Sourcing a tapered aluminium pole in UK

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  • 13 Feb 2020 08:26
    Reply # 8744472 on 3055881

    Has anyone ever contacted The Hampshire Flag Company to see what they would be prepared to offer? Their heavy duty architectural flagpoles, and possibly the GRP poles, might be suitable for use as a mast.

  • 12 Feb 2020 13:44
    Reply # 8742365 on 3055881
    Anonymous member (Administrator)

    Hi Christopher.
    This subject has been quite thoroughly discussed here.

    I suggest you have a look

    Cheers,
    Arne

  • 12 Feb 2020 13:00
    Reply # 8742310 on 3055881

    Hi folks,

    I did make some enquiries about light poles a few months ago for my Wylo II project, and was unsurprisingly given the brush-off by ALC.  I'd be interested to hear the result of any discussions with Mallatite.

    I have been toying with the idea of making up composite masts (i.e. Ali tube with a tapered wooden topmast, as per Annie's Fantail), but the longest tube that seems to be available off the shelf (even from a giant like Thyssen Krupp) is 5m (possibly 6 if you're lucky).  What do people think about the idea of joining two of these with an internal sleeve, say of 2m length or so, riveted or screwed in position?  My rig is due to be based on Asmat's schooner rig, but with a slightly higher aspect, so the mainmast needs to be about 12.5m (12.8 is what I actually worked out, but I think I could get away with 30cm less) from keel to truck.  With 5m tubes, I could make a 10m length from aluminium  with a 2.5 / 2.8m wooden tapered topmast.  The foremast is 8.9m, so if I could source a 6m tube it would be ideal, but could probably make do with a 5m tube and 4m of wood.

    Grateful to hear any thoughts...


  • 05 Jan 2020 22:23
    Reply # 8486363 on 3055881

    Hey thanks Asmat,

    i’ll give them a call..


  • 04 Jan 2020 17:27
    Reply # 8474894 on 3055881

    Paul, Aluminium Lighting Company will no longer sell lamp posts for use as masts. Googling around, I've found mallatite.co.uk, who supply tapared aluminium street lighting poles up to 15m tall. Have you tried them?

    Asmat


  • 03 Jan 2020 23:52
    Reply # 8468256 on 3055881

    Hey Guys,

    Thank you so much for the replies, you’ve given me much to think about.

    I’m really looking forward to getting on with it now.

    Mark, all in (including delivery and VAT) the quote was about £1140.

    The next size down - a 10 metre post top column base d 177mm top d 76

    was about £200 cheaper, but this only measured 8.8 metres above the inspection hatch cutout so was too short for me


  • 03 Jan 2020 22:29
    Reply # 8467689 on 3055881

    Hi Paul,

    if we look at the forces at the base of the proposed mast, there will be virtually no bending moment and there will be a shear load of a little over half a ton depending on the sail area set and distance of the C of A above the deck. I am also assuming a bury of about four feet for the mast. The cross section of your proposed mast has a sectional area of about 3.4 square inches and using a value of 20,000 pounds per square inch, this gives a shear strength of over 60,000 pounds, say 30 tons!! I think that it would be fine if you welded in the inspection plate and cut wherever you wanted. I know the welding will reduce the strength of the aluminium by about 40% but that should not be a problem with the loading at the base of the mast and will provide the circumferential strength that is important to stop cracking/bursting at the base. Just drill a hole in the inspection plate to pass your masthead wires through.

    All the best with the project.

    David.

    Last modified: 03 Jan 2020 22:32 | Anonymous member
  • 03 Jan 2020 21:31
    Reply # 8467236 on 3055881

    The bottom couple of feet of the mast is probably out of sight, out of the weather and not in the way of anything, yet easily inspected at any time. And a little bit of bulk and/or a couple of kg of extra weight down there is nothing. If the top 10.8 m is OK then there must be a dozen ways of beefing up the bottom 0.2m. Apart from the other normal considerations, the compromised lower 10” of mast needs to be strengthened so that it cannot crush or stretch in circumference. You then need to consider how it will be stepped.

    In writing: “Make the step as a socket, and the situation should be better, but I still wouldn't trust it” I do wonder if David T is being a little too conservative. David, would there be anything wrong with inserting a nicely fitted 0.4m (say) internal sleeve, or wooden plug, and then (as you suggest) housing the heel in an outer sleeve or socket? This outer sleeve could possibly even be a metal clamp or series of clamps strong enough to resist stretching or opening up around the circumference. Alternatively, a larger diameter piece of aluminium tube for an external sleeve can be packed to fit – or 3mm aluminium sheet folded into any sectional shape will do if fastened to itself and packed to fit. Whatever, the internal plug or sleeve  must resist crushing, the outer sleeve or housing must resist stretching. The mast step itself, which could be part of the solution, must meet all the other usual requirements. I think that is still being careful and conservative.

    Paul, I do feel strongly that if the sail plan is already decided, you should not compromise by shortening the mast. You could, as David suggests, change the sail plan if you think you can’t make the foot of the mast strong enough – but do be generous with your allowance for halyard span at the top of the mast, and paired-downhaul spans between the boom and the deck. Good luck with your split rig, you will like it.


    PS here's another thought: make the mast slightly more than 11m so that the bottom 6" is below the hatch cut-out and comprises the full circumference. Then just sleeve or plug the bottom of the mast up to a point, say, 6" or more above the hatch cut-out (the more the better).


    Last modified: 05 Jan 2020 07:49 | Anonymous member
  • 03 Jan 2020 18:16
    Reply # 8465705 on 3055881

    Paul, 

    well done in sourcing more or less what you wish.  
    Dare I ask how much you are paying

  • 03 Jan 2020 14:20
    Reply # 8464020 on 3055881

    As suggested by others, it's probably an insurance thing that has made them reluctant to talk about using the poles as masts.

    Doubtless if you looked to buy a simple tapered lighting pole from their suggested supplier, they'd sell you one, no problem.

    Just don't mention the word "mast".

    With the generous help available on this forum, you can get the spec right for your order.




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