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Thread: Hoop pine mast ?

  1. #1
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    Default Hoop pine mast ?

    For the Aussie boatbuilders among us.

    Would you consider making a mast for a thirty-footer from hoop pine? The mast would be perhaps 35'-40' long, including the bury. I was asked this question the other day and said No, try to get oregon, but afterwards I started thinking, well, perhaps, if it was a bit oversize....

    Any ideas, guys?

    Mike
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  2. #2
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    Default Re: Hoop pine mast ?

    The strength and durability is the same as Oregon so why not ? That said good pinus ellioti ( slash pine) has the same specs as Oregon too and that's what I'll use .
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  3. #3
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    Default Re: Hoop pine mast ?

    Many thanks, Pete.

    Anyone care to corroborate?

    Mike
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    Default Re: Hoop pine mast ?

    I was talking to a mate about it the other day and he seemed to think hoop might rot a little more easily but that might also come down to the particular boat and the way the mast was treated .
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  5. #5
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    Default Re: Hoop pine mast ?

    Ross Lillistone mentioned to me once that Hoop was only slightly heavier but stronger then Sitka Spruce. I certainly built my masts out of it.

    I found this table here. http://www.recreationalflying.com/tu...html#table_2-7


    I don't know about Hoop's susceptibility to rot, though Boatcraft Pacific just says 'take the normal precautions'. I understood that hoop was way better than slash pine when it comes to rot, and that it was not a good idea to use slash pine for boats. By slash pine I mean radiata. Is that what you mean Pete?
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  6. #6
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    Default Re: Hoop pine mast ?

    Radiata being pinus radiata .
    Slash .... pinus elliotii, it's the Northern version of plantation pine , the one we see up this way other than hoop.

    I'd very much like to be able to use slash as I have a small woodlot that contains around a 100 65 year old trees, very straight and around 400 mm diameter . John,would you have a look at the links below, there seem to be quite a few similarities between the two. I'd like to hear what you think about them.

    https://www.daff.qld.gov.au/forestry...ees/slash-pine
    https://www.daff.qld.gov.au/forestry...rees/hoop-pine
    '' You ain't gonna learn what you don't want to know. ''
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  7. #7
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    Default Re: Hoop pine mast ?

    Peter, I think this is actually quite a good topic to pursue a bit further though I'm not sure who best to quiz over it. We need to ask someone who really has some recent experience of using all the newly locally available timber species plus the experience of using the tried and tested timbers. Timbers, like fish, have so many readily confusable common names it makes things quite confusing.

    Here's some examples. I go to Bunnings and I buy Tassie Oak, but actually it's Victorian Ash or Mountain Ash or some similar species I believe. I can buy Radiata at Bunnings or other timber and hardware stores too but some of that comes from SE Qld plantations so is it sometimes slash pine? Then I go to Bretts where I buy my Hoop pine, but they call it clear pine. But if I go to Bunnings, the clear pine there is actually a finer grained select grade Radiata imported from New Zealand.

    We are talking mainly softwoods here, so from an architectural viewpoint, none of them are good outdoors in terms of durability. No common softwoods (except maybe Huon pine) are, but some of them are good for boat building if really well protected and maintained. You never get epoxy treatment in domestic construction but you do in boats and that obviously makes a huge difference in durability. So maybe kiln-dried or well-seasoned slash pine and even radiata might be okay if epoxy (CPES etc) treated? I know this goes against old-time experience but that experience would have been pre-epoxy and modern coatings.

    As well as rot, there's shrinkage and hence movement to think about for boat building timbers. Radiata has high numbers here, but I wonder about the clear pine from Bunnings? I suspect it would be much much better, looking at its finer grain and close growth rings. If you buy non-structural unseasoned radiata from Bunnings these days it is really wet and really heavy, and shrinks to billy-o. Much worse than Radiata was say 20 years ago. But the kiln-dried stuff is not too bad.

    What I'm getting at is that times have changed. There are many new timbers available and many new timber treatments available. For us locals up and down the east coast, there are different timbers available. I suspect some of the old-time views about some of these timbers are right, but others maybe need updating based on the new timbers and treatments available. It would be great if we could find some real definitive and trustworthy data on all of this which goes beyond the 'old knowledge'.

    A good reason to get some really good info on this is because if you go to the specialty timber suppliers to buy the best timbers the old-timers would recommend for each job on the boat, it costs an arm and a leg these days..it's just not affordable.
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  8. #8
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    Default Re: Hoop pine mast ?

    It's very hard to get that information, boatbuilders usually buy the best they can afford and treat it well ... thus the result lasts well. They don't like to experiment too much.

