Why can't most catamarans get over the hump ?

Discussion in 'Multihulls' started by tommymonza, May 4, 2014.

  1. tommymonza
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    tommymonza Junior Member

    So I have researched many of the threads on here and I am quite curious why some even so called light weight fast catamarans can't seem to get over the hump and breakout and start hauling azz?

    I grew up sailing on planning C and MC scows and graduated to a Hobie from there . Since than I have been an avid sailor of the Prindle 16 which is far superior in design ,sea handling, and performance over the Hobie 16.

    From there sailed a Hobie 21 .Which had a much better load carrying capacity .

    So?

    Even when heavily loaded the Slim non daggerboard hulls of the Prindle will provide a good turn of speed and acceleration in a puff , so why can't modern large catamarans provide the same turn of speed.

    I am pretty sure I know why but I need some affirmation from the all knowing on this board.

    I once chartered a 2001 Gemeni for a week and sailed it heavily and it was a fair boat but speed was unimpressive as I expected.

    The following year I charterd a Seawind 1000 with 2 retractable outboards but fixed keels thinking I was getting into a much more performance oriented Catamaran. All I can say is a experienced attentive sailor as I could have smoked by that Seawind helmed a by a little less experienced sailor as I in the Gemini

    I understand the drag of the fixed keels of the Seawind but for all it's sparseness it was a real dog . I do not want to beat up on that particular design in general, I just expected more.

    A couple years ago I chartered a Lagoon 44 flybridge and it was the same experience for performance as the cSeawind but twice the ameneties and drag with 2 saildrives in the water and twice the weight .

    Which brings me to another ?

    Recently I had a good friend puncture a decent size hole barely above the waterline through the hull of his 5 year old Lagoon 44 on the corner of the dock .

    I have years of background building fiberglass performance powerboats and large wood epoxy composite sportfishing boats.

    So I volunteered to help him out and fix it with another very experienced gentleman .

    What blew me a way was there was a simple outerlayer of 1708 on the ouside covering a layer of 3/4 balsa core and than a little bog on the inside and a single layer of 1708 .

    This is a very heavy boat so why save a 1000 lbs and maybe a few thousand dollars to not provide an extra 2nd skin of protection on the outside to guard against a puncture and soaking of the vulnerable balsa core?

    So why can't they get over the hump and move obviously they are trying to build them a l light as possible in the hull area.

    I would think at one point say 20 to 25 knots of wind with full sail as I have sailed botht he Lagoon and Seawind in on a close reach why can't they seem to bust out and run?
     
  2. Mr Efficiency
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    Mr Efficiency Senior Member

    Do i detect a plaintive undertone ? If you are pretty sure you know what the cause of the deficiency, as you see it, is, can you suggest the remedy ? If they were designed to plane, you would promise not to ***** about them being a dog in light airs ? No boat can be all things to all men. There are cruising boats, and there are racing boats, you can't always have the best of both worlds.
     
  3. gypsy28
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    gypsy28 Senior Member

    The cats you have mentioned in your post are all relatively heavy, comfortable CRUISING catamarans (mini keels, shorter masts/lower sail area etc.), that sail as you would expect a floating home to sail (still better than a leaner IMHO :D)

    Look into performance cruising cats and you will enter another world of performance. Designers like Schionning, Pescott, Grainger, Oram, Crowther (to name just a few Aussie designers) would sail rings (literally) around the cats you mentioned. All have Daggerboards, lightweight construction, taller masts with bigger sail area. These types of cats most certainly "get over the hump and breakout and start hauling azz" :D

    Your comparisons of lightweight beach cats to large heavy cruising cats is a little bit bizarre TBH

    As to the Lagoons construction. I dont know the laminate schedule that Lagoon uses for its cats, however, they have lots of cats sailing the world over, so I can only presume the construction must be OK atleast.

