Pros and Cons to different types of keels

Discussion in 'Boat Design' started by Emma23, Oct 19, 2010.

  1. ancient kayaker
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    ancient kayaker aka Terry Haines

    Couldn't agree with you more Paul, and under sail is a nicer ride usually, space permitting of course, but the optimum boat characteristics should be determined by how it is going to be sailed, not how it would be sailed by an expert.
     
  2. PAR
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    PAR Yacht Designer/Builder

    Most cruisers become fairly expert in short order. Other wise they sell the boat and by a condo with a water view.
     
  3. RThompson
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    RThompson Senior Member

    Good point, theres also potentially higher headroom with wine glass sections, however I wasn't trying to give an exhaustive list of benefits or otherwise of different keels - more I was pointing out how much of a compromise a keel was: "...or any combination of many different things".
    Also at the end of the day a sailing yachts' keel forms a critical part of the yachts propulsive system and hence the keels propulsive performance should at least be considered, even it it is discarded or downgraded as a low priority. A yachts sailing performance doesn't have to be all about bashing to windward or racing round the cans (nothing goes to windward like a 747).

    Maybe I misunderstood the statement, but surely you are not suggesting that there is one correct description of cruising followed by one 'silver bullet' cruising keel design (and anyone acting outside that description is uninformed or stupid)?
    I don't think many people, certainly not me, is advocating that evry small cruising yacht should have a particualr type of keel because 'its the best'. -best for who? doing what? where?
     
  4. alan white
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    alan white Senior Member

    I'm just going to add to the debate in favor of the long shoal keel, which is what my own boat has. Pointing is not her long suit but any shoal keel design can be fitted with a centerboard or a swing keel.
    Mine has a decently cutaway forefoot which helps when tacking the boat. The best thing about this type of keel is the amazing tracking in most conditions and the gentleness of the helm. Beaching is possible and so is launching and retrieving single-handed (she's 15 ft and about 1300 lbs).
    Another benefit is the ease of balancing the rig, or rather, the way she balances no matter whether reefed or with headsail.
    Speed is not a problem. I race on Sundays throughout the Summer and I rarely finish ahead of centerboard dinghies except in very light air in which case she'll even ghost past the occasional Hobie 16. But I am not concerned since she moves along smartly enough and I don't mind losing when I know my boat has been sailed well. In that sense I tend to sail against my own average time.
    I think that each sailor has his own preferred type of sailing and hence preferred sailboat type so who can say what keel configuration is best?
    What matters is that one builds or buys the boat that will fulfill that preference. Knowing what a boat design will or will not do is what matters. You don't want to be stuck with the wrong boat.
     
  5. dskira

    dskira Previous Member

    I edited you.
    No you didn't misunderstood my statement.
    It was a stupid statement, made in a unprofessional manner, being pissed off by this stupid conception that long keel is old fashion and nostalgic without merit.
    So I apologise about that. I should know better.
    Daniel
     
  6. RThompson
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    RThompson Senior Member

    "...being pissed off by this stupid conception that long keel is old fashion and nostalgic without merit...."

    No need to apologise, although it made me smile a bit in empathy -I can fully appreciate the frustration when coming up against a narrow opinion impervious to reason. Seems to be a common affliction in the world of boats :)

    On another note, theres been no further word from Emma. She asked about keels - theres a few points to consider discussed above...
     
  7. gunship
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    gunship Senior Member

    hmm, a question about twin keels. what makes them as effective as a single keel, the ability to hold more ballast than an equal draft single keel or something more complicated?
     
  8. PAR
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    PAR Yacht Designer/Builder

    They are not as effective as a single keel in most regards. They do offer lateral resistance at typically a shallower depth then a single appendage, but at the cost of considerably more wetted surface, which means drag, which means slower.

    With few exceptions, bilge keels are reserved for those that sail in wide range tidal areas, where having to take to ground is common, not the exception.
     
  9. ancient kayaker
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    ancient kayaker aka Terry Haines

    Twin bilge keels can be compared to a biplane in which the greater efficiency of a monoplane is sacrificed for reduced wingspan. The biplane has the advantage of greater maneouverability especially roll rate, and a smaller hangar. Similarly, a twin keel boat can venture into shoal water and will stand up at low tide, but windward ability and some speed is lost. A centerboard, daggerboard or leeboard(s) offers a compromise but requires more attention from the crew; again the greater efficiency of the daggerboard must be set against the self-retracting capability of a pivoted board if crew attention is lacking.

    A missing requirements input is expected performance. If this is desired over safety and convenience then the daggerboard is indicated. If not then the choice depends on availability, I would say, unless you are planning to build it. If there is a need for trailering and low bridges are found in the area, that might militate against the twin bilge keels.
     

  10. FAST FRED
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    FAST FRED Senior Member

    "They do offer lateral resistance at typically a shallower depth then a single appendage, but at the cost of considerably more wetted surface, which means drag, which means slower."


    True in light winds , where the usual cruiser will be using the Iron Topsail.

    But Hull Speed is based on the LWL, not on the appendages , so the boat will still have the same TOP speed (it will just take more breeze).

    FF
     
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