Worse design

Discussion in 'Boat Design' started by gonzo, Jan 26, 2010.

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  1. BTG YACHT DSGN
    Joined: Oct 2008
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    Location: Poland, Warsaw

    BTG YACHT DSGN -sailing is believing-

    Don't be so pessymistic with that boat ;) The designer even tried to make her look like a retro one... (but he didn't succeed :p )
     
  2. Loveofsea
    Joined: Jan 2007
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    Location: Southern California

    Loveofsea New Member

    Easy, the ability to move the fuel tanks fore and aft at will is not a design flaw, it is an enhancement that was designed into the hull as was the lifting strake.

    I don't have a problem with trimtabs enhancing the handling characteristics of the hull because they are integral to the hull, not the lower unit. You shouldn't have to make the lower unit do what the hull is supposed to do, that's all....
     
  3. Easy Rider
    Joined: Oct 2009
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    Easy Rider Senior Member

    Love,
    I have to admit lots of professionally designed boats have the fuel tank(s) in the stern .. or even the bow. This is bad design in my book but at times safety issues dictate that fuel shouldn't be right beside an inboard engine. I have an outboard boat (Winner) whose factory fuel tanks are right against the transom. The most likely load (2 passengers) are w a y far fwd. It's a good thing the hull is a very deep soft riding hull or we'd get bounced a lot. I removed the aft tanks and have run portables since but felt w the weight fwd the boat wasn't running right and moved all fuel and a kicker all the way aft. The boat ran much better with the aft CG and the thought crossed my mind that the designer may know more that I gave him credit for. I think it's quite likely they (Winner) discovered the boat liked the aft CG during testing. The boat runs even better w a slightly aft of center CG (as would be expected) and I plan to build a 4 person center council w fuel under the seats. Unless the fuel tanks are small I think the only really good place for them is at or very near CG. Like the skiffs here on Thorne Bay that frequently have their tank far fwd to ofset the solo operator weight aft there are variations that have merit and can be (kinda sorta) OK design. In this case the operator decides the location of the fuel tanks.

    Easy
     
  4. Obsession
    Joined: Jan 2010
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    Location: Chicago, IL, USA

    Obsession Junior Member

    1.) Do you feel that you shouldn't use power trim on all boats that use an outboard or sterndrive with power trim to adjust the trim angle of the boat too? 2.) Would you argue that sterndrives/outboards should produce no stern lift and no bow lift at all? 3.) Why is a trimtab integral to the hull in your book and a lower unit not -- the lower unit is more strongly attached to the boat than most trimtabs.

    Is there a quantifiable disadvantage to the add-on lower unit foil vs. designing the same stern lift into the hull? Sometimes, probably. Always, I'm not sure. I generally dislike them, but I suspect there are a few cases where it can be an advantage.

    Another question is does the stock outboard/sterndrive anti-ventilation plate have the ideal design for all hull applications as there aren't any options there other than the overall unit - it's one size fits all.

    I myself have never fitted one, though I did have one on a used merc 150 that I didn't remove as the engine was a bit heavy for the 18' boat and it helped it plane faster.
     
  5. mark775

    mark775 Guest

    I believe that one actually formed these plots in a skiff. I also am familiar with the sportfishing scene in CA...I wonder, can you supply us with some credible known references to back up the more incredible claims (including having spent more free time in a skiff at sea than probably ANYONE and avoiding notoriety associated with such a feat)? How 'bout a pic of the WonderBoat? A name?

    scan0005.jpg

    I believe, but honestly, Santiago, I feel that you may have unwittingly exaggerated your claims.
     
  6. Loveofsea
    Joined: Jan 2007
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    Location: Southern California

    Loveofsea New Member

    Mark775- You say this:

    LoveofSea Say this: "Seeing the force ten definition picture, I now realize that I was wrong about what a 50 knot wind actually looks like. Further, I wanted to appear a bigshot and expanded upon my endeavors because I knew nobody would be able to call me on it. Chalk it up to being "caught in the moment". I really do love the sea, and will start keeping an actual log with photographic evidence and stop trying so hard to be accepted by strangers that I will never meet. I am Sorry."

    You have got to be kidding!

    Please forgive me if this sounds unkind, but i don't really care if anyone believes me or not. I have taken videos of every trip since '95 if i should ever need to prove anything. Everything i have said here is true. I run these seas in earnest, i'm not looking for your acceptance or anyone elses. I sincerely apologize if that offends you...

    Here is a pic of the skiff at the 2CB buoy, a hundred miles off the California coast :)

    One thing that puzzles me about that picture of my plot is that it shows 6ft which means i took it at the ramp, but it only shows 128nm which would account for a trip to SCI, from which the crumb trail ends.. Every once in a while i forget to reset my trip log, that's probably what happened. That loop from the Cortes to Nicolas is usually around 225nm by the time i get back to the ramp.

