Beneteau Antares Hull

Discussion in 'Powerboats' started by ScottA, Dec 9, 2013.

  1. ScottA
    Joined: Apr 2005
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    ScottA Junior Member

    Hi All,

    I have a Beneteau Antares 30, I am wanting to know why the builder has not included a full keel to protect the prop rudder ect. At displacement speed it seems to have the same wave pattern as my friends Island Gypsy 30, his has a full keel, but his boat will not reach speed. What are the pros /cons of full keel /not full keel? Also what are the sea keeping strengths/weaknesses with my hull. I have included some pics of the hull.
    Regards Scott
     

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  2. Mr Efficiency
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    Mr Efficiency Senior Member

  3. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    A full keel as you describe it generates a lot of drag and places a big flow shadow in the path of the prop, both eating into efficiency and speed. Your boat has a small skeg, which is for directional stability (tracking) and this is about all you need. You can enlarge the skeg, which will improve tracking and low speed wander, but at the cost of more drag and a lose of some speed.

    The seakeeping aspects of your hull are pretty typical of powerboats shaped like this. It'll suck in a steep following sea, wallow around at low speeds and roll pretty good in some conditions like at anchor, trolling or drifting. These are the compromises in the design, so they can offer other aspects in the package (everything is a trade off).
     
  4. daiquiri
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    daiquiri Engineering and Design

    Besides what has been mentioned above, The keel which is cut well before the transom helps decreasing the turning radius of the boat, because it decreases the area of lateral resistance, shifts the center of lateral resistance more forward and makes the rudder work hydrodynamically better and with bigger authority.
     
  5. ScottA
    Joined: Apr 2005
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    ScottA Junior Member

    Thank you for your replies,
    Would you say my hull is semi disp or planning?
    from this I conclude the following(Pls correct if wrong);
    My hull in a following sea does wallow around at low speed but if I apply more revs and speed it seems to straighten out (have a sort of sucking back experience, what is this?), The same is into a head sea, I apply a bit more speed and it levels/straightens out, but does a larger keel track straighter at lower revs and speed. In a big sea where speed is out of the question is a big keel more stable and a more comfortable ride, and where conditions are more favourable the smaller keel is faster?
    Do I share any hull traits with a disp cruiser (IG 30) as we both have similar wave patterns at about 7-8knots?
    I am looking at going to a larger boat about 34 foot hull at waterline and looking to concentrate on coastal cruising so would like to choose a hull optimum to these conditions - looking for a turn of speed if desired or needed, but looking at comfort and seakeeping at first priority.
    I have 3 boats in mind;
    Beneteau Antares 36 - Much the same hull shape as what I have but heavier and twin engine.
    Beneteau Swift trawler 34 - Seems much the same as I have now, but seems to have bigger section at the underwater bow, Forefoot?
    Clipper 34, CHB? - Has large keel and is only capable of 8 knots
    Are there any other recommendations?

    Regards Scott
     

  6. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    You have a full plane hull form and no skeg (what you're calling a keel) will help much at low speed, in terms of stability, though a larger skeg will help (slightly) with low speed tracking, she'll still wallow around, just not as much.

    This is a function of the hull shape and straight shaft propulsion, plus the realities of driving a big, fat hull at displacement speeds. It's just not designed for these speeds and there's not a lot you can do, other then find a "sweet spot" when low speed motoring, so you can control her better. Simply put, it is more a skipper issue then anything you can bolt onto the bottom of the hull.
     
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