Small trailerable cruising cats... biggest flaw?

Discussion in 'Multihulls' started by rayaldridge, Nov 18, 2010.

  1. Steve W
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    Steve W Senior Member

    Ray, how about using 2 recycled sailboard rigs instead,1 in each hull,as im sure you know k designs uses this tandem rig on some designs and it allows you to keep the rigs up when folded.
    Steve.
     
  2. Steve W
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    Steve W Senior Member

    Oh,another quick folding system that has been used with some sucess is the solid wingdeck hinged in the middleso the hulls tuck under.Shark cat 20x10 ,Maine Cat 22 x12 and Viva 27 x 14 all use this system. Course the mast has to come down first and you cant use the tandem rig.
    Steve.
     
  3. rayaldridge
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    rayaldridge Senior Member

    Steve, that's not a bad idea. I think Bernd Kohler has a little cat that uses two windsurfer rigs. But I have a Nacra 5.2 rig that I hope to use, and no windsurfer rigs.

    The problem I see with cats that fold the hulls under, though that can work well, as in some of Richard Woods' designs is that then accommodations must be mostly in a center pod. I want to keep windage down, and it's hard to get sitting headroom in a central pod without making it pretty high. I think this also requires a more elaborate trailer. Thomas Firth Jones designed a small cat that folds in the middle like a Shark. Maybe the worst aspect of this solution, in my personal situation, is that the slip I have available to use is only 10 feet from wall to wall, and folding in that manner means the hulls would be lying on their sides in the slip, collecting crud on the topsides.

    Again, I appreciate the thought you and others have given to my problem. I have to say, it's really been stimulating, and helpful-- the thread sat here for a long time before anyone ventured an opinion, so I wondered if maybe my list of design goals was just too silly to be taken seriously. I really think there's a design niche there to be explored, and I wonder why the Simpson design was not more popular. Maybe it's the weight.
     
  4. jamez
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    jamez Senior Member

    With a cedar strip build, and the extensive aluminium fabrication holding it all together, it would not have been a 'cheap' boat to build, maybe no cheaper than a Trailer Tri 680/720 - just conjecturing here :D Re the mast and folding, if thought was given to designing a suitably strong step, a set of appropriately sized temp bungee stays could be hauled up the spinaker halyard to hold the mast in place during folding.

    Folding system aside I think as a cruising design its got a lot going for it. Roomy hulls, nearly 1.8 headroom, a sensible low aspect rig which combined with 4.5 metres beam would give great stability. I thought it would be nice built non-folding ( I keep my boats on a swing mooring) with a single cockpit between the hulls like a Tiki. However the plans were only availble as the folding version so any modifications, like new beams, had to be self engineered. Went in the too hard basket and now I'm building a Tri;)
     
  5. Fanie
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    Fanie Fanie

    No come on Jamez ! Too hard ?

    There is going to be a perfectly common not-too-hard solution to make a cat foldable.
    It's simply a matter of you have to sit and play with it, it will come. Remember there was a time the tri-guys had the same problem, then when someone comes up with a solution it was like 'of course'.

    I was going to play with some ideas, but other things came in the way. Will play some more when there's a gap.
     
  6. Steve W
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    Steve W Senior Member

    Ray,dont forget,when a Farrier is folded and kept in a standard marina berth,it would also get barnacles and slime on the topsides of the amas if not antifouled. The Viva has accomodations in the hulls but clearly they cant be used folded. You know,ill bet that you could incorporate a system into the hinge pin of the Takeaway so you could leave the mast up, there is a lot of depth to those ladder beams and if you were to have a decent diameter pin, say 1.5", it could extend up enough to support a tabanacle and be ridgid enough to support the mast with the shrouds disconected temporarily while folding and then rig something for support while folded, lots of details to figure out.
    Wait a minute,you are only talking something about 20ft x 10ft so you only need it to reduce about 2 ft to fit your slip or to trailer,that may be easier.
    Off topic, i recently picked up a cool beachcat on ebay which i want to use as a beach cruiser.Is an old Pacific cat 19,designed by Carter Pyle in California in 1959 ,mine was built in 1970, they have got to be one of the first fiberglass surfcats but the cool thing is they have cockpit wells for your feet and a solid bridgedeck where i was hoping to be able to pitch a dome tent, it has a beutiful organic looking main crossbeam and real sweeping sheerline like a Newick tri,kind of a big rig though so reefing mods will need to be made. I picked up a 1.2hp x 14lb outboard which tuck neatly into one of the aft lockers,im excited. Paid $305 for it with an almost new Galvernized trailer and my son and i drove a 2700 mile round trip in my old Tdi Passat to get it.
    Steve.
     
