recommend me a loftsman

Discussion in 'Boat Design' started by peterroderick00, Sep 7, 2013.

  1. peterroderick00
    Joined: Sep 2013
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    peterroderick00 Junior Member

    i have an aluminum offshore performance boat on paper ,in side,top,fore &aft to build & need any recommendations anybody could give me for a loftsman skilled in this kind of boat to help me develop it from the chine down & professionally loft the rest...ive been following threads that have been posted on this forum for quite some time now about hull design & ive come to the conclusion that paying a professional will probably save me a lot more than it`ll cost me to not & id like to make sure the boat does a little better than look real cool OUTTA the water...any help`ll be appreciated thanks in advance
     
  2. TANSL
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    TANSL Senior Member

    I'm sure I can help. Send me additional information, if you believe it appropriate, to my email: 657677483@orange.es
     
  3. Ad Hoc
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    Ad Hoc Naval Architect

    A knowledgeable local naval architect of boat builder should be able to assist, if you have any local to you?

    One assumes this is for a build?..if so, then you could even provide the lines, as offsets, to someone who is well versed in maxsurf/rhino and then if you provide them with the frame spacing, they can provide you with cutting files. It is the same thing one is done by "hand" on a scrieve board, the other by "computer" pressing buttons. So long as the person doing either method is experienced and understands shapes, and fabrication, you'll get the result you need.
     
  4. peterroderick00
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    peterroderick00 Junior Member

    you're right ..its for a build for myself .. I`ve built 2 aluminum boats now..1 from bruce Roberts & 1 from my own design, I'm a compitent fabricator & an avid boater & I had the thought to try to wring some speed out of a hull thru the thought that lighter is faster..i have at least a fair understanding of hull design when built with aluminum, but I don't want to guess at things like frame spacing or longitudinal thickness, etc. not many guys on the east coast use aluminum & I'm in mass. now & my work carries me between here & atlantic city nj...it seems that the industry in mass mostly caters to sailboats & in south jersey mostly caters to sportfishing ..should I be scared to allow a naval architect that doesn't usually design for performance answer my questions ,or do you think any operating naval architect will be ok?...I can look one up in the yellow pages I guess?..im just kinda scared to just go using the first guy I trip across ya know?....word around the campfire says to use about 22 - 24 deg. in the transom for about the first third (starting at the transom ) & fair out to 58 or 60 toward the bow....whats maxsurf/rhino?..& thanks for the reply
     
  5. Mr Efficiency
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    Mr Efficiency Senior Member

    If your boat is 22-24 degrees at the transom, and you are aiming to have a light boat to enhance speed, you have a conflict to start with, since unless you adopt some kind of water ballast system, the hull will sit too high on the water and be a rock and roll nightmare at rest, and a probable handful at speed with potential chine-walking and laying over in cross winds.
     
  6. Ad Hoc
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    Ad Hoc Naval Architect

    It really depends if you’re happy to communicate via email/web, in lieu of face to face meetings as such? If you’re happy to go down this route then there are many options available. You could seek assistance in that regard from those “not too far away” from you, such as 2 very experienced designers here (click on their names):-

    1) PAR

    2) Tad

    I’m sure either of these shall be able to give you want you want/need via email and a good experienced service too.

    It is just a computer program for drawing lines. It’s what the mould loft used to do by hand, but is now done by pressing buttons!
     
  7. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    I can loft your boat up full size if desired, though being local may be more of a convenience to you, but with UPS, this may not be as important as first glance suggests.

    I think you are underestimating the industry. There are several aluminum builders in the northeast, including Massachusetts and New Jersey, with 95% focusing on powerboats, not sail. There are also several (many) other hull material builders in the area, that could loft the lines, which has little bearing on hull material choices made.

    It sounds like you need more than lofting though. It sounds like you need scantlings worked out, likely full up hydro and weight studies as well. This is considerably different then producing full size lines from the offsets.

    The choice of hull material (wood, aluminum, steel, 'glass, etc.) has very little bearing on how a hull is designed. Of course you do have some compensations for weight, strength and stiffness between the various choices, but the hull form itself will remain the same, across all the materials, with some volume distribution necessary for some materials (like steel or a heavy GRP laminate).

    I interpret the above comment as you have a good idea of the usual way scantlings are applied to aluminum hulls, because that's what you've been doing. This is a fair bit different than understanding the dynamics of the structure and the associated load paths within it.

