Some lateral thinking for Christmas.

  • 30 Dec 2021 21:41
    Reply # 12226339 on 12212428

    Graeme, windward ability in storm conditions is a huge topic, and probably with no clear answer. Boats can do remarkable things in amazing amounts of wind, but it is the sea state that usually causes the problems.

    I have sailed to windward in F8+ in 70 foot ketches in rough seas in the English Channel with no problem, and also in more sheltered waters in 30 foot boats, and in all cases found that we needed sails big enough to drive the boat through the seas. One thing is clear and that is that the storm rig must be efficient. Perhaps the words efficient and sufficient should be used.

    The idea of dropping the junk rig and hoisting a smaller dedicated storm rig may not be so stupid. The rig might be easy enough to draw, but not so easy to rig with batten parrels and sheets, as you say.

    Any one got any thoughts?

    Cheers, Slieve.


  • 30 Dec 2021 21:11
    Reply # 12226259 on 12212428

    I wish it was that easy Arne, but I'm afraid it's not. I don't know where you got the rig areas from, but it looks like sailboatdata.com and if that is the case then you're not getting the correct numbers. They give SCOD as 26.11sq.m/ 281 sq.ft, Co26 as 21.65 sq.m/ 233 sq.ft and Splinter 21 as 15.14 sq.m/ 163 sq.ft, and we know that the last one is definitely wrong. The website seems to quote either full mainsail plus 100% fore-triangle or full main and working jib (which is often 100% J but with shortened luff). The SCODs all use a large Genoa and they also fly spinnakers, and with a displacement/ ballast of 4207/2100kg or 50%, and a waterline length of 21 ft to the Splinter's 1262/408kg or 32% and LWL 17ft then it's obvious that they will handle the chopped waters much better than the Splinter.

    From Amiina we've learned that large sail area does not necessarily result in a faster or better boat, regardless of handicap if you have to reduce area to keep the boat sailing. When sailing alongside a SCOD you see that they can carry their sail in strong winds as they can keep going when well heeled, which the Splinter can't. With their displacement and ballast the SCODs can sail through choppy seas, just as the Folkboats can, so it's no surprise that these boat are always amount the leaders if they can get through the first tidal gate.

    No-one would respect a JR SCOD if it had additional fore and aft rig area, and you would never get the rest of them to sail without their spinnakers. Such is the nature of the race.

    I believe that we can only compare rig efficiency on a particular hull if we are comparing similar sail areas. Jon Stone's comments in JRA NL52, P29 shows that Poppy easily beat a Konsort on both the reach and the beat and as my previous boat was a Konsort and as Poppy had a typical cruising sail area that was proof enough for me that we were on the right track.

    I know from experience that it is all too easy to theorise, so everything I say from sitting in front of the computer must be taken with a large pinch of salt.

    Cheers, Slieve.


  • 30 Dec 2021 19:57
    Reply # 12226137 on 12212428
    Anonymous member (Administrator)

    Storm sails

    Slieve wrote: It is the lee shore or man overboard situation that requires some proper design. How much sail area would be required and what aspect ratio and outline profile would work best?

    I have never been in either of those situations in gale conditions, so I would be very keen to learn from anyone who has. 

    I have broad reached under sail catcher, and that was what prompted the idea of using an expandable version of it as a storm sail -  but thinking only of broad reaching and/or just keeping some control over the boat. For going to windward in a gale, maybe not such a good idea. Maybe Jan's idea of extending it downwards as a water sail is a better idea.

    [Edit: I should say, I have found that in a strong wind, the SJR on my little trailer boat did not work well to windard when reefed down to top two panels. I could barely make progress to windward. Its is a good lesson - over-canvassing simply because its easy to reef  does have its limits.]

    Anyway, I do think that the sail catcher is the key to keeping the storm sail separate from the working sail, yet in place and ready for quick deployment, and an optimised storm sail might be a better option than a heavily reefed working sail. There is no reason why the storm sail could not share the same boom, and be available from within the sail catcher – with some sheeting and mast parrel details not yet properly thought through.

    I would quite like the idea of a proper, purpose-built heavy weather sail, optimised for, say, 30 knots of wind plus, and capable of making to windward.