    Firstly most small pine logs , hoop, slash or radiata are largely sapwood thus expecting too much from them is unrealistic, this refers to anything under 100 years old and less than a slow grown 24'' diameter. The link on slash elliotii gives a few critical comments on that . Very little comes on the market these days of 40 year cut cycles that isn't largely sapwood. The recycled hoop in my workshop is a very different animal.

    However I've milled a few of my trees (slash ) and not what I would regard as the good ones . One small section was nailed to the side of the house 25 years ago as an attachment for mud shower for the children. It was nailed on with a couple of bright 3'' nails, no paint, no varnish but very good drainage. it's still there or was last time I looked..... exposed to full sun and rain for 25 years. It hasn't rotted and the exposed (very bleached) surface is sound. The lesson is not letting fresh water sit . Drainage and the ability to dry is all.

    Your comments on timber treatments are spot on, things like LOSP can change the characteristics of otherwise non durable species remarkably.

    On other species it can be fun to run a few tests. I've run quite a few on slash, hoop, rose gum and camphor laurel for things like bending, gluing, screw holding and split resistance . Thus far camphor laurel has proven the best at bending and split resistance . That was something of a surprise but then I found some photos in an old WB showing Chinese builders planking a workboat with camphor sawn from some quite small logs . Apparently it is a standard builders timber but regarded as rubbish here !
    '' You ain't gonna learn what you don't want to know. ''
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  9. #9
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    Default Re: Hoop pine mast ?

    My 'bible' for timbers and their uses has always been the CSIRO's 'Timber Engineering Design Handbook' of 1962, by Pearson, Kloot, and Boyd. And on checking it again now I find it does indeed mention hoop pine (Araucaria cunninghamii), which I thought it didn't. It also shows that hoop pine's properties are very close indeed to those of Pinus radiata.

    That being the case, I found it surprising that in the (very useful) table given in the link by Johhno in Post #5, radiata pine doesn't get a mention -- even though the table dates from the same period and one of the two authors is also one of the authors of the TEDH. What weren't they telling us? Is this possibly because radiata is usually only available in such short knot-free lengths that it wasn't considered suitable for aeroplane structures, which this paper concerns itself with?

    Pete, your comments about camphor laurel are interesting. (I always think of you when I see them every year on my way to South West Rocks for our annual holiday.) Lovely trees, that somehow look as though they ought to be figs. It's good that they have more than decorative uses.

    The Queensland Government's comments in your second link in Post #6 are useful, but it's interesting to note that the figures given for radial and tangential shrinkage differ from those in the TEDH.

    I also note that with the exception of its green density (which hardly matters), oregon has similar properties to both radiata and hoop pine

    So -- thanks very much to you both for your assistance. My conclusion is that the advice I gave was wrong, and that hoop pine could indeed be usefully considered as a mast timer in lieu of oregon.
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  10. #10
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    Default Re: Hoop pine mast ?

    Quote Originally Posted by PeterSibley View Post
    I was talking to a mate about it the other day and he seemed to think hoop might rot a little more easily but that might also come down to the particular boat and the way the mast was treated .
    Fibreglass the outside then at least 7 coats of two pack polyurethane.
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  11. #11
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    Default Re: Hoop pine mast ?

    If you are pining away for more information...

    http://www.conifers.org/

    http://www.conifers.org/ar/Araucaria_cunninghamii.php

    Ethnobotany


    Widely planted in Australia, both ornamentally and in timber plantations. The timber is "a first-class softwood varying from almost white to cream or light brown. A plain timber of even texture without prominent grain or growth rings. Peels easily; the Australian plywood industry was founded largely on hoop pine. Virtually odourless. Durable in the dry but may be susceptible to fungi. Easy to work. Readily accepts a wide variety of stains and finishes. Uses: Plywood, cabinet work, furniture, flooring, mouldings and linings, boat building. At one time used for butter boxes, fruit boxes. Widely available" (Newbury [no date]).
    In historic times it was an important source of timber for masts and spars of sailing ships. Here is a relevant historical account: "The Spitfire having sprung her topmast, some of the party landed at Magnetical Island for the purpose of cutting a pine spar on the morning of the 17th September... The formation of this island also is granitic, immense boulders of this rock lining the shores and being piled on the summits and strewed over the slopes of the hills in wild confusion. Lofty pines spring out of the crevices of the rocks, giving considerable beauty to the scenery. The timber of this pine is rather heavy, but tough, and with a beautiful grain, qualities which recommend it for house and boat building, furniture, &c. It appears most nearly allied to the Araucaria Cookei (the Moreton Bay Courier, December 15, 1860).

  12. #12
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    Default Re: Hoop pine mast ?

    Thanks Dave, they're good links.

    Mike
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