On-deck Movable Ballast for Racing Keelboats-History and Modern Applications

Discussion in 'Sailboats' started by Doug Lord, Aug 26, 2011.

  1. Doug Lord
    Joined: May 2009
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    Doug Lord Flight Ready

    I've raised this topic before in terms of fast monohull keelboats for use by disabled sailors. Julian Bethwaite and Sean Langman have worked on conceptual designs using either lead or water to drastically increase righting moment. One of the Herreshoffs designed several very fast race boats in the 1800's using on-deck ballast comprising lead or brass on a sliding cart. Then, of course, are the sandbaggers and others I may not be familiar with. I'm interested in two main things:
    1) other present or historical examples of on-deck movable ballast*,
    2) thoughts on how this type of ballast could be used on racing sailboats to increase righting moment while still allowing self-righting.

    * not limited to just the width of the deck...
     
  2. Chase_B
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    Chase_B Junior Member

    if the pilot/capt. of the boat has limited motion or ability to move around the deck quickly,.. one could put ballast in a tube going from one side to the other ,..sub deck , that has a movable ballast inside of the tube,.. these could be controled with cables attached to each end of the ballast running thru pulleys to the helm and connected to crank handled drums,.. for safety,..if you put spring loaded swedge type ends on the ballast ( just incase a cable seperated) where the swedge would apply pressure to the inside of the tube and stop the ballast from moving inside the tube until the cable could be repaired,..sounds like allot of extra things that could go wrong,..but imagine a ballast free wheeling side to side ,..and if your disabled to the point that you can not move fast enough to trap the ballast,.. it wouldn't be all that hard to build something like this ,..and it being below deck,( just under the top side skin)..it is one less thing to maneuver over on top side,..

    Just a thought :)
     
  3. Doug Lord
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    Doug Lord Flight Ready

    On-deck Movable Ballast

    ======================
    Thanks for your comments, Chase!
     
  4. Doug Lord
    Joined: May 2009
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    Doug Lord Flight Ready

    On-deck Movable Ballast: Sandbaggers

    A bit on sandbaggers:

    Sandbaggers, a type of broad shallow open or partly decked sailing boat ("Annie"c.1893) carried tremendous sail area for their size. The ballast was a canvas bag of 50-60 pounds of gravel that the active crew moved whenever the boat tacked. It carried up to 1600 square feet of sail. They were raced on the Hudson River and along Connecticut, Long Island shores, and New Orleans in the latter part of the19th century, the sport died out--because of the necessary size of the crew, the immense labor involved and a change in the racing rules in 1885"

    ========
    More from the Bull and Bear site where two sandbagger replica's have been built as part of a youth sailing program:
    http://www.bullbearsailing.com/ good video under "Sandbaggers": http://www.bullbearsailing.com/video

    Originally built in the 1860's, Sandbaggers were work boats used in New York Harbor to shuttle cargo, such as oysters, to market. The fastest boat to market could set the price of the day. Owners and crew then started to race them with wagers on the outcome. The racing boats had a length restriction, but none on the sail so they kept getting bigger and the masts, boom and sprites longer. In addition to this making the boats faster, it made them tip over more easily. To compensate, the crew would literally move cargo, which evolved to sandbags, from side to side to keep the boats upright. Hence the name "Sandbagger!"

    Picture-b& w -uncredited, color- "Bear" from the Bull and Bear site:

    click on image---
     

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  5. Doug Lord
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    Doug Lord Flight Ready

    On-deck Movable Ballast

    Of course, trapezees, sliding seats/planks, hiking are all means for the movement of 'on-deck' ballast. The thing I'm interested in is ways to allow that kind of movable ballast-in terms of weight- but not have it have alive. It is also essential that inanimate ballast not be allowed to pin the boat down in a knock down and that it not impede self-righting in boats that require self-righting with no crew assist.
    Ideas and thoughts about this very welcome....
     
  6. CutOnce

    CutOnce Previous Member

    From outside the box

    Perhaps it is worth considering things from a different perspective.

    What about a small (16-18 foot), very light planing sportboat-type, with bulb ballasted keel, fully decked, with self draining sitting-in cockpit well for the skipper and optional deck seated crew? Light enough to easily plane downwind, ballasted enough to self recover from knockdowns. Simple rig, with self tacking jib and perhaps a fractional asymmetric spinnaker with a built in launcher.

