Results 1 to 11 of 11

Thread: Sail design.

  1. #1
    Join Date
    Nov 2008
    Location
    Upstate, SC USA
    Posts
    1,451

    Default Sail design.

    Beuhler liked a sail he called a modified Dhow and used it as a steadying sail on his Diesel Ducks as an emergency sail. I'm interested in using a similar design on my boat. I've researched all I can using his books and website. I am in the planning stage to build my boat this fall. I would like to incorporate his sail ideas. I know I will need to add support structure to my hull and cabin to take a mast behind the cabin. In his book, he talks about using minimum rigging to reduce windage and a tabernacle to drop the stick to get under structures. My boat is a good bit smaller and lighter than his Diesel Ducks at 28 foot with a displacement of 16,200. Can anyone give me guidance on mast sizing, sail sizing, and rigging?

    http://dieselducks.com/index.html

    Running on what Beuhler called a modified Dhow to steady the boat.





    The design I am working with.



    Plans in hand and ready to start building this fall.
    This sig line is proudly provided by The Wooden Boat Magazine Forum. If it ain't The Wooden Boat Mag, it just a rag.

  2. #2
    Join Date
    Apr 1999
    Location
    Hyannis, MA, USA
    Posts
    47,392

    Default Re: Sail design.

    Nice boat. I could not tell from the other thread but does she perhaps have a dory (narrow lengthwise plank) bottom?

    Do you really want a steadying sail or do you imagine something that will extend your range, maybe get you home if a breakdown. I don't really think this hull can be made suitable for the latter. A steadying sail helps hold the bow into the wind and slows roll under way but does not really give much power.

    I would not rig this boat anything like the Beuhler, which has radically different weight proportions. Also, loose footed sails like that rarely stabilize the boat when you're off the wind: rather the vortexes over luff and leech induce wobble.

    I'd be inclined to look to a rig that's more like a steadying sail, mast rising from the cockpit sole and braced against the aft end of the house. This makes for a mast that can hoist things as well as hold up a proper flat cut steadying sail.

    Given you Loop ambitions, hinging the mast step on the cockpit deck will make for easy striking and the mast should be light enough that you can then get it atop the house.

    Three stays: The shrouds with a bit of follow (athwartships line between chainplates abaft the mast) and a low slope head stay to the stem. It might or might not be worth the cost to hang an ultra low aspect sail from that headstay. Hard to cut and will only really work going to weather.

    You'll need to consult an NA to be sure you don't make the thing too big for the boat's stability and you engineer the mast as light as is safe.

    G'luck

  3. #3
    Join Date
    Mar 2014
    Location
    Ronneby, Blekinge, Sweden
    Posts
    785

    Default Re: Sail design.

    Quote Originally Posted by ben2go View Post
    Beuhler liked a sail he called a modified Dhow and used it as a steadying sail on his Diesel Ducks as an emergency sail.
    [...]
    Can anyone give me guidance on mast sizing, sail sizing, and rigging?
    For steadying/emergency you don't need a very large sail, 3 square meters will do I think.
    Mast and rigging depends on sail size.

    /Mats

    Elected Swedish Yourneyman of the Year 2019

  4. #4
    Join Date
    Nov 2008
    Location
    Upstate, SC USA
    Posts
    1,451

    Default Re: Sail design.

    Quote Originally Posted by Ian McColgin View Post
    Nice boat. I could not tell from the other thread but does she perhaps have a dory (narrow lengthwise plank) bottom?

    She has a V bottom with a good bit of rocker but is planked flat either side of the centerline.

    Do you really want a steadying sail or do you imagine something that will extend your range, maybe get you home if a breakdown. I don't really think this hull can be made suitable for the latter. A steadying sail helps hold the bow into the wind and slows roll under way but does not really give much power.

    Yes, steadying with the ability to extend range and be able to get home if the engine dies. I am planning for a new Beta driveline. Being a former pilot, I like redundancy.

    I would not rig this boat anything like the Beuhler, which has radically different weight proportions. Also, loose footed sails like that rarely stabilize the boat when you're off the wind: rather the vortexes over luff and leech induce wobble.

    I understand that and wondered how a lose luff and foot would work.

    I'd be inclined to look to a rig that's more like a steadying sail, mast rising from the cockpit sole and braced against the aft end of the house. This makes for a mast that can hoist things as well as hold up a proper flat cut steadying sail.

    That's my origianl plan. At first the mast was going to be just big enough to lift the dink on to the cabin roof cradle for long passages, rough weather, and storage. I have plans for a light weight pram that can take a small 2.5-5hp outboard. Going based on stated weights plus a little extra added for insurance, 250lbs max.

