Flat Sails are Okay - mehitabel

  • 11 Jan 2011 20:42
    Reply # 493646 on 490687
    This has been an interesting thread and there would seem to be lessons to be learnt from it.

     

    It is noticeable that the rigs that the writers are happy with are the simple, solid and reliable ‘traditional’ western junk rigs as defined by Hasler and Mcleod, and with some similarity to the Derek van Loan design. There doesn’t seem to be the same following for the more complicated rigs of the ‘90s, with their multiple running lines and adjustments. The hinge battens do not seem to be recommended, particularly the commercial ones which have a habit of breaking.

     

    Given the many advantages of the junk rig the weakness to windward of the flat sails seems to be acceptable, but this is where I would like to play “devil’s advocate”.

     

    If we take a standard rig as described in Practical Junk Rig and simply change the panels from flat to cambered we should end up with the same reliable structure and ease of handling. We should also end up with a better lift/ drag ratio and with the total force vector angled further forward. This would give a few options as follows.

    If sailing to windward and sailing at the speed of the flat sail there should be less heel.

    If sailing to windward with the same heel as the flat sail the speed should be higher.

    There would be the option to press to windward at about the same speed as Bermudan rigged boats but with a self tacking, smoother ‘shock absorbed’ ride and less spray if necessary to make a tidal gate such as rounding a headland before the tide turns, or darkness falls or crossing the harbour bar before the tide falls too much and even getting to the other harbour bar before last orders are called. The same applies to the lee shore situation.

     

    The camber does not only affect windward performance. There is more forward directed drive and speed on all points of sail up to the dead run when the sail is fully stalled.

     

    Possibly the most significant point would be the affect in light winds. Generally when sailing the winds are not ideal and where the junk rigs copes with strong winds with the easy reefing, it is the light winds that can be tedious. With the better forward drive the cambered sail can easily give up to a knot extra speed which although it does not sound much can be a 20% improvement.  For the voyager that can be a significant improvement to the daily run and well worth having. Please remember this is referring all points of sail.

     

    Although most new cars are offered with a cheap small engine model to encourage interest, most drivers will buy a bigger engine/ performance model simply as there is little pleasure in being left in the slow lane. Similarly with the junk rig. It may be unsporting but it is fun to catch up with a close hauled boat, sail a 360° round her and then disappear tracking 20°s higher. It is very encouraging to get into harbour and have crews from Bermudan boats that follow you in go out of their way to complement you on outperforming them.

     

    The beauty of the cambered sail is that you have the choice to sail as a flat rig or faster, and all with the same ease of handling, reliability and durability.

     

    I can almost hear the comments such as ‘but they are more complicated to make and set up.’ This is not necessarily the case and is a bit of a myth which I believe has been put out by the sail makers to justify their prices or lack of understanding of how to make the rigs. For the home sail maker without a large lofting floor making a junk sail panel by panel there is hardly any difference, just a little in the detail. I plan to write more on this latter point in the not to distant future, but in the meantime please accept that this is the case.

     

    I will not ask for comments on what I have just written as I feel they will come thick and fast. Good. I feel we have to get away from some of the light weight flimsy rigs and get back to basic. And please remember I did say that I was being “devil’s advocate”.

     

    Cheers

    Slieve

  • 10 Jan 2011 10:32
    Reply # 492574 on 490687
    David commented on getting enough sail area onto a short boat.
    Graham mentioned the 'afford' concept elsewhere.
    Several people have related their reasons for liking their rigs, and that's been good reading!

    This is a bit more about my decision-making for our flat rig.

    When I converted mehitabel to junk rig, I sold the Bermudan sails and the storm sails and drifter, and cut over 3m off the mainmast and almost as much off the foremast. Phew, that felt good.

    The masts had started to break in the middle of the Pacific. (Fixed and ocean-proven now, besides being shorter, and further reinforced.) 

