Racer Recycle

Discussion in 'Boat Design' started by FAST FRED, Dec 12, 2005.

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    FAST FRED Senior Member

    My dream boat is a very efficent motorsailor similar to the Herrishoff Marco Polo,

    BUT new a build is exppensive , just for the hull & deck.

    So with all these super fast Volvo racers that will be scrapped after a couple of seasons , how about a RECYCLE?

    Take the huge rig off , and scrap the 20ft deep keels.

    Install a low AR keel to protect a good sized propellor in a grounding , and a tiny mast or three to serve as get home power.

    Say 300ft of sail per mast would alow the dink to be hoisted , some get home sailing , or fun on reaches , and perhaps a mount for flopper stoppers.

    With immense volume inside a light weight interior for 4 could easily be installed , as well as fuel tanks for 4000 miles .

    The fantastic light weight and long water line should make a dream come true.

    The dream is 5 nmpg at 12K.

    Anyone care to shoot at this concept?

  2. sharpii2
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    sharpii2 Senior Member

    Will it fly?

    I think the concept is good, but the mileage is a bit off. You are expecting to get about 2.4nm per gallon at 12kts. And I'm assuming you hope to get this in zero wind conditions. To get that kind of speed, roughly 1.5 * sqrt WL, you will need approx. 5hp per ton if not more. Assuming your diesels will give you 16hp/hrs per gallon, your engine can produce up to 38hp and stay close to your 5gph limit. So 38hp/5hp per ton gives you an allowable displacement of approx 7.7tons. A Volvo 70 displaces about double that (I checked).

    If you were willing to modify your dream somewhat, you may get that kind of performance with the sails up and drawing well. On calm days you might get 8 to 9kts. Also, enough fuel to give you 2.4nm per gal for 4000nm is going to weigh in at about 6 tons all by it self if not more. Almost half your displacement.

    I love your idea, retro fitting an old boat for a new use, but I think your performance expectations are a wee out of line. To be economical at all, it will have to be driven (under engine alone) at significantly below LWL speed (6 to 7kts). (kind of like the early 20th century ocean liners). Then, maybe, you could cut your tankage in half. If you can stand that, your concept does not seem unreasonable at all.

    My $0.02 worth.

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    FAST FRED Senior Member

    A Volvo 70 displaces about double that (I checked).

    AS a "racing boat" I would guess at least half the weight is mast and keel.

    SO at half the weight with a stripped hull the performance should be a bit better.

    60 years ago the Marco Polo was considered a 10K cruiser , 2 additional KPH for light weight construction might be possable.

    Even the ground takle is lighter today!

  4. Raggi_Thor
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    Raggi_Thor Nav.arch/Designer/Builder

    I don't understand why you want to motor if there is wind :)
  5. marshmat
    Joined: Apr 2005
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    marshmat Senior Member

    The keel bulb of a VO70 is on average about 10,000 lb.

    I do think the idea would be workable. I'd note that the VO70 hulls are designed for 20 knots plus, with sail power equivalent to about 400 hp. They rely very much on dynamic forces for their handling characteristics and so I'm not sure if you'd get the low-speed performance you're after. Just a thought, I'm not sure if it has any validity to it.

    My big concern would be that a VO70 is built pretty light to start with, and they take a hell of a beating over the tens of thousands of miles of testing and racing which they endure. Already after one leg we've seen cracked bulkheads, two keel failures, a missing daggerboard (although they think that's from hitting a container), etc. Not sure if there's going to be a lot left after the race to work with, without rebuilding half the structure.
  6. narsil
    Joined: Nov 2005
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    Location: canada

    narsil Junior Member

    a great idea, i read alot over at sailing anarhcy and the consensus on these high tech builds is they they arent built to last... you have to watch the construction many boats are using aluminum honeycomb combined with carbon fibre, just add salt water and viola instant battery with resultant corrosion.
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    FAST FRED Senior Member

    OH Well, Back to the drawing board!

    Thanks for the opinions folks,

    Now if anyone is a Cert Aluminum welder ,

    and wants to spend a winter in sunny warm Florida...........

  8. gonzo
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    gonzo Senior Member

    Compare the lines of Marco Polo to a Volvo racer. The first has very fine lines, the second is closer to a planing dinghy. You would be better off buying an older cruiser/racer and converting it.
  9. Robjl
    Joined: Nov 2005
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    Location: Adelaide

    Robjl Senior Member

    don't forget..

    Don't forget the hardware folks. The gear on these racers is worth a fortune.....if you can use it. Even the motors, though too small for the racer they are in, are suitable for a smaller boat, the motors are young and have usually done little work.
    But with all this remember that the hull only represents about about 20% of the cost of the boat... if the hull is all that can be re-used... then add the cost of the changes needed for another life...you havent saved much and what have you got?
    Talk to any sailmaker and ask about the suitability of the used racing sails for cruising...I'm sure you'll get the same response I got...totally unsuitable...don't even think about cutting them down.
    I reckon this one is busted FF.

  10. h_zwakenberg
    Joined: Nov 2005
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    h_zwakenberg HullDrag/32 programmer

    yes, for another reason too: if you scrap the keel and mast in an effort to lighten everything, where's your waterline going to be? Right!
    So, what are your handling qualities, stability, etc. going to be?

    Bottom line: you want to end up with appr. the same waterline, so mass should stay about the same. If you allow for some heavier interior and lower/lighter mast, you still need to have a keel that is able to provide ample stability.... This would be a very costly undertaking, better start from scratch of from an established cruiser...

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