waterballast set-up for 40ish foot (almost) racing yacht

Discussion in 'Boat Design' started by patrick2wd, Nov 7, 2014.

  1. Joakim
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    Joakim Senior Member

    Sofomarin scoop seems to be the one used in these classes. Here is a short description of one Class 40 boat:
    "1 * electric ballast pump, Rule 17A, 14400 litres per hour 12 VDC or equivalent.
    Sofomarine snorkels, valves, vents and skin fittings for ballast system."
    http://www.class40racing.com/Standard-Specification

    Note that using scoop when the boat is already heeled requires a good speed. The high side of the ballast tank may be even at three meters. You need 15 knots speed to get even the tank filled up slowly. At two meters you still need 12 knots. Thus you can't fill the windward tank on a beat using a scoop.

    It's not hard to find a 12 V or a 24 V motor that has the power required to pump, but it is much harder to find a suitable pump, especially at reasonable price. Yamaha used a pump similar to engine raw water pumps. They aren't cheap either. Cheap and efficient solution is not that likely to be possible.

    You could use motorised valves or solenoids, but that won't be cheap. A solution using cables and a handle outside would be much cheaper.
     
  2. terrnz
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    terrnz Junior Member

    I think you will find the leeward tank is filled then the boat is tacked?
     
  3. Joakim
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    Joakim Senior Member

    You need 9 knots for 1 m or 6 knots for 0.5 m, thus filling even the leeward tank with a scoop is not that easy on a beat. Sure you can fill the tank, but you may need to sail slower than you would like and to other direction you would like for quite some time.
     
  4. terrnz
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    terrnz Junior Member

    Have you ever sailed on a BOC or Class40? 60 secs to fill the windward tanks on an old BOC60 and that was nearly 30 years ago.
     
  5. Joakim
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    Joakim Senior Member

    No I haven't and this boat is not one of them. Using scoop is fast, if you have enough speed and big pipes. We are now talking about a 40 foot boat with up to 1500 liters of water ballast and not a pure racing boat.

    1500 liters in 60 seconds is over 3 m/s through a 100 mm pipe. For a water level 1 m above sea + absolute minum pressure drop for 100 mm pipe you need 11.5 knots speed to get enough pressure at the 100 mm scoop.

    You are not having 100 mm pipes/scoop, you have much more pressure drop in the pipes, even a Class 40 boat needs something like 16 knots of wind + optimum angle + optimum water ballast to reach 11.5 knots. So that is not going to happen.

    If you use say the DN50 scoop in the catalogue and have some more realistic pressure drop for piping, it would take 5-10 minutes at 11.5 knots speed. At 10 knots it takes 50% longer and at 9 knots 3 times longer. Even at 20 knots it would take 2-4 minutes.

    If you are able to get the top of the ballast tank at sea level, it still takes 4-7 minutes at 11.5 knots, 15% more at 10 knots, 30% more at 9 knots and 60% more at 7 knots.
     
  6. terrnz
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    terrnz Junior Member

    if you are sailing round the world 5-10 minutes to fill the tanks (less if you have more than 1 scoop) is not an issue. If you are racing round the buoys it is an issue only if you want to dump and pick up. Side to side transfer is not a problem. If you want to use water ballast around the buoys just fill up at the dock!
    if you are talking about using stored power, ie electrics why are you not thinking of an engine driven pump like an Erikson?http://www.aes.net.nz/ESP.HTMl here is the link.
    As I have mentioned elsewhere in the thread I have discounted class40 style water ballast for my project, too much beam, too much drag, too much weight, too expensive. That is not say I would not fill my fresh water tanks on a windy day and gain another 20% righting moment. I much prefer the concept of a canting keel subject to tidying the engineering. You might look as SKF's work in this field, there are patents published.

    What are the design parameters of the boat, target speed, displ, L/D, SAD, righting moment? What kind of sailing and where
     
  7. patrick2wd
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    patrick2wd Junior Member

    parameters are not really clear, Ill discuss this with my client tomorrow,
    sailing is offshore and bloody fast..
    we have an initial design, but nothing concrete yet,

    were also looking into building it within class40 parameters, but in carbon, so it could be possible to build a similar boat in epoxy.
     
  8. terrnz
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    terrnz Junior Member

    You can build in epoxy with glass as well? Depends how far you want to push the envelope and of course the budget! Carbon concerns me over its impact resistance. I have had a few of those over the years.
     
  9. patrick2wd
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    patrick2wd Junior Member

    yes, thats the plann if we decide to buildt the boat within class40 parameters.
     
    Last edited: Nov 22, 2014
  10. patrick2wd
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    patrick2wd Junior Member

    does anyone has a sort of a blue print for waterballast, for study purpose?
     
  11. terrnz
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    terrnz Junior Member

    mate, I sent you 1 already and you can get the equipment specs and models off any number of class 40 manufacturers specs.
    Are you really in the industry? I am not any more and am not a professional designer but frankly you scare me with the questions you ask and your own admission you have never sailed on even a class 40 yet you are proposing to take money off some one for such a design.
    Get some time on the water, please!
     
