Trailerable sportboat weekender?

Discussion in 'Sailboats' started by Steam Flyer, Aug 4, 2008.

  1. Daniel Noyes
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    Location: North Shore, Massachusetts

    Daniel Noyes Junior Member

    Hi Flyer
    How about a sharp bowed scow type hull?
    I'm interested in this sort of boat, my design ideas ar more influenced by the scow type hull than a sport boat. Both types rely on heeled water lines to sail up wind and flat wide aft sections for down wind performance. The scow type hull does this more efficently, ie. smaller crew and no ballast/keel. look at E scows these 28 footers are trailered all over and with a reef system for the main sail could be sailed in a more leisurly manner than racing encourages.
    Here is my take on a 26' Spirit of Tradition racer, sharp bow scow designed specifically for rough water. http://www.flickr.com/photos/dansdories/3180445195/
    cheers
    Dan
    http://dansdories.googlepages.com
     
  2. Steam Flyer
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    Steam Flyer Junior Member

    It depends very much on the boat. There are a lot of trailerable sportboats, like the Melges24 is justone example and some pics have been posted in this thread, where the keel root is clamped into a box built into the floor structure of the hull. The forces on the keel while sailing are much higher than a "normal" boat due to the big sails, ballast bulb, and high speeds. But the keel can be lifted by block & tackle to park the boat on the trailer, or the whole boat can be lifted by the keel root (raising the keel) via a single-point hoist such as are commonly used for small keelboats.

    A set-up like this is the most common, rather few have any possibility of raising the keel while underway for shallow water. But lifting it to park on the trailer is easy enough to do for every day sailing.

    A few other boats have a daggerboard-style keel foil with a bulb on the tip; such -can- be raised while underway for shallow water and/or going downwind (not many do that). The only one I've seen like that in the US is the Elliott 770. This is the configuration I'd prefer, but it does compromise performance.

    FB- Doug
     
  3. mattotoole
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    mattotoole Senior Member

    Doug,

    I like this idea too, as with the S2 7.9 and the Santana 23D, belly-ballasted with an efficient daggerboard that can be raised while sailing. They're not really sportboats though -- more J24-ish.

    Unfortunately you're right about the compromise. A lot of a sportboat's peformance comes from the RM -- a heavy bulb on the end of a deep keel.
     
  4. alberto88
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    alberto88 Junior Member

    I think not good idea for this type boat for raising keel up and down while sailing; downwind sportboat needs the area of the keel to plane off; and something like E770 much slower than a shaw or similar sportboat for sure. Also, cannot raise while boat is moving for most performance foil shape, as keel trailing edge is very fine and will break.

    Actually, Shaw has only 80-90kg of lead; performance comes from righting moment of crew, not from bulb. Way to put a lot of bulb weight is like THompson, Magic or Melges 24, these boat all slower than a Shaw anyway, with much bigger rig and more cost also.
     
  5. mattotoole
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    mattotoole Senior Member

    Alberto,

    Some of us are limited by shallow water and ramp launching. For example, in a bay where I sail regularly, I can't have more than 2' draft for about half a mile. This is common on the east coast of the US.

    Modern sportboats aren't designed to move at all with the keel halfway up. It wiggles around in the slot unless it's locked all the way down. This might be OK for short distances in calm conditions, but otherwise I'd worry about damage.
     
  6. Steam Flyer
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    Steam Flyer Junior Member

    Exactly.

    My design brief would be for a boat capable of shallow-water operation... a necessity in many locations and very desirable for a boat that doubles as a weekender. A compromise against performance, yes... the boat probably would not beat a Melges 24 or a Shaw 6.5, but it could still be plenty fast and a lot of fun.

    FB- Doug
     
  7. mizzenman
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    mizzenman Junior Member

    Thanks for your reply!

    I gues the speed loss is due to the wheighted dagger-board not being completely locked in the trunk.
     
  8. Steam Flyer
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    Steam Flyer Junior Member

    Part of it... although IMHO a carefully designed & built trunk could hold the foil in place as rigidly as a drop-in box. But the weight of the trunk itself, plus the built-in lifting gear, are just added weight. Then there's the issue of how long a daggerboard foil can be fitted into the hull & trunk... some of the sportboats have -really- long keel foils, when raised they often extend above where the boom would be... obviously it is not possible to extend a trunk this high!

    All boats are compromises!

