Translators note: this page was the hardest to translate. It has technical terms for sure but the principle behind the Ve-scull like many a great invention (reinvention in this case) is very simple thus hard to put into the right words. This page shows the limits of machine translation - human intervention is stiil necessary for subjects such as these. kiwi

The short history of the birth of the Ve-scull - the page of theory

This page explains the theoretical mechanism and principles behind the Ve-scull.

First, we will try observing the underwater movement of the oar.

As we observe the changes of movement, we notice that the end of stroke turn is instantaneous.

 

this is the traditional sculling oar

this is the movement of the Ve-scull

 

With the traditional oar very wasteful angular motion limits high-speeds. The traditional oar blade is symetrical (see drawings on this page) so when it arrives at the end of the stroke the oarsman changes direction by using the other side of the oar.

The Ve-scull on the other hand being asymetrical and more vertical in the water turns at the end of the stroke staying in its own laminar flow. The change of direction at the end of the stroke does not create the same eddy wave. This has been obtained by turning the blade 90° - at rest it is on the same axis as the keel line of the boat.

Look at the change of the water flow at A B and C positions in the figure illustrating the movement of the traditional oar

Look at the change of the water flow at the A B and C positions in the figure illustrating the movement of the Ve-scull

Next, the 2nd feature of the Ve-scull, the bending of the oar arm.

Please see the picture below:

The axis of rotation of the blade was revised. The oar blade exerts its force in the water around this axis. When the arm is moved to left and right natural rotation gives the correct angle of attack. In addition the rope also controls the correct angle of attack.

The third feature is the thrust rope. With the Ve-scull the oar is more vertical and trys to go deeper and more vertical still with each stroke. The thrust rope takes up this force and permits rowing with two fingers (see video). In addition the tension on the rope also controls the correct angle of attack. A television crew asked if it was easy enough for a monkey to row and... a monkey was found, and rowed! The video will be shown on Japanese TV February 2006.

The movement in the water compared to the zigzag of the traditional oar is more a series of S curves. The angle of attack of each curve differs with the thrust applied and the speed of the oar. At rest the oar floats up to the position seen above. Starting to row it digs deeper and tries to reach the vertical. The rope stops it at the perfect angle for maximum thrust forward. The rower applys more or less effort in order to reach the desired speed but does not have to worry about the oar jumping out of the oarlock because it sort of finds the right position and is held down by the thrust rope. Very hard to describe in words but the videos speak for themselves.

A propeller is the closest one can get to the principles of the Ve-scull, the blade twists slightly to a propellor like shape during the stroke. Taking this analogy further presenting the I-scull! Effective thrust can be generated without wastefulness.

© Copyright 2006 - Doi Atsushi. Translation © Copyright 2006 - Tony Grant. The Ve-scull and I-scull are Patent Pending world wide.

Translators notes

This translation is the work of Google Japanese to English beta version and Tony Grant with the invaluable help of the original author Doi Atsushi assisted by Koji Matano. The original version of these pages can be found at www.gl-labo.com. Koji Matano works as Timberline Small Craft, he has also translated "Building the Herreshoff Dinghy" into Japanese. Once again thanks to Douglas Brooks for introducing me to the Japanese boat building scene.

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