    Not trying to rain on your parade, but, it sounds like you'll need some professional help to iron out the details, sort through scantlings and produce the lofting. If this boat needs to qualify for specific class, regulation or other requirements, you'd be best advised to pay the bucks, if for no other reason than you can get it insured.
     
  8. peterroderick00
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    peterroderick00 Junior Member

    im certainly not ABOVE including a water ballasting system(certainly not a bad idea)...is it weight that reduces chine walking?..will trim tabs control that?..it seems the offshore performance boys are always fighting to shed the lbs,but nobodys using aluminum out there...ill email these 2 guys & see what they say
     
  9. peterroderick00
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    peterroderick00 Junior Member

    & PAR..your definetly not raining on my parade..this is the info im looking for!..& the whole reason for registering to post a thread was for the fact that I realized those things ..or more specifically that I didn't realize things like hydro & weight studies etc.,doyou do these things as well as lofting?
     
  10. Mr Efficiency
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    Mr Efficiency Senior Member

    Another reason alloy may be off the menu in performance offshore monohulls is the difficulty in obtaining the best shape for rough water ride, you are pretty well stuck with an underbody where the deadrise angle at the centreline is the same from the forefoot back, which isn't as good at cleaving water, imo. Tabs may help a lightweight boat that is perched high on the water at speed, but that would depend on a few things, like whether you are using singles or twin engines etc., you may be able to use drive trim to some extent, or strakes tailored to your lightweight boat.
     
  11. peterroderick00
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    peterroderick00 Junior Member

    forgive my ignorance but wheres the forefoot?..& I had the thought to set the strakes a bit closer to the keel than the chine which seems to be the going tradition as far as I can see...until someone told me that raising strakes don't really raise anything..they just knock down the spray associated with offshore performance boats...or so they said...they sure look like they`d push the hull up as the boat moved forward to me??...but ill be damned if I don't atleast LISTEN to anybody willing to gimme an education...hence forth my original post...I`d probably be better off paying a pro to just tell me the truth...& by the by it`d be a twin engine application ...side by side or staggered im not sure yet...more food for thought I guess
     
  12. Mr Efficiency
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    Mr Efficiency Senior Member

    I'm not a pro, but I believe I've picked up a few clues over the years. Strakes certainly can stiffen up crosswise tenderness in fast boats, but they can only do it if they are in the water, and a light boat going fast may be too far out of water for effective use of them, and of course the nearer they are to the centreline, the less will be the righting lever, but still more effective than none there. The forefoot starts where the flat keel line ends.
     
  13. peterroderick00
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    peterroderick00 Junior Member

    ya know what...that's 1 of my biggest questions(forefoot) ...does the last 1/3 of the keel have to be flat?...or should it be??...THAT was the straw that broke the camels back & showed me just how little I knew about it & pretty much sealed the deal for paying an architect...it seems as if a performance keel should carry atleast SOME camber through the entire length to have a good cutting action ( like a samurai sword for lack of a better parallel )& as far as the strakes go ...I about figured as much..in large part most hull design kinda seems to be common sense ...its just the idea that the smallest changes can have the biggest effects one way or the other..& im guessin one of you guys might be able to give me atleast a better starting point...in the 15 mins. I`ve spent on here I`ve picked up more already than I have in the past 4 years I`ve been payin attention to the whole subject....maybe if the boats too light a deeper v with wider than normal strakes & chines would benefit the hulls performance??..im sure that fix comes with some oversized bag of things youd have to trade other attributes for as well
     
  14. Mr Efficiency
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    Mr Efficiency Senior Member

    Pretty sure the Cigarette hulls had a little bit of rocker in the keel line, which I'd guess made it easier for the bow to rise to a wave, rather than bury into it, in, e.g., following seas. But the other side of the equation would be a little bit of porpoising. But you can't argue with something as sucessful as those hulls.
     

  15. Ad Hoc
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    Ad Hoc Naval Architect

    Well, there lies the problem. What is your SOR?....Statement of Requirements?

    All hulls can do just about anything. But not every hull will be suitable for YOUR application. Thus, without an SOR it is just general chit-chat about hulls without an objective in mind. The whole design revolves around the SOR.

    You need to define what you want the boat to do, and what is your "wish" list. Then the hull lines can be drawn accordingly, rather than a scatter gun approach of what may or may not be best in the aft or fwd 1/3 of hull etc.
     
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