Results 1 to 10 of 23

Thread: 4-sided sails on Raid sailboat

Hybrid View

Previous Post Previous Post   Next Post Next Post
  1. #1
    Join Date
    Jul 2016
    Location
    Bodfish, CA
    Posts
    436

    Default 4-sided sails on Raid sailboat

    Who knows how to setup and trim 4 sided sails for speed, efficiency, pointing ability?

    Clint Chase Deer Isle Koster (KDI is preferred over DIK).
    14 feet, about 250 pounds with gear, and about 100sf sail area. CNC kit with some early design details that were changed such as kick up control of rudder.

    The KDI gets picked up next week and goes immediately to Pocket Yachters Palooza in Port Townsend. The three day cruise that follows is tentative, unknown sailboat, never sailed in area, and not sure about sleeping on board, also tweaked my back while changing brake rotors on truck.

    But , other day sails on way back are under consideration, such as Humboldt Lagoon(s) and maybe coastal rivers to inland.

    Ants
    Name:  1031EB96-76D6-40FE-9C88-E2ACEBCC50BB.jpeg
Views: 812
Size:  3.91 MB



    Name:  7D7257C7-51F8-453A-A412-DD3285D2C916.jpeg
Views: 851
Size:  4.56 MB
    Last edited by AntsUiga; 07-10-2021 at 04:01 PM.

  2. #2
    Join Date
    Sep 2007
    Location
    San Francisco Bay Area
    Posts
    2,095

    Default

    I "watched" the development of the Deer Isle Koster on the Wooden Boat forum, it's a gorgeous boat and a wonderful camp-cruiser.

    About balanced lug sail trim...low stretch halyards are your friend. If the downhaul on the front of the boom is not 2:1 already, make it so. 3:1 ....mmmmm. Maybe. 4:1 is probably too much. However, you want that leading edge nice 'n tight. The most common balanced lugsail oopsie looks like this.

    Name:  picpenobscot14105f.jpg
Views: 606
Size:  85.2 KB

    See the big crease from the back of the boom up forward to the front of the yard? If you get that, try two things...1.) easing off on the boom downhaul and then topping up the yard harder and then...2.) tightening down on the boom downhaul.

    you have a little bit of this going on already in the photo you posted. You can also try making a change so the boom rides an inch or two further forward, relative to the mast.

    Wonderful boat!
    1968 Selmer Series 9 B-flat and A clarinets
    1962 Buesher "Aristocrat" tenor saxophone
    Piper One Design 24, Hull #35; "Alpha"

  3. #3
    Join Date
    Sep 2007
    Location
    San Francisco Bay Area
    Posts
    2,095

    Default

    I'm still hoping that an SSS "raid" - small boat cruise is in the works for someday. It would be fun to see your Koster out with RoG
    1968 Selmer Series 9 B-flat and A clarinets
    1962 Buesher "Aristocrat" tenor saxophone
    Piper One Design 24, Hull #35; "Alpha"

  4. #4
    Join Date
    Jul 2016
    Location
    Bodfish, CA
    Posts
    436

    Default

    Any interest for the next SSS Raid is always good!

    I have one on the calendar with TSCA on Tomales Bay in September.

    I have been searching for useful ways to improve sail trim. The search has not yielded an overabundance of good information. In general, the sail attachments are not fixed, or are open to many variables. The sail is fixed on the tack of the boom, but the location of the boom relative to the mast can move up or down, forward or aft. Simple - Yes, but subject to lots of options.

    On this boat, there is a fixed fairlead and hook on the yard with a ring to hold yard close to the mast. As for your suggesting to move the yard side of sail, there is a limit (1-3 inches) by adjusting the lashing. If that does not work, the attached fairlead get screwed to another location.

    Ants

    Name:  5BEDC336-1DEF-46EE-A03B-308A4EBC27F3.jpeg
Views: 772
Size:  3.62 MB

  5. #5
    Join Date
    Sep 2008
    Location
    SF Bay Area
    Posts
    380

    Default

    Ants,
    Alan suggested: “You can also try making a change so the boom rides an inch or two further forward, relative to the mast.” Wouldn’t moving the yard aft do the same?

    I
    t looks like the eye plate on the yard was moved aft at some time. Which moved the yard forward. If it went back to the original position would that help? Maybe the attachment point on the yard needs to be adjustable? Or you could try using a lashing temporarily to find the right attachment point.
    Name:  81D05C6F-8A57-474F-AE91-E538FE382BC5.jpeg
Views: 670
Size:  753.6 KB
    Last edited by Dazzler; 07-11-2021 at 10:46 AM. Reason: Added italicized sentence for clarity.
    Tom P.

  6. #6
    Join Date
    Jul 2016
    Location
    Bodfish, CA
    Posts
    436

    Default

    Both excellent suggestion from Alan and Tom.

    My concerns are based on a set of photos without seeing the boat in person. It would be nice to have a general plan when I can move and adjust things.

    Step 1 would be to unlash sail from everything, support it on 4 corners and see what shape gravity gives the sail. How full is the luff? What happens when tension is applied to each corner? All this confirm how well the sailmaker did their craft.

    Step 2 may be to add yard and boom and see how that impacts horizontal sail shape.

    Step 3 would be to use lashings to move checkout to mast. Then the fore and aft attachment point to yard and boom can get scrutiny.

    Step 4 would to take best lashing points and go sailing.

    Then, the set of reef points need to be tested.

    When all seems good, time to go with permanent attachments instead of lashings. There is an abundance of loose blocks, cleats, and multi-part purchases to play with.

    If the hard on the wind performance still seems to suffer, a jib on a furler is an option that should help.

    Just because it is an option, there is also a spinnaker cut to Sabot dinghy size to play with.

    Ants

Posting Permissions

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