Mast from a Tree or from metals ?

  • 05 Mar 2019 08:10
    Reply # 7199949 on 7199892
    David T wrote:

    I have yet to come across a carbon fiber mast on a junk rig yacht, we are probably all a bit too poor for one of those! But I wonder whether a carbon mast would really be worth the expense, unless one has an endless supply of money to throw around.

    When I worked at Kemp Masts Ltd, I built a carbon mast as a learning project, having access to a building space, and materials at trade prices. Eventually, I ended up with a serviceable mast, but it wasn't easy. Don't try this at home, children.

    That was in the mid 80s, I think, and the mast served aboard Lliutro, and then Ivory Gull, for about 25,000 miles in my ownership, plus some more after that in subsequent ownerships. I heard early this year from the current owner of Ivory Gull that it had broken.

    So, it gave at least 30 years and 30,000 miles of service, but no, it wasn't worth the expense and trouble of making it, and it wasn't any better than a hybrid would have been.

    Professionally made, it's different story, and there are Freedom yachts with Pearson masts that have been converted to JR. Even so, I've seen broken examples of those masts.

  • 05 Mar 2019 05:31
    Reply # 7199892 on 7184461

    This is a discussion that could go round in circles, inside out and back again, and so on and so on. As David Tyler has indicated depending on your locale and availability of various materials, cost, skill level, various option will present themselves as most suitable. Even with my small amount of junk experience I have seen some successful masts of various materials. Footprints with her staved mast, which has large diameter in the lower portion, but is not that heavy, but labour intensive to build. I think Alan on Zebedee has solid trees. They seem to have worked quite well having circumnavigated the globe. David Tyler had all alloy masts on Tystie, they also were successful over many tens of thousands of miles of ocean cruising. La Chica and Shoestring with welded steel masts. They seem to be working quite well. The Hybrid mast which Annie built for Fantail. It seems well proven now. I have yet to come across a carbon fiber mast on a junk rig yacht, we are probably all a bit too poor for one of those! But I wonder whether a carbon mast would really be worth the expense, unless one has an endless supply of money to throw around.

    It seems to me in thinking about Annie's new boat, and the direction I would go in if I do put a junk rig on my catamaran, that the hybrid alloy/wood mast is a very good compromise, especially here in New Zealand. It combines the necessary strength, reasonable weight and minimised bulk, availability of suitable materials, and matching the skill levels of most of us amateur builders. If however I was to build a single mast rig with a big sail such as Footprints has I would probably be looking at a self built staved mast of affordable timber, or perhaps one of the welded steel masts.

    Anyway, we should all get out sailing and enjoy whatever it is we have and works well!!


  • 05 Mar 2019 02:42
    Reply # 7199729 on 7184461
    Deleted user

    Have you looked at birdsmouth masts?  I haven't tried one yet but from what I've read they seem like easy and simple way to go, as I understand it they're much more tolerant of flaws or scarfs especially if you go with 8 staves and can be cut single handed with just a 7 1/2" rotary saw/skillsaw and a long bench for masts of pretty much any size, help is very desirable for assembly though.

    ovals, teardrop, or even wingmasts are all doable with birdsmouth construction.

    Here's a birdsmouth spar calculator for round spars with good instructions, although for some reason you have to scroll way down for the list of abbreviations for the fields.
    If you scroll down the last couple calculators show how to cut staves that'll make a clean multi sided spar with no need for planing.

    I plan on just buying decent lumbar and cutting out what staves I can and using up the leftover on other projects, I think I'll make some planters for practice soon, I've got some roses I need to transplant sooner than later.

    Bill F

  • 04 Mar 2019 07:48
    Reply # 7197282 on 7196539
    Annie wrote:
    David wrote:No. He wouldn't.

    He simply takes the view that the hybrid method is the easiest, least skilled, least expensive, most pragmatic way of getting an unstayed mast.


    Really?  I thought you didn't like wooden spars.  However, as it would cost me over $2,000 to buy the extra timber required, I guess I'd better stick with the hybrid.  Shame.

    The question was not whether I like, or don't like, wooden masts; the question was whether or not I would disown you for liking them ;-)

    In some parts of the world, you can go into the forest and cut yourself a mast, and for a heavy displacement boat, that has to make economic sense, so long as you have the wherewithal to transport it and clean it up, and can accommodate the extra diameter.

    In some parts of the world, good mastmaking timber is routinely grown and milled, and then, so long as you have the wherewithal to convert it into a staved mast, and can accommodate the extra diameter, that will make sense.

    In some parts of the world, tapered aluminium flagpoles are readily available, and so long as transport is available, and the cost can be borne, that will always be my personal favourite way of getting a light, stiff, long lasting, low maintenance mast.

    But in most parts of the world, it's easiest to buy, transport, make and assemble a hybrid mast. That's all I'm really saying. But the question is hypothetical now, as far as Fánshì is concerned, because the tabernacle has already been sized to suit a hybrid.