    FB- Doug
     
  9. mizzenman
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    mizzenman Junior Member

    Yea, the boom is a problem. Production boats solve that by using high freeboard and a high cabin, but I don't like that.

    I would find a open boat where the board is raised by a removable krane more interesting.

    One could use two kranes of different hight. One that reduced the draft to say 0.7m,but still passed under the boom. And one that pulls the board fully upp for trailering.
    Off course if you are talking about a keel wheight of say 400kg,the kranes could become to bulky to handle!
     
  10. Steam Flyer
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    Steam Flyer Junior Member

    I would like high enough freeboard that the crew are not dragging their feet in the water; plus a cabin with sitting headroom for weekending.

    Production boats generally make a lot of compromises away from performance; especially here in the US.

    Did you see the Melges 24 and Shaw 6.5? One of them might be just what you're looking for.

    That's a good idea; another thought I had was to incorporate a track or guide for the front of keel root into a stanchion running from the hull up to the cabin top, with a tackle for lifting the keel at least that far. Then your 'high set' removable crane could raise the keel the rest of the way but not while sailing. This would minimize the added weight & loss of performance.

    Size is obviously an issue. Over here (eastern US) there are minimum sizes for offshore races and many keelboat fleet races. Also I'd like to keep the boat's beam at 8'6" (2.62m) and overall dry weight at 2500lbs (1130kg) for trailering.

    There are a number of possibilities on the market now, my two favorites are the Rocket 22 and the Flying Tiger 7.5, both would need slight modification for my purposes. And they're expensive enough that I'm reluctant to buy one and then start hacking at it!

    FB- Doug
     
  11. K4s
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    K4s Junior Member

  12. mattotoole
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    mattotoole Senior Member

    Doug,

    I think we're on the same wavelength. A few thoughts:

    A lightly weighted daggerboard plus bilge ballast would be structurally efficient, and cheap to build. No fancy keel casting, simpler keel structure and lifting mechanisms, use the daggerboard case for mast support, etc. It wouldn't perform quite like a sport boat but it could be an improvement on some older designs. Money saved here could go into a lightweight rig.

    I'm thinking of a lighter, updated Santana 23D, with a modern rig like a U20/U24. Maybe bigger, but not as big as an S2 7.9.

    It should be suitable for single/doublehanded sailing, and seaworthy enough for coastal runs off the Carolinas. Good shortened sail options, stablity, etc.

    Of course a Farrier tri would do nicely, but they might not let us race.
     
  13. Steam Flyer
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    Steam Flyer Junior Member

    Well, the multis have their issues IMHO... they can be somewhat lighter with no ballast, but the structure is more demanding. And having more than one hull is no guarantee of speed, for example the Antrim 27 rates level with the F-27 tri and the winner of races between them depends on course & condition... and the Antrim is roomier inside.

    It's funny you should mention the Santana 23D because I currently have one. Cool boat, but not a sportsboat by a long shot. The ballasted hull & plain daggerboard works but it's notably tender compared to a J-24 or similar.

    IMHO a bulb is a good solution, but the stability it adds doesn't translate directly to better performance because it doesn't "kick in" until heel angle gets large. Obviously getting the right combination of balanced hull shape & keel & bulb is critical to highest performance. This is one reason why I'm hesitating to start committing the money to build a design of my own.

    A 25-footer could be plenty roomy for short-duration cruising (heck my wife & I cruised in a 19 footer, albeit a pudgy roomy one) and offer a huge leap forward in performance over older boats.

    Have you seen B&B Yachts speedster

    http://www.bandbyachtdesigns.com/ec22.htm

    This boat beat a Tornado Cat... respectable performance!

    FB- Doug
     
  14. mattotoole
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    mattotoole Senior Member

    All true but no shallow water for the Antrim. Also no question that a tri is a lot of stuff to build. The tri may be easier for 1-2 people to handle in the ocean.

    A completely different idea -- maybe a better one! I could enjoy one of those for sure. The performance/simplicity ratio looks amazing.
     

  15. Steam Flyer
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    Steam Flyer Junior Member

    It is a promising design, although I suspect a big margin of it's performance comes from being built more lightly than a boat for long-term workaday use. But as an economical expedition-type racer, it's the tops. The designer/skipper is no slouch either.

    It's be interesting to compare how much this boat would cost to build & commission versus somethinglike an i550; and see them race each other.

    FB- Doug
     
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