    Given you Loop ambitions, hinging the mast step on the cockpit deck will make for easy striking and the mast should be light enough that you can then get it atop the house.

    My plan has been to use a hand operated winch to lower the mast forward into a cradle lashed on deck or prehaps a removable one that has a quick release deck mount.

    Three stays: The shrouds with a bit of follow (athwartships line between chainplates abaft the mast) and a low slope head stay to the stem. It might or might not be worth the cost to hang an ultra low aspect sail from that headstay. Hard to cut and will only really work going to weather.
    We think alike on the stays. I knew any head sail would be very small and only useable in a favorable wind direction.

    You'll need to consult an NA to be sure you don't make the thing too big for the boat's stability and you engineer the mast as light as is safe.

    Good advice. I'm currently looking at options in aluminum. Possibly a used sailboat mast and pole cut down and polished up.

    G'luck
    Thanks Ian. You're always a great help.
    This sig line is proudly provided by The Wooden Boat Magazine Forum. If it ain't The Wooden Boat Mag, it just a rag.

  5. #5
    Join Date
    Nov 2008
    Location
    Upstate, SC USA
    Posts
    1,451

    Default Re: Sail design.

    Quote Originally Posted by mohsart View Post
    For steadying/emergency you don't need a very large sail, 3 square meters will do I think.
    Mast and rigging depends on sail size.

    /Mats
    From the research I have done thus far, you're right on. 3 sq. meters would be roughly 11 square feet if I'm remembering my conversions right. Steadying sail is a breeze. I was hoping to utilize the mast for a little extra umph and to get to shore in an emergency. lol
    This sig line is proudly provided by The Wooden Boat Magazine Forum. If it ain't The Wooden Boat Mag, it just a rag.

  6. #6
    Join Date
    Mar 2014
    Location
    Ronneby, Blekinge, Sweden
    Posts
    785

    Default Re: Sail design.

    Quote Originally Posted by ben2go View Post
    [...]I was hoping to utilize the mast for a little extra umph and to get to shore in an emergency. lol
    Sure. But I doubt you'll be able to go higher than 90 degrees against the wind with that hull and that kind of sail. For off-wind a tiny sail will work, it will only take a little more time.

    /Mats

    Elected Swedish Yourneyman of the Year 2019

  7. #7
    Join Date
    Nov 2008
    Location
    Upstate, SC USA
    Posts
    1,451

    Default Re: Sail design.

    Quote Originally Posted by mohsart View Post
    Sure. But I doubt you'll be able to go higher than 90 degrees against the wind with that hull and that kind of sail. For off-wind a tiny sail will work, it will only take a little more time.

    /Mats

    I'll have to catch the wind on a broad reach.
    This sig line is proudly provided by The Wooden Boat Magazine Forum. If it ain't The Wooden Boat Mag, it just a rag.

  8. #8
    Join Date
    Apr 1999
    Location
    Hyannis, MA, USA
    Posts
    47,392

    Default Re: Sail design.

    3 square meters is about 32.3 square feet.

  9. #9
    Join Date
    Nov 2008
    Location
    Upstate, SC USA
    Posts
    1,451

    Default Re: Sail design.

    Quote Originally Posted by Ian McColgin View Post
    3 square meters is about 32.3 square feet.
    Quite right. I didn't multiply properly.
    This sig line is proudly provided by The Wooden Boat Magazine Forum. If it ain't The Wooden Boat Mag, it just a rag.

  10. #10
    Join Date
    Mar 2014
    Location
    Ronneby, Blekinge, Sweden
    Posts
    785

    Default Re: Sail design.

    The thing is, you may need a sail area of perhaps one square meter to stabilize the boat.
    But a bit more sail will let you steer away from some rocks more easily.
    You still won't be able to sail against the wind, if that's your wish install side swords.

    /Mats

    Elected Swedish Yourneyman of the Year 2019

  11. #11
    Join Date
    Nov 2008
    Location
    Upstate, SC USA
    Posts
    1,451

    Default Re: Sail design.

    Quote Originally Posted by mohsart View Post
    The thing is, you may need a sail area of perhaps one square meter to stabilize the boat.
    But a bit more sail will let you steer away from some rocks more easily.
    You still won't be able to sail against the wind, if that's your wish install side swords.

    /Mats
    Yes, it would be nice to have sails to help in the event of an engine out event to get to a safe anchorage or limp home. I never expected to sail to windward.
    This sig line is proudly provided by The Wooden Boat Magazine Forum. If it ain't The Wooden Boat Mag, it just a rag.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •