Catamaran Thoughts

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  • 19 Sep 2019 04:40
    Reply # 7888520 on 7887134
    Howard wrote:

    Arne:

          Thanks for the link.......   I guess it's time I went through the details about sewing sails a bit more carefully......... sewing seems to be a mental block for me for some reason......It is outside my normal field of endeavor.  That usually doesn't stop me from taking on a project.   I have an excellent potential coach locally...... sewing is her passion, largely quilting, which is very popular here.


                                                                                   H.W.

    I had never imagined myself as a sewer, but having gone through a very rapid apprenticeship with David Tyler when making sails for our two boats I found I quite enjoyed sewing. I bought myself a semi industrial walking foot sewing machine a few years ago and have since made two sail covers and numerous other canvas projects for my boat, and so have certainly gotten back the investment in the sewing machine. If I want to know how to make a cover of some sort I look online for instructions, and also go and look at finished products on other boats.
  • 18 Sep 2019 14:34
    Reply # 7887134 on 7869048

    Arne:

          Thanks for the link.......   I guess it's time I went through the details about sewing sails a bit more carefully......... sewing seems to be a mental block for me for some reason......It is outside my normal field of endeavor.  That usually doesn't stop me from taking on a project.   I have an excellent potential coach locally...... sewing is her passion, largely quilting, which is very popular here.


                                                                                   H.W.

  • 18 Sep 2019 09:51
    Reply # 7886855 on 7869048
    Anonymous member (Administrator)

    Howard,

    You are not the first one to feel that sewing a sail would be a daunting undertaking. Over the years (in particular on the Yahoo JR Group), there were many clever suggestions on how to avoid sewing the panels together along the battens. Most solutions were in the nuts-and-bolts category. No matter how many times I repeated that the sail doesn’t have to be rolled up and pushed through the sewing machine, it didn’t sink in. Avoiding sewing seems to be a big issue to those who have little or no experience with a sewing machine.

    Roger Taylor has a sound enough argument for his method. On his long voyages, he must deal with any problems without any help. In case a panel rips (that doesn’t happen) or a batten breaks, it will be quite doable to lash together two ‘fresh’ battens and thus reef away a broken batten or a ripped panel.

    For my coastal sailing, there is less need for this. So far, the only acute structural problem I have had was in Johanna’s yard, when a weld broke. The rig was still usable and we returned to base under sail.

    In case Ingeborg’s sail decides to rip in a panel, I will most probably complete the trip without doing anything to it. The oversize boltrope will ensure the integrity of the sail.  However, if the trip is to last for several days, I guess I would tie the ends of the battens above and below the rip together. If the weather eased and allowed me to, I might ‘sew’ the battens together on 3-4 places to secure the slack panel (.. using needle and twine...).

    There are three bits in the rig (apart from the mast), which must be over-engineered and maintained, so that they never break: Halyard, topping lifts and mast lift. Ingeborg carries a spare halyard...

    Arne


    Last modified: 18 Sep 2019 09:51 | Anonymous member (Administrator)
  • 18 Sep 2019 02:39
    Reply # 7885982 on 7885465

    Why?

    How can you state that Roger Taylor’s sails, where the batten panels are joined with ‘hinges’, are easier to make at home than for instance my sails, assembled the way I do it (..barrel  cut panels, assembled using ‘Amateur Method B’...)?

    What needs floor space, is lofting each panel, so there is no difference between Roger’s and my need for it. A browse through this album showing the construction of Ingeborg’s sail, will confirm this.

    The sewing machine I use is a domestic one with a normal arm, and I have made six junk-sails (and a few others) with it, so far.

    Arne



    Having never attempted a sewing project of that magnitude, It appears to me that handling a lot less cloth would be easier...  Less to wrestle through the machine as less space required.    That said there are obviously more pieces to make and hem, more total work.   I haven't done any machine sewing in quite a few years, but as I recollect handling large items is a bit of  headache........     Sewing is not my forte.   I have to confess that I have not read through your descriptions of the process you use in detail, so I spoke in ignorance.....

                                                                  H.W.

  • 17 Sep 2019 21:33
    Reply # 7885465 on 7885416
    Anonymous member (Administrator)

    Howard  wrote:  
    .......   Even more so would be Roger Taylors "hinged panel" sail, so his builders could make a cambered sail at  home on an ordinary sewing machine easily.  

                                                                            H.W.

    Why?

    How can you state that Roger Taylor’s sails, where the batten panels are joined with ‘hinges’, are easier to make at home than for instance my sails, assembled the way I do it (..barrel  cut panels, assembled using ‘Amateur Method B’...)?

    What needs floor space, is lofting each panel, so there is no difference between Roger’s and my need for it. A browse through this album showing the construction of Ingeborg’s sail, will confirm this.

    The sewing machine I use is a domestic one with a normal arm, and I have made six junk-sails (and a few others) with it, so far.

    Arne


    Last modified: 17 Sep 2019 22:51 | Anonymous member (Administrator)
  • 17 Sep 2019 21:11
    Reply # 7885435 on 7884668
    Anonymous wrote:

    Many thoughts on this subject, too many to try listing in one post, so will try to mainly cover the question of hull size  for a habitation unit and then include a thought or two about Junk rig and  adaptability to a Wharram type cat.

    Right now am working in the habitation unit of my Pahi, which compares in size to a Tiki 26, except in that cabin width has been expanded (width is 2.1 metres compared to 1.2 or so of a Wharram hull at deck level).There is a settee bench and double berth on the inboard side, a small galley, stowage lockers and a writing station(with flap down surface),  on the outboard side of the hull. Forward and aft of this basic living area are single tunnel berths, as per the usual Wharram way/style, with storage under.

    Living space for for 2 is acceptable in this hull, but two more could squeeze in for a drink or a feed (provided they are not obese and don't mind getting cozy with the other two.

    Being a proa ama in this /my case, this ama hull is about a metre shorter than the other or lee hull, which means that I lose roughly 1/2 metre of tunnel space beyond each single berth, by living in the shorter hull, and this is the  best use (for habitation) I think I can make of an 8M hull.

    Assuming I had built  the habitation unit on the 9M hull,  which is what the lee hull measures on my Pahi, then there would have been a fair amount of extra elbow room and locker space, plus more stowage space under seats and berths.

    Having two hulls, means that a wash compartment and heads is separate from the main habitation space, providing much aditional stowage space as welll in the second hull.

    Considering then,  conversion of a 30 ft Wharram, with 17ft beam -- an expanded living unit/cabin would measure over 8ft from the mast bearing girder midway between the hulls, to the outboard side beyond the galley..... thus providing considerably more habitation space than that in an 8M hull.

    Stealing/annexing half of what usually comprises excessive open deck space (on a standard Wharram), for cabin space to one side(of midway betweenhulls), overcomes the 'culvert/tunnel hull limitations and helps create facility to step a junk main mast.

    Talking of Junk rig and Wharram  -- James told me that he( along with Ruth) had started out with an attempt to Junk rig  a Lifeboat, then  went on to concentrated on double canoes. He did in fact dabble with a battened lug on Tehini, but early on it was found (apparently) that a smaller and more efficient rig suited the speed potential of a multihull better than greater sail area provided by junk rig.

    Here I wonder whether  going the route of using a single/una Junk sail of higher aspect ratio, will likewise be better than a shorter biplane set up.  


    There is more than a little merit in the idea of joining a half bridge deck cabin with one hull, at 50% beam.... or even more...... presumably a non standing space.  It would expand internal space, provide that dry all weather location to sit with all around view, allow good protected access forward, view over the top when helming, and access from the side and aft both, as well as a hard point where two intersecting walls could support the mast partner.  It would also provide good access to the foredeck.   An aft facing doorway / hatch would be infinitely preferable to a side access in many conditions...and you would have that.  

         It's an interesting thought, and compatible with the flexible hull beam joint.


                                                                 H.W.

  • 17 Sep 2019 20:52
    Reply # 7885416 on 7885201
    Anonymous wrote:On that subject: two years ago, I attended the OCC meet in the upper Fal estuary, and James and Hanneke brought the first example of the Mana 24. James was very interested in Weaverbird's rig, and asked to see both boats sailing together. The wind was very light and fluky in the area off Ruan Creek, but it was clear that Weaverbird was faster and more easily manoeuvrable than the Mana 24, with its sleeve luff, gaff-headed wingsails, and James, I think, recognised that our modern cambered junk rigs are an enormous improvement over the flat junk sails that he used on that early voyages.

