Building a Moth aluminium mast

Discussion in 'Sailboats' started by revintage, Sep 9, 2020.

  1. revintage
    Joined: Nov 2016
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    Location: Sweden

    revintage Senior Member

    Building a non foiling Moth mast, I will only use cheap components from the backyard by building the mast using a 6m 50x2mm 6060-T6 tube combined with a glued aluminium luff track made from cutting a double keder rail in two. About the joint between track and tube, I contacted Hamish at West/Wessex in UK and he recommended G/Flex 655. The mast will be max length 6250mm, stayed and keel standing.

    To make it a little stiffer in the lower part to withstand the forces from boom and vang, I am thinking of adding an inside stiffener tube. I have seen this on the Elvstrom Trapez and the Australian Starling, where they use aluminium tubes as stiffeners. The older US Moths used Alspar sections(without stiffeners) and it should be softer than the 50x2 tube with track due to thinner walls, but they where deck standing and might withstand more bend, depending on alloy.

    Below to the left are the two alternatives I have come up with so far. If using the windsurfer mast stiffener my idea was to glue it with 5200 to the front inside of the mast tube. The 45x2(or 40x2 or 40x1,5mm) would would be riveted to the front and also held by the boom bolt. Would really appreciate some input and other ideas on the subject.

    Attached Files:

    Last edited: Sep 11, 2020
  2. messabout
    Joined: Jan 2006
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    Location: Lakeland Fl USA

    messabout Senior Member

    It appears that the boat uses a free standing mast. If you have the original sail, you will need to have a mast that matches the cut of the sail. If you do not have the original sail then why not consider a different arrangement? You could use a sleeve luff sail, like the Laser, and have no need for the sail track. You could even use a lateen sail such as the Sunfish rig. In either case the mast is simple and involves no questionable parts assembly.

    That is a pretty little boat. Sure to be fun to sail.
  3. revintage
    Joined: Nov 2016
    Posts: 414
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    Location: Sweden

    revintage Senior Member

    Dumped the mast building project when I suddenly realized I have an old Flipperjolle 6m mast tube(old version) at my summerhouse 240km from here. Will pick it up next time I go there. Have some second thoughts about keelstanding and will instead make a mast base with the mast standing just above deck level. About the stainless heavy deck ring I will probably substitute it with a 12mm HDPE slab. Will try without stiffener but will probably add a 40x2mmor 40x1.5mm when needed. The 1st image is taken through the Europe dinghys mast hole.

    flippermast.png mastbase.png skrov.jpg
  4. OzFred
    Joined: Nov 2015
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    Location: Earth

    OzFred Senior Member

    Have you considered looking for a second hand carbon Moth mast? I think getting some weight out of the rig really helps in such a small, tippy boat. It seems you're not that interested in keeping it class legal (as a Europe).

  5. revintage
    Joined: Nov 2016
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    Location: Sweden

    revintage Senior Member

    Hi Ozfred,
    This is a no- to lowbudget build so a carbon stick even SH is out of the question at the moment, though I will talk to a friend and neighbour, who is a windsurfer and also one of Europes best DN iceboat builders, about it. As I have a boltrope sail, the alu lufftrack ha to be glued on using either 3M 5200 or West G/Flex. The boom is from a broken 49er carbon lower mast that I got for free.

    Actually just realized(see above), I had a suitable 50mm round alloy mast with integral luff track in the shed, that I have used for another project, so zero cost. Also recutting a 10.5sqm Blaze sail I bought for a next to nothing, to be class legal.

    I am rebuilding the Europe to a Lowrider Moth to follow the IMCA rules, ie 1250mm beam, max 8.25sqm SA.

    After trying it out, the next step will be a new sandwich inner bottom, sloping, above waterline to be selfdraining and lighter. Maybe also a carbon mast if the alu does not work as intended;).

    The Moth will not be acceptable for racing against the real Lowriders due to the large wetted area of the Europe, but no problem, as there are not any other nonfoiling Moths in Sweden. Just for fun, then.
    europewings.png frankenmothcut.png dubbel.png
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