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Thread: Mast steps

  1. #31
    Join Date
    Oct 2002
    Location
    Plymouth
    Posts
    7,276

    Default Re: Mast steps

    Quote Originally Posted by solent clown View Post
    more good advice there chaps. My climbing days were in the military many moons ago, great fun, and I still have some of my gear - probably should all be thrown away but my harness is still good. I am pretty risk averse these days compared to back then, so I will not be relying on luck, Safety first.

    There is a lot of windage and weight aloft for a small boat, with fixed steps. Some have talked of whistling wind noise as well and it won't enhance the look of the thing either.
    So not for me, certainly not for use on the coast or Channel.

    I have a webbing ladder but it is still very hard work as a vertical climb is not like going up a conventional ladder, set at an angle. You need good knees as the lift takes the joint out sideways and thus gives it a lot of stick.

    Somewhere on't web there is a pattern for making a footboard with jammers which works in principle a bit like this:

    http://www.atninc.com/atn-mastclimbe...quipment.shtml

    It looks good because the lift is initiated by bringing the legs up and then down using the most powerful muscles - and the knee joint stays more in sync with your coccyx.

  2. #32
    Join Date
    Apr 2016
    Posts
    467

    Default Re: Mast steps

    Quote Originally Posted by doug748 View Post
    Somewhere on't web there is a pattern for making a footboard with jammers which works in principle a bit like this:

    http://www.atninc.com/atn-mastclimbe...quipment.shtml

    It looks good because the lift is initiated by bringing the legs up and then down using the most powerful muscles - and the knee joint stays more in sync with your coccyx.
    The most useful developments in single rope technique are from the word of caving. There are sophisticated rope walking systems but, for simplicity, the Frog ascending system built around Petzl gear is hard to beat. I've used my set-up in the deep cave systems of the Picos de Europa and most memorably at Pot 2 in the Vercors which is a single open shaft of about 1,000 feet. These systems have to be efficient for that amount of ascent keeping the body weight close to the rope.

    If you compare the efficiency of climbing in this video ... https://www.youtube.com/watch?v=OLK6P8vaAMU ... to the poor-efficiency commercial Mastclimbing set-up in the link above you will see what I mean. A Frog system will also be very much cheaper. Use a triangular Maillon Rapide on the loop of a harness - never an ordinary carabiner.
    Last edited by Poey50; 05-12-17 at 11:51.

  3. #33
    Join Date
    Dec 2002
    Location
    Gloucestershire
    Posts
    4,117

    Default Re: Mast steps

    Quote Originally Posted by Carmel2 View Post
    If your wife is shorter than you space them out so she can use them. What rivet gun are you going to use?
    I don't use mast steps (as you may guess!) but I have riveted on the mast whilst aloft. I used a scissor jack riveter but when it "goes" be prepared for the most horrendous bang and clatter plus a chorus of barks from any dogs around!

    A "soft" riveter would be great. Is there such a thing as a hydraulic one?
    I'd rather be naked
    www.mastaclimba.com

  4. #34
    Join Date
    Dec 2002
    Location
    Gloucestershire
    Posts
    4,117

    Default Re: Mast steps

    Quote Originally Posted by Poey50 View Post
    A Frog system will also be very much cheaper.
    How much does the course cost?!

    I suspect delicately, it might be better suited to the fairer sex!?
    I'd rather be naked
    www.mastaclimba.com

  5. #35
    Join Date
    Apr 2016
    Posts
    467

    Default Re: Mast steps

    Quote Originally Posted by Graham_Wright View Post
    How much does the course cost?!

    I suspect delicately, it might be better suited to the fairer sex!?
    I know you have a commercial interest which I don't want to promote or undermine so having pointed in the direction of the Frog I'll just leave it there.

  6. #36
    Join Date
    Nov 2001
    Location
    Me: Johannesburg South Africa Yacht: Durban East Coast Africa
    Posts
    5,599

    Default Re: Mast steps

    Quote Originally Posted by Graham_Wright View Post
    Better to rivet - M6 would only engage on a couple or so threads.
    Possibility, my mast wall thickness is about 5 mm thick so on the M6 machine screws I have used would be about 5 threads.

    When I calculated the maximum normal load my weight is 80Kg and as there is the load point is about half the distance to the upper support screw the pullout load would be about 40kg taken by 2 screws and if I happen to stand on the end of the step we only have a 1 to 1 so absolution maximum in my case would be 80 kg over 2 screws.

    Also as the load on the screws are mainly shear in the bolt the shear load of the thread is a lot lower and only on the upper screws as their is no pullout (shear) on the lower that is mainly holding your weight.

    If I were going to manufacture the fixed ones I posted I would have a flat bat connecting the upper legs together thus allowing may be 4 or more screws taking the weight as the lower brace load is not pulling the screw out so that screw is only locating the brace and anyway if I was fabrication I would use the same size flat with 2 holes one each side of the brace. The brace would also be extended to about 25-30 mm above the foot support to ensure better foot location.
    Life is too short not to have a sea view
    Distantshaws tinyurl.com/ybrn7prn

  7. #37
    Join Date
    Dec 2002
    Location
    Gloucestershire
    Posts
    4,117

    Default Re: Mast steps

    ………
    I'd rather be naked
    www.mastaclimba.com

  8. #38
    Join Date
    Dec 2002
    Location
    Gloucestershire
    Posts
    4,117

    Default Re: Mast steps

    Quote Originally Posted by Rogershaw View Post
    Possibility, my mast wall thickness is about 5 mm thick so on the M6 machine screws I have used would be about 5 threads.

    When I calculated the maximum normal load my weight is 80Kg and as there is the load point is about half the distance to the upper support screw the pullout load would be about 40kg taken by 2 screws and if I happen to stand on the end of the step we only have a 1 to 1 so absolution maximum in my case would be 80 kg over 2 screws.

    Also as the load on the screws are mainly shear in the bolt the shear load of the thread is a lot lower and only on the upper screws as their is no pullout (shear) on the lower that is mainly holding your weight.

    If I were going to manufacture the fixed ones I posted I would have a flat bat connecting the upper legs together thus allowing may be 4 or more screws taking the weight as the lower brace load is not pulling the screw out so that screw is only locating the brace and anyway if I was fabrication I would use the same size flat with 2 holes one each side of the brace. The brace would also be extended to about 25-30 mm above the foot support to ensure better foot location.
    I agree they are in shear but, bearing in mind the vibrations in a mast, I would be concerned about them loosening.
    Last edited by Graham_Wright; 05-12-17 at 12:46.
    I'd rather be naked
    www.mastaclimba.com

  9. #39
    Join Date
    Dec 2002
    Location
    Gloucestershire
    Posts
    4,117

    Default Re: Mast steps

    Quote Originally Posted by Poey50 View Post
    I know you have a commercial interest which I don't want to promote or undermine so having pointed in the direction of the Frog I'll just leave it there.
    ………
    I'd rather be naked
    www.mastaclimba.com

  10. #40
    Join Date
    Jan 2005
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    The possibilities are endless.
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    10,916

    Default Re: Mast steps

    Quote Originally Posted by Graham_Wright View Post
    I don't use mast steps (as you may guess!) but I have riveted on the mast whilst aloft. I used a scissor jack riveter but when it "goes" be prepared for the most horrendous bang and clatter plus a chorus of barks from any dogs around!

    A "soft" riveter would be great. Is there such a thing as a hydraulic one?
    Mine was done with a compressed air rivet gun, a hand one will kill your hands and you will be at it for ever and a day! Yes the noise is something, especially if you are down below at the time
    Hide a collection of bones in your snowman as a surprise for the children when it melts.

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