      James if anything is driven by inertia.   There are many ways that his cats could be improved, but he is successful, and has a cult following.   The cambered junk rig should be an acceptable change in keeping with his KISS philosophy.   Even more so would be Roger Taylors "hinged panel" sail, so his builders could make a cambered sail at  home on an ordinary sewing machine easily.  

                                                                            H.W.

  • 17 Sep 2019 18:30
    Reply # 7885201 on 7884668
    Jeremy wrote:

    Talking of Junk rig and Wharram  -- James told me that he( along with Ruth) had started out with an attempt to Junk rig  a Lifeboat, then  went on to concentrated on double canoes. He did in fact dabble with a battened lug on Tehini, but early on it was found (apparently) that a smaller and more efficient rig suited the speed potential of a multihull better than greater sail area provided by junk rig.

    On that subject: two years ago, I attended the OCC meet in the upper Fal estuary, and James and Hanneke brought the first example of the Mana 24. James was very interested in Weaverbird's rig, and asked to see both boats sailing together. The wind was very light and fluky in the area off Ruan Creek, but it was clear that Weaverbird was faster and more easily manoeuvrable than the Mana 24, with its sleeve luff, gaff-headed wingsails, and James, I think, recognised that our modern cambered junk rigs are an enormous improvement over the flat junk sails that he used on that early voyages.
  • 17 Sep 2019 11:04
    Reply # 7884668 on 7869048

    Many thoughts on this subject, too many to try listing in one post, so will try to mainly cover the question of hull size  for a habitation unit and then include a thought or two about Junk rig and  adaptability to a Wharram type cat.

    Right now am working in the habitation unit of my Pahi, which compares in size to a Tiki 26, except in that cabin width has been expanded (width is 2.1 metres compared to 1.2 or so of a Wharram hull at deck level).There is a settee bench and double berth on the inboard side, a small galley, stowage lockers and a writing station(with flap down surface),  on the outboard side of the hull. Forward and aft of this basic living area are single tunnel berths, as per the usual Wharram way/style, with storage under.

    Living space for for 2 is acceptable in this hull, but two more could squeeze in for a drink or a feed (provided they are not obese and don't mind getting cozy with the other two.

    Being a proa ama in this /my case, this ama hull is about a metre shorter than the other or lee hull, which means that I lose roughly 1/2 metre of tunnel space beyond each single berth, by living in the shorter hull, and this is the  best use (for habitation) I think I can make of an 8M hull.

    Assuming I had built  the habitation unit on the 9M hull,  which is what the lee hull measures on my Pahi, then there would have been a fair amount of extra elbow room and locker space, plus more stowage space under seats and berths.

    Having two hulls, means that a wash compartment and heads is separate from the main habitation space, providing much aditional stowage space as welll in the second hull.

    Considering then,  conversion of a 30 ft Wharram, with 17ft beam -- an expanded living unit/cabin would measure over 8ft from the mast bearing girder midway between the hulls, to the outboard side beyond the galley..... thus providing considerably more habitation space than that in an 8M hull.

    Stealing/annexing half of what usually comprises excessive open deck space (on a standard Wharram), for cabin space to one side(of midway betweenhulls), overcomes the 'culvert/tunnel hull limitations and helps create facility to step a junk main mast.

    Talking of Junk rig and Wharram  -- James told me that he( along with Ruth) had started out with an attempt to Junk rig  a Lifeboat, then  went on to concentrated on double canoes. He did in fact dabble with a battened lug on Tehini, but early on it was found (apparently) that a smaller and more efficient rig suited the speed potential of a multihull better than greater sail area provided by junk rig.

    Here I wonder whether  going the route of using a single/una Junk sail of higher aspect ratio, will likewise be better than a shorter biplane set up.  

