Dix Radius Chine Designs

Discussion in 'Boat Design' started by bjl_sailor, Jun 10, 2004.

  1. bjl_sailor
    Joined: May 2004
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    bjl_sailor Junior Member

    Hi All:
    www.dixdesign
    I'm wondering if thre are folks out there who have actually seen any of Dudley Dix's designs that are part of his DIDI series. These are 'radius chine' plywood boats. I am very intrigued by their design and layout. Very modern and light with modern underbodys. yet they promise easy construction and roomy below decks spaces that can be pretty well customised in terms of fit and finish... My concern though is also their compelling feature. They are designed such that most of the hull is sheathed with regular plywood sheets in large flat nearly whole sheet expanses. The only part that is cold molded are the bilge chines. The photos and drawings I've seen portray a very smooth curvey modern hull but in 'real life' do the large flat expanses make the craft look slab sided and boxy? Without actually seeing one in person I can only wonder...

    http://www.dixdesign.com/didi40cr.htm
    http://www.dixdesign.com/radply.htm



    On another note, as I contemplate construction of a larger cruising boat is his recommendation NOT to sheath the exterior of his radius chine designs in glass but to merely impregnate it with epoxy. My feeling despite the weight cost is that it would be amuch need requirement for durabilty-- And how much would laminating and layering a 40 ft boat cost both in terms of weight and money/time?
     
  2. Suede
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    Suede Junior Member

    Crusin´ in a box....

    Hi Bjl,

    I don´t think you have to worry, even if it starts almost a full ply panel it´s only about 2 ft midships and 1 ft aft...and the radius is almost 3 ft at mid.
    You see it on this link
    http://www.dixdesign.com/toft.htm
    (it´s the wide stringers that is the radius part).
    Most DIY´s of biger Dix-boats seems to glass their hulls, for extra safety and easy maintenace. Even an extra 1/4-ply is often added.

    I think I used about 0,5 kg epoxy per sq meter (appr. 1 pund for 10 sq ft I think) for coating, wetting out and filling with a 6 oz glass. Cost was appr the same as for a layer of 1/2 ply.

    rgds
    Olle
     
  3. mike1
    Joined: May 2004
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    mike1 Junior Member

    Bjl,
    I knew Dudley he used to live in the same area as I do , He's a very down to earth Yachty guy and very approachable.
    I have spoken to a freind who sell kits for Dudley's design's he aslo has a home built dix. he says that most folks dont even know that his boat never came out of a mold. but of course any chine boat could be seen as slab sided.
    he also questioned the no glass with Dudley who insisted that it was not necessary.
    why not email Dudley and ask him.
    Dudley has now imigrated to the USA.
    Mike
     
  4. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    The curved turn of the bilge on these designs really "fools" the eye into thinking it's a round bilge boat, though the experienced eye catches it rather quickly. Most folks don't have this ability and the vast majority of your friends wouldn't have a clue.
     
  5. bjl_sailor
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    bjl_sailor Junior Member

    Didi Radius Chine

    Thanks for the feedback all. I've ordered the study plans for Mr. Dix's Didi 40CR and am going to take a good hard look at it - I haven't seen anything else quite like it in terms of construction and layout. I'll probally even go so far as to make a 1/4" -1' scale (40") balsa wood model carboned off the plans before building. The only thing I'm not crazy about is tiller steering on a 40' boat. However the light displacement allows this -- saving a bundle in cost and complexity and giving it what I woiuld suspect is a sport boaty feel. The Didi 40 CR doesn't appear to be a trade winds boat so much as something that will weekend and vaca on the NewEngland Coast quite well. I'll have sprightly volumous weekend "condo" that can do the Newport to Marion Race. However her shallow bilges and light displacement wouldn't make her my first choice for long distance trades cruising.

    Building it light will be another challenge. I've already discussed this with Dudley and keeping it light is key. Interior fit out will be closer to an austere J Boat rather than a sumptuous Cabo Rico or Cheoy Lee.

    These are all design and implementation choices that I can live with. Do any of you know of any other simular design concept out there?

    cheers
    bjl
     
  6. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Don't knock the tiller on larger hulls. If the hull and rig are well balanced you'll not find a better, more responsive nor simpler setup. I've got one on the 50'er I'm building, though there is covered wheel steering in the pilot house.
     
  7. MURRAY HOOPER
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    MURRAY HOOPER New Member

    U S sailing yachts

    I am new to this site and find it very interesting.With all the boat smart people out there , I hope someone will know about a centerboard 22-24' sailboat built by United sailing Yachts?
     
  8. SeaDrive
    Joined: Feb 2004
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    SeaDrive Senior Member

    I follow the discussion of several sites related to amateur boatbuilding, mostly plywood boats. The consensus is that a light glass sheathing is very instrumental in keeping the ply from checking. The importance varies some with the kind of wood in the ply. For some, e.g. fir, it is essential: epoxy without glass will not control checking.

    I had one boat built with fir marine ply, epoxy coated without glass. The flat sides and bottom (it was a Bolger box) did not check, but the arched cabin top checked a lot.
     
  9. bjl_sailor
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    bjl_sailor Junior Member

    The Didi40 CR is based on his DIX38 -- which is a very performance oriented boat. The scantlings in that design call for 12mm (1/2") okoume ply sheathing with resin coating ecncapsulation and no glass. For the 40 CR, basically a stretched cruising model with a redesigned interior, the option is presented to increase the sheathing thickness to 16 mm with a 4mm additional layer of ply in addition to the first 12mm -- I'm think I might do something 'in between' -- but I'm planning on finishing the top sides with one 12mm sheathing and then follow up with 1/8" x 8" wide thick mahag veneer 'planked' on the boat where it shows (1/8" okoume where it don't)and then sheathed in 7 OZ cloth and finished clear. Alot more work,weight and cost but a nice way to finish and strengthen the hull... hopefully not exceeding the weight limits to keep her sprightly...
     
  10. Suede
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    Suede Junior Member

    Two things to bear in mind with epoxy is...it doesn´t like UV´s....and it doesn´t like heat. So a clear coat has to be kept protected with an UV-resistant cover that means more maintenace. For heat, most peaople recomend to avoid dark coulors if you plan to cruise in very hot and sunny areas.
    Maybe you can put your final veneers on top of the glass and just varnish the outside the normal way.
    I´m sure a 40´mahogany will look cool.....

    rgds
    Olle
     
  11. henrikb
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    henrikb Senior Member

    Olle!

    I have admired your boat at Dix site for some time now, would be very interesting so see some more pictures!!

    Always nice to see some other "backyard boatbuilders" here in Sweden!

    Hälsningar!

    /Henrik Borg
     

  12. Kwiksilver
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    Kwiksilver New Member

    Hi guys,
    I`ve sailed close to the Didi 38 "Black Cat" that I believe won it`s class in the Cape to Rio a few years ago. The boat seems to have a lot of freeboard, probably due to the flat-sided appearance, or could be high in the water when at min. load. I believe it`s a very light boat for it`s size - the advantage of plywood construction.
    Dudley is an experienced yacht designer - I`d trust his judgement on the subject of sheathing in glass or not. I`ve also chatted to him over e-mail - very helpful & approachable.

    Cheers
    Steve
     
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