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FD long range cruiser from De Vries Lentsch

Discussion in 'General Yachting Discussion' started by Santelia, Sep 24, 2011.

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  1. Santelia, Sep 24, 2011
    #1
    Santelia

    Santelia Member

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    Hi all,
    among other choices I'm considering the purchase of an old 49' long range cruiser from De Vries Lentsch, full displacement steel hull with round stern, raised pilothouse and portoguese bridge. No upper sundeck neither flybridge at present, so also planning to add them.
    Anyone has experience on such vessels?
    Much roll and pitch witout stabilizers?
  2. AMG, Sep 24, 2011
    #2
    AMG

    AMG YF Moderator

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    Hi, hard to answer without knowing the boat, but if you add something on top, it will probably roll a lot...
  3. JWY, Sep 24, 2011
    #3
    JWY

    JWY Senior Member

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    Sounds like you're describing a Lowland. If so, great yacht, classic design, elegant cabinetry, beautiful aesthetics. Your additions will change the profile and appearance as well as the weight above water line.

    Judy
  4. Santelia, Sep 25, 2011
    #4
    Santelia

    Santelia Member

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  5. nilo, Sep 25, 2011
    #5
    nilo

    nilo Senior Member

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    being a canoe stern she will definitely pitch more than today's designs. i would second lars and will recommend that you should not consider to add an additional level; unless you do a very through engineering. i doubt you will be able to obtain the initial stability calculations; so it would not be an easy task!
  6. JWY, Sep 25, 2011
    #6
    JWY

    JWY Senior Member

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    No disagreement, Nilo, but I would like to add a clarification. There are modern canoe stern designs that do not pitch.

    Judy
  7. nilo, Sep 25, 2011
    #7
    nilo

    nilo Senior Member

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    underwater hull design

    of course judy; pitching is due to the underwater hull design of these old boats.
  8. Santelia, Sep 26, 2011
    #8
    Santelia

    Santelia Member

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    Hard to believe that adding a handrail and the light weight of a helmstation and a couple of settees can have a significant impact on stability. Nohing that cannot be easily corrected, for instance, by adding a small tank at bilge.

    As far as "old" canoe stern behaviour is concerned (never heard of "new" canoe stern), do you think that adding a large structural swimming platform at water level can decrease the pitch rate? Just to add a point, is well known that canoe stern is the best boat end to decrease turbolence in pure displacement water flow.
  9. K1W1, Sep 26, 2011
    #9
    K1W1

    K1W1 Senior Member

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    Hi,

    As whatever you are going to add to the top of the boat will be kind of permanent it might be cheaper and easier to add some fixed ballast low down.

    You will be best off to have someone competent do some calculations or you might well become a statistic like these guys did.

    The report makes some interesting reading in regard to the effects of multiple additions and alterations.

    http://www.uscg.mil/hq/cg5/docs/boards/amerialtair.pdf
  10. JWY, Sep 26, 2011
    #10
    JWY

    JWY Senior Member

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    Santella -- a naval architect or marine engineer can best answer your questions, but you have had professionals here all comment that the added weight on the upper deck will most likely affect stability. Perhaps you're right in that it doesn't "sound" like that much weight. So lay it out: take some stainless rails the length you will use, then take some wooden boxes the size of your seating, and helm, then take a scale and weigh out the electronics, controls, and gauges you would install. No bimini? Don't forget the miscellaneous like cushions, wiring, and six-packs. And then body weight - if you have Europeans that might only be another 250 lbs for 2, but if Americans, that can add on another 400 lbs before lunch.

    Canoe stern models such as Sea Spirit Passagemakers didn't just add a swim platform, they had an established naval architectural firm design an appropriate hull form. The Cheoy Lee 66 long-range cruiser was a canoe stern that was reformed as the Serenity 68 with more changes than just the addition of a swim platform with particular engineering to reduce the weight above waterline.

    I recommend professional help.

    Judy
  11. Santelia, Sep 26, 2011
    #11
    Santelia

    Santelia Member

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    All interesting replies and considerations.
    Surely I'm not going to add anything without a proper engineered project.
    Very interesting the report in the link too.
  12. JWY, Sep 26, 2011
    #12
    JWY

    JWY Senior Member

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    Please let us know if you proceed with this purchase and subsequent project. I know we would like to hear a happy ending and how you got there.

    Judy
  13. david_japp, Nov 10, 2011
    #13
    david_japp

    david_japp Senior Member

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    hi
    she will certainly roll without stabs but rolling is something you can get used to. stabs can be retro fitted as we have done to our 62ft 1961 Van lent built round-bilger ...what is the boat you are contemplating buying?
  14. NYCAP123, Nov 10, 2011
    #14
    NYCAP123

    NYCAP123 Senior Member

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    It looks like you're talking about a boat weighing 40-50,000 lbs. The conversion you're talking about could easily put 2,000 lbs. or more up top with your guests. That's significant. Roll stabilizers will certainly make cruising more comfortable, but I think adding ballast is most important. Should anything happen to the stabilizers you could be in real trouble. Definitely have a professional look at it.
  15. Wolf Hound, Jan 2, 2013
    #15
    Wolf Hound

    Wolf Hound New Member

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    Thank you, K1W1.

    The report you attached is well worth reading.

    The principles involved, although on a smaller scale (with consequently smaller margins for error) also apply to pleasure vessels.

    Many ignore stability calculations because of the complex mathematics involved--- it's easy for eyes to glaze over.

    There were many fairly straightforward rules of thumb used by 19th century shipmasters, of which one side of my family was largely comprised.

    The old sailing ships of course used moveable ballast, particularly when sailing light, of stones or pig iron or brickbats (or whatver was heavy and handy and cheap) so our circumstances are different, but perhaps applicable modifications of some of these old rules could be developed.

    I heard a few of these rules cited by a great uncle when I was a young boy, but I'm afraid they're now lost to my memory...

    Wolf Hound