    Last modified: 17 Sep 2019 11:19 | Anonymous member
  • 15 Sep 2019 15:22
    Reply # 7881586 on 7881310
    Anonymous wrote:

    Howard,

    I can’t help feeling that your strict demands on the next (first?) cruising cat will keep you high and dry forever. You criticize some Wharram cats for their insufficient beam, and call them ‘absurd’. The numbers may look odd, but have these designs gained a reputation of being flipped? I think it is better to see how a vessel works in practice, rather than getting too hung up in specifications, in particular when not having practical experience of the boat type.

    Besides, your demands on payload seems very high, since you appear to plan to cruise solo, most of the time. Why not think a little smaller for the first boat?  A Tiki 30 or 31 or a Pahi 31 seem to take about one ton. Is that so bad for one or two persons?

    If a Tiki 26 passed under my nose, I would grab it, for sure. That one is just big enough to receive a little deck pod (‘day cabin’) which gives both all-round view and shelter. The hulls would just contain a couple of berths, a galley, a loo and some stores.

    My own cat sailing experience is thin, indeed; one Hirondelle 22 and one Tiki 21, and only 2-3 hours in each.

    The trip in the Tiki 21 happened last summer. The light, little cat surprised me by sailing very well, being quick, easily driven and manoeuvrable with only a 15sqm Bermuda rig (the original rig for my Frøken Sørensen). Scaled up to 26 or 30 ‘, and with that deck pod (low, sitting height only) added, I think it would be a great cruiser for one or two. The 26-footer is said to weigh 700kg and with a loading capacity of 770kg. Not bad, that either.

    I suggest you don’t invest too much in the first boat. If it turns out that you like cruising, you may be happy with what you have, or you may look for something bigger, now with firm experience to guide you. In case you don’t like it, there is less risk of losing big money if you start small.

    Arne

     


    Arne:

          Good observations as usual..... However what I see is that people are only counting personal things, food, water, stores, and tools and spares as payload.  That technically is "payload", however I'm looking at the difference between basic design empty displacement and loaded displacement, and using the term "payload" for lack of a better term.  Included in that is virtually everything on board, including things like ground tackle, batteries & charging system, all galley equipment including cooking and eating and prep utensiles, stove, refrigerator or ice chest and ice, nav and com and computing equipment and entertainment, books and charts, dinghy and oars, a bicycle to get around ashore, mattresses and bedding, safety equipment, life jackets flares, life raft.  Motor(s), fuel for motoring and cooking, the tanks for water and fuel.

         The point is that the loaded displacement is the target weight, and the designer's empty weight does not include those kinds of things in most cases.   What does the boat weigh when I step aboard ready to load it for a cruise?    How much is left for food, water, fuel & clothing, fowlies, etc?     Virtually all owner built boats are over built I suspect.... A bit extra here and there adds up.  

           This is the reason behind my seeming obsession with "payload".     Mulithulls are very weight sensitive unlike monohulls.   I want to stay as small and light as possible while having sufficient living space.   The smaller Wharrams if you've ever been inside one, are quite tiny and cramped, hence the description people use "like living in a culvert".  There is also the matter of windage.  A deck pod is a much bigger windage issue in a smaller boat.  The small Wharrams were not intended to have any sort of pod for that reason. Lacking any sort of centerboard or daggerboard, they are known for making more leeway than is really desirable as it is.  

           There would seem to be a large difference between cruising from a shore base, and being based aboard, and I'm viewing things from the latter rather than the former perspective  

          There is a reason that wider beams have become the norm.... describing the beam of that boat as "absurd", was probably un called for.   It is one of Wharram's oldest designs, from the era when that was the norm. Beam is the safety margin.

           There currently is a T26 available at a very reasonable price.... at a rather unreasonable distance from me, that I would love buy to use locally in the interim.    I have my eyes open for such things all the time for exactly the reasons  you stated.

    here is a photo of a Tiki 26 currently for sale in Naples Fl for $3K..... too far for me, it's on the wrong coast.    A very impressive 1700 lb payload for a 1550 lb boat, 26.5 sqM sail area, and a very  nice length beam ratio.   Roughly 58%

         Something like this would have the interior completely ruined by keel stepped masts.... a rather absurd solution on this scale, but there are logical locations to support struts.  

          For the time being, I am working on my canoe trimaran.... it won't be done in time for this season needless to say.   

                                             H.W.

          

    Last modified: 15 Sep 2019 20:29 | Anonymous member
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