What is the best alternative rig for this dinghy?

Discussion in 'Sailboats' started by Mark O Hara, Jul 6, 2020.

  1. Mark O Hara
    Joined: May 2020
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    Location: Mariveles, Bataan, Philippines

    Mark O Hara Junior Member

    The design was based on the Minto Dinghy and it’s pretty much what the yard owner wanted. I sailed it successfully myself on a few occasion but the new owner doesn’t like it saying it capsizes too often so I reduced the length to the mast the boom and cut 0.9 m 2 (10’2) off of the sail altogether, but now he wants the complete rig changed. If you were to re-rig this boat for a novice what rig would you suggest?

    Sailing Dinghy Specifications

    Length 2.9m (9’ 7”)

    Beam 1.2m (47 ½ “) .

    Depth .5m (20”)

    Draft .2m (9”)

    Board Down .55m (22”)

    Weight 72.5kg (160lbs)

    Sail Area 4.3m (46 sq. ft) now 3.3m (36 sq. ft)

    Max Power 2-4hp

    Persons 1-3 218kg (480lbs)
     

    Attached Files:

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  2. Alik
    Joined: Jul 2003
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    Location: Thailand

    Alik Senior Member

    Beam 1.2m, I believe at WL is 1.0m? Dimensions are very similar to Optimist, but sail area is larger, and CE of sail is much higher. Rudder not deep enough to control the boat downwind.
    I would suggest to use standard Optimist sail, can buy ready0made stuff...

    P.S. And stop drawing boats bow to left. Does not look professional ;)
     
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  3. Will Gilmore
    Joined: Aug 2017
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    Location: Littleton, nh

    Will Gilmore Senior Member

    Gaff.
    Shorten the mast while keeping the sail area the same or slightly less. Also, shorten the boom just a little, to keep the CE where it is fore and aft. The gaff rig will probably still move the CE back a little.

    The gaff rig will drop the CE to give her less heeling force. She will go better with the wind, but won't go as well into the wind.
    https://c8.alamy.com/comp/A4BH3G/a-...he-australian-wooden-boat-festival-A4BH3G.jpg
    Very salty looking, as well.
    Or
    A crabclaw, like a Sunfish, is very simple and they sail well too.
    [​IMG]
    It will be unique.

    -Will (Dragonfly)
     
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  4. Mark O Hara
    Joined: May 2020
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    Location: Mariveles, Bataan, Philippines

    Mark O Hara Junior Member

    You mean a sprit rig like this? :D
    OPTSail.jpg
    That was my first choice but I was over-ruled. I'll put that forward again. Thousands of kids can't be wrong!
    Whatever it will be it has to be scratch built in the yard as anything imported here is bloody expensive!
     
  5. Alik
    Joined: Jul 2003
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    Location: Thailand

    Alik Senior Member

    You can get second-hand parts for this rig in any yacht club... Or build of alu pipes, I believe there are drawings on Optimist class website.
     
  6. fallguy
    Joined: Dec 2016
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    Location: usa

    fallguy Senior Member

  7. Will Gilmore
    Joined: Aug 2017
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    Location: Littleton, nh

    Will Gilmore Senior Member

    Lug rigs have their aesthetic appeal as old fashion and salty classic crossing. The cross spar is actually called a 'yard'. Very piratey:D. They have some advantages sailing down wind because of the overlapping sail area forward of the mast. It's as an efficient foil for reaching (sailing with the wind in any quarter but astern) that they fall short of the Burmudian rig, for example.

    But, they are simple and easy to work.

    -Will (Dragonfly)
     
  8. Alik
    Joined: Jul 2003
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    Location: Thailand

    Alik Senior Member

    I don't think 'unique' is required. Any 'unique' has disadvantages which are not evident at beginning. But they would cost a lot if it does not work.
    Practical is required. The boat should be able to go upwind efficiently, also in light wind against tide. And here Opti rig works.
    Try the working one first. Then, try to develop something unique, but with chance to step back if it does not work.
    Just an advice from me, as dinghy sailor...