    When the sportfishing community here in So Cal declared 'war' against the Channel Island reserves back in '00, i quit the sport that had consumed my entire life. I now do underwater photography exclusively, so i am no longer part of that community. i do not use scuba gear to do my photography, so i am not a part of that community--i freedive with my camera, but i do not hunt so i am not a part of the freediving community either.

    Obsession, to answer your 3rd question:

    3.) Why is a trimtab integral to the hull in your book and a lower unit not -- the lower unit is more strongly attached to the boat than most trimtabs.

    As i have stated very clearely, the lower unit and the hull have two different functions. The L/U is for propulsion and steering and the hull is for lift and planing. In an optimal situation, why would you have one do the work of the other?
     

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  7. Obsession
    Joined: Jan 2010
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    Obsession Junior Member

    To back this up, I ask you what the disadvantage is of using the lower unit to provide some slight additional lift. Why not consider the lower unit and the hull as a whole system? I'm not arguing for the add-on foils, but if something is deemed "bad" it should be bad for a quantifiable reason. Does the add-on hydrofoil cause more drag? In those cases, I agree, it's a sub-optimal compromise and not one I would choose. Some however report that they've added a hydrofoil and it increases their time to plane while not affecting their top speed. In these cases, with thousands of boats already using the lower unit's or outboard's power trim to plane faster, adding a slight bit of lift does not seem wrong unless there is a drawback in doing so (breaking the anti-ventilation plate when hitting something could be a drawback; does the lift cause undue stress anywhere? and back to drag... any other reason they're bad?)
     
  8. powerabout
    Joined: Nov 2007
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    powerabout Senior Member

    The lower unit and prop are critical on a race boat as both can supply lift to either bow or stern depending on the design.
    So saying the LU is only for propilsion and steering is completely false even on a production boat.
    Your prop for instance LoveofSea, is a bow lifting style as are most production props and as it will pull the rear of your boat down and therefore is an ideal choice for a displacement boat or a bow heavy planning boat
     
  9. souljour2000
    Joined: Aug 2009
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    Location: SW Florida

    souljour2000 Senior Member

    Loveofsea---your still wrong about saying that all boats should not be able to take water over the bow...I hope we never have some fascist law in boatbuilding that makes designers build boats to ridiculous standards so that all boats are idiot-proof...even car designers cannot prevent old ladies from pushing the gas pedal instead of a brake and crashing into a storefront....these kinds of actions can never be prevented and I seriously am fearful for your life out there if you have people/family that love you...because your kind of arrogance is what gets people killed...You've managed to drive off one of the most knowledgeable people we had in here..someone who had tons more experience, real-life, anecdotally and otherwise and in many more areas of boating than yourself...when you are new to a forum..showing your *** to that community is an especially ineffective way to get your views weighed fairly by others...having listened to your argument carefully..I still think your full of grade-A Bologna with extra fillers and preservatives...despite the latter... your stuff still has gone bad ...a few months back in fact...so I don't mind saying I hope you move on...why not take a Galapagos trip in your super-boat?..I'll pay for the gas...
     
  10. troy2000
    Joined: Nov 2009
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    troy2000 Senior Member

    If that isn't the ugliest boat I've ever seen, it's gotta be close.
     
  11. mark775

    mark775 Guest

    It's so ugly that I want it!
    And, Santiago, post a pic of your boat!
     
  12. hoytedow
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    hoytedow Wood Butcher

    That boat brings out the 1950's in me. I love it!
     
  13. troy2000
    Joined: Nov 2009
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    troy2000 Senior Member

    I used to have a boat that was a take-off on a '57 Chevy--complete with fins, dash, steering wheel, tuck and roll Naugahyde seats, and two-tone paint job in red and white. It actually looked great. But they didn't try to shape the whole boat like a car; they just sort of suggested a kinship.
     
  14. Loveofsea
    Joined: Jan 2007
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    Loveofsea New Member

    Obsession

    If a fin makes a boat work better than without one, then the disadvantages are probably negligible, penalty of drag notwithstanding. All i have said is that for optimum performance, the hull does its job and the lower unit does its job, and one should not have to compensate for the shortcomings of the other. I'm quite sure that no one would use them if they didn't help correct a problem inherent to the hull, that's all.

    As far as stresses go, the fin would definately cause additional stress to the engine bracket which would transfer straight to the transom.

    <mod note: removed off topic paragraph>
     

  15. Willallison
    Joined: Oct 2001
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    Willallison Senior Member

    I've asked before and no doubt you've posted pics elsewhere, but could you please post another pic of this skiff of your Loveofsea?
     
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