's the problem for people who haven't experienced the minor nature of the real differences.

    Whereas I'd be pretty sure that theory of that time would not have recognised control of twist answer spar/sail bend/shape interaction as the main performance producing developments of the last century.

    MIK
    I agree with Mik here. If we compare a 'standard' marconi (sloop or cat) set-up with non rotating mast, sail in mast track, there will always be quite a separation bubble in the front third of the mainsail. Likewise with a lugsail, there will be a separation bubble in the first third of the sail whatever you do. So that thick lug mast is operating in an already disturbed area. Whether it's sitting on it's own to leeward of the sail or part buried in the sail on the other tack, it looks like it's doing bad things but it's operating in an area that's already disturbed. So, there's little difference between good and bad tacks, and the lug isn't far behind a typical marconi rig. Interesting that the lug rigged keyhaven scows all use minimal luff in front of the mast, presumably to keep the mast in the middle of the area that is already disturbed. (Though this requires a vang to control twist)

    A marconi rig will still come out ahead on lift to drag and pointing ability as you can control the important things better - sail draft and twist so angle of attack and draft match the airflow all the way up. A single long spar on the luff is less windage and by bending it you gain more ability to control the sail shape as the wind increases. (But the lug won't be far behind if it's well set up)

    One thing we should think about more - many of the adjustments we make with a marconi rig as the wind increases (flattening the sail, letting the top twist off...) are a response to the fact we've got too much sail area, and are trying to de-power. Also that we're racing, so aren't going to stop and reef.

    So we get woodeneye on a reach in 20 knots in his laser, (correct me if I'm wrong!): extreme down and outhaul, but loose vang to let the top twist off. Trying to keep the sail flat for less power and letting the top flap so it doesn't pull you in.

    With a lug, my approach would be different - I can easily reef and keep the fore-aft balance, so I'll be at second reef with lots of downhaul and vang, but looseish outhaul for lots of draft. I can handle more absolute power than I could in lower wind as the power is much lower down, so I'll really fly. Lots of vang, so the sail doesn't gain draft as I ease the sheet in the gusts.

    Some preconceptions we should be careful about taking marconi/sloop experience into sailing a lug rig:

    In a sloop, we're used to looking at the mainsail, which we keep quite flat and trimmed close to the centerline of the boat. This is correct, as the jib has done much of the work of already turning the wind through an angle. With a lug, the mainsail is the foresail, so both angle and draft need to be greater.

    I stronger winds, I think we're better off with less sail area and low down draft/power than we would be with too much sail area and all the tweaks we go to on a marconi rig to lose some of that power.

    I spent some time working at a sailing school on a lake where we occasionally go extreme winds. I set up an 18 ft sloop with a much smaller/lower aspect rig that still kept the helm balanced, and had great fun on days when everything was closed as there were trees blowing through the air. People thought I was crazy, but the low down power was easier to control than the higher aspect rig in more normal conditions.

    Ian

  14. #43
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    I think a little bit differently. If there is enough sail in front of the mast there will be significant lift from the clean luff - with no mast - for most boats - which usually don't feather to windward the maximum sailforce is close to the leading edge where the air has to make and "abrupt" turn. It is also the place where the sail force has the most forward component . Then you lose the area further back with the separation bubble at the mast.

    Again .. speculatively - as Arvel Gentry shows it is really important not to try and guess too much.

    We do have some observed facts - that the sail is not too different from tack to tack. And if it is well sorted for twist and mast/sail combo then the performance gap to conventional rigs is not too different either.

    We can say both of these things are true on a macro scale. To really know what is happening would require wind tunnel of CFD studies.

    MIK

  15. #44
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    Quote Originally Posted by warm beer View Post
    Simon, in how much wind are you experiencing round-up death rolls? Full sail? Do you have the sail flat or full bodied when this happens? Last weekend I was in enough wind for little whitecaps, and going downwind I had the downhaul and outhaul very tight, and I was very stable. When I eased both, I noticed less stability. Later I was reading about sail settings in different conditions, and it said that for higher winds downwind, with unattached flow, a tight flat sail is recommended. Mik, does the flat sail make the boat more stable, in those conditions, or is it a question of efficiency and performance?
    20knots full sail guarantees a death roll but that's understandable. What caught me by surprise is that last time we death rolled it was blowing in the low teens. The boat was unstable and I was fighting it constantly. Had a couple close calls and then one got away from me. I still don't have an on the fly adjustable outhaul so the sail was set pretty full from earlier in the day when the wind was 8knots or so. I'll definitely try the flat sail trim. Another possible issue is that we were in shoal waters and I had the dagger board half way up. This probably cost us a lot of roll damping.
    Simon
    My building and messing about blog:
    http://planingaround.blogspot.com/
    The folks I sail with:
    West Coast Trailer Sailing Squadron

  16. #45
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    Quote Originally Posted by Boatmik View Post
    I guess you saw this when I put it up Simon. It's on the other side of things.

    Rig playing too is great, but also with this experience I got on top of some of the other things that have been changing in the racing environment in the last ... eeeeek ... decades!!!!

    Sailing unstayed Cat Ketches and Cat Yawls safely and efficiently downwind in strong winds | Michael Storer Wooden Boat Plans
    Yes I've seen that. It's tremendously helpful to actually see what's happening. I've played with this some and in light winds it all works great. However, when going fast it all falls apart for me. My corrective inputs to the tiller and sheet get confused and I'm pretty sure I set up a pilot induced oscillation. Need more practice.
    Simon
    My building and messing about blog:
    http://planingaround.blogspot.com/
    The folks I sail with:
    West Coast Trailer Sailing Squadron

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