Van de Stadt 36 Seal - JR conversion

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  • 17 Nov 2020 09:44
    Reply # 9369642 on 9338306

    Eero,

    As you may know, on a similar sized boat, Tystie, I went from 1 mast to 2 masts to 1 mast to 2 masts, over 15 years and 85,00 miles. After all that experience, I would venture to say that there isn't a single right answer, only a compromise that kind of works for you. I think that 55 sqm is as big as I would want to go in a single sail, unless that sail is either of maximum AR or is a SJR. Then up to 65 sqm becomes reasonable to handle, but really, the 80 sqm of Peregrine is way over the top for an offshore cruising boat, though it might be fun on short passages.

    So, if you go for a single sail, I would make it with as high an AR as the the boat will stand, and I think I see in your sketch 3 that you think the same. With that single sail, maybe you could put some forward rake on the mast, as was done on Fantail with the aim of not ruining the bed. 

    I like Graeme's suggestion of a SJR as well, but I think for this boat the sail should be of high AR, and would need 7 or 8 sheeted points, with upper and lower sheets. These are not nearly so bad to handle as port and starboard sheets on a schooner rig.

    I don't see a better form of schooner rig than the one that you've drawn. The sheeting looks tight for single sheets, but not completely impossible.

    On balance, I think I'd go for the single high AR sail in sketch 3 set on a mast with about 3˚ of forward rake, which should put it clear of the L shaped seat and water tank, leaving only the table to be rebuilt. On a practical, pragmatic level, the battens for this sail seem to be 6 metres long, which is sensible in terms of available materials and in manageability when rigging and repairing the sail.

    Last modified: 17 Nov 2020 10:52 | Anonymous member
  • 16 Nov 2020 21:31
    Reply # 9368674 on 9338306
    Anonymous member (Administrator)

    There is another possibility if you want a sloop rig with the mast a little further aft, and that is to consider a SJR, which typically has higher balance.

    Here is one of Slieve's SJR sails superimposed over Arne's Johanna sail, with the geomtric centre lines of the two sails in the same position.

    As you can see, this puts the mast centre line somewhat further aft.

    In the current "Featured Boat" you can read that Pete H. put an aerojunk rig on Blossom to solve an accommodation problem in much the same way.

    When placing a SJR sail plan, people have found that the geometric centre line of the SJR (near enough to a vertical line through the mid point of the boom) can coincide with the geometric centre line (through the so-called "centre of effort") of the original bermudan rig. This makes use of an assumption that the original bermudan rig is in the right place with regard to under water profile, rudder etc.

    The above drawing will be pretty close to that).


    I am not sure if this helps. Also not sure if a single sail as large as that is a practical proposition !) but if you want a sloop, it is another possibility to consider.

    In the current "Featured Boat" you can read that Pete H. put an aerojunk rig on Blossom to solve an accommodation problem in much the same way.
    Last modified: 17 Nov 2020 01:23 | Anonymous member (Administrator)
  • 16 Nov 2020 19:14
    Reply # 9368348 on 9338306

    Arne,

    first: sorry for this long radio silence. My work has kept me busy and I wanted to do my homework and try to find suitable places for the mast(s)

    Yes, you are right, it seems to be very difficult to fit the mast for a sloop version so that the lead is ok, but also not standing in the middle of my beloved bed. That is pity, I started to get fond of the sloop version because of its simpleness. Modifying the cabin layout leads to a major project which I try to avoid.

    The schooner version seems a bit easier with the masts, but there seems to be very little space between the sails leading to double sheets and that sounds like a mess. I want to go for simpleness and not to make complicated solutions. Therefore, the sloop version seems so tempting.

    When locating the CLR should I include the rudder? In this boat, with a big rudder it makes a difference as can be seen in the attached sketch. It bothers me that lead of the current version is more forward than the recommendation.

    Eero

    PS. I tried to upload a DXF version also, but the format seems not to be supported for upload.


    1 file
  • 02 Nov 2020 13:15
    Reply # 9340029 on 9338306
    Anonymous member (Administrator)

    Eero,

    just a quick note.

