Auto-Feathering Device

5 Sep

The primary use of the arms in rowing is to connect the drive train of the legs (and core with back rock) to the levers (oars) which move the boat. For a conventional rower, 70% of the power comes from the legs, 20% from the back (core and lats) and 10% from the arms. So if you have an arm impairment, you are not necessarily losing that much power per se.

But the arms (and hands that go with them in most cases) can serve some other useful functions in rowing, especially feathering. Feathering (a) reduces wind resistance against the blade spoons, and (b) reduces the chances of the blades hitting the water going back to the catch (because they have higher clearance and also because they are flat, if they do hit, they skim the water without impeding its motion as much as a squared blade would). But if you have an arm/hand impairment, the manipulation required for feathering can be a real challenge. As a result, we tend to default to square-blade rowing for adaptive rowers with arm impairments.

A high school science “InvenTeam” from Northampton, Massachusetts, USA developed a mechanism that would automatically pivot the blade to perform the feathering action based on the position of the blade in the stroke and not requiring any hand or wrist manipulation. Their website includes a small blog that provides some deeper examination of their development and testing process:

  • “The Northampton High School InvenTeam invented Auto-Oar, a device that eliminates the need for wrist strength during the rowing motion. This will create a more efficient rowing stroke for adaptive rowers who lack wrist strength or have limited fine motor skills. Auto-Oar transfers linear motion into rotational motion to automatically rotate the oar from a perpendicular position relative to the water to a parallel position, called “feathering” —a motion traditionally generated by the rower’s wrist movement. The device is adjustable to accommodate different sized adults and stroke lengths. It is a lightweight and waterproof addition to an existing oarlock and oar. The initial cost for a set of two is approximately $250.”

As it happens, a while back, Ben Marsden of Marlow came across a similar innovation that was featured in a YouTube video for a very simple “auto-feathering” mechanism. It was developed by a Bob Hurley in Georgia, USA using an simple string mechanism to pull the over and back over very similarly to the Northampton High School approach. One enhancement that he made was an oar handle that could, with a click, be changed from fixed to rotating. The rotating mode allows for the auto-feather function and the fixed allows for actions like manoeuvring the boat. Hurley also made a great video of his invention in action, but unfortunately he has now taken it down. It has been two years since he posted it and I have been in touch several times with him, but he has not responded to enquiries for some reason, but here is short piece about his work that was featured in Rowing News.

I actually did a bit of a patent search and it looks like a number of people have tackled this problem and filed their inventions:

  • Rowing Apparatus” (1995 – US5685750A) – An intriguing mechanism which not only includes auto-feathering, but also provides the ability for “two independent power paths for each oar, one for the hands, another for the feet. It allows the use of arms only to propel the boat, legs only to propel the boat, or a combination of arms and legs to propel the boat. It has many applications for handicapped users because it can make use of any two limbs, for example one arm and one leg, even if they are on the same side of the body.”
  • Oar operating Mechanism” (1937 – US2167636A) – This version is starting to look more like the present day approaches: “primary object of the present invention to provide operating mechanism in which the blades are caused automatically to assume vertical attitudes when lowered into the water, and may be caused to assume horizontal or substantially horizontal attitudes when lifted clear of the water.”
  • Feathering Device for boat oars” (1937 – US2154018A) – A somewhat opaque filing which appears to use a spring mechanism for the feathering:  “spring urging the flattened portion of said oar shaft into engagement with either said side or bottom of the car look and contacting a prescribed path on the periphery of the oar shaft as the latter is rotated in the car look, and a protuberance rising from the periphery of said oar shaft in the path of contact of said spring for engaging and flexing said spring during rotation of said oar shaft.
  • Automatic feathering oar-lock” (1905 – US826058A) – A way-back example near the turn of the century described as “The main object of this invention is to provide an oar-lock which will automatically turn the oar axially as the oar is swept back and forth by the rower, the amount of rotation given to the oar being substantially ninety degrees or less, so that as the oar is pulled through the working stroke the blades of the oar will stand perpendicularly in the water, while during the recovery the blades will stand approximately parallel with the surface of the water or with their rear edges slightly depressed, so that the blades will feather the water during the recovery.”
  • Bow-facing and self-feathering oar” (1896 – US557318A) – Over the years a number of people have designed various contraptions to spin rowers around to be bow-facing (so they can see where they are going!).  This one going back to before the turn of the century also worked in a mechanism for “self-feathering” – “For automatically feathering the oars I have provided an eccentric oar-blade, that portion below the longitudinal center of the oar being widest and adapted by its increased bearing in the water to tend to rotate the blade into a horizontal position. In order to permit the oar to thus feather with its return movement, I have provided a joint in the blade-stem and have so arranged the parts that the oar-blade is permitted to make the necessary quarterturn with its reverse movement, but is held in its vertical position during the stroke.


Auto-Feather patent

Auto Feather patent 2

Auto Feather patent 3

Auto feather patent 4

One Reply to “Auto-Feathering Device”

  1. This may be of interest, my memory of the TV programme was that a sensor on the flesh wrist signals the prosthetic wrist to feather.

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