Pocket cruising boats

Discussion in 'Sailboats' started by Guillermo, Apr 30, 2006.

  1. gilberj
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    gilberj Junior Member

    That's fine.... this is about pocket cruisers and the Meadowlark is not commercially bring built. At 8000 lb design disp she still qualifies as small.
    Have you looked at the Presto 30?
     
  2. Guillermo
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    Guillermo Ingeniero Naval

    Thanks, gilberj. Presto 30 is a nice boat, but I am looking specifically for boats under 8 m (26' 3") designed to fulfill RCD Categories A or B (most of them are probably designed/built after 1998).
     
  3. Guillermo
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    Guillermo Ingeniero Naval

  4. Guillermo
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    Guillermo Ingeniero Naval

  5. Angélique
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    Angélique aka Angel (only by name)

    Designer: Arend Lambrechtsen ---> Wadkrabber - ( all links are in Dutch, perhaps you can read it through a translator ? )

    Builder: Nijman Jachtbouw, but their website is offline since a few years, so it looks they're out of business.

    Far as I know only one Wadkrabber was built in ± 2004, in B category, which is now for sale here, perhaps the plans can still be ordered from the designer.

    -- click pics to enlarge --
    wadkr5.jpg wadkr1.jpg wadkrabber-4.jpg wadkrabber-1.jpg wadkrabber-5.jpg

    --- some of the pics were to big for uploading --- 1 --- 2 --- 3 ---

    Some specs: L 8.00 m, B 2.45 m, D 0.36 m / 1.68 m, sail area approx 31 m², empty weight approx 1,900 kg, 13 Hp inboard diesel.

    What I remember from the website of the builder is that she can be built as B or C category. The B category has a lead ballasted centerboard, in some NACA shape, which is operated by a hydraulic cylinder and hand pump, if I remember well. The C category has the ballast on the bottom of the boat and the centerboard can do without the hydraulics, again if I remember well.

    My thinking hereby is that between the two versions there's no or not much height difference in the position of the ballast when the board is up. So I don't understand why the version with the ballast in the board gets a higher category. When lying ahull I would have the board up, so both versions would act the same in this situation I think.

    Of course the version with the ballast in the board can sail with a bit more cloth up, but is this enough to move from C to B category . . ? ?
     
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  6. Guillermo
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    Guillermo Ingeniero Naval

    Thanks, Angélique, nice to enjoy again your always helpful posts. :)

    One of the B category requirements at ISO 12217-2:2013 is having a minimum rigthing energy > 54000 kg.m.deg which implies the needing of both a high area under the positive zone of the GZ curve as well as a high displacement in the Minimum Operating Condition. (Well, or one of them very high if the other is not so high, of course)

    Difficult to achieve for a boat under 8 m with an unballasted board and that's probably why the Wadkrabber needs a ballasted board to reach Category B.

    And that's why I am somewhat surprised about the Whisstock design number 123, mentioned in my post #161 of this thread, being able to reach Category B. I would love to hear from the designer.
     
    Last edited: Sep 5, 2015
  7. Angélique
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    Angélique aka Angel (only by name)

    Thanks for the Wadkrabber B vs C category explanation Guillermo [​IMG]

    On his Wadkrabber page the designer doesn't mention the design category and only speaks about the version with the ballast inside on the bottom.

    I'll try to translate the below Dutch quote which is about the ballast (only 300 kg) and the righting moment . . .
    Below my translation in a attempt to do better than the automatic translator which couldn't cope with the jargon . . .
     
  8. Angélique
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    Angélique aka Angel (only by name)

    The Whisstock design #123 page you linked in post #161 contains a lot of kinda hidden inline links to extra info, some of those links are underlined and some are not and are just plain text which is only changing color when moving the cursor over the text, and some of the linked info pages contain the same kinda hidden inline links to more info, and so on...

    Did you see this one ? - Design 123 – Design Data
     
    Last edited: Sep 7, 2015
  9. Guillermo
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    Guillermo Ingeniero Naval

    Thanks for the link.
    With that stability curve, asuming it corresponds with the displacement of 1452 kg at the designed waterline, the area under the positive zone is around 32.5 m.deg and so the energy would be 47,196 kg.m.deg, not enough to reach category B, although not that far away from 54000.

    Of course numbers should be properly worked for the right MOC displacement and the stability curve in that condition, but it serves as a clue.
     

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  10. philSweet
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    philSweet Senior Member

    Not sure if American stuff is of any interest to you, but Seaward Yachts used to make a very nice 24'er, but seems to have discontinued it. It was one of the better pocket cruisers I have seen.

    http://sailboatdata.com/viewrecord.asp?class_id=7600

    Currently, the smallest they seem to offer is 26R which has a Length Over Everything of about 28', LWL 24'8". Which is no longer what I would call a Pocket. It is, however, a thoroughly modern small design.

    http://www.seawardyachts.com/26rk/
     
  11. RHP
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    RHP Senior Member

    The Seaward 24 is indeed a very nice yacht and 24' is a great size for a pocket cruiser. Personally anything smaller in my opinion is too small.

    There are lots of great, cheap, secondhand yachts out there including my own yacht, now 40 years old, the Achilles 24.

    Overall length 23 ft 9 ins (7.24m)
    Waterline length 19 ft 6 ins (5.94m)
    Beam 7 ft 1 ins (2.14m)
    Draught fin keel 3 ft 9 ins (1.14m)
    Draught triple keel 3 ft 3 ins (1 m)
    Hull GRP
    Deck GRP balsawood sandwich
    Displacement 2600lbs (1180kg)
    Ballast 1314lbs (596kg) iron bulb
    Sail area 206 sq ft (19.15 sq m)
    Accommodation 4 berths
    Headroom 4 ft 6 ins (1.37m)

    Layout
    http://farm4.static.flickr.com/3557/3488935110_7b7859f0cb_o.gif
     
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  12. Guillermo
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    Guillermo Ingeniero Naval

    Thank you, philSweet and RHP.
    I know there are excellent and seaworthy sailboats under 8 m with no RCD categorization, able to ocean crossings as many of them have proved once and again, but I am interested specifically in small boats categorized as "B" or "A" under the European Recreational Craft Directive, be them built in Europe, the USA or wherever. As the Directive entered in force in 1998, most probably most of such boats are designed/built after that year.
     
  13. RHP
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    RHP Senior Member

    Guilty as charged Guillermo, I had a rush of blood to the head and forgot the RCD requirement!
     
  14. Guillermo
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    Guillermo Ingeniero Naval

    No problem :)
    Thanks anyway.
     

  15. Angélique
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    Angélique aka Angel (only by name)

    There are several accommodation layouts, the max number of crew accommodation is the four-berth layout, so I guess ‘‘full load displacement’’ (see the small print above the stability curve) means the calculations were done for 4 crew members plus their gear and supplies aboard, which could mean she's heavier there than the 1452 kg at DWL as DWL weight could be something between light ship and full load displacement.

    Don't know what the extra crew weight plus gear and supplies means for the stability curve and the EU RCD categorization, as I don't know at which position in the boat this extra weight has to be placed in the calculations . . . :confused:
     
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