Incredible "Secrets of Yacht Design" website located...

Discussion in 'Sailboats' started by pkoken, Jan 6, 2005.

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  1. JSI - NavA
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    JSI - NavA Justin

    Ever thought of simply doing some research on any of these subjects? Actual, published data, say, from SNAME (Society of Naval Architects and Marine Engineers) might be handy for most of the claims you've made. Try looking for the "Principles of Naval Architecture" published by SNAME. It should answer all of your questions on speed, stability, motions, you name it. In the context of ships, but water is water, and in the end it still needs to float.

    Or you could find something cheap at Borders and still be in better condition.

    Cheers
     
  2. sailsmall
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    sailsmall Senior Member

    Frank's typical resonse to suggestions like yours is that East Coast yacht designers are conspiring with US Sailing and PHRF-NW handicappers to prevent advanced designs such as the Mac26x from competing on an even field with such obviously flawed designs as the TP52. He seems to have clammed up suddenly, but maybe he'll come out of hiding and express it in his own, more entertaining, manner.
     
  3. Mark 42
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    Mark 42 Senior Member

    East is least... West is in a conspiracy...
    I guess that leaves the Great Lakes region and the desert areas.

    I guess the M26 is like a landsailer and capable of up to 3X the
    true windpeed somehow. Frank's gonna be jealous that I thought
    of it first.
     
  4. water addict
    Joined: Jun 2004
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    water addict Naval Architect

    Many others have suggested as per above. Technical training is an avenue for being brainwashed by the establishment according to the great miggie. Only those with no background in anything at all are worthy - in other words, all floating craft should be designed by my 2 year old before he gets corrupted by the evil, conspiring, entrenched heirarchy.
     
  5. petee
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    petee Junior Member

    Mac26X

    I had a Mac26X 2000 which I bought due to the price of around $22K with 25 HP Honda 4 stroke.
    I sailed it quite a lot offshore as well as ICW here in Florida.
    My opinion: it is built rather light! Thin hull although it does have a liner also.
    Lots of fun for week-ending, but porta potties ain't my thing!
    Docking was a chore as the boat would blow off just as you were almost to the dock, so windage is a problem.
    After sailing it for a year or so I was able to sell it at no loss, so their value holds up anyway.
    Rigging for sailing at the dock was ok, but in 90 degrees in the parking lot
    it took about 45 to 60 minutes.
    My Hunter 280 1998 followed which I enjoyed much more , however had to let it go when I retired and been landlocked ever since here in north Florida!
    You will see under"boat building" wooden boats, my post as I contemplate building a catamaran ,at age 71 not sure how this will work out. Pete
     
  6. Mark 42
    Joined: Feb 2005
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    Mark 42 Senior Member

    Consider a Trimaran instead.

    Click the picture for more info.
    [​IMG]
     
    Last edited: Aug 18, 2005
  7. mighetto
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    mighetto New Member

    Move West Young NA

    I am quite pleased that SNAME is getting some attention. If you read through the TP52 thread you will see that it was analysis to the capsize risk ratio of SNAME that exposed the TP52 as not being worthy of Trans Pacific work. Hence I proposed that they be called TransPortable and not Transpacific. Ted Brewer has a great spread in the August Good Old Boat. On page 13 (as in 4 times 13 is 52) there is a comparison of the Bristol 29.9 to the C&C 30 the Catalina 30 and the Ericson 30 which are said to have high capsize numbers. However SNAME is clear that the ratio is to be calculated with the boat at half load for an ocean crossing. With such loading the numbers are lower. Brewer apparently is free to speak out now. He really has important things to say about design and of course the old books at Borders are what he now corrects.

    On page 15 is an excellent diagram of two hulls one wide with a fixed bulb fin and one thin with the bulb retracted. He stats "Both shapes are one half of the same oval. It's obvious which one will remain upside down longer". Unfortuantely it is not obvious to those who have been trained by US Sailing acredited sailing schools. Things obvious to the untrained are points of disagreement to those trained in a closed minded society. Points like why buy a boat that sinks when flooded when technology exists that can keep them floating. This is proven technology not only in the Mac26 boats but also in the Etaps and Potters and others.

    Brewer also points out the fraud in Teeters video - the one where he sandbagged a mac26x and was able to flip her but only with the mast down. This presentation meant to descredit a superior and proven design.

    "Having the weight of the rig aloft greatly increases the boat's transverse moment of inertia, in other words, its resistance to the kind of snap and roll that can occur when hit by breaking sea."
     
  8. SailDesign
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    SailDesign Old Phart! Stay upwind..

    Just goes to prove that a little knowledge is a dangerous thing... And mighie has VERY little knowledge when it comes to naval architecture.
    Steve
     
  9. Skippy
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    Skippy Senior Member

    Spaghetto: Teeters ... was able to flip [a mac26x] but only with the mast down. ...
    "Having the weight of the rig aloft greatly increases the boat's transverse moment of inertia, in other words, its resistance to the kind of snap and roll that can occur when hit by breaking sea."


    So Frank, how high were the breakers in the little pond they did their test in?
     
  10. mighetto
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    mighetto New Member

    little man takes on Brewer

    Just goes to prove that a little knowledge is a dangerous thing... And mighie has VERY little knowledge when it comes to naval architecture.
    Steve


    Oh I think I am fast coming through my amature designer phase. Yes I am ready to take on the professionals. Lets try this out. The Internet is blasting the hell out of the professions because so much of what would have been secret or discussed only in cloisters is now available on the world wide web. So Steve, try to keep up. Make a comment or two on the following. Keep your sailors wit about you.