    PS Look at the guy with his aft mast rigs - 'brainwash' with his 'unique' rig which only works in his imagination.
     
  9. Will Gilmore
    Joined: Aug 2017
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    Location: Littleton, nh

    Will Gilmore Senior Member

    I was using unique as a relative term, perhaps poorly chosen. The crab claw rig is practical enough to be the rig used on one of the most popular sailing dinghies in the World, the Sunfish. As you know, the Sunfish is the first sailboat of many life long sailors. I learned on an Opti and think the world of them. They are actually the most popular sailboat in the world and truly an international design. I own a Windmill, the envisioned next step, and knew Clark Mills as a good family friend. The sprit rigged Optimist is a great beginner's design. It just isn't the only tried and true dinghy rig that would meet the OP's criteria.

    I'm not pushing one over another, here. I'm just explaining that even though I used the term 'unique' I was not talking about a rig that is unknown or untested. The Crab Claw is, in fact, as old a design as any known sailing rig and about as simple a sailing rig as they get. They are well respected performers and easy to control. There is no costly unknown involved. Putting one on an open dinghy in the Western Hemesphere is what is 'unique'.

    If it comes down to practicality where performance and simplicity, availability and affordability are all factors, either one of those two rigs could be argued for. Craigslist abounds with both, in any given area. The Sunfish is probably going to be cheaper.

    -Will (Dragonfly)
     
  10. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    The Sunfish uses a Lateen sail not a crabclaw.
     
  11. Will Gilmore
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    Location: Littleton, nh

    Will Gilmore Senior Member

    No.
    Lateens don't have the boom.
    [​IMG]

    Crab claws are footed and usually symmetrical. The polynesian crab claws could change direction by switching the tack from one end of the hull to the other.
    [​IMG]

    At least that's the difference as I learned it.

    -Will (Dragonfly)
     
  12. messabout
    Joined: Jan 2006
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    Location: Lakeland Fl USA

    messabout Senior Member

    Sunfish uses a lateen rig and they do have a boom. The terms crab claw or lateen can be nearly but not quite interchangeable. The crab claw has a yard and a boom and the leech is usually allowed to sag to leeward. The lateen, as on the Sunfish, uses a tight leech. One of the tuning techniques with the Sunfish is to honk the boom down in such a way that it has a serious bend. When vanging the boom the yard is also bent somewhat. This is a brisk breeze adjustment that hauls some of the camber out of the sail. (Sunfish uses no vang but there are ways to hold the boom down)
     
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  13. sharpii2
    Joined: May 2004
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    sharpii2 Senior Member

    My understanding is that although they may look alike, the boom Lateen sail and the crab claw work completely differently.

    The boom of a boom Lateen sail is designed to be more or less parallel to the waterline. Airflow is supposed run mostly parallel to it. This is the reason it should have a tight leech.

    The boom of a crab claw is clocked up usually quite severely, maybe 30 to 60 degrees, so the airflow goes across it. This way, the boom acts as the leech of the sail, and the loose part acts as the head.
     
  14. Ike
    Joined: Apr 2006
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    Ike Senior Member

    Frankly I would do what I did for the 7' 11" sailing dinghy I built based on a Monk design. But I wanted to keep the rig simple. It is cat rigged. The mast is unstayed and probably 3 to four feet shorter than it could be. The sail has a long pocket on the luff that simply slides down over the mast. A line from the tack goes to a cleat to tighten it. Another line goes from the clew to the end of the boom, through a hole in the end of the boom. I tie it off and there is another 6 or 7 feet used to sheet the sail. No sheaves, no blocks. The boom is attached to the mast with a pintle and gudgeon , the same as are used for the rudder. Later I could make a longer mast and cut a new sail. The Sail is simply nylon I purchased at a fabric store. It's as simple as it gets, and it sails well and is perfect for a beginner.
     

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  15. Alik
    Joined: Jul 2003
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    Alik Senior Member

    This rig has big disadvantage - not possible to reduce sail area... With Opti sail, just take off the sprit.
     
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