  7. dstgean
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    dstgean Senior Member

    Pictures! We need pictures!

    Dan
     
  8. AnalogKid
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    AnalogKid Junior Member

    Seconded.
     
  9. rayaldridge
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    rayaldridge Senior Member

    Analog. I think you're right that the key here is that the hinges don't have to carry the forces involved in sailing-- they only have to carry the forces involved in folding the boat for trailer or slip. Then they can be reinforced for sailing by some sort of mechanism. Thomas Firth Jones got me to thinking down this track. He had the same thought when drawing his folding design Brine Shrimp. In that case, the beams hinge upward along a central line. He uses I-beams in his later designs, so to strengthen his beams, he just bolted a block of I-beam inside the flanges of his main I-beams. That wouldn't work for me, because my hinges open laterally rather than upward, but I think the principle can apply, somehow. I don't mind bolts, because they can be tightened rapidly, if the mechanism is positive enough to make the boltholes line up perfectly. Boats that rely on rig tension to hold folding mechanisms in place, like some small tris, worry me. I can't help but wonder what happens if a stay lets go out on the bounding main.

    Jamez, when I was looking at the drawing of the Simpson you posted, I noticed that the trailerable weight was 700 - 800 kilos, and the displacement was 1100 kilos. That struck me as low payload for a cat that size, but I'm really not familiar with what's acceptable. On the 20 footer I'm drawing, I'm hoping for a 600 kilo payload. That's on hulls scaled up from Slider, my 16' beachcruiser.

    I think you're on the same track as me when it comes to the mast. I've thought about using the trap wires as temporary back stays.

    Fanie, I hope you're right about there being a solution that will seem obvious in retrospect. I think you probably are right.

    Steve, I think you've figured out where I'm going with this too. Because I want to step my mast well aft of the forward beam, I'm using a central spine to hinge the beams off of, similar to the Simpson folder, but with the hinges reinforced by bolt-on structures. The central spine does mean that I have to take a few inches from the individual cabin width, but It presents some opportunities, too. I plan to use a single central rudder and board, which means no board intrusion into cabins, and no tiller linkage to have to unship when folding. I'd thought about putting a little outboard in a pod-type well built into the spine, but eventually decide to put the motor on one transom. But anyway, it means that the boat can be motored and steered when folded.. I'm actually going to see if I can work out a 12 foot beam for my 20 foot cat. That gives a lot more deck space on the central deck, which is the nicest place on a boat that size. With a boom tent, you have a lot of real estate under cover. The Nacra rig has a fixed gooseneck, so I'll have to do something about that to have a boom tent with standing headroom, as I do on Slider.

    You've really got a piece of history there. It's funny that folks will spend gobs of cash on china figurines or antique chairs, but when it comes to the history of the multihull in the West, the history is being left to rot in backyards, or sold for a pittance on Ebay. I'm envious of you. Got any pictures?
     
  10. ThomD
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    ThomD Senior Member

    What ever happened to that New Zealand folding cat everyone was excited about a few years back. It used a kind of playpen system to establish a central tramp was, really cool, then he "ruined" it all with a plan to build an even bigger boat. Never heard any more.

    I prefer the idea of fixed decks etc. and the whole G32 thing in this size. What is more no one has provided plans for such a thing to satisfy the evident demand that was there even at 30 thousand plus decades ago. Particularly if it could be simplified. It is tougher than it seems to be due to the fact that the natural displacement for that kind of thing is 200 % of the dry weight, which means some very careful design. The boat you are making can have 100%, a fifty fifty thing. Some of boats that use folded amas are closer to trimarans at 50% of the dry weight.

