Rudder / Paddle / Tiller

I didn't see a more obvious place for this post, but if there is one, please let me know. I'm new to the site.

When I was a young kid, my grandfather had a jon boat with a gas motor, but he wouldn't let me use the boat with the gas motor. He had what he called a "strong-arm motor". This was, essentially, a clamp on rudder with a larger than normal paddle portion. I could both propel and steer the boat with this contraption by simply moving the tiller handle repeatedly side to side through the range of its travel.

I've Googled until my fingers hurt looking for plans for this sort of thing, but to no avail. I mentioned it to my neighbor and he was intrigued. He has a small jon boat that we would like to use in small lakes and backwaters without a gas motor.

Does anyone recall this sort of propulsion device? Can you point me to plans to build one? What about modifying a rudder with a larger paddle?

Thank you in advance.

 

http://www.simplicityboats.com/yulohpage2.html

There are a bunch of different ways to do this. Some are lift based and involve mostly symmetrical motion about the centerline. Others have a drag component and involve feathering the return stroke and providing most of the propulsion on just half the stroke. Both can be quite efficient depending on size, speed, and biometrics.

The other term for the gadget is a scull. But many will insist that sculls and yulohs are different animals and can be defined by whether or not the leading edge of the blade is always the same, or switches back and forth. You probably didn't care about that as a kid, and probably don't need to now either.

So how old is your grandkid?

 

Thanks for the reply and the link, Phil. I actually do have a grandchild, a 6 year old. Way to soon to let her loose in a boat of any description other than the bumper boats at Putt Putt.

 

The best propulsion might be oars but if not, sculling will work providing the hull is easily driven.
When I was a kid I learned to sail in a "Sabot" (7.5' plywood, V bottom pram dinghy). Oars usually got in the way so if becalmed I would 'scull' by working the rudder (tiller) back and forth. Not very efficient but classier than paddling with your hands.
One clever guy (his dad actually) in our club clamped a pair of diving fins on the rudder and that made a big difference but also disqualified him from racing.

 

I suggest that you try sculling with a simple oar. With a little bit of practice you can make the boat go very well. The little kids in the Bahamas scull their dinghys at a rate that make it seem as though they had a motor. Old time fishermen sculled boats most efficiently and quietly. Some duck hunters use that method because it is quiet and unobtrusive when you get the hang of it. Actually it seems to be a lost art for most of us.

If you want to dream up a rudder propulsion system, I suggest that you check out some of the articulated fins in the scuba diving store. Those fins will give you some ideas.

 

hello dimomdcreek, the Chinese used a yuloh which is very similar to a sculling oar. They were used on some very large boats and some boats would have more than one but were mostly used on smaller sampans. And of course they had these all figured out when the rest of the world was still paddling with sticks and bones. So if you google Yuloh's you'll probably have more info than you could ever want but it's interesting stuff and might be worth a try. Have fun...........................g