    Last modified: 04 Mar 2019 07:49 | Anonymous member
  • 04 Mar 2019 06:24
    Reply # 7197230 on 7196539
    Annie Hill wrote:


    Really?  I thought you didn't like wooden spars.  However, as it would cost me over $2,000 to buy the extra timber required, I guess I'd better stick with the hybrid.  Shame.

    I wonder if a timber mast need cost this much. The mast on 'Footprints' is built of straight grain pinus radiata, (8 staved). Not an exotic or expensive timber at all, and 20 years on it is still doing everything expected of it. I bought an awful lot of straight grain marocarpa timber for all the framing for my catamaran for a surprisingly small amount of money from a local timber yard. In fact I was surprised at how little the timber cost , which is not often the case with things we buy these days. Macrocarpa is a timber with a good balance of strength, lightness, rot resistance, and economy. Based on the volume of timber required for a wooden mast I think that even for a few hundred dollars I could purchase enough timber for a replacement mast for Footprints, and there is a limited amount of epoxy required. Of course such a mast would need to be owner built, otherwise the labour cost would make it a very expensive mast.

    And of course the other downside as opposed to the hybrid mast is the weight and bulk of an all timber mast. At 300mm diameter for the lower mast, 'Footprints' mast is a bit like having a tree growing up through the fwd cabin.

    Last modified: 04 Mar 2019 06:56 | Anonymous member
  • 03 Mar 2019 22:53
    Reply # 7196663 on 7184461
    Anonymous member (Administrator)

    Wood or aluminium (or hybrid) for masts?

    I guess I am internally divided on this matter. Common (cold engineer’s) sense tells me that it depends on what is cheapest or most available and what is easiest to work with for the builder. Transport is another factor. It is a lot easier to transport two halves and then joining these next to the boat.

    I think I have better control of the weight of wooden masts now than before, so they need not be as heavy  and over-built as before (but still a bit heavier than aluminium). However, a wooden mast will still be about 50% thicker than aluminium, so will have a higher windage. The ‘sail area’ of Johanna’s wooden mast (1.6sqm) could really be felt when in a deep-reef situation.
    A wooden mast is a clear winner in one situation. If you have it running through your bed, as I use to, the dry spruce-mast is so nice to touch. Even though I have insulated and covered Ingeborg’s aluminium mast, it is not the same.
    (I just ‘ordered’ a knitted woolen jacket to cover all that orange PVC. That would be nice...)

     

    Green or not
    Aluminium is not green, initially. Apart from digging it out of the ground, it takes around 12kWh pr. kilogram to produce the finished metal. However, it lasts very well, and scrap aluminium is a real resource which can be recycled by spending only about half a kWh pr. kilogram, so in the long run, it is much less bad than it looks to begin with.

    So it is with everything: The longer we keep, maintain and repair our things, the greener they get. (My car is 19 years, and is still good, thanks to having been maintained like an airliner...)

    Arne


    Last modified: 03 Mar 2019 22:59 | Anonymous member (Administrator)
  • 03 Mar 2019 20:14
    Reply # 7196539 on 7195977
    David wrote:No. He wouldn't.

    He simply takes the view that the hybrid method is the easiest, least skilled, least expensive, most pragmatic way of getting an unstayed mast.


    Really?  I thought you didn't like wooden spars.  However, as it would cost me over $2,000 to buy the extra timber required, I guess I'd better stick with the hybrid.  Shame.
  • 03 Mar 2019 08:10
    Reply # 7195977 on 7195731
    Annie wrote:All things being equal, I would have a wooden mast.  However, (a) I couldn't afford  to buy the Douglas Fir I would have required and (b) Mr Tyler would have disowned me.  However, I would trust one more than alloy, it's a much nicer (and greener) material and I personally think the weight issue is overrated.

    No. He wouldn't.

    He simply takes the view that the hybrid method is the easiest, least skilled, least expensive, most pragmatic way of getting an unstayed mast.

  • 03 Mar 2019 00:21
    Reply # 7195731 on 7184461
    All things being equal, I would have a wooden mast.  However, (a) I couldn't afford  to buy the Douglas Fir I would have required and (b) Mr Tyler would have disowned me.  However, I would trust one more than alloy, it's a much nicer (and greener) material and I personally think the weight issue is overrated.
  • 01 Mar 2019 09:11
    Reply # 7193078 on 7184461
    Anonymous member (Administrator)

    I was a little un-precise when I stated that my 'modified cone-tapered mast' would be easier to build. I had a pole mast in mind, and in particular a dug out pole mast. Straight lines are easier to make and follow, then.
    If the mast is built from staves, I bet the barrel-taper is as easy as anything. After all, that is how barrels are made!

    (My grandfather happened to be a barrel-maker, among other things...)

    Cheers,
    Arne

    Last modified: 01 Mar 2019 09:13 | Anonymous member (Administrator)
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