[Rhodes22-list] Ro, Ro, Your Boat...

[Bill Effros]

Robert,

How do gondolas work?

Does the Japanese boat weigh a ton and half?

Bill Effros

salm at mn.rr.com wrote:
> Thanks.
>
> Original Message:
> -----------------
> From: Robert Skinner robert at squirrelhaven.com
> Date: Wed, 06 Sep 2006 11:41:23 -0400
> To: rhodes22-list at rhodes22.org
> Subject: [Rhodes22-list] Ro, Ro, Your Boat...
>
>
> Reference:
>
> Wooden Boat Volume 192, Setember/October 2006, page 54
>
> "A Different Way to Ro -- Complex Japanese traditional 
> oar makes sculling simple"
>
> The article describes a long oar (~18') that is built
> in two major sections and affixed to the transom with
> a simple rounded and domed pin.  The inboard end of the 
> oar is attached to the bottom of the boat with a rope,
> allowing the oar handle to move in an arc.
>
> The mounting method allows the oar to rotate about its
> long axis as well as moving back and forth laterally.
> The transom pin transfers the longitudinal force vector 
> to the hull, and the rope prevents the oar handle from
> rising up as the sweep pushes against the water.
>
> The inboard component of the oar is fastened solidly to
> the sweep, but bent downward.  Thus, when you push 
> sideways on the oar handle, the torque on the oar 
> rotates the sweep so it gets a bite on the water.
>
> The person using this oar has only to move the handle
> back and forth to drive the boat.  All but lateral
> forces are controlled, so the operator's effort can
> come mostly from the large muscles in the legs as he
> stands beside the oar.
>
> The angles used in the design of the oar are critical,
> and the article gives dimensions for all components.
>
> As I read the article, several things came to mind:
>
> 1.  The pin used in Japan could be replaced with a
> removable oar lock set in a permanent block on the 
> transom.  The block could be made of almost anything,
> wood or plastic, and could be thick enough so it 
> would require no holes thru the transom except the 
> mounting bolts.  The hole for the oar lock could be
> open at the bottom to drain freely.
>
> 2.  There is no reason why a long oar couldn't be
> built with sections of aluminum tubing connected with
> an off-the shelf paddle to test the concept.  The 
> hole in the bottom of the oar would be replaced by
> a collar on the oar in the prototype, possibly by
> a gymbrel in a final version.
>
> 3.  For a prototype, the rope that would ordinarily 
> be attached to the cockpit floor could be attached to 
> a board that you stand on.  In the finished version,
> a fold-down attachment such as a hatch handle could
> be set in the floor.
>
> 4.  The Japanese design makes no provision for using
> the oar to row backward, as the forces would lift the
> oar off the pin.  I'd want something to keep the oar
> in place so I could use it to slow the boat down when
> approaching a dock, etc.  If the oar lock mentioned
> above were secured in its socket with a pin, and there
> were a bail over the top of the oar, then the oar 
> could not rise and come loose, or get lost.
>
> As regular paddles are limited by their length when
> used to scull, and longer oars would generally have
> to be made for the boater's own situation, why not
> go for an elegant and powerful solution.  The Pardeys
> used a long sweep instead of a motor on a blue water 
> 29' TALEISIN (IRRC), and Lyn describes its use.
>
> http://www.landlpardey.com/
> info%40landlpardey.com
>
> If you want a copy of the article, contact:
> Woodenboat
> 41 Woodenboat Lane
> P.O. Box 78
> Brooklin, ME 04616-0078
> 207-359-4651
>