Conversion to Gunter Rig

Discussion in 'Sailboats' started by Jamie Kennedy, Mar 16, 2016.

  1. Jamie Kennedy
    Joined: Jun 2015
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    Location: Saint John New Brunswick

    Jamie Kennedy Senior Member

    I am interesting in build a gunter rig for my 21 foot Yngling, as part of an idea for modifying the boat for offshore cruising and adventuring. The idea is to be able to lower and store the upper mast in rough seas. The existing mast is an absolutely beautiful Melges spar, super light and strong and bendy, which I can step myself at the dock, or even at the mooring, but not before a storm or in a storm or after a storm while at sea.

    So my question is, do you think it would be possible to build the gunter rig in such a way that I could use some of the existing sails without much modification. The boat came with 3 mainsails and 3 jibs. The older ones are in good enough shape to use for cruising. The newest sails I will keep for the river and racing mast.

    Here is the existing sail plan. As you can see, there is not alot of mast above the hounds.The mast is deck stepped, on top of the cuddy cabin. There are no running backstays. I like the idea of retaining a backstay even with a gunter rig, and accordingly would like the lower mast and sliding gunter to have similar bend characteristics for flattening the mainsail in stronger winds. I don't mind adding some weight and some windage. When lowering the gunter, and once the gunter has been lowered completely, I might need to have a running back stay to the lower mast. Once lowered, I think I would have a storm main, made from my third sail, rather than use the gunter main, made from my second sail.

    Problems I see, and possible solutions:
    1. The gunter main would have to have some of it's luff removed, and a new bolt-rope fitted, in order to accommodate the area taken up by the gunter spar. Is there enough sail area up there to even justify raising the gunter? Why not just a shorter masthead offshore rig? So my thinking is, the gunter spar could be even taller, and I could add some extra sail at the foot as well as modifying the top. The gunter rig would be for light to light-medium winds, and the gunter spar would not need to be strong enough for use above 20 knots, so it could be reasonably light, and reasonably small in dimensions.
    2. Is there a better way? How about modifying the boat and rigging so that in a storm the existing mast can be dropped from being stepped on deck to being stepped on the keel? This would have to be done with the sails down. The forstay and shrouds and stays would need to have some way for being shortened and lengthened, and then the sails re-hoisted. Getting to the forestay could be a bit tricky at sea. Perhaps a forward hatch is needed, and/or perhaps the forestay at least, could run internally. This gets into issues of watertight bulkheads, closing off the open cockpit, etc. I do like the idea of being able to raise and lower the entire rig vertically by those 3 feet, for strong winds and perhaps for night sailing in general.
    3. Even with a full crew, the Yngling tends to round up very easily when flying her spinnaker above a broad-reach. For this reason alone I has an assymmetrical spinnaker or flying jib in mind. I don't see it being used in strong winds, but could be very useful in light winds. I don't like the idea of weakening my existing mast with an extra halyard entrance so it would go to the existing spinnaker halyard. Can't remember if it is internal. Anyhow, for the gunter rig I think it would still only go to the top of the lower mast, and not onto the gunter spar. Make sense? Still not sure if a flying jib or gennaker is needed as there is existing main and jib already have alot of power even for light wind. It is for very light winds and ocean slop I am wondering if some sort of light flat-cut flying sail might be warranted, and how it might be strung. Perhaps in really light air it too could go to the top of the gunter spar.
    [​IMG]


    Here is a classic Yngling wipeout...
    https://www.youtube.com/watch?v=tOrobluiwH8
     
  2. Jamie Kennedy
    Joined: Jun 2015
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    Location: Saint John New Brunswick

    Jamie Kennedy Senior Member

    [​IMG]Here is the German Sonderklasse with it's high aspect ratio gunter-rig...
     
  3. Jamie Kennedy
    Joined: Jun 2015
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    Location: Saint John New Brunswick

    Jamie Kennedy Senior Member

  4. Jamie Kennedy
    Joined: Jun 2015
    Posts: 541
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    Location: Saint John New Brunswick

    Jamie Kennedy Senior Member

    I should also mention I've been getting alot of ideas and inspiration from the Scamp, and Scamp sailors like this fellow, whose name I think is Mike.
    Thank's Mike. Don't get up. ;-)

    This Scamp is interesting in that it shows the cutout area to facilitate the raising of the mast. On most newer Scamps I think you just drop it in, but this gives me some ideas for the Yngling, which is a longer boat after, but comparable in size in the cuddy area. This has me leaning towards a strategy of stepping the mast on the keel, and then being able to raise and lowering up to and down from deck height somehow, while adjusting the now semi-standing rigging, and sails. Eliminates the Gunter business uptop, but complicates things down below. It would be about a 3 foot range of adjustment, possibly done in stages. There are both upper and lower shrouds to contend with, as well as the main boom and gooseneck, and the forestay and jib. I'm thinking transitions would need to be done with the mainsail down, but the jib, at least a shorter storm jib, might be kept up. Rather than reef points I think I envision storm jib, storm main, full jib, and full main. Basically just two position, up and down, other than being dropped all the way down. It is still a very long mast to be hanging off the back of the boat when lowered completely, even if then unstepped somehow and stowed forward. This might still be useful in extreme storms but I am not really sure. Might be better to keep things simple and watertight forward, and keep the mast upright while at sea, even in storms, but have it dropped to keel level with bare poles or storm jib only. What would Yrvind do?

