yet another mono/tri question

Discussion in 'Multihulls' started by HeavenBound, Jul 16, 2009.

  1. HeavenBound
    Joined: Jul 2009
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    Location: Ontario, Canada

    HeavenBound Junior Member

    Greetings from Canada!! Last year I got my first sailboat in 30 years, after spending alot of time and money in drag racing and high performance motorcycles. It is a stripped down Taser( missing alot of parts). There was enough to get it onthe water but not much else.I'm fortunate that my wife does want to sail, but we are not as agile as we once were, and found the Taser to be too tippy.So this year I purchased a '76 Hobie 14 in great shape, and have loved the stability, speed, and learning to sail all over again. My question is has anyone tried to make a trimaran out of these two boats?? From what I've read on this site the Taser, being a planing hull and the Hobie a displacement hull will still work,although some loss of speed due to larger wetted surface. Also as both are approx. 14 feet will this end up being like the Weta, and prone to pitchpole?? I do hope someone has tried something similar to this and can advise us. The main reason I'm considering this is because as I near 50 years old, sitting on the trampoline for long periods of time is becoming painful( back injuries) and the cockpit of the Taser is rather comfortable. We sail on small inland lake, winds are fairly light most of the time( 15-25 kph) and from some of the comments I've read it would be alot of fun to try to and get it to plane on the main hull often.
     
  2. Doug Lord
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    Doug Lord Flight Ready

    Super 20

    Here are some old(36 years!) pictures of an experimental 20' tri I designed and built years ago. The boat had a planing main hull and amas(outside hulls) styled after a Hobie cat but symetrical instead of asymetrical.They were excellent in waves no tendency to pitchpole. The main hull would plane and it was quite fast in winds over 10 knots. The disadvantage of a planing main hull is the extra wetted surface in light air-but you can't beat the room and the thrill of planing!
    Good luck with your boat-go for it!
     

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  3. Richard Woods
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    Richard Woods Woods Designs

    sorry, I count three hulls so doesn't that make it a trimaran?? Or maybe that's why you called it "experimental"?

    Richard Woods of Woods Designs

    www.sailingcatamarans.com
     
  4. HeavenBound
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    HeavenBound Junior Member

    Thank you so much for the pictures, and the vote of confidence Doug. Any ideas whether the Hobie hulls will eliminate the need for the centerboard? This is my first attempt at " boat Building" and all help is appreciated
     
  5. Doug Lord
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    Doug Lord Flight Ready

    Thanks ,Richard- brain fade or something more? Yeah, it was a tri!
     
  6. Doug Lord
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    Doug Lord Flight Ready

    -----------------------------------------
    There is a lot of shallow water where I used to sail the boat so I tried little fins on the amas-you can see them in the pix. Worked ok in combination with the narrow amas. But I wouldn't get rid of the board-you'll appreciate it going upwind in enough water. The asymetrical Hobie hulls will work a bit better than mine did-be sure to put the flat side outboard... A symetrical ama would be faster if it was a low wetted surface design but it would cost some shallow water performance-everything is a tradeoff.
    ------------------
    There is a potential BIG problem that I'm sorry to say I didn't catch until now: the hobie 14 hulls may add too much weight to the Tasar! When sitting level you don't want either outside hull touching the water on a boat this size-in my opinion. You need to weigh the Hobie and consider the weight of cross arms you might use. Chances are it will be too much weight.
    There are numerous catamaran hulls that you can pick up inexpensively-I got a 20' hobie miracle for $300 in good shape. To use the 14 hulls and carry two people you'll probably need something about that size.
    Sorry I didn't catch this earlier.
    ============
    PS As you can see Richard Woods-a great multihull designer- posts on this forum ask him for his advice-PM him.....

    ===============================
    Heres some info on the Tasar that shows that it was designed for about a 300lb TOTAL crew weight. That gives you a starting place. For performance you wouldn't want to exceed that weight by more than about 40lb max.:

    "The Tasar is a 14-foot (4.3 m) fibreglass 2 person sailing dinghy with a mainsail and jib. Designed by Frank Bethwaite of Sydney in 1975, the boat is technologically advanced. Aimed at a husband and wife/parent and child crew, it is designed for a combined crew weight of 140 kg. The hull weighs 68 kg, and is of sandwich foam construction. he hull has a fine angle at the bow to reduce wave impact drag with unusually clean and sharp chines aft to ensure very free plaining and outstanding stability. The foam cored hull is stiff and light and the advanced hull shape, together with an innovative rig which combines a rotating mast with a fully battened main sail, allows the Tasar to plane upwind with the crew normally hiked. The wide beam and a cockpit designed for comfortable hiking make the Tasar easy, fun and very exciting to sail in winds up to 25 knots (46 km/h)." from wikipedia
     
  7. Chris Ostlind

    Chris Ostlind Previous Member

    Doug, did it plane with both amas out of the water... as in, it really planed on its own, main hull dynamic lift...? Or, did one of the amas have to be immersed, leveraging said main hull up via mechanical advantage, in order to, er... plane?

    If the former, where are the pictures of the event? If the latter, then it really didn't plane, now, did it?

    The mythical club joining ceremony lives still, does it not?
     
