Galion 22 conversion

<< First  < Prev   ...   40   41   42   43   44   Next >  Last >> 
  • 08 Sep 2017 23:51
    Reply # 5071230 on 5070816
    Anonymous member (Administrator)

    Jami,

    I agree with ueli lüthi  and his way of approaching mast dimensions. My rough way of estimating a boats max righting moment is to multiply its displacement with an estimated righting lever, which on your boat should not be more than 1/5 of the beam

    Mr= Disp x beam /5 = 1542kg x 2.21m / 5= 681kpm

    I would aim for a an aluminium (lower) mast with about twize the yield strength of the estimated righting moment. I try to keep the wall thickness no more than 4% of the diameter.

    I suggest you look up what tube is available between 12 and 15 cm, and what alloy (temper) is being used.

    The mast of my 2.15ton Ingeborg is 15 x 0.5cm, of 6082-T6 alloy, and that is slightly oversize for your lighter boat, me thinks (yield strength, My=2037kpm, weight 6.38kg/m).

    Arne

    Last modified: 09 Sep 2017 12:38 | Anonymous member (Administrator)
  • 08 Sep 2017 19:19
    Reply # 5070816 on 5070598
    Jami Jokinen wrote:

    …150/4 mm and 140/4 stuck together maybe? Or 140/4 and 130/4 if I would drop the SA to about 23 m2?

    hi jami

    the required mast dimension depends a lot more on the weight and the righting moment of the hull than on the sail area. (you will reduce the sail area in stronger winds anyway…)

    the mast should be able to heel your boat while jumping over steep waves – be it with more active sail area or with stronger winds.

    try this calculator to find an approximation to the righting moment of your boat and the breaking strength of different mast profiles.

    ueli

    Last modified: 09 Sep 2017 06:31 | Anonymous member
  • 08 Sep 2017 18:00
    Reply # 5070598 on 5070195
    Ok, thanks. That leaves no option to use the old mast as the top, then.

    I have to make a "telescopic" mast using two aluminium tubes, because 6000mm is the longest I can get here. 150/4 mm and 140/4 stuck together maybe? Or 140/4 and 130/4 if I would drop the SA to about 23 m2?

    My first sketch can be seen here. 

    I'm starting to fear a bit that the bury won't be very generous with the mast going throug the foredeck. This would add to the reasons for dropping the SA and to get along with a slightly shorter mast. I would not like to drop the AR any lower than 2.10.


  • 08 Sep 2017 17:10
    Reply # 5070512 on 5070195

    I don't think that 110/4mm is strong enough or stiff enough, Jami. Weaverbird's mast, carrying 22 sq m, is 165/3mm. I value stiffness in a mast, and this is a stiff strong mast. 22 sq m is equal to a bermudan main + no 1, for my Duette 23, and I would have thought this to be big enough for a Galion 22. OK, put on as much area as you can, but you'll need a strong mast to carry it. Something around 140/4mm as a minimum, but 150/4mm would be better.

  • 08 Sep 2017 13:12
    Message # 5070195
    So here we go again!

    After a succesful JR conversion of my Joe 17 trailer sailer (which is now sold without the rig) I am starting a new project. 

    I bought a 1968 Galion 22 and sailed it home in a 6-day trip with some open sea passages and quite harsh winds, including the eye of a thunder. This convinced me of the seaworthiness of the Galion. I like the boat very, very much.

    I'm planning on doing preliminary work this autumn, sewing the sail during the winter and doing all of the epoxy work in the spring.

    The Galion 22 has a deep hull and a longish keel. The ballast ratio is 45% (about 750kg of the total weight of 1600kg). Details here.

    The bermudan rig relies a lot on the genoa, and the sail area with no 1 genoa is a bit over 23 m2. I am aiming at sail area of 25-26 m2 on the JR. 

    At first glance this would seem quite good with Arne's Johanna-type sail with AR 2.10-2.15 and boom length of a bit under 4000 mm.

    One of the first things to consider is the mast dimension. 

    There is no reasonable way for me to get my hands on tapered aluminium poles. The straight tubes that can be purchased here are 6000 mm. 

    I have the hybrid mast left from Joe 17. It is 6000mmm of 100/4mm aluminium with about 1m of spruce at the top.

    If I start with a 110/4mm tube (6000mm) and add to this the old mast cut to proper length, would it be enough in terms of strength?

    I want to be nicely on the safe side with the rig, because we have some heavy seas and winds here, even one can't call the Baltic sea a real sea :)



    Last modified: 08 Sep 2017 15:10 | Anonymous member
<< First  < Prev   ...   40   41   42   43   44   Next >  Last >> 
       " ...there is nothing - absolutely nothing - half so much worth doing as simply messing about in junk-rigged boats" 
                                                               - the Chinese Water Rat

                                                              Site contents © the Junk Rig Association and/or individual authors

Powered by Wild Apricot Membership Software