    And earlier, in BC, we'd had the chance of a friendly race to weather in a rising wind - our boat still a Bermudan cat schooner against the junk schooner 'Tristram E' which has flat Hasler-McLeod sails. She gained on us and then passed us at dusk smiling and hardly heeling with full sail while we were reefing because of too much camber inducing too much heel. It wasn't the area that was the problem, just the (Bermudan) camber. Gusts did very little to upset Tristram E, but they sure rocked mehitabel.

    The junk rig let me put 75 sqm of sail onto shorter, safer masts where we'd had only 65 before. And all the times I tied in reefs while riding the pilothouse roof now seem ridiculous. Still better, I'm positive we could pass our old selves in a tacking race now, and not think about reefing. Maybe even Tristram E.

    About affording, we couldn't have afforded to have sails of any kind made for us. But we enjoyed making flat junk sails. We couldn't have afforded time or other resources for experimenting or even copying the up-to-date junk rig innovations. But I could understand and somewhat customise Hasler & McLeod's blueprints.

    It's a small change from 60 degrees to 45, compared to sailing versus not sailing. That sort of explains why I'm enthused about the not-cutting-edge aspects of the junk rig. Recognising 'enough' of one thing makes another thing possible.

    Thanks,
    Kurt

  • 08 Jan 2011 21:07
    Reply # 491762 on 490687
    What a fascinating thread! And how wonderful to hear that Ron Glas is being used, loved and cherished as she deserves.  I had the privilege of going aboard in 1983 when in the Outer Hebrides: Badger and Ron Glas were anchored together and Badger was more that a little overwhelmed to be in such company when she had thus far only sailed from Morecambe Bay to Scotland.

    That both the owners of Methitabel and Ron Glas are happy with their performance does not surprise me in the slightest.  I was always very contented with Badger in the 110,000 miles of sailing with her. And I think it's worth remembering that we sailed about 10,000 miles with no engine and a similar amount with a Seagull outboard motor, which could only be used in a flat calm.  Zebedee is also engineless, with classic PJR sails (in fact they used to belong to Badger) and seems quite happy, although I think he is now curious to try a bit of camber.  Yes, it would have been nice to have gone at 5 knots to windward rather than 4, because we did a surprising amount of distance close-hauled, but on the other hand, we arrived rested and I never missed cooking a meal.  In flat waters she would tack through 80 degress by compass, but more common was 90.  Out at sea with a swell to knock her around, the tacking angle was more likely 110 to 120.  For all that, she made better progress hard on the wind over a 24 hour or greater period than does Iron Bark, with her supposedly more powerful gaff rig and extra 5ft of waterline length.  I'm sure that part of the reason for this is that ease of handling ensures that one shakes reefs out early.  With so many reefing options, too, there is no need to be either over or under-canvassed.

    I have put shape into Fantails sail, largely because both Paul and David offered me so much help and encouragement and it only seemed fair to try out their ideas.  At the time I also did it for Fantail's sake, thinking that there would be a lot of negative local reaction to my 'experiment'.  I was quite wrong there: people are interested and intrigued and often surprisingly positive.  At least to my face - I sometimes wonder what they say behind my back!

    Easy-going sailors like easy-sailing boats and I think the diverse owners and boats are a fascinating part of the JRA.  May our battens never break!
    Last modified: 08 Jan 2011 21:07 | Anonymous member
  • 08 Jan 2011 21:05
    Reply # 491761 on 491544
    TONY AND SALLY SUMMERS wrote:

    question- will cambered sails increase heel?

    More lift always comes with the cost of more induced drag, and drag induces heeling. As long as your lift/drag ratio is improved, you come out on top, with a nett gain in performance. But, if you have more lift than you need, you can always reef, and heel less. Clearly, if sail 'A' has twice the lift of sail 'B', without also having twice the drag, it only has to be half the size to deliver the same or better performance.
    That is my aim - to get sufficient drive from efficient small sails, because frequently it just isn't possible to put a large enough area of (inefficient) sail on short, heavy boats.

