Physics of paddling vs. rowing

[wtarzia]

I am a little confused about this despite having done a lot of both rowing and paddling though never having studied the actual science of it. Today while we were walking her dog my girlfriend asked me why some boats are paddled and others rowed.

I had the usual answer about narrow hulls built to conserve effort and materials and used to sneak between things (ice floes, stream banks), thus paddles better, and of course the advantage to face forward and see where you go, especially in a a boat used for close navigation (between obstacles) and hunting (where paddling might be quieter, etc.).

Then she asked which was more powerful. I gave the stock answer, "Well, a paddler or rower can develop about a half a horsepower...." and then I stopped. A paddler is using her whole body as the lever and fulcrum power mechanism (though it is transmitted to the hull), whereas the rower is only part of the lever/fulcrum. The oar is a longer lever and you use two of them, but they swing through a greater arc usually, so transmit their power more slowly, whereas the paddler for a similar caloric expenditure might get in more paddle strokes in the same time for as an oar sweep. Then there is the distance between the oarlock and the handle as compared to where you hold a canoe or kayak paddle, and how you actually paddle -- twisting the body, fore aft movement of torso, etc. (I am simplfying rowing by ignoring sliding seat methods).

By the end I had to say, I just don't know how to explain the power difference between rowing and paddling if the same human with the same muscle mass were to be compared doing both. I said, "My colleagues at Wooden Boat Forum will know!" And here I am. We might start with the "fact" (I read it somewhere) that a fit paddler can develop about half a horsepower at maximum. A rower too? Why or why not? Ignore sliding seat rowing for simplicity sake. -- Wade

[Peerie Maa]

One thing to consider is internal friction in the power plant. To maximise efficiency humans need to pull or push fairly slowly, or they waste too much energy in their joints and muscles. Rowing uses leverage to allow the force to be applied slower and for longer, putting more work into the boat and less in warming up the body.

[skuthorp]

I've paddled a 500km race or two in KI's and K2's, and I row and paddle often these days in a Macgreggor canoe. Rowing is faster, more energy efficient at least as far as I'm concerned. But it depends on the water, in narrow places paddling is better, in a decent sea paddling is safer. I presume you are comparing double paddles to oars? There are worlds of difference depending on the blade profiles etc.

[Uncle Duke]

And... let's acknowledge the difference between "ordinary" rowing (skiffs, etc) and "sliding seat" rowing, where you gain the (very significant) extra drive of the legs.
Huge difference in power, but limited usefulness in the real world.

skuthorp:
500km race
Dude! I genuflect!!!! In U.S. measure, that qualifies as "too many" miles!!!!!

[py]

I'd have thought rowing is considerably more powerful. Paddled boats have always been small and light-heavy boats are rowed. Ever seen a fisherman tow a net out behind a canoe? They do a mighty job with a row boat. Seems to me the geometry and the use of a fixed fulcrum substantially favours rowing.

[Ian McColgin]

I did not know that any human in any configuration could put out a half a horsepower. But whatever . . .

Rowing is more powerful, whether sliding seat or work boat style. Ever try to paddle a couple tons of fish to market? That's what the full-body power of the dory stroke recently illustrated in WB is all about.

Working a double paddle uses all the muscles from the buttocks up for propulsion but the legs are used for bracing only, while in rowing sliding or fixed seat all muscles can come into play together or in rotation.

This is not to underrate the joys of kayaking. Especially at this time of year. When I get out in these little snow squalls even though I'm in bright yellow goretex dry suit with insulating foam and a nice modern boat, I am in my imagination Nanook sneaking up on a walrus or one of those commandos paddling up a fjiord to disturb the Nazis or whatever. Each sort of boat has its purpose.

[J. Dillon]

http://www.duckworksmagazine.com/03/r/vintage/marinerscatalog/03/pic2.jpg
Worcester mentions that some yulohs have iron edges worked into the blades. This is to give the blade more weight and also to give it a sharper cutting edge as it moves through the water. The blade on the yuloh I had was quite heavy, being made of oak, but I believe some extra ballast in the blade would have made it even easier to use.

Worcester shows drawings of six types of yulohs, some straight and some curved. He describes the Shanghai yuloh as being curved, with a large blade, making an angle of about 45 degrees with the surface of the water. He says the Szechwan yuloh was straighter, with a long, narrow blade making a flatter angle to the water. The former provided more power than the latter, but the latter gave the boat a bit more maneuverability.
Try this thing. It does take "strong muscles before the boat moves," but once she gets going, then weak muscles can keep her moving.
—R. C. Taylor—

In the above book Wooster tells of one account where a sampan easily beat a cutter manned by British seamen. :eek:

JD
http://www.duckworksmagazine.com/03/images/newline.gif

[seanz]

I did not know that any human in any configuration could put out a half a horsepower. But whatever . . .


Maybe the back half......;):p


My money is on rowing because the mechanical advantage just seems greater. Anybody like to do an experiment? The obvious one would be kayak vs dory Tug-of-War......enquiring minds need to know.
:)

[BBSebens]

Do you like to watch Mythbusters?