    Keep the weight down to 550-650 pounds, including a 200 pound bulb. Keeping the cockpit small with the boat fully decked would allow complete knockdowns with no water ending up in the boat. Huge buoyancy, no concession to cabins or below deck access while sailing. Sailing equivalent of "Weebles wobble but they can't fall down".

    This option would be very simple, cost effective to build, weight is attainable using conventional materials. Think about a slightly smaller i550, less the cabin, bunks etc. A bit smaller rig, with a fractional jib and self tacking.

    It could be done to use commonly available rigging from a popular one design dinghy (29er?). I think this type of idea has a chance of catching on if it is actually, fast, fun and above all safe. Something a 55+ year old ex-dinghy sailor could single hand at 20 knots and end up grinning on planes downwind with kite. Day sailor only, with no motor, no cabin, no complexity and safe, speedy fun. Possible to sail two-up at over 20 knots for greater thrills - understanding the crew is able to move from side to side.

    I don't think this type of boat would be close to competitive with trapeze dinghies or all-out sportsboats like a Viper or VX, but aimed at the right audience it could be a winner. And with pricing in the $10-15k range it could be really popular as a one-design. Kind of an update on the Tempest, removing a lot of weight, the trapeze and going to a modern lightweight rig and planing hull.

    Just a very different take from the arms race mentality of bigger rigs, huge righting moment (sliding ballast, canting etc.), complex righting moment mechanisms. This kind of boat would by design heel upwind, conceding the lack of crew mobility. Adapt modern self tacking, efficient rig on a lightweight planing keelboat, acknowledging from the start that it is a safe, self recovering boat where knockdowns are expected (and planned for). Simple, safe, fun and fast(ish). I'm not ready for this kind of thing yet, but I can see far enough in the future to know I'd like it in ten years or so.

    --
    CutOnce
     
  7. Doug Lord
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    Doug Lord Flight Ready

    On-deck Movable Ballast for Racing Keelboats

    Once, good idea but there are already loads of conventionally ballasted keelboat types on the market. Specifically for disabled or physically restricted sailors there are the Skud 18 and Martin 16 among others. Your targeted pricing is well below any of these boats-is it realistic? Are you talking homebuilt or production?
    What I am trying to look at is systems that can be incorporated to up the performance of boats like this dramatically without increasing the physical demands on the crew any. I think it is possible utilizing bits and pieces of new and old technology and could result in really high performance planing monohulls suitable for people with limited physical abilities or just people who don't want to exercise the capabilities they have the way they would have to to sail a skiff but want the speed and performance of a skiff. I'm looking at a production boat-not a homebuild design.
    ---
    Other possible current examples:
    A) RS K6

    http://www.rssailing.com/index.asp?boattype=Performance Keelboats

    "Skiff style sailing downwind - no capsizing. Young or old, big or small - jump straight into a high performance boat and have the time of your life. K6 sailors are passionate about their boats!"

    RS K6 Specification

    Designer Paul Handley
    Length 5.8m 19'
    Beam 1.82m 6'
    Sailing weight 280kg 616lb
    Sail area main / jib 19.7sq m 210sq ft
    Sail area spinnaker 26sq m 310sq ft
    Hull construction Epoxy GRP foam sandwich
    Spars Carbon composite
    Sails Mylar semi battened mainsail and jib. Twin patch radial cut spinnaker.
    Foils Keel - GRP vertical lift with encapsulated lead bulb. Rudder - lifting GRP.
    =======================

    B) Open 5.7 http://www.open570usa.com/

    " The Open 5.70 is the best all around one-design racer as it combines good performance with excellent versatility. If you also factor in cost and quality then Open 5.70 really stands out. The boat can be easily sailed single handed, double handed or with a crew of three. The spacious and comfortable cockpit make it very accessible to all types of sailors, old or young - allowing for father & son teams, husband & wife teams, and all women teams for example. It's exceptional stability ensures the boat is easy to handle in all conditions while still challenging those who are experienced as well as forgiving those who are new to sportboat sailing. Finot was very crafty and smart when he designed the boat and it becomes amplified when you're racing around the marks."