  • 08 Jan 2011 20:04
    Reply # 491728 on 491544
    TONY AND SALLY SUMMERS wrote:

    all very fair points David, I will try and assess performance a little more accurately over this coming year ,especially windward performance against big seas. Im prepared to be converted!!

    question- will cambered sails increase heel?

    Arne, the "dashboard" is just the same-- in fact we have been repainting it this week--I must say for two-up sailing its a brilliant space. does become an issue with more than two crew awake!

    meanwhile Ron Glas and Mehitabel will continue with the low tech approach---Kurt  if youre on your way to the Med and we are slowly heading for New Zealand we may cross paths. tonyand sally

    I think we'll be going west. Trying to avoid too much of that you-know-what sort of sailing. I hope we can meet somewhere. Cheers, Kurt.
  • 08 Jan 2011 19:59
    Reply # 491726 on 490687
    Arne, I enjoyed your remarks about your sails and the Hasler-McLeod design in this topic and the 'History' topic. 

    You wrote:

    My sloop "Johanna" is so generously rigged than in a F6 she will be down at 4 panels and in a F7 she only carries 3 panels. In these conditions she has been transformed into a fully fanned sail with very moderate camber – and she performs very well. The yard is still peaked to 70° producing an effective luff. Only in "light" winds, F5 and below, will the parallel batten panels come into serious use. In other words; the lower panels become my "genoa 1" while the fanned top section becomes the "storm sail". It’s a paradox, but it works.

    Arne

    That illustrates one of the greatest features of the junk rig - we get to change sails without changing sails. No fuss at all. In your case, you start with a curvy 'genoa' in your full sail, for light airs and windward legs; in our case, we have a harder and flatter one for comfort and because we lack the will to point high. Both boats keep their storm sails handy, with moderate camber that can drive us when it's needed most. Brilliant.


    I seriously considered following your design ideas when I made our sails. If I thought I could have sewn it right the first time, I might have done so and had no regrets, perhaps. I wasn't keen to trial-and-error and do lots of recutting and sewing on deck, out there. And the other reasons I've mentioned also contributed to my choosing to sew flat. I applaud your work!


    Now I want to see how well our top three panels will perform hard-as to windward in light wind, say 10 knots or less - using that fan-sail camber to point as high as we can and go slowly but steadily. 

    Could we point higher than we can with full sail? Any guesses? And how about in 25 knots? (I should know this, but I've always used as much sail as was up...)

    Thanks,

    Kurt


  • 08 Jan 2011 17:04
    Reply # 491646 on 491544
    Anonymous member (Administrator)
    TONY AND SALLY SUMMERS wrote:

    question- will cambered sails increase heel?

    Yes, in the same wind, the more powerful, cambered sail will lead to more heel than the flat sail – that is, when close-hauled. By reefing earlier you can keep the heel within your limits and still go faster to windward than with the flat sail.

    On a reach even the cambered JR sails a lot more upright  than a Bm rig since easing the sheet on a JR is much more effective than easing the sheet of a genoa.

    However, I understand that you are happy with the performance of "Ron Glas" so this should not be an issue. Before going for a really long voyage with those old sails, maybe I should suggest that you reinforce the edges of the sail, either with a hand-stitched rope or with a machine-sewn webbing? As long as the edges of the sail don’t fail, then the integrity of the sail will not be lost even if a panel should get ripped.

    Arne

  • 08 Jan 2011 11:17
    Reply # 491544 on 490687
    Deleted user

    all very fair points David, I will try and assess performance a little more accurately over this coming year ,especially windward performance against big seas. Im prepared to be converted!!

    question- will cambered sails increase heel?

