Minimum cruising cat-size & cost

Discussion in 'Multihulls' started by Alex.A, Feb 24, 2010.

  1. Alex.A
    Joined: Feb 2010
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    Alex.A Senior Member

    Thanks Richard - sound advice - Which is why i am here and asking.
  2. magwas
    Joined: Oct 2009
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    magwas Senior Member

    What about the following statements?:

    - Junk rig is easier (less force) to handle than Bermuda, which becomes important when short handed.
    - Swing wing is also a junk rig, which have better aerodinamics than bermuda
    - It is much easier to reef
    - Junk rig can be built from cheaper materials, which is still a valid reason for some.

    What about these statements?:

    - Biplane rig is easier (less force) to handle than Bermuda, which becomes important when short handed.
    - The center of effort is lower, hence risk of capsize is less/can be powered more.
    - The mast can be shorter, which means easier building.
    - Hobie Trifoiler is biplane. It holds a speed record for a very long time.

    I think there is no such thing as "better in every sense". There are differents people with different priorities.
    And unfortunately something which is better in most respects than alternatives not always the more popular. For example in Hungary most of the people use mountain bikes, while road bycicles are much more suitable for the terrain and climate, and in a lot of cases cheaper. It just happens that our road and track cycling association has been managed very badly for many years, while MTB has achieved a lot. This has the impact even those who use bicicles only two times a year. There are a lot of cases where better alternative did not (or not yet) win mainly because the supply chain prefers the other alternative. This in some cases (like with recumbent bike) means that the better alternative costs so disproportionally more that cost eradicates other advantages, making the better alternative stuck as a niché forever. If the two were produced in the same volume, their price range would very considerably overlap (an unfaired recumbent needs the same technology and amount of materials like a normal bike).

    And you are right that sticking to conventional ideas is safer in most cases.
  3. Timothy
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    Timothy Senior Member

    If you argue that modern materials make working sail rigs obsolete for cruising then I would hazard a guess the future is not the Bermuda but some type of free standing balanced cat (una) rig with rotating, perhaps canting, mast(mono hull or tri) and code 0 or a kite for off wind work.
  4. Alex.A
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    Alex.A Senior Member

    What i had in mind was a rig similar to that on the Wharram -Tahiti Wayfarer - which would be a mastless rig.... made up of 2 booms , not solidly connected to the hull/s but then the rigging takes all the stress'! As the rigging also then needs to be (easilly) adjustable, it starts to get complicated. The plus would be that the rig would go over if overpowered- without structural damage or fear of capsize - possibly minimal damage to rig either? This could remove capsize as a major worry for catamarans? From sails at any rate....
    Also with all sail down - there is no windage at all. A storm jib could be used from the deckhouse structure which would keep it low and small in size - just for some amount of control.
    Either as a main only, ketch or bi-rig configuration - or even bi rig with ketch to give maximum options and redundancy for damages in storms - but then you'd have a hell-of-lot of stays all over the place....
    The reason for crabclaw interest then is obvious. It can be varied quite widely according to conditions - ie vertical mostly but more horizontal as wind picks up. If reefable , even more options?
    As the crabclaw is a lifting sail - what would the stresses be on the beams where it attatches? The variable stays idea - is it viable? 3 stays - fwd and each side - no backstay.....
    Fwd stay to hull and sidestays to beams.
    Would - in theory - allow for canting mast too.
    I am thinking for a cruising cat 8m - possibly 9m. loa by 4m beam+-
  5. magwas
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    magwas Senior Member

    I thought that the rule of thumb is that transverse GM should be close to longitudinal GM in case of multihulls, which would mean beam is close to loa. Did I miss something?
  6. Fanie
    Joined: Oct 2007
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    Fanie Fanie

    Hi Guys, sorry I'm a bit late, the thread is almost over ! :D

    I want my boat to be trailable, I want to launch at different locations.

    Quite recently I was thinking of having more than one set of main beams I can interchange, a suggestion from a friend. The reason is if your'e going to sea, the long beams hence a wider cat for stability. When on the fresh, you use the short beams and you have a narrower cat. Waves is much less of a problem on our small dams (lakes) so you can use the narrower boat to fish between the trees.

    For sea going I want a cabin for long trips no compromise unless one do day sailing then you go out and come back at night or have to live without the protection. The cabin trailers seperate since we're almost never going with only one vehicle.

