front rowing system for canoe

Squidly,

I get the picture, but it seems like the pivot point in the circular track will just move, leaving the blade in the same place? Are you using a sliding seat somehow connected to the pivot point?
I know this is just a concept picture, but on my sliding rigger boat, I had to have the pivot point about 2.5 feet from the centerline of the boat using 9 ft oars. Actually I just copied a skull, but it does work properly.

Marc

 

Squid,
That is a wild concept. The load on those bearings must be very high and also the channels. Has one ever been made? And thanks for the graphics to explain.
Easy Rider

 

upchurchmr and Easy Rider

upchurchmr, there is no pivot point in the track, thus Easy Rider is correct the "load on the bearings is high(leverage-wise)" but we are only talking about the load of one(or 1/2) of a human, and mostly a very small fraction, because rowing isn't max effort power lifting. Consider how the pedals on a light-weight bicycle are 90' from the crank arms but easily support the entire weight of even the heaviest man, for years and with countless 'soft' impacts. I've never heard of even a very fat man bending the pedal/crank of even the cheapest bike, but I've heard of some kids doing it in 'suicide jumps'.

In reality, I'd probably want the 'carrier' and oar to be separate so the oar be feathered for recovery stroke as well as dipped up and down a little.

The Carrier would have a short pipe into which you would slip the oar, and the pipe would itself be able to pivot up and down a little as shown.

 

Squidly,

Sorry to be so slow, but I don't see any load on the bearings. If you pull on the handle, the bearings will allow free movement, so you are never going to pull the blade thru the water.

I must be missing something, so I'll just lurk and see if something pops out to let me understand.

Marc

 

The whole system would be better if one cut off the inbd section of the oar and rigged line and pulleys from hands and feet to the oar at a point 18 to 24" outbd of the channel. Then there would be almost no load on the bearings at all. An automatic feathering device could easily be part of it as well.

 

ERider, I was considering that but didn't like the whole "lines" thing

with the Ron R. Rig but that is certainly an idea.

Mostly I wanted something that would leave the center of the boat open(unlike a RR rig) and where the oars could be easily deployed or removed, and would hopefully still be regular oars (unlike the double jointed rig or using lines.

With lines I'm thinking you'd need at least 4(power and recovery) and at least that many pulleys(if rower and oars are both amidships).

That sounds like a lot of lines to attach/detach and keep sorted.

I was hoping for a gizmo that could be clamped onto most canoes or skiffs and the cylindrical "Oar Holder" could accommodate most standard oars. I guess it would have a hinged top and might be a top and bottom Vee so as to clamp and hold a variety of oars.

And, no, nothing like this has ever been made to my knowledge.




upchurchmr.....the wood colored "T" oar in this pic would be fixed at 90', thus the oar shaft would stay at 90' of the section of track it was in.

 

Squidly

I finally got it. Thanks.

So the effective length of the oar would be measured from the center point of the circular track arc to the blade. The handles would be a certain distance from the same center point, so the leverage could be adjusted by choice of the track arc radius.
Perhaps the track bearings would take a high load, but I would much rather deal with that than all the lines/ pulleys/ structure inherent in the RR rig.
I also finally caught the elegant simplicity of the tube mounted with a horizontal pivot to slip the oar into - allowing feathering.

This is much better than I thought, when will you start construction?

Perhaps instead of the multiple bearings shown in the picture, you could just have a wheel with a vertical axle on each end (oops, probably 3 wheels to insure the "carriage" doesn't twist).

You also need to get right on naming the parts so we know what I am talking about. This duplicates the motion of the RR rig while allowing you to control the leverage by choice of the track radius without all the claptrap. The circular track could be replaced by an unequal length 4 bar mechanism which might be easier to imagine/ design for the bearing loads.

Would you use this with a sliding seat?

Nice concept,

Marc

 

Props

I always wondered how people rowed boats when they couldn't see where they were going.

I just scribbled a drawing to see how I would do this and I thought I would rather look at a sliding seat with handles that that was attached to a rack gear.

This in turn would rotate a shaft behind the paddler with the pinions on a (can't remember the exact term) a scrag clutch that allows rotation one way and drives in the other.

This in turn would rotate two props via bevel gears.

When the seat went forward the rack gear wouldn't rotate the shaft, on the return it would, and drive the props.

 

upchurchmr, now that you mention it, cylinderical might not

be too good, as it would be tricky to get a close fit and still rotate without binding.

Sliding seat rigs all have square oarlocks and rounded-square collars on the oars, so the oar is in one two distinct positions. First thing I did learning to row was cut some indicator notches in my oar grips so my hands would always know which way the blade was without me looking.

