Short gaff rig, one halyard feedback

Discussion in 'Sailboats' started by Hampus, Nov 30, 2013.

  1. Hampus
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    Hampus Junior Member

    Hello!

    I like gaff rigs. They are well suited for the kind of sailing I do except on one point. I find that two halyards are a hassle while sailing short handed. I'd like some points of view on the one in the attached PDF. The boat is a conceptual design I did as part of an assignment. I'm happy enough with the boat to keep working on it until it's completely finnished, in two years maybe when I'm hopefully done with the course...

    A few notes on the rig. I got the idea from Daniel Bombigher's Ti' Schpountz while searching for information on more manageable gaff rigs.

    The curved board on top of the gaff is there put the halyard a bit above the centre of gravity of the gaff. I guess the mast could be cut off a bit at the top to better take advantage of the benefits of a gaff sail. Any comments on this type of rig is much appreciated.

    Never mind the too small propeller at an awkward angle, I'm aware of it.

    /Hampus
     

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  2. Doug Lord
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    Doug Lord Flight Ready

    I like it and it solves the problem of what to do with the diagonal batten on a"square top main". I produced RC models using a very similar system-for those boats it allowed a more or less rectangular planform with no hassles from a diagonal batten.And I did a 16 footer with almost the exact system except the "gaff" was surrounded by foam.
    I like your position for the "peak" halyard better than the guy that inspired you but you'll have to experiment to make sure that it allows the gaff+sail to pull up smoothly. By having a stop on the mast that the throat end of the gaff hits, you could tension the leach if desired.
    PS-both boats below used and adjustable upper outhaul-only adjustable before sail was hoisted on the 16. Could have made it adjustable under sail but too complicated.....

    Pictures, L to R: 1) 16' "Tantra"-note there is no diagonal batten-used a single halyard, 2) America One rc model-again note no diagonal batten :
     

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  3. wet feet
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    wet feet Senior Member

    [​IMG]

    A fairly sizeable boat with a single halyard gaff sail.It is attached to the gaff in a number of places.
     
  4. gggGuest
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    gggGuest ...

    Hmm, looking at that my first thought is that it would actually cost less to put the last few feet of the mainsail on and have a bermudan rig, and that some of the advantages of a gaff rig are gone.

    What advantages of a gaff rig over a bermudan rig do you think you have retained with this design?
     
  5. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    I've used a single line halyard on gaffs previously and you can get away with it on sails smaller then 100 sq. ft., but over this size, you'll need the control of both a throat and peak halyard. The arrangement is a bit of trial and error, but once you find the balance point, it works fairly well. There are disadvantages in regard to shape controls, but on small craft some accommodation usually can be made.
     
  6. Tad
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    Tad Boat Designer

    Apparently the single line halyards on the Perry designed schooner Jakatan do work.....but they don't allow the usual sail shape adjustment that is standard with two (Throat and peak).

    It's a bit hard to see in this drawing and it's complex (expensive) but workable. Both the peak halyard block and the gaff throat are attached to big heavy cars on a full mast-height track(the full battens in the sails also run on that track). There is a fixed length of line between the gaff throat and the peak halyard car. Peak halyard runs through the running block (on the car) and up to the masthead shive......simple but not adjustable except when the sail is down. Also obviously requires halyard winches of some power.....

    Jakatansp.jpg
     
  7. tdem
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    tdem Senior Member

    Most traditional dutch boats have a gaff sail with a nicely curved yard, which may have an effect similar to the curved headboard you have.

    According to my book, on fishing boats and most sails less than 25 square meters a single halliard is often used.

    The pictures seem to show an arrangement with 2:1 going to the head and 1:1 to the peak, kinda like this: http://resources21.kb.nl/gvn/FSM01/FSM01_T-187_X.jpg although often there is a second block higher up the mast for the second part going to the peak.
    -Thomas
     
  8. NoEyeDeer
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    NoEyeDeer Senior Member

    What hassles? Various boats have been using diagonal battens for ages with no apparent hassles. They have to be cheaper, simpler and lighter than a separate horizontal "gaff", especially if you also need an extra masthead crane to support your horizontal "gaff" (which you will).
     
  9. Hampus
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    Hampus Junior Member

    Thank you all for your input. I'll keep all of it in mind as I keep working on this.

    gggGuest. You're right, the mast is too long. Adjusting the headboard on the gaff, I think the mast could be cut just above the fore stay, thereby shortening the mast while keeping the sail area. I could extend the gaff a bit and run the luff straight up without the curve in it, that would further increase the sail area while keeping the center of effort lower than with a bermuda rig. Also, with a sail that's more square than triangular in shape the center of effort won't move as much forward as you reef.

