Results 1 to 5 of 5

Thread: Tacking angles

  1. #1
    Join Date
    Aug 2009
    Location
    St. Augustine, FL
    Posts
    683

    Default Tacking angles

    I was asked to put up some info on tacking angles for the MC41 and compare it to the MC 30.

    Sorry that I can't compare since I haven't sailed the 30, but here is a post I put up on the Maine Cat Yahoo Group.

    After 4+ years here are our results.

    We typically tack through 120 degrees over the ground.

    In general, we try and sail in the low 40s AWA depending on wind/wave conditions. In higher winds and protected waters we will go as high as perhaps 37 AWA, but still find our tacks to be 100 - 110 degrees over the ground.

    Note that we are not terribly aggressive with our use of the daggerboards. It seems that lowering them does not bring us closer to the wind, but does seem to decrease the weather helm creating less rudder drag and maybe a bit more speed.


    Fair Winds,
    Mike & Susan
    s/v TabbyCat
    currently in Martinique

  2. #2
    TYRNTLZRDKING Guest

    Default Re: Tacking angles

    Dumb simple question.
    Can your daggerboard be put down half way?
    I thought I read somewhere the MC30 board floated, so you needed to release it and let it drop quickly to let it lock down to the bottom?

  3. #3
    Join Date
    Aug 2009
    Location
    St. Augustine, FL
    Posts
    683

    Default Re: Tacking angles

    Jeff,

    We can position the boards to give us up to 7' draft and anywhere in between. They have a downhaul and uphaul for depth control. Yes, they float, but underway the pressure on the board in the trunk requires a bit more mechanical advantage.

    Most of the time we have them @ 3 feet which makes them 6 inches lower than the rudders; kind of an early warning system. When beating to windward with lots of weather helm, we will lower a board to 4 - 5 feet, depending on the waves and frequency. At anchor, we raise the boards completely to eliminate the noise of the boards banging in the daggerboard trunks.

    Early on, while sailing in 25+ on the Chesapeake Bay with a nasty short chop, we broke a board lowered to 7 feet. Since then, we have been a bit gunshy. It may have been a manufacturing defect, but we will never know for sure since most of the board snapped off and floated away. Dick V replaced it under warranty.

    Fair Winds,
    Mike
    Last edited by Yoga O; 24th January 2010 at 04:31 PM. Reason: clarity(?) and additional info

  4. #4
    Join Date
    Oct 2009
    Location
    on "Key of D" currently in Australia
    Posts
    86

    Default Re: Tacking angles

    Our boat is not an MC-40 so our experience will not equate 1 on 1 with yours but it should be close.

    When we lower our boards all the way instead of having them protrude a couple of feet below the hulls as you do our COG on the GPS improves by about 5 degrees and our speed increases by a few 10ths of a knot. Overall our VMG will improve by as much as 0.5 knots in a 15 knot breeze. We figure this is worth the effort.

    We have sailed upwind between 8,000 and 10,000 miles in the past eight years and never broken a board. MC has a good reputation for quality so I doubt you will find broken boards to be a problem.

    I hope this is useful information.

    Steve

  5. #5
    Join Date
    Oct 2009
    Location
    Friday Harbor, Wa
    Posts
    73

    Default Re: Tacking angles

    I usually sail with one board fully lowered and the other just down far enough to get the top of it flush with the deck. I don't sail with them both full down. It was detrimental to overall speed as near as I could tell.

    When in the Bahamas, just flush with the deck was standard for both boards all the time. I think that's about 4'-4.5' draft, about 2-2.5 feet below the hull.

    During the time I was having a custom job (since abandoned, for the MC) designed, I asked about the efficiency of a daggerboard vs mini-keel. From my not too technical comprehension, the difference was significant. It was so much that I gave up worrying about ever needing a full board or two boards down. One board at half depth will be equally as effective as two mini-keels with much less wetted surface and resistance.

    Someone with the numbers could probably tell me the actual relationship but for me, that was all I needed to know. Tacking angle always remained the same no matter what--it is the set of the sails to the wind. Leeway, however, was certainly improved with a full-down board.

Tags for this Thread

Posting Permissions

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