    LOA 18 feet 9 inches
    LWL 18 feet 9 inches
    Beam 8 feet 4 inches
    Bow-sprit 5 feet
    Draft (keel up) 8 inches
    Draft (keel down) 5 feet 9 inches

    Displacement 992 Lbs
    Ballast 405 Lbs (foil: 75 + bulb: 330)

    Main Sail 182 sq. ft.
    Jib 90 sq. ft.
    Spinnaker OD 378 sq. ft.
    SA (upwind) 272 sq. ft.
    SA (downwind) 560 sq. ft.

    I 21.52 feet
    J 7.30 feet
    P 25.33 feet
    E 10.24 feet
    SA/D Ratio (Upwind) 43.75
    SA/D Ratio (Downwind) 90.08
    D/L Ratio 65.6
    Stability 3.30

    Architect Finot Group

    =======
    Left picture=K6, Right Open5.7

    click on image:
     

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  8. Doug Lord
    Joined: May 2009
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    Location: Cocoa, Florida

    Doug Lord Flight Ready

    On-deck Movable Ballast for Racing Keelboats

    Here is an example of a keelboat designed to sail with disabled or able body crew. It is conventionally ballasted and was called a "lead assisted skiff" by its designer.
    Skud 18 http://www.skud.org/?Page=18384

    "The SKUD18 is the result of collaboration between Access Sailing’s Chris Mitchell and B&B Technology and Innovation - Julian Bethwaite and Martin Billoch.

    By combining Mitchell's unique understanding and ideology of sailing for people with disabilities with 20 years of Bethwaite's high performance skiff experience, the result is the innovative 'lead assisted skiff' (LAS), the SKUD18.

    The boat is an exciting challenge for able-bodied and disabled sailors alike. This boat has been designed from a performance basis, to offer scintillating, crisp and snappy response to sailors regardless of their mobility.

    Mitchell, designer of all Access sailcraft and support equipment notes, 'The SKUD18 is very versatile and can be handled by a variety of crew configurations. The helmsperson can transfer manually and be steering with tillers, or be in a fixed seat on the centreline using a manual joystick, push/pull rods, or a servo assist joystick with full control of all functions. The forward crew can either be on the centreline, transferring manually, even riding trapeze. As its name denotes, the SKUD18 is a SKiff of Universal Design and can be sailed by people with all levels of physical ability.''


    Current Specifications

    Crew 2
    Paralympics:
    1 Class 1 disabled sailor
    1 female
    LOA 5.8 m (19 ft)
    LWL 5.5 m (18 ft)
    Beam 2.29 m (7 ft 6 in)
    Draft 1.7 m (5 ft 7 in)
    Hull weight ~ 400 kg (880 lb)
    165 kg (360 lb) (keel)
    Mainsail area 10.5 m2 (113 sq ft)
    Jib / Genoa area 5 m2 (54 sq ft)
    Spinnaker area 20 m2 (220 sq ft) (Asymmetric)
    RYA P
     

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  9. Doug Lord
    Joined: May 2009
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    Doug Lord Flight Ready

    Innovation in disabled sailing technology in boats like the 2.4 meter, Skud 18 ,Martin 16 and others has shown that modern electronics can be reliable in steering and sheeting these small boats. What I'm looking for in this thread is ideas to help improve the performance of boats with a crew that doesn't want physically demanding sailing but does want high performance sailing in a boat that is self-righting- and designed as a production boat.
    I'm not speaking of disabled sailors specifically though ideas here may result in designs that could be helpful. I'm thinking along the lines of a boat where the crew can move a short distance side to side if required and that uses some form of movable ballast-probably moved and controlled electronically. I'm thinking of a boat that could be launched at a "normal" ramp and that was capable of being tied up at a dock. So whatever form of movable ballast is used would have to retract into the boat on the centerline.
    I've worked for a long time on a sort of "dinghy" that could be self-righting and also could develop massive righting moment while sailing level. That design concept, the Trapwing, is not what I'm talking about here mainly because the system for creating RM on that boat is exceptionally wide- it is truly a lead assisted skiff and has great potential for maximum skiff like performance.
    -
    Here is that thread and a picture of a model of the concept-again NOT what I'm talking about here:
    http://www.boatdesign.net/forums/sa...isabled-physically-limited-sailing-37048.html
     

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