    Ted Brewer in Good Old Boat March 2005, stated that boat designers in the 1950s through 1970s, himself included, were influenced by ocean racing design rules. These rules ignored the advantages of fractional rigs because there was a rating advantage in going with a smaller-sail-area mast head arrangement. His controversial article claims that vessels designed in this time period were purposefully under canvassed for ocean-racing-rating advantage and that Genoas became popular because they represented a way of getting more suitable sail area on these designs. Genoas provided a loop hole in the design rules in other words. A Genoa is usually 50 percent larger than the standard jib for that vessel.


    Today many view mast head sloops as ocean crossing vessels and fractional rig vessels inappropriate for that work. But there are no physics supporting this belief. Mast head sloop rigging is an artifact of ocean racer design rules and nothing more because a fractional rig sloop can assume mast head configuration just by reefing. Furthermore, Brewer states that - in the absence of the design rules - there will be a trend to smaller head sails and larger mains (like on the M). His statements are based on old head sail technology, however.

    Prior to 1999, head sails on rollers did not include necessary reinforcement so that they could be rolled in further than jib size. This meant that it was easier to reef the main when conditions warranted that. Because head sails like those standard on a MacGregor Yachts can be rolled to storm sail size, they are easier to reef than the main. This is probably true on most sloops with roller reefing (as opposed to furling) systems. They also can be rolled in while tacking and backed out again so that there is no disadvantage (in comparison to a jib) in maneuvering. Brewer in Good Old Boat August 2005 argues against roller furling head sails in smaller offshore yachts. He challenges his readers to disagree, which I now do.

    The added weight aloft of the roller mechanism is minimal (about the amount of a pulley). There is no problem there. Rolled head sails can be removed from their stays just as a sail using a tuff luff is. It need not remain on the stay as Brewer implies. In fact, sailors now know to remove the sails from the rollers even when in port during storms and hurricanes. The owners manual for the Mac26x instructs operators to drop the mast in extreme conditions. This is analogous to chopping down masts which captains would order when caught in extreme conditions during the days of commercial sail. This valuable heavy weather technique is not available to a vessel with a keel mounted aluminum mast. Deck stepped masts are superior when such mounting allows the mast to be dropped.

    The only potential disadvantage to a rolled Genoa on the Mac26x is that when the Genoa is rolled in to a smaller size there might be a decrease in performance. However, a rolled head sail is like a vertical batten, its performance might be better in some conditions and often reduced performance is not a concern when the objective is to depower anyway. The idea that a storm jib can be positioned low to the deck is silly when you think of sea spray that requires the storm jib to be raised anyway. Macgregor Yachts instructs its operators to use the rolled Genoa as a storm jib.

    Brewer does make interesting points about plugging the aluminum mast on both ends and not installing inner halyards. The air trapped inside the mast prevents some vessels from turning turtle after a capsize. However so does side floatation and ocean worthy freeboard, like on the Mac26x.

    Brewer, spends some time explaining the difference between a cutter and a double headsail sloop in his earlier article. This discussion has high value for Mac26x owners and those considering ocean crossings. He argues that there is safety in having a second head stay and that combinations of the double-head rigs are desirable in heavy weather. If the single head stay gives way the mast could be lost unless something like a solid boom vang has been mounted. In the later article he implies that carbon fiber masts are foolhardy because ultra-light rigging does not provide transverse moment of inertia enough to resist the kind of snap roll that can happen in a breaking sea.

    Can we chat about the content of the above rather than me now? I love Brewer because I believe he writes in a way that gets readers to think. Unfortunately the foolish take what he says at face value without analysis. Let Fly
     
  11. SailDesign
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    SailDesign Old Phart! Stay upwind..

    You have a long ways to go, Migho. That does not stop Mr. Brewer from making accurate observations, but it has stopped you from drawing the correct conclusions from them.
    I would suggest going to school/college for at least a year to study yacht design (3 would be preferable). There are many courses available. Then spend 25 years in the business. Then, and ONLY then, go back and re-read these threads. I guarantee you will be embarrassed as heck.
    Steve
     
  12. mighetto
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    mighetto New Member

    You have a long ways to go, Migho. That does not stop Mr. Brewer from making accurate observations, but it has stopped you from drawing the correct conclusions from them.
    I would suggest going to school/college for at least a year to study yacht design (3 would be preferable). There are many courses available. Then spend 25 years in the business. Then, and ONLY then, go back and re-read these threads. I guarantee you will be embarrassed as heck.
    Steve


    Embarrased for you perhaps. You still do not get it. In times of fast technology change, of which this is one for monohull sailing, anyone claiming to have more than 5 years of experience is delusonal. You will be changing your views just as Perry and Brewer are if you care about your craft.

    For example, any analysis of design that pretends that speed is not important (for safety and comfort) is faulty from the get go. Any that ignores the very real objective of designing sailboats that can be crewed by two likewize so. Any promoting vessels that sink when flooded ditto. Virtually all analysis from the east coast, with the exception of folks like Bolger (and a few brave others) requires out of hand rejection based on the track record of utter design failure established there. TP52s argh - lets go there only as required.

    Dance with me. The music is wonderful right now. There may not be a better time to discuss Surviving Capsize. Page 14 Good Old Boat. See especially the table on page 16. Alas - speed is not a row. Other than an Internet school, I doubt schools can keep up with the significant change in design thinking now taking place.
     
  13. Roger MacGregor
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    Roger MacGregor New Member

    You, Frank, are an embarrassment to the MacGregor 26x owners community. I'm ashamed to see a delusional neophyte such as yourself misrepresenting our fine product.
     
  14. usa2
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    usa2 Senior Member

    well said Mr. MacGregor.
     

  15. K4s
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    K4s Junior Member

    Presumably this new thinking is being done by graduates or members of these very schools,evolution of design is the process.Perhaps you should evolve or you may end up like the dinosaur.
     
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