Junk rigged Iroquois ?

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  • 29 Aug 2020 20:47
    Reply # 9198731 on 9197964
    Anonymous wrote:

    Yes, I did consider a single mast, which probably suits the relatively narrow overall beam.  The problem is that transporting and installing a mast of that size, without the use of a boat yard and crane, would not be easy.

    The biplane also has the advantage of always having a spare, readily installed !


    The logical way to handle a tall mast is to hire a power line contractor to haul it, and set it up on the boat. They have trailers designed for carrying tall power poles, and their line trucks could easily lift a mast in place if they can get close enough to the boat.  Arne's aluminum base, wood top section would make sense, and be reasonable in weight if you made the top section laminated up and hollow.

                                                            H.W.

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  • 29 Aug 2020 10:13
    Reply # 9197964 on 9175854

    Yes, I did consider a single mast, which probably suits the relatively narrow overall beam.  The problem is that transporting and installing a mast of that size, without the use of a boat yard and crane, would not be easy.

    The biplane also has the advantage of always having a spare, readily installed !

    1 file
    Last modified: 29 Aug 2020 14:03 | Anonymous member
  • 28 Aug 2020 19:33
    Reply # 9196663 on 9175854
    Anonymous member (Administrator)

    I would have taken a closer look at a single (central) mast solution. It could either be a freestanding mast in a braced tabernacle or a fully stayed mast. There is a much wider staying base on a cat, and besides, it is faster to tack downwind, so less need for squaring out the sail.

    And  -  a single sail is both cheaper to build, and easier to handle.
    Just an armchair opinion...

    Cheers,
    Arne

  • 28 Aug 2020 17:06
    Reply # 9196294 on 9175854

    I'm disappointed to hear that you abandoned the idea.  I've been toying with solutions... I love a challenge even if it's just an intellectual challenge.  I've come up with some really interesting and unique solutions, some of which might provoke a bit of mirth.... so I'll keep them to myself for the moment.   "Outside the box" is where I live.   By far the simplest solution to avoid compromising interior space would be to leave the mast where it is and rake it forward, using a split rig with maximum possible balance area.

       What bothers me most about this boat is the narrow beam and pathetic payload numbers..... They make it very difficult to find empty weight and CWL for good reason. 

                                                                      H.W.

  • 26 Aug 2020 12:41
    Reply # 9191192 on 9175854

    Having been tormented with whether to proceed, I have decided not to buy the Iroquois.  I decided that the masts would end up too heavy to readily manhandle, and not suitable for a first project. Had she been closer to my base I may have taken the plunge.

    She is basically a sound boat, though with a few things to sort out.  The interior was stripped, so a nice clean sheet.  The current rig is on its last legs, so ripe for a conversion.

    If anyone else fancies taking her on, she is in Dunoon, and at £5,500 a real bargain.

    She is about to be put on eBay, but contact me if you would like to speak with the owner direct.

    So perhaps back to the crazy junk rigged proa.  I can do that for the cost of the new rig for the Iroquois.

  • 22 Aug 2020 16:29
    Reply # 9184021 on 9183537
    Anonymous wrote:

    Howard,

    Alleda and Oryx both have tabernacles.  Besides never going to look as neat as keel stepped mast, I see advantages.

    The mast is not as long, so lighter, easier to manage.  I am sure Pete could handle his on his own.

    A crane is not required.

    Raising / dropping requires the mast to be well braced with stays fixed on the pivot line.  With the mast to the hull side a temporary strut would be needed.  With a BM rig the boom is used as a lowering point, a similar temporary strut would be used, again braced.

    I think the rigid pivot point normally used is not ideal, it needs to be a soft hinge of some sort, so will not be overly stressed if out of line.

    And all needs to be done on a calm day, ideally on the hard. 


    An alternative might be to use a keel stepped mast, and build a collapsible structure that could be bolted in place that would include the pivot point and a means for lifting the mast vertically so that it could be tilted.   Hard points in the deck would be built in for the purpose.   Considering the small weight of a mast, the vertical lift would not be much of a challenge.  You'd lift one mast and lay it down and secure it, then move the rig to the second and repeat.  The lifting mechanism for bringing the mast out of the hull could be as simple as eye just above the partner... run a line from it over a block and to a sheet winch or just use a multi part block and tackle.  The cost and complexity of this "jury tabernacle" would probably be considerably less than that of building two tabernacles, and the weight would be less than a single one as it is not required to carry mast loading while sailing.  It would be bundled up and stowed in it's own bag below decks most of the time.   How often do you drop a mast?   I can't see much reason to do it very often unless you live up a creek with a low bridge.... It would be nice to be able to drop them if you were running way back into the mangroves for a typhoon.   In most cases it's going to be easier and faster to climb a mast than drop one.


                                                                       H.W.

  • 22 Aug 2020 09:42
    Reply # 9183537 on 9175854

    Howard,

    Alleda and Oryx both have tabernacles.  Besides never going to look as neat as keel stepped mast, I see advantages.

    The mast is not as long, so lighter, easier to manage.  I am sure Pete could handle his on his own.