Maybe a square collar made of two "V"s that would compress on a range of different sized oars, and the collar would be mounted on a hinge allowing it to flop approx. 90' for feathering.

You are right only 3 bearing needed, I was just doing what was easy to show in Solidworks. But I'm leaning toward 2 bearings on each end of the carrier, thus as long as the track is of equal width, the track itself wouldn't need to be circular but might be some ergo-metric 'spline' shape. Sort of like those "bio-stroke" bicycle front sprockets that are elliptical instead of round to supposedly work better with your leg's "natural motion". I've pondered how the rest of an Internal Combustion Engine might change if engineers weren't tied to a sin curve but could choose any 'cam' they wanted....but I digress.

I'm not going to build this right away, although others have my permission, but I might do some more design figuring out what off the shelf stuff could be used, and how the track could be made as easily as possible. I'm guessing the curve would be layout on flat metal and the walls would be strips first tack welded as they are gently bent into place.

 

Poida, once you row backwards you soon realize how important

it can be to have a good view of your wake to see how even and correct your stroke is.

They tell you to turn your head every 5-6 strokes but it is easy to forget.

I ran my old shell up on the bank unexpectedly several times at full speed, rudely snapping out of a "Walter Mitty Moment" I was having about viking long ships or trirems.

 

Squidly,

How about just bending a square piece of tube, then cutting a slot in "the top". Another idea is to not use a channel. Bishop-Wisecarver has a system of wheels with a v-shaped groove in the rim, these run on anything with a 90 degree edge, like a piece of square tube layed so that two edges are in a horizontal plane. Might be tough to bend square tube that way. Take a look at their web site. http://www.bwc.com/pr_detail.php?idx=1087?WT.mc_id=DNMCnpn

Marc

 

upchurchmr, thats a good tip re:"V" wheels.

Have one piece of square track set on 45 with "V" wheels on either side.


The requirements I'm laying out for myself are:

1)All parts should be off the shelf at decent hardware store(maybe sliding glass door track and wheels?). Whole rig shouldn't cost much more that $100 of the shelf, not counting oars.

2)No welding or special machining.(although if someone wants to make a better one doing so that is all good).

3)Needs to be able to clamp-on and off to 95% of canoes without drilling any holes or even leaving scuff marks.(maybe Stanley "quik-clamps" or just C-clamps with grippy pads.)

4)Should work with standard dory wood oars or sculling shell oars without damaging or modding the oars.

5)Might need two different dimensioned designs, one for fixed seat with dory type shorter oars and one for sliding seat with sculling oars. Probably use 9quart ice-chest, door track and wheels for sliding seat. Not sure about arrangement for fixed seat, as standard fore and aft canoe seats don't seem like they are in the right spots, or height.

6)Should be able to also be used as conventional backwards rower, and/or have two facing(or same direction) in fore and aft of standard canoe.

7)Shouldn't take more than four hours to construct with drill, clamps, hacksaw, jig saw, screw-gun (once the plans are worked out) and shouldn't take more than 5 minutes to install or remove.

 

I admire your vision. Good luck with the actual design. In trying to build my sliding rigger, I had similar goals, since I had just a little more tools available than in your list. I seriously failed, but the goal still kept me on the relatively cheap side. The first place I had trouble was the wheels, I had to get a friend to build them on his lathe.

When you get started please let me know.

Marc

 

Back Strain

Why don't you just mount a truck mirror on the side of the boat so you can see where you are going? Oh all right it defeats the engineering exercise.

Rowing a conventional dingy with a fixed seat is only suitable for a short distance due to the curvature of the lumbar spine when leaning forward.

The sliding seat allows your back to remain straight and your legs do all the work with the arms only finishing the stroke when the oars have nearly finished their motion.

If you want a system for rowing over a long distance this should be taken into consideration.

Or attach the oar to the handle of an outboard motor.

 

Poida;you are devilishly practical. Attach the oar to an outboard handle eh? Good thinking. Alas, we are dealing with a problem that has been with us since long before the outboard came our way. Some of the old down east lobstermen rowed standing up and facing forward. They claimed that they wanted to see the rock that were certain to hit. Standing to row a canoe is not a great way to stay dry however.

SD why does the track need to be curved? If curved it would cause any point on the oar to move in and out for no immediately evident reason. Sailboat sheet block travelers have nice roller bearing slides that might be adapted to this experiment.. The only argument I have with this all too simple trick, is that the stroke, or movement of the blade, will be too small. The cantilevered load will put a fearsome strain on the oar holder unless the oar is short. With this system the oar need not be long as it will move the same distance without regard to length. The blade will be perpindicular to the direction of movement at all times which, at least intuitively, seems an advantage.