Building a leeboard on my 16ft sailing dinghy

Discussion in 'Sailboats' started by Konstantinos Ampatzidis, Jan 18, 2020 at 9:52 AM.

  1. Konstantinos Ampatzidis
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    Location: HELLAS

    Konstantinos Ampatzidis Junior Member

    Greetings to the great FORUM!
    I have build a 16ft sail dinghy with a daggerboard. The method was stitch and glue with plywood, fiberglass, and epoxy. The alum mast is a 470 international mast. Total sail area about 18sq.m. Hull weight about 400 kg. My dinghy has a DAGGERBOARD. I am a starter on sailing and I am not interested in performances.
    Additionally, I have discovered that now I need a small cabin on it, for making better coastal vacations during the Hellas hot summertime.
    In order to have the most appropriate space inside the small cabin, I am near to change the Daggerboard and to make a LEEBOARD out of the Portside (one side first). Regarding the higher CENTER OF GRAVITY ( because of the small cabin ), I plan to add some permanent lead ballast on the hull.
    The Leeboard will be strong laminate plywood with fiberglass and epoxy. I am planning also to have the solution to add on the edge (throw some holes and inox bolts ) some additional weight (steel or lead planks). So the LEEBOARD not only will give its surface (as a wing) but also will add the appropriate ballast under the sea surface.
    After the above, I would like to ask some friends to give me their respectful opinions.
     
  2. messabout
    Joined: Jan 2006
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    messabout Senior Member

    Your 16 foot boat, at 400 kilograms, is already far heavier than a boat of that size needs to be. Adding ballast will diminish performance even more. You do have a lot of sail for such a small boat so that will help overcome the disadvantage of excessive weight.

    Lee boards are workable but inefficient when compared to dagger board or centerboard. The single lee board will be even less efficient when on Port tack if the boat is heeled to some degree. In addition, adding weight to the lee board will unbalance the boat to some extent, depending on how much weight you have added.
    The boat will work better if you leave the dagger board in its assigned location. Beginning sailors have enough trouble while perfecting their sailing technique. Modifying the boat so that it behaves in a different manner will make the learning process even more problematic.

    Post a picture of the boat if you can.
     
  3. Konstantinos Ampatzidis
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    Konstantinos Ampatzidis Junior Member

    I would like to thank you for your advice. You can see my boat
     

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  4. gggGuest
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    gggGuest ...

    If you are determined to try a leeboard then I think you'd be well advised to rig up something, preferably without making too many holes in your nice craft, that would enable you to see how well it works before you do anything to the daggerboard case. It would be most depressing to do a shed load of work and then find the boat will hardly tack or some other issue.
     
  5. Konstantinos Ampatzidis
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    Konstantinos Ampatzidis Junior Member

    Thank you. For the Leeboard it will need one hole Φ40mm (at the upper seer of the Portside ) in order to pass its axle. It is a good idea to be tested it first and if all works well after to cut the Daggerboard box Inked19 JAN 20_LI 2.jpg
     
  6. alan craig
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    alan craig Senior Member

    Nice looking boat. May I suggest that you rig a tent over the boom instead of a cabin, to give protection when camping. Then add a removable flat board which joins the two seats to make a large sleeping area.
    A leeboard needs to be protected from moving in the wrong direction (to windward, or when used on the "wrong" tack) or it will rip out leaving a hole in your boat.
     
  7. Konstantinos Ampatzidis
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    Konstantinos Ampatzidis Junior Member

    Thank you. Your advice inclouds the practical use of both the budget and simplicity. The tent is a good solution for the hot summer, indeed. Thanks.
     
  8. Squidly-Diddly
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    Squidly-Diddly Senior Member

    Try to make the leeboards do double-duty as multi-purpose plank. On one hand you will be told how to make the most optimized size and shape of leeboard, which will then be only able to be used as a leeboard.

    However, IMO there is no perfect size and shape of leeboard, because conditions will always be changing, so no point in chasing that ideal. Instead, figure out a plank(s) that could serve as "removable flat board which joins the two seats to make a large sleeping area." and maybe a few other uses such as gangplank for landing on muddy shores, two-tier cargo carrying (to keep stuff off the bottom of boat and dry) and dining table .

    Also, make a combo tent/spare sail. Sounds like your main issue is hot sun, so you just need a shade tarp.
     
