Double end power boats?

Discussion in 'Boat Design' started by duluthboats, Jul 7, 2003.

  1. Easy Rider
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    Easy Rider Senior Member

    Gonzo,
    Sharpies are not double ended boats. They only have rounded transoms. A double ended boat is pointed or highly rounded below the water line. The Bartender is a planing hull and I don't consider them double enders. Their performance would hardly change at all if one gave them a flat stern. Perhaps I need to change my scope on what a double ender really is. I know my Willard Nomad is a double ender but it would be more efficient if it was pointed instead of rounded but like TAD says ..volume. Millions of people think the early Ford Mustang is a sports car.

    Easy
     
  2. Joe Petrich
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    Joe Petrich Designer

    My own interpretation of a double ender is a vessel whose hull shape comes to a pointed or rounded end above and below the water. I think my definition is fairly broad. Needless to say, I love narrow efficient boats.

    So I might call this a "planing double ender". It's a Fairliner Torpedo designed by Dair Long who designed the fastest boats of WWII, the air-sea rescue boats, and built by the Fairliner division of Western Boat Building Co. in the late 40s. There are no hidden planing surfaces. The bottom comes to a point at the end. The performance was quite good with 6 cylinder power Although the picture doesn't do it justice as it is moving fairly slowly.
     

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  3. 334REG
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    334REG New Member

    viajero

    In the late 60's I sailed a double ended 65' ketch to Hawaii from Sausalito. She stayed in Lahaina for years as a dinner cruise excursion. Her name was VIAJERO spanish for traveler. Would love to know her whereabouts now or if she is still around. Reg
     
  4. Easy Rider
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    Easy Rider Senior Member

    Hi Joe,
    They had cars in the 20s and 30s that looked like that too but that didn't make them double enders. The word double implies that both ends of the boat are the basically the same. An Adirondack Guide boat and a canoe are double enders. A Pea Pod, Viking Long Ship, and basically a dory are double enders. Pseudo double enders are common but "true" double enders can be turned around and run backwards as well or almost as well as forward. Many to most people think the Grand Banks yacht is a displacement hull but almost nobody would say they are a "true" displacement hull ..because the're not. Ther'e is this very valid element of degree. If you were addressing a group of stock brokers I'd say you could get away w calling the Fairliner Torpedo a double .. but here???. My Willard isn't really a double ender in my opinion. It has a full rounded transom and would not go gracefully backwards nor does the stern really look like the bow. all to 12-15-09 423.jpg

    all to 12-15-09 427.jpg

    Look in the April issue of Woodenboat Magazine to see many many real and true double enders.

    Easy Rider
     
  5. Joe Petrich
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    Joe Petrich Designer

    Easy,

    I would have to politely disagree with your statement that a true double ender can be run backwards as well or almost as well as forwards. By that definition the only true double enders would be ferry boats and canoes. Also some tugs with cycloidal drives actually run better in reverse in some cases despite their hull shapes being different fwd and aft. The Wedel Foss shown below is a good example of this. I would say your boat is a double ender. In any case I think there is enough ambiguity in the term to allow for different interpretations.

    Cheers,
    Joe
     

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  6. Easy Rider
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    Easy Rider Senior Member

    Joe,
    Our ferry boats don't go backwards. Calling them a boat is a stretch too. I guess your'e right on all counts. Perhaps I'm in the purist category. Some things are grey and some black and white. The double end boat concept is obviously hard stuck in the grey however there are many double end boats in April Woodenboat Magazine that are 100% double enders.

    Cheers
    Easy
     
  7. TollyWally
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    TollyWally Senior Member

    Joe,
    Are you relations to the Petrichs of Western Boatbuilding, Fairliner, etc.?
     
  8. Joe Petrich
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    Joe Petrich Designer

    Yes I am.
     
  9. messabout
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    messabout Senior Member

    One more to add to the planing double ender list. OK so it's a sailboat and a full on racer at that. The International 10 sq. meter canoe is a double ender because the rules dictate that it shall be. Yes, I know it is not in the same category as that intended by the original post.
     