    My idea with the large main and rather small fore sails was that you'd reef the main in comfort from the cockpit while keeping the fore sails as long as possible which is why I don't want to shift the center of effort forward when reefing. The shape of the main can be kept quite intact even when reefed while a reefed (partly furled) fore sail isn't, in my experience, good for anything other than down wind sailing, or reaching at best. It might not work, but there is a thought behind all of it ;)

    /Hampus
     
  10. TeddyDiver
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    TeddyDiver Gollywobbler

    Most Colin Archers pilot cutters had single halyard as did Fram. (had no better picture of the arrangement than this model of Fram) Tom Cunliffe's book 'Hand, Reef an Steer' has a good drawing too.
    BR Teddy
     

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  11. Baltic Bandit

    Baltic Bandit Previous Member


    Well the notion of a reefed sail not being useful for much other than offwind sailing really ignores what modern batten technology has done. Basically "square headed mains" are the modern gaffs, but they accomplish this with much stiff batten materials (Carbon) and stronger sail cloth that is strong enough to act as the gaff halyard on the diagonal battens.

    If reefed mains were so ineffective at other modes of sail, you wouldn't see them in modern ocean racers like the Volvo or the Jules Vern or the Mini Transat.

    And frankly if you are carrying the drag and weight aloft penalty of a gaff, its kinda odd to hear you be concerned about the performance of a reefed main.

    The main reason that most modern inshore racing boats don't have much of a reef setup is that with bendier masts, you can pretty much carry the same main to about 30 knots. and very few inshore/nearshore races experience much more than that before everyone runs for home
     
  12. Hampus
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    Hampus Junior Member

    Hello and thanks for your input. If you read my post again, carefully this time, you'll see that my concern is for reefed foresails, not mainsails. I still maintain the point of view that a partially furled foresail isn't good for much but downwind sailing.

    /Hampus
     
  13. Baltic Bandit

    Baltic Bandit Previous Member

    Again that's only partially true. Depends on how the sail was designed. Minis because of the limitations on sail counts, do carry reefable jibs and kites. but both require going forward to reef them.

    And the thing is that regardless of whether you reef with a Gaff or with just a Bermuda without even a "fathead" you will be shifting CE forwards unless you do something about your sailplan fwd of the mast. the intactness of the main's shape doesn't have much to do with this.


    Now alternatives to a foot reefing jib like on the Minis, is to have one that is designed to be "roller reefed" Sailmakers have designed these for bigger cruising boats. Quantum even has a batten design that allows for a battened jib to be reefed. This latter is important in that it allows a higher aspect jib that in turn loses more area up high when rolled than down low - minimizing the adverse effect on shape.

    Its also in part why the cutter rig was developed. with the Cutter and roller furling (and this is basically what the Volvo boats do) you build your foresail area by selecting a combination of foresails to unroll or roll up. all from the comfort/safety of the cockpit. They have even developed a system for rollerfurling asso kites.

    Now it is a touch more pricey and has some drag penalty for the extra forestays - but a gaff is going to be pricey as well and generate at least as much drag.

    Look if you like gaffs go for it. But recognize you are doing it cuz you like gaffs, not because you are optimizing your sail plan
     
  14. michael pierzga
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    michael pierzga Senior Member

    Gee..modern roller jibs go to windward just fine when reefed.

    They use a bulking device in the luff of the sail.

    I sail with a bulked luff staysail...plenty fast upwind when reefed....remember to move the sheet leed forward.
     

  15. Hampus
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    Hampus Junior Member

    Baltic Bandit: You do make some valid points. In my experience, the foot reefed jibs tend to do better than the furled ones. I've used foot reefed jibs both free flying and on a jib boom. It's true what you are saying about the minis, but if I'm not mistaken, the minis go mostly downwind and everything about them from their hull shape to their rigs are optimized for planing down wind.

    The roller reefed sail with battens are interesting although I suspect, without having done the math, more than a "touch more pricey" where the cost of the extra fore stay is negligible compared to the price of the battened sail itself.

    I don't defend the gaff for the sake of the gaff although I still believe the gaff rig has it's uses, as do many other rigs mostly long forgotten. When talking about optimizing a rig or a sail plan or anything else for that matter, we must first decide what we are optimizing it for. Is it speed, price, ease of use, upwind/downwind performance, ease of maintenance, single handed sailing, short handed sailing, light wind sailing etc. and I realize I failed to give the criteria behind this design.

    I'm guessing from your posts that you come from a racing background? That's fine and I value your input. This boat however is not a racer, if it was it would have looked completely different, from the full keel, to the D/L Ratio to the sail plan. She is "designed" (remember it's just a concept done as an exercise for a lesson) for long term coastal cruising with a crew of two and occasionally just one. I may very well (most likely in fact) have failed in creating the best rig for the task. I'm very happy with where this discussion is going though.

    Micheal Pierzga: Yes, I have tried the padded furling genoa and I'm still not convinced (yes, I did remember the sheet lead :) ). Whenever I had to reef I would usually hoist a jib or at worst a storm jib on the inner stay. I had problems in medium strong winds though, when the genoa was too big and the jib too small.

    /Hampus
     
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