    I use that sail setup because I liked what I experience with it. The aft mast like I had works easy, the wife should be able to handle it also. Also with the eye on fishing, you want to stop the boat quickly and be underway also as quickly. I haven't seen any other mast/sail setup to offer me this. Pull one line and the sail is gone, pull the other and you're sailing. Even I can manage that ;)

    There are two hulls, each gets a mast and a sail. You can sail one sail or both. Easy to still get a large sailing area with relative short masts and relative easy to handle sails.

    I want to mount two smallish outboards for motoring (if you want to). Not all places are suitable for sailing, especially our fresh water places have more turbulent winds and are not too great to sail on. In this case the masts and sails are left at home and the small outboards are your propulsion. Small means better economy and displacement hulls allow for good motoring, better than planing hulls in any way.

    I hate bloody tents. They take the same time to pitch than it would the boat and I' d rather pitch the boat. Even if it takes double the time to pitch the boat I would still rather pitch the boat and have a proper berth and a protected place.

    I want up to 8 berths (4 x double) and even if it would be crowded I don't like the tri setup or the mono setup. It allows every one a bit of privacy and besides you would only sleep below or do your private things there. The real life activities are up in the cabin or out on the open, fishing, braaiing loafing about and the likes.

    So if things work out the setup is versatile and can adapt to my personal preferences. Things like unsinkable etc goes without saying.

    As Alex said, SA is going backwards to 3rd world on the moment. I'm having stuff made for my hull making process, but the frustrations and poor workmanship as well as the time to get anything done here is like an outer body experience. Apart from that the gov wants to control every single person and corruption is on the order of the day even from those that have a little bit of power.

    There are a group of people in CT that is currently attempting to change this, if they don't succeed I would be moving elsewhere. I made up my mind about it and I do have an option that is very very attractive for me on the moment.

    I'm limiting my the hulls I'll make to around 10, maybe 11 meters. Beyond that size it becomes difficult (for me) to handle and it is still trailable (barely).

    I already have about 12 hulls (6 cats !) to make if I can get the equipment finished in time and if the customer would wait that long, part of the reason I'm a bit scarce on the forum off late. The drawings and time spent to get everything together seems endless.

    The first purpose of this venture is to make my own boat. Secondly I think boats are expensive. Our economy here is up to nuggets and less and less people can afford boats. Most people buy these stupid ski boats because it is the only trailable option they have and few can afford the marinas. I would like to see that changed. Just the safety of a wider boat is notable.

    Someone mentioned you take the boat home and work on it there - exactly ! You get everything ready from home and when you launch you are ready to go.

    I am currently assembling the jig for making the hulls with. Big job with very little help so it's a bit time consuming, but I'm getting there. If all goes well I may be making the first set of hulls in a month or two.

    Great thread ! Some valuable comments made, for you old salties thanks for that. As for size, I'm just glad no one suggested to Alex another 6m little cat or tri, it won't work on our coast.
  7. Alex.A
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    Alex.A Senior Member

    8/4+. 9/4.5+. For lower rigged boat?
    With your skills Fanie - you'd get work elsewhere surely? Been thinking of this option more and more myself, thesedays..... dont like all this kill the farmer stuff coming back! I love this place but things are going downhill quickly! Would like to sail into the sunset but may have to move first - which would change my boat options/needs too......:confused:
  8. catsketcher
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    catsketcher Senior Member

    Do it if you want to

    As an innovator myself I have to second Richard's comments re innovation. I am the lucky owner of a heap of multihull magazines from the early 60s onwards. (The result of lots of collecting and a generous gift) What you realise when you look through the mags is that a heap of these ideas have been tried.

    Take the Crab claw sail. A proa was made by the Prout brothers in England and a commited sailor put considerable resources into making it work. It took more than 4 minutes to tack with 5 people. It was a disaster when compared to the normal rig.

    Take the freestanding mast. I love wires. I go against Rob Denney here but you lower the stresses on a rig by making the mast act as a compression strut rather than a cantilever beam. You get to hang sails off the wires up front - genoa and storm jib (I LOVE my storm jib on the inner forestay). People think there is something better about the freestanding mast - I don't really think there is. When I raced Lasers we broke masts still. In fact I broke more Laser masts than any other boat I raced. I also get to tune my mast to exactly match the characteristics of my mainsail. You can't tweak a freestander without adding carbon or shaving some off.