    A crane is not required.

    Raising / dropping requires the mast to be well braced with stays fixed on the pivot line.  With the mast to the hull side a temporary strut would be needed.  With a BM rig the boom is used as a lowering point, a similar temporary strut would be used, again braced.

    I think the rigid pivot point normally used is not ideal, it needs to be a soft hinge of some sort, so will not be overly stressed if out of line.

    And all needs to be done on a calm day, ideally on the hard. 

  • 21 Aug 2020 16:46
    Reply # 9181827 on 9181536
    Anonymous wrote:

    Howard,

    thanks, useful photos.

    i would locate the masts in tabernacles close to the hull side, much as Pete did in Oryx.

    ideally without the struts, or at least ones that are to some extent hidden.  Like your idea.

    anyway may go for a look this weekend, so will have to give it some really serious thought.

    Surprisingly  a tentative note on the Iroquois page got a couple interested in the mast.  One noted that the fore beam corrodes at the ends, and is the same mast section, so if I end up having to cut it up it could come in use or be sold.


     Sections of that mast could become your boom perhaps..... It would be nice to simply step the masts on the keel and forget about tabernacles.... That would involve sacrificing some internal hull space, but the further forward you were, the less important that space would be... a juggling act between sail balance area and ideal mast location.  Here's a cut away image of the boat and one of the forward berth where the mast would  need to go.  Not much of a berth, but the berths in general are not much.  The bridge deck cabin has a big compression post through the middle...which would no longer be necessary except to support the cabin top...Note in the photo that there is another support strut further outboard suggesting that the cabin top is not particularly strong.  With a small strut replacing the big one, and the table top designed to drop, this cold become a decent double berth.   

    Looking at tabernacles in general, I'm trying to imagine the process of lowering the mast.... Forward or aft?   How do you stabilize and control it, how do you lift and lower it, the line angles that work against you as you lower it, becoming increasingly parallel with the mast.... what are you lowering it onto?  Where are you winching from?  How are you mitigating the parallelism issue?  (strut?)  What do you do with it when you get it down... and all this with the boat in the water..........   There seems to me to be good reason people use cranes, and you don't see many tabernacles.  It's anything but a simple or safe process.  The risk of damage or injury is significant and the environment not optimal.    I work with very heavy stuff all the time, own a crane and a very large forklift and loader.  Even with those I take a lot of time planning what I do so nothing gets damaged or broken and nobody gets hurt.... I usually work alone because it's safer than having lots of enthusiastic help.   There's a reason why the rigger is one of the most important men in a crane operation.


                                                               H.W.

    3 files
  • 21 Aug 2020 14:56
    Reply # 9181536 on 9175854

    Howard,

    thanks, useful photos.

    i would locate the masts in tabernacles close to the hull side, much as Pete did in Oryx.

    ideally without the struts, or at least ones that are to some extent hidden.  Like your idea.

    anyway may go for a look this weekend, so will have to give it some really serious thought.

    Surprisingly  a tentative note on the Iroquois page got a couple interested in the mast.  One noted that the fore beam corrodes at the ends, and is the same mast section, so if I end up having to cut it up it could come in use or be sold.

    Last modified: 21 Aug 2020 14:57 | Anonymous member
  • 21 Aug 2020 01:25
    Reply # 9180348 on 9175854

    Mark:

         The way I read that photo is that the original mast step is being used as a hard point to brace from, and those two big pipes are bolted down to the mast step, the compression post is probably still there, and it may be bearing the weight of the masts via those huge pipes.  I'm a bit baffled as to why the tabernacles are not resting on the deck, the deck being reinforced to bear that load, and why the masts are not further forward considering the fact that the Iroquois is a masthead rig.   I would probably step the tabernacles further forward right on the deck, reinforcing it suitably.... probably about where the diagonal struts connect.  Fore and aft loading could be carried by the cabin sides....  The silly big side window removed and a couple of sensible ports or sea hatches installed.   It would not take a lot of glass fiber to turn the sides into beams effectively. unidirectional roving top and bottom, and glass laid on the bias along the side to form a shear web.   A good hard point could be built into the corner for a strut attach point.  A clever and elegant way to handle lateral loading would be to build a sun shade that was structural... perhaps carbon fiber and that tied the the cabin top sides and mast step all together.  It could end up looking pretty nice, the sun shade effect camouflaging the fact that it was structural.  Two short stiff struts would connect from the tabernacle to the "sun shade".    The two struts to each tabernacle top would form a V.   You could put a cross bar between the tops of the tabernacles  if you wanted for additional stiffening, and it would also serve as a hand rail or whatever.  I'm also imagining that grab bar along the roof becoming a structural element and simply continuing on to the longitudinal strut.

         The way this boat is set up I would imagine the helm would be far from balanced...  look at these photos.  Note that the boards are pretty much directly beneath the mast step. 

         Note that it was I think the Gemini that had centerboard issues, not the Iroquois.... I tend to get them confused.  I can't find the site where it was being discussed.


                                                        H.W.



    2 files
    Last modified: 21 Aug 2020 01:26 | Anonymous member
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