    The start point would to design the storm sail first, to suit the hull, then figure out how to carry and deploy it. With my lack of experience in this area, I would appreciate knowing of instances where junk rigged boats have managed to sail to windward under gale conditions, under top triangle or heavily reefed sail, to get some idea of what would be necessary, and what would work. Arne has written of getting good results from sailing under his fanned top section. Would this work to windward  in a gale? Has anyone done it under top panel alone?


    Last modified: 30 Dec 2021 21:03 | Anonymous member (Administrator)
  • 30 Dec 2021 15:25
    Reply # 12225617 on 12212428
    Anonymous member (Administrator)

    Slieve mentions below that it would be better to race a SCOD or Contessa 26 with a JR.
    I agree, and for a special reason: Both the SCOD and the Co26 are in my view quite under-rigged. It would be very easy to upgrade these boats with sloop junkrigs, now with much larger sail areas, even with moderately tall masts or without going extreme in any way.
    The diagram below shows the SCOD. Its working Bermudan SA is 26sqm while the suggested JR is 43sqm. This raises the SA/disp. ratio from 10 to 17 and lets a converted SCOD sail away from the originals on all legs.

    The handicappers would punish the JR SCOD badly, but who cares? The message to the onlookers would be that the JR simply is faster. Any argument about sail area can be met by showing the shorter mast of the JR.

    Cheers,
    Arne


  • 30 Dec 2021 13:06
    Reply # 12225475 on 12212428

    Graeme wrote, “Actually, I have been thinking about the sides of the sail catcher being large triangles normally rolled up or folded - able to fold out and become the storm sail. How about that?”

    Now that is an interesting idea, not necessarily KISS, but a good building block. It raises the question – what do we want from the ideal storm canvas?

    Without looking too far my thoughts are that for running off or broad reaching then the shape is not too critical, and even the sail bundle has been known to work. It is the lee shore or man overboard situation that requires some proper design. How much sail area would be required and what aspect ratio and outline profile would work best?

    Something for the little grey cells.

    Cheers, Slieve.


  • 30 Dec 2021 01:04
    Reply # 12223895 on 12212428
    Anonymous member (Administrator)

    Jan wrote: Down at the bottom: Seeing as the sail-catcher is de rigeur on a SJR how about making it double up as a drop-down watersail? 

    Then you'ld have to empty it. The sail catcher is the lady's hand bag.

    Apart from the boat hook and various other odds and ends, you could stow your tops'l there (and your water sail).  I like the idea of them being stretched out on bamboo poles lying in the bottom of the sail catcher ready to go, ready to just clip on. 

    Actually, I have been thinking about the sides of the sail catcher being large triangles normally rolled up or folded - able to fold out and become the storm sail. How about that?

    Last modified: 30 Dec 2021 01:06 | Anonymous member (Administrator)
  • 29 Dec 2021 22:25
    Reply # 12223631 on 12212428

    Topsails, like puppies, are not just for Christmas!

    Ever since we chased Iron Bark II, flying the full rig, up Roaringwater Bay a few years ago I've wanted a stripey topsail!

    I got fairly brain boggled yesterday reading about them in The Gaff Rig Handbook so it's great to see Slieve suggesting the Yard Topsail type and its attachment. Another thought I had on sticking with standard junk design and KISS is to splash a bit of money on light but very strong fabric for the top panel, dyneema perhaps. Or having a storm sail available in the sail catcher as Graeme suggested and not relying on your light/medium air top panel in rare storm conditions, which will probably never occur for a coastal boat but should be planned for. 

    Down at the bottom: Seeing as the sail-catcher is de rigeur on a SJR how about making it double up as a drop-down watersail? 

  • 29 Dec 2021 20:56
    Reply # 12223434 on 12212428

    Another day of festive eating under my belt, so hopefully now back to normal and the post-Christmas diet.

    I agree that small boats should not need additional panels for local sailing, but I asked the question at the start of this thread in an effort to encourage lateral thinking, and thoughts on the best sail area for sturdy rigs for long distance cruising boats.

    I did have an idea which I'm offering very much with tongue in cheek.

