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  • 09 Feb 2025 18:24
    Reply # 13460948 on 13453927

    Just remember to use a softer putty-type glue instead of the shown epoxy. The bolt at each ends are important. They take up the shear load which transforms the two independent tubes into a beam.

    - Arne

    Rerigging Ilvy, I sticked to Arne's excellent tutorial - except for one thing: I didn't glue those two tubes of the yard together, but only lashed them firmly every 20 cm or so. Of course I did put those bolts at the ends, as those are essential.

    No issues since, works like a charm!

    Cheers,

    Paul

  • 23 Jan 2025 13:09
    Reply # 13453927 on 9327660
    Anonymous member (Administrator)

    Here is how I built the yard for my 26' Ingeborg: 

    https://bit.ly/2IpCWtR

    Just remember to use a softer putty-type glue instead of the shown epoxy. The bolt at each ends are important. They take up the shear load which transforms the two independent tubes into a beam.

    Good luck,

    Arne



    Last modified: 23 Jan 2025 13:31 | Anonymous member (Administrator)
  • 22 Jan 2025 22:16
    Reply # 13453723 on 9327660

    All good stuff! I will take all the info I can get!


    Just wondering about this yard. I can't find any good places to start. Big pipe or two pipes? How do I size it? I'm at a loss


  • 22 Jan 2025 09:40
    Reply # 13453356 on 9327660
    Anonymous member (Administrator)

    Jeffrey: Firstly, your diagram.

    If this is your proposed sail (The Amiina Mkll) then I presume you are in contact with Slieve, who I think will have advised you to put the geometric centre of the sail (CoE) - which is pretty much the mid point of the boom - in line with the CoE of the bermudan rig. And I presume that is what you have done here. 

    The mast shown on this diagram is slightly higher than you need (It was the mast Amiina had with the Mk l rig and they never bothered to shorten it. As far as I am aware that was never a problem and I would think probably a good thing. Better slightly too long than slightly too short). Anything higher than the height of that original mast head should be OK.

    You might be able to get the boom (and thus the entire rig) just a little lower, if you want to.

    Joining the tubes

    I don't feel competent to advise on your welding idea. Welding would destroy any epoxy in the vicinity of the weld, and ditto probably Simsons. Also I don't think welding in the way you suggest will make the mast any stronger in bending - might even make it weaker. Simsons "in addition to" epoxy also seems pointless to me, they have totally different characteristics.

    You might be over-thinking this. A 2' overlap between the two tubes will be very strong. The idea of glue is to (a) fill the annular gap between the two tubes and seal it up,  (b) prevent the top tube from telescoping downwards into the other, and (c) prevent the top tube from twisting, relative to the other. (b) will probably be taken care of by making a fairing to smooth the transition between the two diameters. Perhaps that could be made by epoxy and glass. (a) and (c) ought to be taken care of by the internal glue joint which ought to be either epoxy or polyurethane rubber - I have used epoxy but perhaps polyurethane rubber would be better here. I don't have a lot of experience I can only report on what I have done.

    I would have thought with a normal mast the strongest point needs to be at the partners (or at the top of a tabernacle). If you can arrange it so that the tube overlap is spanning the partners (or the top of a tabernacle) then you are probably making the best use of your materials as far as bending is concerned. 

    I suggest a diagram showing your proposed extension, in relation to the partners and/or tabernacle, and hope someone more qualified than I am will advise.

    Ditto the yard.

    Last modified: 22 Jan 2025 10:16 | Anonymous member (Administrator)
  • 22 Jan 2025 03:29
    Reply # 13453326 on 9327660

    Graemee!!!!

    thank you so much for your time. such a kind thing to offer :-)

    for reference I have a 120 degree angle on my yard to the mast. and I will be extending the Mast from the head up. my final height was determined by the following steps

    2/3 the height of a sheetlet above the deck. plus the height of the square section of sail. Plus the height of the fan section of sail (if the luff of the fan section was standing straight up and down and not at an angle) plus an additional 2 ft for block and tackle and fudge room :-)

    AKA 36 ft total height (27 ft of tapered lamp post and 9ft of extension)

    the way I was thinking of adhering the Mast extension was by drilling four holes at 3/4", opposing one another 6 in away from either Terminus of the pipes and fill welding the holes once they are sleeved. in addition to this polyurethane glue you speak of. also epoxying the step where the opposing diameters meet????

    my thought is, the weak point of that joint would be either Terminus of either pipe? this would keep the heat of the weld away from that weak point.

    now I really need to figure out what I'm going to do about this yard. is there some conclusion or new standard for building a yard? is it better to just use a big pipe or to use the tension pipe system AKA Arnie's two pipes epoxied together? I've also read about people lashing together the two poles.


    1 file
  • 21 Jan 2025 08:57
    Reply # 13452872 on 9327660
    Anonymous member (Administrator)

    Jeffrey: Different sail types may have different requirements.

    Height of boom above deck

    If your split junk rig is  a McGalliard type, then it might have running parrel-downhauls. (Slieve’s notes Chapter 11)

    If this is the case, then you need to allow for the parrel spans. The rule of thumb for this is: minimum distance between boom and deck = ½ x height of a sail panel, plus allowance for blocks. That's the minimum.

