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modifying a Sangria to junkrig

  • 12 Jun 2025 13:50
    Quote
    Reply # 13509535 on 13487971
    Anonymous member (Administrator)

    Bonjour Jacques

    In terms of mecanical efforts, the more burry (height between the mast step and the stuck) the best. A rule of thumb is to have a bury of at least 10% of the mast height. 

    In your drawing,  the mast step is positionned quite high in regard to the bottom of the hull. 

    I would rather put it as low as possible. 

    There are at least two different options. One would be to cut the longitudinal plywood reenforcement to give way to the mast, the other would be to move the mast laterally a few centimeters to position the mast against the longitudinal reinforcement. It could even be possible to build the mast step as a tube (as on the laser) that would be glassed to both longitudinal and transversal reinforcement. 

    In this case, you would have at the lower part,against the hull, a few glassed layers of plywould to flatten the hull shape and provide a horizontal support to the mast. 

    Eric
  • 12 Jun 2025 07:48
    Quote
    Reply # 13509474 on 13509020
    Anonymous member
    Anonymous wrote:
    Jacques wrote:

    Arne,

    Some News :

    Mast : In september , I get back a street lamp in aluminium ( 10 m , diameter At the bottom  : 16 cm At the top : 10 cm )

    Questions :

    What thickness for mast floor ? 

    What thickness for " étambrai " (in french) : 60 mm 6 x 10 mm ?  for reinforcement deck ?  Omega ou Porque 

    PS : Bermudian Ring For sale  !!!

    Have a good day 

    Jacques


    Here is how I built the mast step on my Ingeborg. It may not be the quickest way, but it is quite straightforward. My main motive was to create the biggest possible glued area between the mast sole and the hull, to exclude any chance of it ever to come loose. I have used this method on 3-4 boats and they have all worked well.


    http://bit.ly/2sf2tsW


    Good luck!

    Arne

    Photos : Inside - stuck & mast step draft - How do you feel about this plan?


    3 files
  • 12 Jun 2025 07:07
    Quote
    Reply # 13509473 on 13509469
    Anonymous member
    Anonymous wrote:

    Jacques, can I ask you where you buy your lamp post ?

    From Mairie d'Arzon ( We don't discuss money , at present !!).
  • 12 Jun 2025 06:32
    Quote
    Reply # 13509469 on 13487971
    Anonymous member

    Jacques, can I ask you where you buy your lamp post ?
  • 11 Jun 2025 09:00
    Quote
    Reply # 13509020 on 13508582
    Anonymous member (Administrator)
    Jacques wrote:

    Arne,

    Some News :

    Mast : In september , I get back a street lamp in aluminium ( 10 m , diameter At the bottom  : 16 cm At the top : 10 cm )

    Questions :

    What thickness for mast floor ? 

    What thickness for " étambrai " (in french) : 60 mm 6 x 10 mm ?  for reinforcement deck ?  Omega ou Porque 

    PS : Bermudian Ring For sale  !!!

    Have a good day 

    Jacques


    Here is how I built the mast step on my Ingeborg. It may not be the quickest way, but it is quite straightforward. My main motive was to create the biggest possible glued area between the mast sole and the hull, to exclude any chance of it ever to come loose. I have used this method on 3-4 boats and they have all worked well.


    http://bit.ly/2sf2tsW


    Good luck!

    Arne
  • 10 Jun 2025 22:20
    Quote
    Reply # 13508870 on 13487971
    Anonymous member (Administrator)

    Eric writes: "The vertical effort is very low. The only effort is lateral..."


    Yes and no. I agree, Jaques' strengthening in that area is probably more than adequate - provided the mast is fixed firmly in position at the heel.

    Pitching in a seaway does create quite a lot of downward momentum to the mast. We had a famous case many years ago of David Lewis last voyage, in a junk rigged boat. He never got out of the Hauraki Gulf. The mast "jumped" out of the mast step, in a choppy sea - and then fairly quickly punched its way through the hull.  End of voyage. He was rescued.

    Last modified: 11 Jun 2025 05:16 | Anonymous member (Administrator)
  • 10 Jun 2025 20:50
    Quote
    Reply # 13508836 on 13487971
    Anonymous member (Administrator)

    Bonsoir

    Stuck is the english word for étambrai.

    I suppose that "mast flore" is for the "mast step". 

    The vertical effort is very low. The only effort is lateral. A few cm should be enough.

    Amicalement

    Eric

    Last modified: 10 Jun 2025 20:53 | Anonymous member (Administrator)
  • 10 Jun 2025 08:43
    Quote
    Reply # 13508582 on 13488558
    Anonymous member
    Anonymous wrote:

    Jacques,
    Now, in the hope that the mast position can be accepted, I have drawn  a taller sail, taken from The Johanna 60 series of master sails, with AR = 1.98 (instead of the previous 1.89).This is about the tallest sail I dare to suggest. In case you will do most of your sailing, crossing oceans, I suggest you go for the lower version.

    Arne


    (..full size diagram under Arne's Sketches, Section 8 - 36...)

    Arne,

    Some News :

    Mast : In september , I get back a street lamp in aluminium ( 10 m , diameter At the bottom  : 16 cm At the top : 10 cm )

    Questions :

    What thickness for mast floor ? 

    What thickness for " étambrai " (in french) : 60 mm 6 x 10 mm ?  for reinforcement deck ?  Omega ou Porque 

    PS : Bermudian Ring For sale  !!!

    Have a good day 

    Jacques
  • 22 Apr 2025 15:47
    Quote
    Reply # 13490462 on 13487971
    Anonymous member

    Arne,

    I'll probably opt for the low version 9.31m  ( sail : AR 1.89 sqm  29.8m²)

    What type of mast should I choose? 

    wood ?

    alu ?

    hybrid : alu-wood ? I fear connexion 

    Carbon ( too expensive)

    Diameter ?

    Thanks for informations 

    Jacques 
  • 17 Apr 2025 15:24
    Quote
    Reply # 13488558 on 13487971
    Anonymous member (Administrator)

    Jacques,
    Now, in the hope that the mast position can be accepted, I have drawn  a taller sail, taken from The Johanna 60 series of master sails, with AR = 1.98 (instead of the previous 1.89).This is about the tallest sail I dare to suggest. In case you will do most of your sailing, crossing oceans, I suggest you go for the lower version.

    Arne


    (..full size diagram under Arne's Sketches, Section 8 - 36...)
       " ...there is nothing - absolutely nothing - half so much worth doing as simply messing about in junk-rigged boats" 
                                                               - the Chinese Water Rat

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