    Plus another one layer of 1708 doesnt sound like much, but must be in excess of 400kg/800lbs once you take into account the cloth weigh plus resin weight to cover the whole surface of the hulls/bridgedeck. 400kg/800lbs is probably a very conservative figure as Im not certain of the Lagoons hulls surface area, the weight figure could be substantially more. All that extra weight decreases payload, and will certainly not help with the performance :p
     
  4. waikikin
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    waikikin Senior Member

    Tommy,
    the boats you've referenced are relatively "pregnant" cruising boats with a fair bit of windage also, the owners of them like to have the space & lounge room with a view from the bridgedeck cabin amenities. Cats have heaps of square meters/yards of "boat" 2 x hulls & a connective structure/bridgedeck.... it comes at a cost of weight or expense if light.... & real easy to fill up with stuff. Plenty of semi production cats or stock kit boats do go good so long as a watch is kept on the kgs, check out Schioning, Crowther & Pescott as a few performance cruisers egs, Gun boat might be another in a bigger production boat but I've never seen one for real plus pretty exxy.
    Jeff
     
  5. tommymonza
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    tommymonza Junior Member

    Well to get to my thoughts .

    What I am looking at is designing and building a small 30 to 32 foot lightweight cat with minimal to no accommodations in the hulls and a small 8 by 8 bridge deck cabin with maybe 5 feet of headroom.

    Where I am twisted after seeing the current Cup races and seeing the designs is should I risk that I can build a light enough hull that can it take advantage of the planing ability of a flat straight running surface over a heavily rockered deep narrow hull such as the Spronk 65 that had recently had a mishap that in all fairness is a very similar hull design as a small Prindle 16 beach cat.

    Of all my research many claim the Tornado design is a superior design and far ahead of its time which the current Cup boats seemed to recently exploited only with more of a flat planing surface similar to a powercat than the cylindrical designs of past years

    So I am getting way off base from my original post already.

    I guess all i am looking for is will a flat bottom planning hull be more efficient that a narrow deep hull with fine ends?

    And if you are going to the flat bottom planning hulls why not increase the width of the hulls at the stern to create more lift and more load capabilities not only from stores on board but wind and wave loads?
     
  6. tommymonza
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    tommymonza Junior Member

    And thanks to all who respond I know as a Newbie I came out of the gate starting a chitstorm , Sorry about that and sorry about the ADD when posting a ?

    Awesome site and awesome people on here too.
     
  7. Ad Hoc
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    Ad Hoc Naval Architect

    You are going to have to define what you mean by "the hump" and "hauling azz" for anyone to answer your question fully.
     
  8. tommymonza
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    tommymonza Junior Member

  9. Mr Efficiency
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    Mr Efficiency Senior Member

    None of those boats featured much accommodation that I could see, Tommy ? Could that be because they are just racing boats?
     
  10. waikikin
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    waikikin Senior Member

    & not pregnant..... the orange foils, spinnaker & green sails help too.
    The fastest boats on the day however were the RIBs "chasing" them around, great spectacle!

    Jeff.
     
  11. oldsailor7
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    oldsailor7 Senior Member

    Tommymonza.
    Try looking at Richard Woods range of Cats. He has some very fast designs with centre cabins in the length range you want.

    The 32 ft Eclipse comes to mind. :D
     
  12. Alan.M
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    Alan.M Junior Member

    Most cat's don't have a "hump" to get over. That is, they don't have to get on the plane to exceed "hull speed".

    Cat' performance basically comes down to sail area : weight. Boats designed to be put into charter are almost always fitted with conservative rigs, and pretty small sailplans.

    I can't think of anyone who would suggest a Lagoon is a light weight, fast catamaran.
     
  13. Ad Hoc
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    Ad Hoc Naval Architect

    For you to understand something, you need to be able to define what it is you're referring to. If you can't define it, then how are you going to understand it?

    That's just a video...it is not a definition.
     
  14. Mr Efficiency
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    Mr Efficiency Senior Member

    Young man in a hurry imo.
     

  15. rwatson
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    rwatson Senior Member

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