  9. Konstantinos Ampatzidis
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    Konstantinos Ampatzidis Junior Member

    Thank you. Yes, the main problem is the strong summer sun! An appropriate tent is the first priority! A cabin seems to be useful in the northern climate and finally in winter days, which is not an option for my way of living. [ Winter for me means mountain endeavors.]
    For the sleeping way, a portable multi-functional laminated plank sounds a good idea!
    Regarding the use - the technics and the construction of leeboard, I am studying the Holland and German classic boats (small and medium), also the homemade Texas small wooden boats which are participated in the annual Texas 200 Race, and many of them use leeboards.
    Thank you again for your advice!
     

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  10. Zilver
    Joined: Nov 2007
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    Zilver Junior Member

    Hello Konstantinos,

    The Dutch boats you show all have double, asymetric leeboards that are not restrained to float sideways up when they're at the luff side of the boat. I think the "texas" way is more appropriate for your purpose. Jim Michalak is the designer of most of these crafts, and he is clearly inspired by Bolger. Googling both their boat will probably give the best ideas. If you opt for the tent instead of cabin, I think there will be no need for a leeboard. BTW your boat looks good ! Cheers, Hans
     
  11. messabout
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    messabout Senior Member

    You little boat is nice looking and appears to be well constructed. I can not imagine that it weighs as much as your original post stated, unless made of steel. It does appear to have an unusually large amount of chine rocker, which implies that it is a heavy boat.

    The tiller could be made a bit shorter and have a hiking stick attached. That would allow you to move about in the boat while under sail. Aside from that, I can see no need to change anything.
     
  12. gggGuest
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    gggGuest ...

    Yes, don't underestimate the loads on the leeboard, as a rule of thumb assume they are pretty much exactly equal to the loads on the rig.
     
  13. Konstantinos Ampatzidis
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    Konstantinos Ampatzidis Junior Member

    Hello Hans.
    Thank you. As I have studied the Duch boats have a flat bottom hull IOT float into swallow channels.
    They use the Leeboards as a perfect solution to win the total space inside their boats.
    The design of their boats was a multi-use one.
    The most useful was the transferring cargo inside the channels.
    The double asymmetric leeboards were designed to give the perfect use of their boats in the environment of the channels.
    On the other hand, the coastal sailing needs have given the leeboards that are designed by Bolger Googlingof and many other naval designers.
    A new small sailing boat designer is also, as you mentioned, Jim Michalak. He use leeboards and is near my plans. After all, I can say: a. I need the most space into my small dinghy.
    b. I need weather protection, IOT use my dinghy more than
    Summertime.
    So I need a small cabin (sleeping for 2 plus porta-potty and stove) to make.
    c. I need to make double leeboards. [ I am not interested in sailing performances. I need only cruising]
    d. Maybe use of ballast to lower the Center of Gravity.
    e. After the cabin construction, the cockpit seats will be for 4 persons.(not for 8 as it is now).
    Finally, someone will be asked why I didn't build all the above from the beginning. The answer is that I had limited knowledge of the boats; and my environment convinced me that this boat will be what I needed! Something which does not exist now. I have learned my boat and I need more things, but there is no money to buy a bigger one !!!
    The Final and the Best idea is that boat construction gives me Action and Positive Psychology!
    Thank you indeed!
    Also, I would like to thank all the boaters that answered my questions!
     
  14. Konstantinos Ampatzidis
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    Konstantinos Ampatzidis Junior Member

    Thank you. That photos are taken in 2014. I have made the hiking stick but is not necessary because I will make the tiller shortest relating to the cabin size.
    Regarding the weight, I have used: a lot of wood inside the bow, more woven fiberglass and epoxy for the inside shole hull and as you said a large amount of chine! Overestimation of a starter builder!
     

  15. Zilver
    Joined: Nov 2007
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    Zilver Junior Member

    I mentioned Michalak and Bolger because I thought that you were planning on using a single leeboard for simplicity's sake.
    The Dutch flat bottom boats are also for sailing on the sea. You can see on the pictures that the small boats (Tjotters) have big low aspect leeboards, suitable for shallow creecks and lakes, and the big ones (Lemsteraken) have long high aspect "sea type" boards for better efficiency in deep enough water. Hans
     
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