    [​IMG]
     
  5. Jamie Kennedy
    Joined: Jun 2015
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    Location: Saint John New Brunswick

    Jamie Kennedy Senior Member

    Just read that Webb Chiles had the mast and boom stiffened and upsized the standard rigging on his Moore 24 Gannet. He also added running backstays as he does considerable sailing in strong winds under jib alone. Definitely makes sense. Perhaps this approach makes much more sense than my ideas of a gunter rig, or being able to vertically drop the mast 3 feet, or lower it completely. I will put this on the back burner for awhile and think some more on hull modifications, but have at it.
     
  6. gggGuest
    Joined: Feb 2005
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    Location: UK

    gggGuest ...

    The typical dinghy gunter rig has the mainsail essentially unchanged and sliders on short strops from the mainsail to the track for the gunter on the back of the mast. That way the luff rope is still straight from peak to tack. If the gunter has a fractional angle so that the straight line from the gunter lines up with the old tack position then all that will be needed is the strops on the tack carefully set in length. This is fairly easy to arrange with a wooden spar.

    I have seen a 14ft singlehander with a telescoping mast stump. Basically the mast stump was supported at gooseneck height, and the mast socketed into it about 6 inches and was held up with a "pin" (10mm stainless). Pull out the pin and the mast dropped to the foot of the stump. Shrouds were arranged by having a second hard eye talurited onto the shroud in an appropriate place. The attachment may give an idea.

    For your boat I would have thought a short or doubled forestay and a line led back to the cuddy to take up the slack might to the job, or possibly a joint. The awkward bit will not be dropping the mast down at sea, but getting it back up again.

    The stump, BTW was a major pain in the neck to fabricate.

    Not a bad plan I suspect. The stumping rig seems a bit complex for serious offshore stuff with minimal crew, and an extra spar up the top is an extra concern when taking the sail off.
     

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  7. Jamie Kennedy
    Joined: Jun 2015
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    Location: Saint John New Brunswick

    Jamie Kennedy Senior Member

    Thanks gggGuest. Very useful information. i've sailed a Mirror Dinghy, but other than that not much experience with gunter rigs. Loved the Mirror Dinghy. Sailed mostly the Cadet as a youngster, also a Jack Holt pram but not a gunter. Was very impressed with the Mirror Dinghy rig and how it sailed. For the Yngling, with three times the sail area, expecting to be able to manhandle the rig at sea is a bit more challenging.

    I am glad I now have a term for the 'stumping rig'. Thanks. Having thought some more about rig loads I think I realize now I can expect to be able to do anything with even just a small storm jib up. I like the idea of the stump going up to boom height, and the boom and vang being permamently fixed to the stump rather than the mast. Thanks for that. The real trick as you say, is raising it while at sea, presumably after a storm with reduced wind but left over swell. Even with the sails down there will be side loads and swings to contend with, and no sky hook. Having the stump go up some distance beyond the gooseneck would help. I think I would still pull from deck level rather than pull from above, but the extra height might be enough to hold the mast steady while readjusting all the stays and shrouds. Still a long way up though, and a very bendy spar to have flapping around. I think there would need to be a way to go up in small increments, loosening and raising as I went, then finally pinning it as you say, once in the raised position. I do like the idea of a reduced height rig though, and it be that the mast only needs to go up in light winds, and can stay down most of the time even in medium winds. A flying jib from the spinnaker halyard to a bow pole could make up the difference in medium winds on most points of sail. Just realized also the downwind symmetrical spinnaker would be lower to the water with the mast dropped 3 feet, and might be too low even for medium wind. I suppose a chicken chute from a smaller boat wouldn't take up much space down below. Cheers.

    Another interesting read from Webb Chiles here...

    http://moore24.org/neaifu-tonga-pounded-report-from-webb-chiles-gannett/
     
  8. Zilver
    Joined: Nov 2007
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    Location: Amterdam the Netherlands

    Zilver Junior Member

    mast lowering method with spring

    Hello,

    In Holland some gunter rigged hire boats (vd Stadt VALK) use the system as seen in the attached picture.
    In the (round) masttube is a spring, a Dyneema line is connected at the top of that spring, en led out of the mastbase via a slippery pin to the tabernacle.

    On the Valk it works great, the mast is more or less in balance on every point during raising/lowering. Might be a bit smaller mast than yours : total sail area of the Valk is aprox. 16 m2.

    Good luck, Hans
     

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  9. Jamie Kennedy
    Joined: Jun 2015
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    Location: Saint John New Brunswick

    Jamie Kennedy Senior Member

    Thanks Hans. Looks like a very fun boat to sail and to race.
    [​IMG]
     

  10. Jamie Kennedy
    Joined: Jun 2015
    Posts: 541
    Likes: 9, Points: 0, Legacy Rep: 117
    Location: Saint John New Brunswick

    Jamie Kennedy Senior Member

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