Sueños Mojados

Discussion in 'Boat Design' started by Saqa, Jan 11, 2015.

  1. Richard Woods
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    Richard Woods Woods Designs

    I doubt he will go that route as he has already said he won't go for the open deck Jazz30 and fit it out to his own requirements.

    http://sailingcatamarans.com/index.php/designs/6-powercats/438-jazz-30-fishing-power-catamaran

    He is using a puzzling approach. He doesn't yet know (or at least won't admit it on this forum) what the deck layout is, what the scantlings are or how it will all be joined to together.

    So has no real idea of either the weight or the CofG of the boat. Yet he has already drawn a very precise lines plan.

    Richard Woods of Woods Designs

    www.sailingcatamarans.om
     
  2. groper
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    groper Senior Member

    saqa, your canoe stern is still not as tennant designed it... move the keel trailing edge well forward so the prop gets some clean water - look at the prowler pics again. The outboard leg is a streamlined profile which is also your rudder, so the drag is minimal. The hulls rear planing pad immersion is dictated by the propeller diameter. You want the bottom of the keel just deeper than the prop to protect it, and the rear planing pad at the same height as the cav plate on the outboard. This will allow you to run std shaft length most likely, long shafts wont be required as the powerheads will be quite high anyway. Again, look at the prowler videos and photos.
     
  3. Saqa
    Joined: Oct 2013
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    Saqa Senior Member

    Richard, I am a bit taken back with this remark
    Didnt I say its hard to tell from the drawings shown so far that its hard to see just how much the forward beam will be getting in the way of an open and level deck
    That I am interested in seeing some 3D renditions to get more of a perspective on it
    That I am interested in seeing how you define open deck with the Skoota 36 example
    That I will try to draw the layout I have in mind and see what are your thots on that being compatable with the Jazz

    On another fishing forum in a conversation with someone who is already drawing up shopping lists for the Jazz I mention that I hope to put the Jazz on the water within 3 years

    So the tone of this post here and your conclusions are somewhat puzzling to me

    http://sailingcatamarans.com/index.php/designs/6-powercats/438-jazz-30-fishing-power-catamaran

    Doesn't the fact that I keep mentioning as level work space as possible from front to back and side to side with a centralish cabin/console right from my original question re the Skoota 20 through to the whole thread culminating in the birth and evolution of of the Jazz 30 tell you the deck layout I am interested in

    Off course I dont know exactly how I will connect these two plastic hulls together just yet

    What do you mean by wont admit?!! I did not think this was some sort of inquisition! Lol, at the momment its standing at I have some ideas but need to work on it more

    I have a pretty good estimate of the hulls weight, motor weight, crew weight, fuel weight and the max boat weight I want to stay under and working on a bridgedeck that will fit into that and be sound. It may not be everyone elses ideal of a real idea but works for me as a point to aim for. I am ok with my approach, as it is at this point my model is at the point where I can see what I can play with where heights above the water is concerned and max beam dimensions I can apply

    I have already demonstrated on this forum that I do have the basic ability to draw a well sculptured hull form and get it on the water with the boat sitting level on splash day with everything correctly placed to accommodate increased crew number without affecting trim. That I can execute fine detail during build

    You can scoff all you like but I am happy with what I am working on its only a paddock basher for banging around here, not a refined sports cruiser
     
  4. Saqa
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    Saqa Senior Member

    Groper
    This will mean redrawing to a similar immersed volume but narrower beam and taller immersed height. I am ok with that. Also keeping the same beam but getting rid of the CS gives me around 9" of draft so less wetted transom then the original drawing and cav plate at the transom level

    What are your thots on going for the 60 instead the 40 due to same weight?
     
  5. Saqa
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    Saqa Senior Member

    Guys, I dont come on here to pick a fight.
     
  6. kerosene
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    kerosene Senior Member

    I don't think other people are trying to pick fights either.

    But you absolutely miss points being made all the time. Richards point about scantlings, structures etc. is that you are creating lines for the boat without knowing how the weight is spread around on the boat. Throwing an arbitrary number for the total weight is not much alone - and even that seems to change.

    I follow a motorcycle forum about vintage performance bikes. That forum gets all the time posters who bought theirs 1st motorcycle ever and then have made horrendous modifications to their 70s/80s japanese bikes. Modifications that in their uneducated mind are "hot stuff" but in fact make the bikes perform worse, often less safe and less comfortable. And these guys - well 95% of them - come asking for feedback but get all butthurt when the feedback is not what they wanted to hear. I see this same exact pattern here.

    People are not criticizing because they are against you, want to guard secrets, hate small guy succeeding etc. They criticize because they think you are doing things in a silly way that will mean huge investment of time and money and result in a bad boat.
    You have never designed a boat, or built one and you choose to use manufacturing method that you see nowhere for the size of boat you are planing. Shouldn't this raise a warning?

