Galion 22 conversion

  • 22 Nov 2017 05:44
    Reply # 5597339 on 5070195

    Thank you, everyone - I'm sorry to disappoint you, but I don't have the skill, the tools or (maybe most importantly) the space to build a wooden mast. I think it's impossible for me to craft even the 4m topmast (on top of a 6m al-tube) from wood.

    It would be very nice to be able to use the al-flagpole (specs in an earlier post), if there was a good and reliable way to strengthen the lower part. But is there?



  • 22 Nov 2017 00:11
    Reply # 5596969 on 5070195
    Anonymous member (Administrator)

    Jami

    In countries like Norway, Sweden and Finland, it should be easy to find a straight spruce tree for a mast.

    Now I looked up the The Cambered Panel Junk Rig, Chapter six to find the needed diameter of a hollow wooden mast. First, I found the fake sale area to give a SA/disp =14:

    Fake SA =18.38sqm.

    Putting this and a LAP=8.3m into the PJR formula produced a resulting mast diametre

    D=19.8cm.

    Even by twisting the PJR formula, the masts come out on the heavy side.

    Another method:
    I also have another ‘home-made’ formula based one the estimated righting moment of the boat and the bending strength of  a (hollow) wooden pole. Since wood varies in strength, I have put in a needed breaking strength 3 times the estimated righting moment of the boat.

    The result was D=17.36cm, or say 18cm.

    I know that Jester used a mast, which was about 18.2cm. This was much taller than this one and Jester was also heavier than the Gallion 22, so maybe a diameters of 17cm would be a better choice for the coastal waters around Finland. I surely would reckon 18cm to be plenty, even if you have the North Sea in mind.

    Arne

    PS: I haven’t double-checked my calculations.


  • 21 Nov 2017 19:18
    Reply # 5596515 on 5070195

    I've been wondering about building a mast, too.  In spruce.  Arne suggests a slightly smaller size than PJR might work - you can find his thoughts on wooden masts here.  I know, I know, wooden masts are too heavy, etc, etc.  However, time was when all boats had wooden masts.  Moreover, your carefully tapered junk mast has most of its mass fairly low down and it doesn't have all the weight of tangs, masthead fittings, roller furler and wires up in the air.  You can even contrive a masthead fitting with wood and webbing to avoid the weight of metal at the masthead, should that worry you. Personally, I think that people overestimate the effect that a wooden mast might have on even a small boat.  But that's my personal belief.  I would probably be building a wooden mast for my boat, if I'd been able to afford the spar-grade material required.

    Gary Pick has a boat not much larger than yours with a wooden spar.

    Last modified: 21 Nov 2017 19:18 | Anonymous member
  • 21 Nov 2017 08:16
    Reply # 5595747 on 5070195

    4. Under the "Something Else" heading. 

    Build a mast maybe?

    Or turn the boat into a ketch with 2 smaller masts of a diameter you can more easily get? Similar to a Hunter Liberty 22.  

    Just a thought and not a very helpful one, I'm afraid.  

  • 19 Nov 2017 19:41
    Reply # 5593631 on 5070195

    Hi Jami,

    one avenue that may be worth pursuing is having a pole section purpose made in China. I have contacted a couple of manufacturers through Alibaba.com and received very competitive quotes for mast sections in the 10 to 12 meter length range ($6 to 800.00 US). The problem appears to be transportation which more than doubles the price, and import duties/taxes which can add another 20 to 25%. The sections I got quotes on were 200mm base diameter with a 5mm wall thickness, parallel for the lower half and tapering to 100mm at the top in 6063 T6 aluminium (heat treated after tapering). The quote I got was for a length of 11.6 meters so that it would fit inside a 40 ft container. I hope that this may be of some help. David.

    Last modified: 19 Nov 2017 19:45 | Anonymous member
  • 19 Nov 2017 12:19
    Reply # 5593334 on 5070195

    The mast issue seems to stay problematic, because the availability of aluminium tubes in different sizes is quite limited, and lighting poles even more so.

    The options so far for a mast with total length of about 10 meters:

    1) 140/5mm al-tube, 6m plus a grp flagpole on top of this. Pros: easy to get, cheap. Cons: Heavy

    2) 145/2.8mm al-flagpole (2.8 meters parallel at the bottom part, total legth 12m -> 2m will be cut off at the top). Pros: Easy (not a hybrid) and light, Cons: Not strong enough. Can something be done?

    3) Grp flagpole (actually a pole for airport wind indicators, 10m or 12m for added strength (2m cut off)) with 7mm wall thickness. Pros: Easy, Cons: Heavy and possible installation problems (tapered all the way to the lower end)

    4) Something else?

    Last modified: 19 Nov 2017 12:40 | Anonymous member
  • 11 Nov 2017 16:38
    Reply # 5581452 on 5070195

    Oh, I have (again) misunderstood... This clears it now, thanks a lot!

  • 11 Nov 2017 15:10
    Reply # 5581350 on 5070195
    Anonymous member (Administrator)

    Jami

    why are you talking about 9 – 10m tall mast? As the two sailplans show, the mast height above wl. is 8.82 and 9.22m. Now I checked the LAP (length above partners) of both rig versions and came to 8.0 and 8,4m. The recommended bury is around 10% of the LAP, not 10% of the total length, so 80 and 84cm bury will do fine. On such a flat, strong deck, I would not have bailed out even if there had only been room for a bury of 8% of the LAP.

    Arne


  • 11 Nov 2017 13:46
    Reply # 5581333 on 5070195

    Oops, and thanks. Now corrected.

  • 11 Nov 2017 13:28
    Reply # 5581326 on 5070195
    Anonymous

    Jami

    Those links only work for you - see this guide for how to make them public.

    Chris

    Last modified: 11 Nov 2017 13:50 | Anonymous
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