    If a boat is cruising long distances and wants more area in very light conditions then is might be practical to have a simple well cambered topsail, built with round and broadseam or angled shelf foot out of spinnaker material, and attached to a light weight yard. With a single block at the mast head for a light weight endless halyard, and an eye attached to both ends of the normal yard it would be a case of -1, dropping the rig, 2, attach clew and tack of the topsail to the normal yard, stretching the foot of the panel tight, 3, attaching the halyard to the topsail yard, and 3, with the topsail hanging down on the outside of the rig re-hoisting the rig. Then to raise the topsail, 4, simply haul the topsail yard to the peak.

    If there is not enough mast then the topsail yard could be attached to a stub topmast which could hoisted by the light halyard and kept erect with the halyard downhaul.

    The diagram below shows a topsail on the Mk2 Amiina drawing, and adds about 15% sail area.

    Also in the drawing was the other idea I was hoping someone would suggest, and it's interesting the Graeme did. I would call it a watersail, but really it is just another panel to stop the wind escaping under the rig and making the hull effectively an end plate. It might add another 15% area, but it would reduce the inefficiency of the pressure loss below the sail. This is the easier option of the two, simply requiring a broad-seamed top edge and clipped tightly stretched along the bottom batten, and tied down to a few points on deck with no spars required. The only refinement would be the need for windows in the panel.

    OK, I'm not fully serious with these suggestions, but am offering them as points to ponder.

    Cheers, Slieve.


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  • 29 Dec 2021 20:10
    Reply # 12223324 on 12212428

    I'm sorry if I've misled you with the emphasis on handicaps in my earlier post. The real meat of the post is in the paragraph, “What is of interest but not possible to confirm with results is the performance when the wind was light and the small boats could not get through the tidal gates and complete the race. In these light conditions Amiina was always well up with bigger faster boats when they had to retire, even with the smaller Mk2 rig. Amiina is a nicer boat to sail with the smaller rig, and I am not surprised that everyone uses about 175 sq.ft.”

    We did not have the right information when we drew up the Mk1 rig, and the boat was a bit of a handful, rather tender and needing to reef too early to a less efficient sail shape. The handicaps were the indicator that the other Splinters were doing something different, and when we found the difference we followed them with the smaller rig and rather than loose performance we ended up with a more pleasant boat to sail and still had good light wind performance. We were not looking for race results, but boat for boat performance, and we got that with the smaller rig. Thanks to the Island Race we have improved the performance and handling of Amiina, and learned about the importance of getting the sail area right. We now recognise that getting the area right is the first step in drawing a SJR sail plan.

    Amiina does remarkably well against the other local Splinters, but will never consistently beat them as they are a keen racing group who spend time and money in getting the best out of their boats. I doubt if Edward is going to spend his weekends polishing Amiina's bottom, having the sails re-cut and shopping for special ball bearing blocks. In one trip I did with Edward we didn't do too well, but then we did have an accidental gybe when close reaching because we were stretched out on either side of the cockpit, probably one of us steering with an ankle placed on the tiller and concentrating on an argument on British politics, while the other boats were probably concentrating on getting to the finishing line. Racing is not the objective, but helps to give a measure of performance.

    You can't really call it racing to be in one of the shortest and lightest boats competing when the water is chopped up by the large fleet. If you want to win the Island Race then use a SCOD or a Folkboat derivative like the Contessa 26. The aim is to test, and to keep the JRA flag flying.

    Cheers, Slieve.


    Last modified: 29 Dec 2021 20:12 | Anonymous member
  • 29 Dec 2021 09:30
    Reply # 12221957 on 12212428
    Anonymous member (Administrator)

    Focus on Real Speed!

    Frankly, I think it was unfortunate that the sail area of Amiina’s rig was reduced in the hope that she would receive a favourable handicap.
    Onlookers (in real life or on the pc-screen) don’t care about corrected time on such a special vessel with a JR. Amiina’s performance will mainly be compared with other splinters: Is she faster or slower on the water than the others (on uncorrected time)?

    Therefore, when optimizing Amiina for more racing, you should spend the energy on wringing maximum speed out of the sail, including in light winds. Accept and then forget about any handicap you receive.

    Good luck,
    Arne


    Last modified: 29 Dec 2021 10:25 | Anonymous member (Administrator)
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