    Otherwise I suppose its mainly a matter of visibility, headroom and sheeting considerations.

    Height of masthead above the yard

    If it is a low yard-angle sail (for example, the Amiina Mkll SJR) then it is tempting to make the mast not quite high enough, resulting in a halyard angle which becomes too great as you get near to raising the last bit of sail. You might have enough height to allow for the halyard span (for the 5-part halyard and its blocks), and enough drift to allow for the wringing effect as the yard moves from side to side – and yet, still not high enough, resulting in too great an angle between the halyard and the mast.

    So, if in doubt, make the mast a little longer rather than a little shorter. Others can speak for other rigs, but I found with the Amiina Mkll SJR type, that for the sail to be easy to raise and for it to set nicely without the need for extra sail-setting parrels, the halyard block at the masthead must be at the very least as high as the peak of the yard, above deck. That’s an absolute minimum for that type of sail. That means a mast height a little more than might seem necessary at first glance. For a low yard-angle sail, don’t skimp on mast height.

    (If your sail is some other type, such as the Johanna type with its somewhat higher yard angle, or a fanned type, with shorter yard, then maybe other criteria apply).

    PS regarding your mast extension, you haven't said if it is at the foot or at the head. In any case, I think the experts would advise against welding. I have made a lapping masthead extension (aluminium tube inside aluminium tube) with epoxy (including a fairing between the two diameters) and it seems OK, but I am not totally happy with the idea, now. I was advised afterwards (and I think correctly) that a better glue for the purpose would be a polyurethane rubber type, such as Simsons. If it is a lap joint of 2' for a 5' pole then it will be plenty, plenty strong enough in bending. The other two forces are the "telescope effect" (axial, downwards) of the halyard - not so great in the general scheme of things - and the rotational forces of the yard - which ought not to be over-looked, but again well within the strength of a good polurethane rubber glue joint. Welding or mechanical fastenings are to be avoided except at the very top or the very bottom of the mast, in my opinion.

    Last modified: 21 Jan 2025 09:30 | Anonymous member (Administrator)
  • 21 Jan 2025 04:33
    Reply # 13452835 on 9327660

    well back at it, here in the cold weathers of chicago.


    the sail I have made is a 305 square ft. Split junk on top of a 2.5 tun displacement of the contesa 26. I plan to go on many dangerous Adventures :-)

    I am extending a 27' tapered lap post with a .188" wall up an additional 6' 6" using a pole measuring 5" OD with .125" wall. I will be setting 2 ft of the 5-in pole into the lamp post and Welding or epoxy in it into place.

    I am having difficulties coming to a conclusion for a final height of the mast. my questions are as follows

    height of mast above deck before the lowest Batten on the sail?

    height of mast above the yard? ( I will be using a five piece tackle for Main halyard)


    for my batons I'm thinking inch and a half schedule 40 T6 aluminum which equals 1.9 inch OD by .145 in wall AKA 48.26 mm OD 3.683 mm wall

    for the top most baton, the one just below the yard. I have a 2-in schedule 40 pipe AKA 2.375 OD by .154 wall or 60.3mm OD x 3.9mm wall


    I'm kind of stuck on the yard. I am in between getting a 4-in pipe with a 1/8 in wall AKA 101 mm OD by 3.175 mm wall


    the alternative would to do the Arnie yard and put two pipes together. but I'm having a hard time finding a smaller aluminum pipe that isn't crazy thick. I'm also looking to get some literature on building and rigging the yard for a split junk. if anyone can point me to some literature, it would be much appreciated :-)


    I'll be spending more money on aluminum than I did on my car, any reassurance would be a gift :-) :-)

    Last modified: 21 Jan 2025 04:34 | Anonymous member
  • 12 May 2021 19:26
    Reply # 10474226 on 9327660

    Howdy y'all

    Thought I'd check and give you a quick update. My sail is all done with. Got a couple lacing gromits to put in but other then that... 

    Making a second attempt at my lower mast partner. I think I have got a better idea on how to cut out an octagonal shape. This time I will be using a router instead of a jigsaw. 

    Today I will be making some shims for the thing.

    The wether here in Chicago is looking up. Still not warm enough for epoxy thoug, won't be much longer.

    I will be taking a break from building soon as I will be out hiking this year. I got 3,600 miles to cover on foot through the Rocky mountain range in central United States. From the Canadian border in Montana to the Mexican border in New Mexico! 

    If the mountains were the sea, high up on the Waves is where I'd be!

    After that I'll be dragging the boat down to Florida to finish he up! 

    All the best till then 


    Hot Dog

  • 22 Jan 2021 08:34
    Reply # 9922206 on 9327660

    Thank you David T, and David W


    I got it all worked out. Those pictures are very helpful!!! Time to start sewing! Woooo

  • 17 Jan 2021 15:58
    Reply # 9870739 on 9327660

    Paul, that's one of my personal photo albums. To look at any of my other albums, or to look at the photo albums of any other member, just click on their name where it's an underlined link (in a forum or in the members directory). Here's mine:

    David Tyler

    Scroll down to the bottom to see my albums.

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