  8. HeavenBound
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    HeavenBound Junior Member

    Well, last September when we finally figured out how to sail again, we were able to get the Taser to plane upwind, with a crew of approx. 440 lbs. It took more wind but still do able. So.... if the taser having 123 sq. feet of sail area could do that, then my plan of using the 118 sq. ft. main sail of the Hobie, and reworking the 90 sq. ft. main of the taser as a fully battened jib/genoa(the Hobie 16's have a battened jib thats where the idea came from) should overcome the extra weight I hpoe. Perhaps this is just my motorsports way of thinking ( more power to overcome extra weight)
     
  9. Doug Lord
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    Doug Lord Flight Ready

    HB, whichever way you go just take it easy and plan ahead very carefully. Your enthusiasm is great to see and will get you thru rough spots. Good Luck!
     
  10. HeavenBound
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    HeavenBound Junior Member

    The advertised weight of the Hobie 14 is 240 lbs. fully rigged, so that does mean a lot more weight. If the ideal crew weight is 300lbs, that leaves only 60 lbs, 100 if we include the extra Doug suggested. So to eliminate excess weight will be necessary. Any more great suggestions???
     
  11. Doug Lord
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    Doug Lord Flight Ready

    You might consider just using very small amas with something like a cubic foot of total buoyancy say 5-7' from the centerline arranged so they are out of the water when the Tasar is level. You're just wanting(as I understand it) to reduce the tippiness-at least so it won't roll over. This would be simple- you could ty it experimentally with styro foam "buoyancy pods" and see how well it works. You could get something like a 2" diameter carbon tube(approx .093" wall) with a ferrule in the middle so you could "unplug" it when you're done. You could use a cheap second hand alum. tube just to try it out.
    This would not add any appreciable righting moment but would allow you to use the tasar without worrying about it rolling over and do it very lightly.
     
  12. HeavenBound
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    HeavenBound Junior Member

    I 've been reading these threads since last October, and still didn't realize just how difficult this will be. It seems that the initial speed will be somewhat diminshed by having the amas in the water, but as stated earlier in this thread most things are a trade-off. I'll go with the Hobie hulls, try to get them as much as possible out of the water, and live with the results. With a small boat as this, alot came be done to move crew weight around and better the situation. One more Question. I've read on some other threads that the stresses on the rigging is 3 times that of a monohull. Is this correct??
     
  13. Richard Woods
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    Richard Woods Woods Designs

    It is quite feasible to do a beach cat as trimaran outrigger/rig conversion. I am just finishing off my Strike 18 trimaran, with a 16fter to come soon.

    However I wouldn't recommend starting with either a Taser or a Hobie 14.

    The Taser is a lightweight, solid decked-in cockpit, low freeboard boat. Thus it will be difficult to add beam fastenings, for example. And there won't be much displacement (as Doug Lord said) to carry the extra weight of two more hulls.

    The Hobie is a heavy boat, but more important the beams are attached on posts, forcing the mainhull to have high freeboard so that the beams fit sensibly.

    The key design point is the position of the beach cat beams. Obviously they must line up with some structurally strong and wide part of the mainhull yet not interfere with the sailing deckarea.

    So my suggestion, if you want to try it out, is (as you are in east Canada) to look for an Albacore as the main hull. High freeboard, long open cockpit, lots of displacement, usually wooden. So all big pluses.

    And I'd look for a different 14ft beach cat.

    Sorry to be negative about your project

    Richard Woods of Woods Designs

    www.sailingcatamarans.com
     
  14. HeavenBound
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    HeavenBound Junior Member

    Thanks to one and all for your expertise on what I thought would be a fairly straight foreward transformation. Well Richard, there are alot of Albacores around in Southwestern Ontario, and maybe this whole plan needs to be totally redone. I guess it's back to square one. Thanks everyone again and when I come up with plan "B" I'll certianly check with you again. WES.
     

  15. catsketcher
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    catsketcher Senior Member

    Sail the Tasar

    In my other life I race Tasars here in Australia. They are great boats and they are good for older sailors.

    Most of the competitive Tasar sailors are over 40 and lots over 50 (the current world champ is from your part of the world and about 45) so I would suggest bettering your sailing skills rather than your building ones. The tippiness you refer to is your boat's way of talking to you. You just have to understand what it is saying and what the boat needs. Putting amas on will deaden you to the wonderful world of dinghy sailing.

    As a quick note - the Tasar has veed forward sections. Sit further back if you feel tippy. Get your wife in over the stern from the shore and support the boat until you push off - sit down the back on the fat stern sections until you have finished pushing the rudder down.

    When sailing - never cleat the main - NEVER. The Tasar has cleats for the mainsheet and the traveller. If the traveller is cleated the mainsheet is in your hand and visa versa. Always sit the skipper on the gunwale and look into the wind to watch the gusts and lean more and ease the main as you get a gust and lean in in a lull. In the end you will learn to be one with the boat.

    I may get a little flack for this but small multis are not very good for improving your sailing skills - they lack responsiveness and feedback - they allow you to sail poorly. A small dinghy is a fab boat as it will let you know when you are not treating it right. Get online and join a Tasar forum - ask questions there and if you decide to get a bigger multi one day you will be a better sailor for it.

    cheers

    Phil
     
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