  12. patrick2wd
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    patrick2wd Junior Member

    ha,

    thanks for your concern..

    but not needed..
    thing is we want to get a "different" boat out on the water,
    within c40 specs, but quite a bit more ballast in it, build in carbon,
    I'm not a pro designer, but keep, or try to, keep up with all new developments there are..

    Im just not wel-known with water ballast (& systems)

    hence the inquiry
     
  13. UNCIVILIZED
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    UNCIVILIZED DIY Junkyard MadScientist

    "patrick2wd, not to be a dick, simply REAL (& honest). But bottom line. Enough is, freaking, enough!!!
    Yeah, I may take some heat for this, which could suck. Though what sucks more, is that this is an interesting topic, & a LOT of good info is being put forth (albeit it's ALL falling upon deaf ears by the one who started the thread on the topic).

    So, first question?
    Have you read ANY of the provided articles, & or links to some great material on this topic... let alone done an research of your own - both online, & in periodicals & texts out there?
    There's a LOT of info on the topic, literally free for the taking/searching [more than Decades worth actually (SIC)]. Let alone if you were to inquire about this topic & your ideas with any designers/firms. Or heck, even a well educated Marine Professional (or advanced amateur). Although to do that you'd need to have some answers to some VERY simple, but significant questions regarding; design, boat use, expected/requested performance, budget...

    Also, and this is important: Some/Most of the questions you're asking (OVER & OVER) have been answered: Repeatedly, in several different formats, & by many different members (with links to field leading experts in yacht design & construction [gee, including leading ones in the field of racing yacht water ballast)], and yet you keep asking these SAME questions. Such as for system diagrams, and types of hardware. As an example.
    The thing is, when questions are put to you (ones which would help in assisting to solve the problems) they're rebuked with very, very, vague comments. AKA dodged faster than a fella running from his wife, as he know that she just found out about his mistress.

    Off of the top of my head, I can recall reading literally, several dozen magazine articles on this topic since say 2000 or so, plus loads of information in it in various books (they are FAR from difficult to find, & or get copies of - Such is a point of FACT!).
    Right now, this idea which you've chosen to put forth here, is one which is at best intellectual ************. Because... without answering some of those (very simple & direct) design & budget questions, NO ONE on Earth can give you significant answers (and I can't help but wonder if you truly want them), as the questions which you're posing are overwhelmingly broad.
    And asked (repeatedly), while evading (repeatedly) helpful questions, that from the outset it's been VERY clear that you're not at all qualified to be a project manager on something such as this (if it were ever at all real).

    In addition, frankly, aside from such behaviors being a waste of (other people's) time, it's both insulting, & rather juvenile. Yet you proclaim to be the Project Manager on this vessel, one which will cost in excess of $1 Millon, or, realistically, over a Million Euros - just to get the boat put together & in the water. Let alone the several hundred thousand per year which it will cost to campaign it.
    If you're sensing that I might be angry you're correct. A fair portion of that being that despite my instinctive misgivings about your background from when I ran across this thread, I put quite a bit of time & information into it in hopes that said info & work on my part would help you to grow as a sailor.

    Is there any, detailed, logical explanation as to why what I've just stated is invalid?
    Do you happen to hold say a Yachtmasters Certificate?
    A US Captain’s License, or anything which qualifies you to do more than skipper a U-boat in a bathtub?
    What other vessels & type(s) of vessels have you been the project manager, or lead man in running them on?
    What major racing have you done?

    I have MORE than enough of a resume/CV, and experience to accompany same, to back up this rant & my blunt questions. Or for that matter, to run a project such as what you’re proposing. And can happily list as much, if my calling you into question on; your motives, your piss poor behavior/manners, & technical qualifications + experience, raises your ire. And or cause you to wonder about my background.
    Although that information is already in the hands of this forum’s staff, along with a copy of 90% of these comments. In reference to my brining concerns about this thread & your repeated transgressions of manners, background, & motivations etc., here in. A thing which never before in my life have I done (flagging anything for mod's). And yes, you were more than given the benefit of the doubt by me, via my reigning myself in, & contacting them with my concerns first, prior to calling you onto the carpet, publicly.
     
  14. terrnz
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    terrnz Junior Member

    uncivilized I agree with you, I out of timidity being a new bod put it differently. If this guy is in the industry, he scares the hell out of me! Ignorant on the most basic aspects of what we purports to be attempting.

    many have given him links , diagrams, and invited discussion of his proposed project yet he has failed to respond in specifics I suspect he is a troll.

    the client could buy a time expired open 40, which is close to a carbon fibre class 40 for a fraction of the new build price or buy a new class 40 for around 300,000 euros sailaway.

    If the guy is in the industry and selling/managing the project then he represents the dark side.

    to be putting together a such a project having never set foot on a similar yacht is unbelievable.
     

  15. TeddyDiver
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    TeddyDiver Gollywobbler

    True or not there's no reason to judge the OP's credibility. IMO keep the discussion in the subject or do not participate at all.
    BR Teddy
     
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