    Arne, the "dashboard" is just the same-- in fact we have been repainting it this week--I must say for two-up sailing its a brilliant space. does become an issue with more than two crew awake!

    meanwhile Ron Glas and Mehitabel will continue with the low tech approach---Kurt  if youre on your way to the Med and we are slowly heading for New Zealand we may cross paths. tonyand sally

    Last modified: 08 Jan 2011 11:17 | Deleted user
  • 08 Jan 2011 10:15
    Reply # 491541 on 490687
    Anonymous member (Administrator)

    Stavanger, Saturday

    Good to see "Ron Glas" on these pages! If the present sails are from 1987, then I’ve actually seen them. I met Jock McLeod in Lerwick, Shetland in 1989 – just 5 minutes after I had bought "Practical Junk Rig" there so I’ve even been on board and had a look. Unfortunately I knew nothing about JR at that time so I didn’t know what to look for or ask about. Still I was amazed to find the running ropes being terminated at the "dashboard" inside the low wheelhouse.

    I rigged my first boat, "Malena" with a flat junk sail and later with the present ( now worn-out) cambered panel sail. With the flat sail I could carry full sail up to the middle of a F5 while the cambered sail (same area) needs a reef in the lower half of a F4 – even now with a hollow and much lighter mast. This however doesn’t mean that the cambered sail feels more demanding to handle. If a max heel limit before reefing were set to, say 20°, then I bet that the cambered sail would perform better to windward than the flat one within that limit, even with an extra panel or two dropped from time to time. Reefing is no big issue and, important; no extra running lines have been needed to control the cambered sail.

    These days I sail only along the coast and my experience is that there are long periods with winds blowing a low F4 and below. It is in these conditions that the cambered sails really excel. This, in my opinion makes the cambered sail greener since one tends to sail more and motor less than with a flat sail.

    Cheers,

    Arne

  • 08 Jan 2011 09:26
    Reply # 491531 on 491390
    David Tyler wrote:
    TONY AND SALLY SUMMERS wrote:

    David, having had a junk schooner and a catamaran before Ron Glas we were well used to easing sheets to get any real drive, however we are astonished at Ron Glas`s ability to drive to wind. 50` off the wind is her fastest and best point of sail, she will point higher but  not as fast with increasing leeway as one pinches, IM talking "normal" lumpy seaway not flat calm -- but this seems OK for 16.5 tons of floating home ,should I want better?

    again is this not down to hull form? Ron Glas has a few vices but sailing aint one of them!


    I'm not after a racing boat's speed to windward, that would certainly be uncomfortable. I'm happy with 5 knots at 30 degrees apparent wind, 45 on the compass, 50 on the GPS after leeway has been added in (that's what a good bermudan rigged boat of the same type and size should do).  I regulate speed off the wind to below 7 knots so that the self steering can manage.
    But what I do need in Tystie is power,  which a flat sail couldn't give me, to keep going solidly to windward against an awkward sea, in a shoal draft boat, 1 metre draft with bilgeboards. And what's more, I like doing it! Powering efficiently to weather in a responsive boat is fun, when the wind is fresh, the sun is shining, the sea is sparkling; and then I can forget I'm an OAP, un-latch the selfsteering, get hold of the tiller and enjoy the feel of a boat going at her best.
    It's all down to hull form and size and weight. Ron Glas is twice the size and weight of Tystie, with a deep keel. With cambered sails, Ron Glas should do 6 knots at 45 degrees, 8 to 9 knots on a reach.
    What it all boils down to is: different folks sail different boats in different ways, and if you don't want to sail that fast, and that close, you don't need more powerful sails.
    We're fortunate to have the evolution of Tystie documented in the JRA Newsletters. I looked back at numbers 38 and 40 today. She's a very sophisticated craft. I'm sorry now that I was too shy to knock on your deck when you were in Whangarei last.
    At the other end of the spectrum of junk rigged boats, one could promote the idea of sailing around the world with a rig made from the contents of one hardware store shopping cart and a few bamboos, put together in a weekend.
    It's amazing, the variety of things humans can do with a good idea.
    Regards,
    Kurt
    Last modified: 08 Jan 2011 09:26 | Deleted user
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