    Sail area:
    It was Sailboat Data which suggested about 79sqm, probably with Genoa 1 set. I would say that 63sqm puts your boat low in the motor-sailer class.
    I suggest you have a closer look at Peregrine in this rally report from 2010. She does well with that rig. http://goo.gl/KIOwkH

    The challenge is to build a strong enough mast, which does not add more than 2.5-3.0% weight to the boat. The sail may look big, but it can easily be reefed, so is much less fuss than a big Genoa, or a 2-masted JR..

    Mast position.
    It is difficult to avoid having a mast in the shown position. There  are two views on this around. One either simply cannot have a mast there, ore one decides to live with them, as I have done.

    Balance.
    After you showed the CE of the Bermuda rig, I have had another go and moved the sail further forward on the mast, without moving that. To get the halyard right, that is, just a little aft of the mast, I have lowered the yard from my ‘normal’ angle of 70°, down to 65°. This lets the sail sit with about 21% balance with respect to the mast.

    Cheers,
    Arne

    PS:
    My QCAD program cannot find the centre of area of any polygon, so now I have printed out the sail and found its CE ( or COA) the old-fashioned way. It turns out that it only sits a few millimetres forward of the middle of the boom, so that can be used when finding the lead.

    Last modified: 03 Nov 2020 18:16 | Anonymous member (Administrator)
  • 01 Nov 2020 21:27
    Reply # 9339059 on 9338306

    Unbelievable! Arne, you made a sketch in no time! That is really cool looking, bold and handsome design! 

    I have tried to make some sketches too. The starting point has been the present sails (roughly 63 m2) and their vertical center of effort. The sloop version version seems to interfere with the interior as the mast would stand in my nice king-size bed. The schooner version would be more gentle for the interior as I tried to keep the main mast at the present position and the forward mast would locate quite forward. This assuming that the sail area and the CLR -> CE lead should be kept roughly the same as before. 

    It seems that you propose quite large sail. But I can see that your own boat also seems to have a quite big sail. You don't see it a problem that the sail is almost 80 m2? 

    Location of the mast(s) is a bit headache to me. Easiest would of course be the present location. For another possibility I think it also could stand just aft of the main bulkhead. There is a water tank under the U-formed seat, but I think that could be moved.

    I have some pictures in an advertisement I made. Recently I have changed my mind about selling the boat, but the advertisement is still there

    1 file
  • 01 Nov 2020 15:00
    Reply # 9338595 on 9338306
    Anonymous member (Administrator)

    Eero,
    I think that Van de Stadt 36 would be awesome with a JR. I think that her big rudder will cope well with the sloop version, and make her and outstanding sailboat.


  • 01 Nov 2020 10:35
    Reply # 9338366 on 9338306

    hi david

    please don't put someone's email into a public forum!

    ueli

    [Now resolved, JRA Chair]

    Last modified: 01 Nov 2020 19:38 | Anonymous member (Administrator)
  • 01 Nov 2020 09:41
    Reply # 9338338 on 9338306

    It looks as if the two Seal 36 boats in the JRA register are both still with their original Bermudan rig. One is yours, Falcor, in Finland and the second is in Opua, Northland, New Zealand. She is called Ms Murphy and her owner can be found in the member's directory by searching the boat name. [Edited to remove email address by JRA Chair].

    Last modified: 01 Nov 2020 19:44 | Anonymous member (Administrator)
  • 01 Nov 2020 08:40
    Message # 9338306

    Hello!

    I am considering converting my Van de Stadt 36 Seal to a junk rig. Not decided though. I have recently joined the JRA and I have been browsing the site for (roughly) similar boats having junk rig. It seems that a sister ship with a junk rig exists:   https://junkrigassociation.org/Resources/Documents/JRA-Fact%20Sheet%205.pdf

    Does anyone know contact information to the owner? I would like to ask him/her for experiences.

    And of course, if someone could point me a close-to model, I would appreciate. Thanks.

    (https://sailboatdata.com/sailboat/seal-36




    Last modified: 01 Nov 2020 08:43 | Anonymous member
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