    The twin rig thing was done in the 80s as a racer - Jazz. It was okay - got a third in the Route du Rhum I think but was dropped. It wasn't fast enough. I for one would not like to have no safe spot to walk - walk to windward always safe on a single sticker - on a twin rig you don't have this option.

    As to speed - why bother. Speed is a furfy. Any well designed cat will go faster than the crew can take in 15 knots offshore. After this you will be slowing the boat down. You want a fast light wind sailor and a nice controlled boat in higher winds. You don't cruise fast so why the necessity to change?

    If you do the research you will probably find many of the innovations listed have been done and dropped. Do it if you want to but it probably has been done - Look up the AYRS, look through old mags, research will save you time and money. In the end build it if you like but get ready to cut it off if it doesn't work. It is probable it will not.

    I am a science teacher and think that the most powerful idea in science is natural selection. In it the premise is that most mutations are harmful but some may be beneficial. As conditions change - (in multi's case) better materials, different markets, different conditions there will be a change in the "gene" pool. This happened in the 60s-80s with the huge change in materials available to build lightweight multis. We have now entered a stable time where there is not much need for change in the gene pool of multis. If we run out of oil or there is a change in water access there may be a huge change again.


    Phil Thompson
  9. Fanie
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    Fanie Fanie

    No I doubt it. I'm probably as unemployable as can be after 20 years on my own :D

    Phil, I chose the free standing masts again for simplicity, no stay's and stuff to interfere with fishing lines. So even if it's not the fastest boat, it would be functional. I built the small tri to test the rig with, and I'm happy with what I experienced.
  10. Alex.A
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    Alex.A Senior Member

    Fanie - i haven't had a job since i was 18 - now 39!! wouldn't look fwd to slavery unless better off....
    Phil - own garden nursery and farm - horticulture - mutations are interesting and often beneficial...... isn't the bermudan one - or at least an offshoot of what went before?
    Model testing - then small boat.... only if ok would i consider large project!!!
    BUT - there's always a but.... curiosity is a human affliction , beneficial or not? At least - trying new things has pointed out to others that they dont work and save others the bother.
    Are we off topic yet?
  11. ImaginaryNumber
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    ImaginaryNumber Imaginary Member

    Have you posted a sketch of your ideal cat? You're such a prolific poster it's hard to know where you might have hidden any drawing... :)

    I'm particularly interested in knowing if you have a demountable design that includes a bridgedeck cabin which allows passage between hulls without going outside. I could imagine this as either the cabin attached directly to the hulls, or perhaps some sort of very short fabric tunnel connecting adjacent hull and cabin.


  12. ThomD
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    ThomD Senior Member

    "- Hobie Trifoiler is biplane. It holds a speed record for a very long time."

    Because at those speeds, the wind is off the nose at all times, therefore no wind shadow over the other rig. I don't much like biplane rigs, but they seem to be a current fad, and those who promote them have taken their interest to higher plane than 60s Ayers articles, etc... I just like wire on a wide staying platform.
  13. Alex.A
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    Alex.A Senior Member

    So where else can a cat be simplified - at least made cheaper ?
    Also easier for the diy builder....
    Given that it must be cheap - what would you all design / use?

    So far i am thinking 9m by 4.5 - 5m. Deep, curved v hull with reasonable rocker and possibly flat section across mid bottom. Single helm position with weather protection and either sealable bimini/cover or basic and low bridgedeck. Flat deck. Entry to hulls under cover/bridgedeck.
    Bi masted or ketch. Like the aftmast setup but.......
    Minimum to no through hull fittings. 9(ish)hp outboard - off aft beam or central through deck. Simplest systems - ie cheap. Single electrical point with rechargeable lanterns for berths etc. Only wiring up the mast to lights/instraments. No fixed water or petrol storage tanks - cans. Porta potti/bucket as heads. Minimum portholes and small. Ventilation a must though - for heat. Kick-up aft hung rudders and tiller........
  14. Fanie
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    Fanie Fanie

  15. Roger L
    Joined: Feb 2010
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    Roger L oldengineer

    Although I used to agree with your requirement, I now think that your "Given that it must be cheap" obscures the main problem that a person faces when building a boat.

    After several building projects, I now believe that building for cheap is an illusion. Money is so much easier to make than boats are to build that the cost of building should be at the bottom of the requirements; not at the top.
    Roger L.
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