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Design Goals

  • Personal performance multihull
  • Cartoppable or trailerable with a minimum trailer
  • Quick assembly
  • Extremely fast, much faster than the typical Beach Cat

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Available in Kit form!
or
New Owner Built Version

Performance Considerations

  • Definition of performance
  • Average windspeed =~ 9knots
  • Three competing technologies
  • -Displacement
    -Surface planing
    -Foiler

  • Displacement performance

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Why a Proa?

Performance Advantage

  • Righting moment can be adjusted from near zero to very large...can always fly a hull
  • Mast stepped in middle of hull --Minimum support weight and windage --Clean aerodynamically, extremely small frontal area, endplate on sail
  • Only two foils needed
  • Lightweight, low stress beams

Displacement Performance

  • Long waterline, high fineness ratio, small displacement/length ratio
  • Light weight, high strength/weight materials
  • Windward performance requires high L/D   - Clean shape and one hull in the water
  • High Bruce Number

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Tiny Dancer Mark I

Specifications

  • LOA 21' 3"
  • BOA 8' 6"
  • Sail Area 118 sq. feet
  • 20' freestanding windsurfer mast
  • Weight 100 lb.
  • Hull fineness ratio 21.5:1
  • Form - Pacific Proa, shunting two-way
  • Crew weight 90 to 250 lb.
  • Bruce Number 1.7 with 170 lb. crew

 

Bruce Number

Definition: Square root of the sail area divided by the cube root of the displacement, a power/weight ratio for sailboats.
Examples:

  • Hobie Wave with 4 adults.....1.0
  • Typical Beach Cat...............1.6
  • TINY DANCER, mkI...............1.7
  • Formula 40, classic..............1.8
  • RC27 Fiberglass...................2.0
  • TINY DANCER, mkII .............2.1

Tiny Dancer Mark II

Specifications

  • LOA 21' 3"
  • BOA 10' 6"
  • Sail Area 180 sq. feet
  • 26' semi-freestanding rotating wingmast
  • Weight 120 lb.
  • Hull fineness ratio 21.5:1
  • Form - Pacific Proa, shunting two-way
  • Crew weight 90 to 250 lb.
  • Bruce Number 2.1 with 170 lb. crew

Tiny Dancer Mark I   Nov. 1997 Tiny Dancer Mark II  Oct. 1998

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Tiny Dancer was conceived as a personal multihull. As such it must be light, and able to be transported on a car's roof rack. It also should be simple and quick to assemble. It needed to be a boat that you would put on your car in the morning and assemble and sail after work. I also felt that the boat design was not worth doing unless it performed well. My definition of performance is high average boatspeeds during a season of sailing and at multiple venues. These requirements resulted in a total bare-boat weight goal of 100lbs.(45.5kg.) for the mkI and 120lbs. (54.5kg.) for the mkII; that includes the assembled boat and spars.

The proa configuration was chosen because of its simplicity and therefore I can design it to be light and fast. Tiny Dancer is a Pacific proa, meaning that the rig is to leeward. The boat sails in both directions, each end becoming the bow in turn. The maneuver of swapping ends is called shunting, and one of the considerations of the design is to make shunting easy and stable. The mast is semi-freestanding and steps in a socket in the main hull. This allowed me to avoid the forward beam-dolphin striker assembly used in a catamaran, and since the loads are relatively small in a boat this size, reinforcing in the hull distributes the rig forces into the beams.

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The hulls were designed with the help of Ted Van Dusen of Composite Engineering. He manufactures world class crew shells, kayaks, and canoes. We used much of his experience with similarly shaped hulls and tank testing at MIT's towing tank to refine the design. The hulls have a fineness ratio of 21.5:1, and according to our data results wave-making at any speed contributed to no more than 5% of hull drag. I first produced a mold for the hulls, using strip-plank technique; cedar over female mold stations. I spent many hours fairing the mold. The hull halves were made in the resulting female mold, and were cured in Composite Engineering’s autoclave. Each hull half weighs 11 lb., and is constructed of carbon fiber over Nomex(R) core.

The MarkII uses a rotating carbon fiber wingmast and a square top mainsail. It is a serious, very high performance multihull with performance potential similar to an RC27, or a soft-sail C-class catamaran. We will be evaluating the boat during the next few months and considering a production run. Let me know if this is the sort of personal, high-performance sailboat that you might consider purchasing. 

The Warren21 MarkII Proa can now be obtained in Kit Form from Composite Engineering in Concord, MA.

Basic Kit = $7,500 ( in US Dollars) Both Kits include a full set of plans, directions and phone or email support. Advanced Kit = $9,000 ( in US Dollars)
  • four hull halves,
All assemblies are fabricated in carbon, using Nomex(R) cores where appropriate. all of the components of the Basic Kit plus a number of small carbon subassemblies:
  • saddle assembly,
  • the mast with the hound, track and foot installed
The hull halves are delivered primed.
  • the mast step,
  • four bulkheads,
  • the tiller extensions,
  • the gooseneck assembly,
  • ruddershafts,
  • the daggerfoil cases.
The owner will need to fabricate the wingseat and the daggerfoils.
The following assemblies will need to be purchased:
  • sail - Shore Sails
  • tramp - Sunrise Yacht Products
  • boom - aluminum tube, beams - 3" aluminum spinnaker pole stock
Assembled Trailer = $ 1,400 ( in US Dollars)
A custom aluminum Trailex Trailer is available from Composite Engineering, or you can buy a standard H20 trailer from Trailex and modify it according to plans supplied. The trailer provides a means to tilt the proa to an angle of 60 degrees for stepping the mast by hand (easy and fast)
For more information, call Composite Engineering at 1-978-371-3132 x27 and ask for Ted Van Dusen or
email Ted Warren at twarren@alum.mit.edu

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