    I have used a film student analogy previously in a similar situation. You get an eager film student who wants to break the mold of modern film making. You know break the cliches and all. Screw tradition, its a shackle. He wants to think outside the box. Then they go and make their art film - without learning first about the trade and the work of previous masters. What will result is piece of crap art film that looks exactly like one made by a naive art student looks like. A cliche in itself. Full of stupid mistakes (of course its art so you can say they are not). You have to know the box before you step outside of it.

    25-30ft cat is a not a small project. By being arrogant towards the experience of and knowledge of others you will make them run away from your thread. Its a loss only to you.

    and btw. I don't mean to pretend that I am one of those with the experience. Learning about boat design is a hobby of mine.
     
  7. Mr Efficiency
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    Mr Efficiency Senior Member

    I do know saqa is making work for himself, if he really is going to make two different boats, one would be more than enough to take on.
     
  8. Saqa
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    Saqa Senior Member

    Kero, while the type of project I want to build may not be conventional, it doesnt mean that I cant enjoy doing it. I have been nothing but positve in contributing from my field of knowledge towards his project. Its his right to choose how much he wants to contribute towards my project and I dont have a problem with that at all. I do have a problem with his condescending and scoffing approach to addressing my project here and now

    I am set on the material I have picked for this project and will try to make the best of it, thats not being arrogant its determination. The boat might be a pig but it might not and I can recycle the materials into other projects around the farm

    I can explain what may have given the impression of ignoring good advice. Its due to claims of leaching it has actually become hard to take on positive contributions. I dont know if you have followed this entire thread but the consensus by contributors were towards a not so immersed transom, which I have tried to work towards without questioning how I should do it and looking to Groper for some guidence towards whether if I am on track. I have not argued with any contribution whether positive or negative prefering to go away with it and learning more about it. I only have a problem with the tone of a couple who have entered this thread
     
  9. kerosene
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    kerosene Senior Member

    I did not mean to refer to anyone specifically. Your use of "he" seems to be directed towards ad hoc, my comments were not really about him.
     
  10. waikikin
    Joined: Jan 2006
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    waikikin Senior Member

    perspective..........

    Hi Saqa,
    harness some Pacific vibe, we had some nice Vakas here a few months ago, like 4 with Fiji, Cook Is, NZ, & Samoa.
    Wake up call around here, lots of fun, good dancing, singing & party:)

    Seems strange that the perspective can be lost, we often get into the world of boats that we find fun & the reality of work & responsibility can drive that away.
    Also you come from an island nation with a long history of seamanship & application of the catamaran concept...

    Your efforts in the skua style runabout & so far in developing your powered catamaran are impressive... in my family we encourage to think aloud & wear encouragement & criticism with the care intended, sometime the harsher the criticism the more the care & love are displayed. Often similar here.....
    I love that your history of construction are displayed here, also the child pictured looking on & in the pics, reminds me of growing up surrounded by boats & their construction, playing with the plane curlies, "helping" sweep up & using the boats, going crabbing....
    My first own boat was a surfcat style catamaran, the windrush 12 had just been launched & demos were off Balmoral Beach I think, we never got a go, but my Dad looked it over well & shortly after on my birthday got plywood, inside a few weeks a beautifully varnished version with an old set of VJ sails(cotton) & a mast & boom created in clear douglas fir reclaimed from large roller blinds from a firm my Pop worked at set sail across the clear waters of Port Hacking.. & that's the start of my catamaran story.

    Jeff
     
  11. Mr Efficiency
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    Mr Efficiency Senior Member

  12. Saqa
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    Saqa Senior Member

    I actually meant Richard as 'he'. Refering specifically to the tone of his comments. If I had that kind of attitude towards contributing or participating I would have scoffed at someone designing a fishing boat without and knowledge or experience of fishing in the thread that led to the Jazz 30 concept

    Mr E
    Bula vinaka

    Jeff
    I can totally picture that :) I am looking forward to actually building the 'flying tupperware', should be very rewarding and fun experience for the whole family
     
  13. Saqa
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    Saqa Senior Member

    Groper
    Is this what you meant? Its 20" from the top of transom to bottom edge + 12" skeg height. 13.5" draft at 800kg. Should be able to put a 20" shaft on that. The skeg is offset 24" forward from the transom edge

    I can narrow the max waterline beam more from current 68cm to immerse it more

    [​IMG]3D 014 by jonny.toobad, on Flickr
    [​IMG]3D 013 by jonny.toobad, on Flickr
     
  14. groper
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    groper Senior Member

    Yep, your hull beam could be reduced some. You might also have to move the volume distribution a bit aswell so that the CoB is closer to the longitudinal center of the boat.
     

  15. daiquiri
    Joined: May 2004
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    daiquiri Engineering and Design

    Is it my impression or you have narrowed the bow too? If you did, then you can expect a wet ride in choppy head seas. If you didn't, then it's probably just an optical illusion - so ignore this.
     
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