  10. Easy Rider
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    Easy Rider Senior Member

    Mess,
    Yes. A real double ender .. Intl 110. I was going to mention it but wasn't sure I had the name right. One thing thats great about flat bottomed sail boats is that when heeled smartly they become a deep V hull. Even though they are quite fast I think they are really full displacement hulls. Even at rest both ends are clear of the water due to enough rocker. Without the rocker it would be a planing hull but even then it's questionable and w power applied it would clearly be a FD hull.

    Easy
     
  11. messabout
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    messabout Senior Member

    Easy; the Int 110 was the brainchild of Ray Hunt a long time ago. It was essentially a double ended, square box with a fin and bulb keel. It was a very spirited boat as displacement types go. Its' strength was as you say; when heeled it presents an elegant vee shape to the water. As good and as simple as the 110 was, it never quite made it to the big time. The reason was that it was boxy and did not look like something that could be percieved as a "proper boat". Those snooty sailors, with their proper boats, too often, could only see the back end of the 110.

    The International 10 Sq. meter canoe is a horse of a completely different color. They IC is a furious planing hull that is a double ender, but the taper of the aft end, is by rule, not to exceed 45 degrees per side. It is no surprise that they almost always configure the aft end, as seen in plan view, to be as nearly flat as the rules will permit. The boat is 17 feet long and one meter wide. More modern ones are less than one meter in beam. They can plane to windward when sailed by a competant IC skipper. A skinney boat with 10 meters of sail needs something other than magic to hold it upright. The IC uses a sliding hiking plank which is highly efficient and I swear it is easier to use than a trapeze. You may have seen these somewhere or at least pictures of them in action. The IC is a small but active class of racing boats that seem to attract technical types. One of the foremost of those technofreaks is a hydrodynamicist at the Annapolis Naval Academy.
     
  12. Easy Rider
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    Easy Rider Senior Member

    Mess,
    Thanks. I can't believe how often I find a remarkable boat has been designed by Ray Hunt.
    Oh ... I didn't know about the 10 sq. meter canoe. I thought you just left off a zero.
    Interesting about the high performance sail boats. I saw a video/movie about sailboat racing and the photography was, as the kids say, awsome. Being a sailor youv'e prolly seen it.

    Easy
     
  13. Tad
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    Tad Boat Designer

  14. Easy Rider
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    Easy Rider Senior Member

    TAD,
    If you were to ask "would it help sell this boat to call it a double ender"? You would answer yes and then call it a double ender as you are selling this boat I'm sure. I think it's the aluminum boat on your web site. That boat looks so good to me I'm going to show it to a friend and he may buy it but I will not call it a double ender because it's pointed or tapered stern does almost nothing to change or enhance the performance or dynamic qualities of the boat. The name of something should reflect some significant or hopefully dominant feature of the thing to hearld what it is. And the performance of the "double ender" you present has almost nothing to do with it's rounded stern w a crease on the CL. Name it something that draws attention to some important feature or design capability. The big problem is when a real double ender comes along what are you going yo call it? If you call the Bartender and your boat a double ender the meaning of the expression double ender has been reduced 80%.
    When you call a flat stern Lund type skiff a rowboat you fog or haze the meaning of the word rowboat to the point that it has little meaning.
    I see on your website "blog.tadroberts" an old fishboat "Sea Star". Now thats a double ender!

    Easy
     

  15. Tad
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    Tad Boat Designer

    And what is your basis for making this statement?



    Below is a double-ended sharpie...Egret. Note that her topsides and bottom terminate in a stern post.
    3665248324_f9eddef14e.jpg

    These are double-enders, Scottish fishing boats, again the bottom and topsides terminate in an obvious stern post.
    Beached_at_Waterfoot.jpg

    This is a dory with a transom...it is not a double-ender and has no stern post.
    dory1.jpg

    This is a Scandinavian double-ender, stern post is obvious.
    dscf0039-300x224.jpg

    This is a double-ended Gunning dory, note the stern post.
    Gunning Dory.bmp.jpg
     
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