    My 21 with water displacement has reached this point. There will be a cabin, this is just the hulls and decks and pods. Also I got this far, and then sorta thought, that if I just dropped it down to 18ish it would make a very nice Miss Cindy platform and be a lot easier to build. In the drawing it is about 7.5' beam x 21', and could obviously be wider and still be trailered.
     

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  11. rayaldridge
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    rayaldridge Senior Member

    Thom, the problem with the G32 was that it tended to capsize pretty easily. To me, that's just not acceptable in a cruising boat.

    There's someone in Pensacola trying to sell a modified G32. The beam was widened to 12'. They want 40K or offers, but it looks like a pretty nice boat.

    http://pensacola.craigslist.org/boa/2091204392.html
     
  12. dstgean
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    dstgean Senior Member

    I think lots of the capsizing issues were that folks that wanted the G32 were also racing them. I read a story fo Mead capsizing one 4x in a race and finishing well. Since I'm planning on going with a reasonably small beam on my Tamanu double cat, I hope prudent reefing will make for a fun and cruisable platform.

    If Ray comes up with something clever, we'll all have a chance to give it a whirl since this is something of a holy grail of catamarans.

    Dan
     
  13. ThomD
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    ThomD Senior Member

    "Thom, the problem with the G32 was that it tended to capsize pretty easily. To me, that's just not acceptable in a cruising boat."

    Not true, the G32's problem is that it is outside the box. It's like saying that an F boat is unsafe because the protential exists at some level that someone would put up the sail while the floats are pulled in. It's a very smart design, but when one sees the tape, now on youtube, one can see how the general public might not like all the talk about capsize. It's just a further example of the capsize myth, in which it is apparently impossible to separate racing from crusing. One can dial in whatever amount of of stability one wants. If Slider is safe, there is some degree of canvas to water ballast where G32 is equally safe, probably more safe. Yet Slider doesn't have a high performance potential, and the new boat won't either.

    But more important, if you want safety, the G32 format is rightable. But this is the key point. As one shrinks the overall length to 16 feet one reaches a point where the boat is now a jarcat, and still has water ballast and rightability, and also a conventional form factor.

    So stability is not the issue, it is really a mater of at what length other than 32 feet is there enough G32ness left to make the complexity worth it. I wouldn't probably bother with it at 16 feet, but it becomes interesting at some point beyond that point. At 24 feet one has a 1-3 form factor which has been used extensively in cats, can hardly be regarded as radically unstable. One probably has the potential for more sail, and lower resistance than the jarcat, and can probably start to justify some of the cost of complexity that is there. Either option, reducing beam, or righting and water ballast has some appeal. A game changing option for folding would be... game changing. Tough though. So far we are at zero for cheap easy to build options of high functionality in any folding form I am aware of. There are advantages to water ballast and righting. The only really complex part is the step. Bad news is that it is mostly a machine shop type of thing. Good news is it won't have the problems of generating parts that are load bearing, folding, and have good marine durability, which is a nightmare in beams. Water ballast is an easy problem. Had a G32 type deal caught on like the Fs, it would have been easy to supply in generic mast step form, unlike the integrated folding beam problem. And the mast step solves the problem of mast raising.
     
  14. sabahcat
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    sabahcat Senior Member


  15. Steve W
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    Steve W Senior Member

    Thanks Sabah, i was looking for my ebay pictures but cant find them (and wouldnt know how to post the if i did)
    A few of the things i like about this cat are the foot wells with hiking straps, i find it tiring with your legs out straight like most small cats and my old Macgregor 36, there is a large 3" drain through the transoms which you can barely see below the bottom rudder fitting. The forward location of the aft beam keeps the crew forward and allows for good sized storage lockers aft for light stuff,ill need to make them watertight though. The forward crossbeam makes for a nice place to attach a fwd net, i used to sail a G cat 5meter that had this feature and i loved laying up there at anchor or in light air. I wish the bridgedeck was flatter though for sleeping on. The daggerboard trunks are in the footwells. That main crossbeam has a very sexy shape when looking from the bow or side view much like a Newick tri,( or the Newick tris look like it)
    Ive wanted a beachcat for a while but not just any beachcat, a P cat, but most of them are in California, so when my son saw this one on ebay i jumped at it.
    Steve.
     
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