They did an episode where Jamie waterskied behind an 8 man rowing crew.

I'm not really sure if that really applies, but it was really neat to see.

[Chip-skiff]

For years I paddled small cats in whitewater (the fun bits separated by miles of flatwater). Then I started building row frames and running larger cats. Given the same sort of water and the same type of boat, I find oars lend much more maneuvering power and perhaps a bit more motive power in the flats (perhaps cancelled by greater wetted area and more windage).

My bonehead analysis is that the oars give you more bite, with more blade area in the water for a greater length of time and/or greater distance. Just as more sail area means you catch more wind. You also have a more efficient lever. For a 9 ft. oar, a three foot length inboard and a six-foot radius to the sweep (hence more swept area).

With a double paddle, you only have one blade in the water, for a shorter time. A fairly long paddle— 7.5 ft. tip to tip, hands 18 in. apart— gives you an 18-inch lever and a 3 ft. radius sweep: potentially more mechanical advantage (but your hand and arm aren't as rigid as a frame and oarlock). And the swept area is considerably smaller. Plus you can't use your weight and leg muscles as you can with a well-set up rowing rig.

http://farm4.static.flickr.com/3360/3189915225_3333f628c7.jpg?v=0

On an 18-day Grand Canyon trip, I paddled one inflatable cat (Jack's Fat Pack Cat, below) and rowed another (Jack's Cutthroat, above), with the same size tubes, same load, etc. The rowing rig (1 swim) was noticeably more powerful in the big stuff and faster on the flats. The paddle cat (4 swims) was scarier, and more fun.

http://farm4.static.flickr.com/3428/3190762626_311a921098.jpg?v=0

Nothing wooden in the shots save the oars (and my head).

[meuritt]

Very interesting. I have a 14' wooden Whitehall with 8' oars. I would say I am not particularly skilled at rowing. GPS report I can get to 4k if I really work at it, but cruise at low 3k or high 2k's

I have a good quality FG kayak, 17' long. I can sprint to 5K, if focused can cruise at 4+ and easy paddle 3.5. I have other, heavier kayak that will take a half k off those speeds.

In my circumstance, paddling is faster, not to mention more enjoyable because I see the waterfowl before they fly off, since I face forward.

Load carrying is a no brainier, the Whitehall will take more freight than all my kayaks combined.

Mike
San Rafael, CA

[George Roberts]

This is sort of like the traditional v. modern debate over double paddles.

Paddling and rowing power output depend on the scantlings of the paddle/oar. They are optimized for different purposes. So neither is better or worse.

For the most part power output is limited by the power source - the paddler and the ergonomics.

[Ian McColgin]

Showing that horsepower does not always equal speed.

Though it can, as any flat water straight line race any distance between the best kayak you can find versus a reasonably good single scull each with a good boatman. The scull wins easy.

But add some wind and waves, maybe a beach launch and some turns and the kayak scores. Unless you're like those Alaskans - she wrote Rowing for Latitude - who found that an adapted scull could be turned into a finastking wilderness camper/cruiser.

And so it goes back and forth. But remember that the human using best muscles and traction can sustain about a tenth of a horsepower - emphasis on sustain - so pure horsepower will be determined by the arrangement that most effectivly puts the largest muscle effort into the water.

Right off the blocks, blade area matters and rowing you can put two blades in, albeit for only half the time.

Sliding seats and even better sliding locks seem to utilize the large leg and torso muscles most effectivly - and they do at high speed with really long oars - but there are friction losses and for cargo horsepower (think tug boat versus a noisy cigarello) there's nothing like a dory stroke off a thole pin, thwart, and a good foot brace. The only muscles that don't go into a dory stroke are those used in the return and those you use to wiggle your ears.

For every purpose there's a boat.

G'luck

[daveboling]

Very interesting. I have a 14' wooden Whitehall with 8' oars. I would say I am not particularly skilled at rowing. GPS report I can get to 4k if I really work at it, but cruise at low 3k or high 2k's

I have a good quality FG kayak, 17' long. I can sprint to 5K, if focused can cruise at 4+ and easy paddle 3.5. I have other, heavier kayak that will take a half k off those speeds.


I think that most of the difference in speed here is due to the displacement hull speed of each craft.

[Thorne]

At a very basic level the difference is mechanical -- rowing uses a lever based on the thole pin / oarlock, paddling doesn't.


Give me a lever long enough and a fulcrum on which to place it, and I shall move the world.
Archimedes

[Uncle Duke]

I've paddled a 500km race or two in KI's and K2's, and I row and paddle often these days in a Macgreggor canoe.
Skuthorp - I'm still fascinated by this.... can you elaborate?
The longest canoe race I've been able to find record of the the "Murray Marathon", which is 404 KM over 5 days - it makes my lower back hurt just to think about it.
Who does the 500 km race? And, over how many days? Do they allow oar-powered boats also?

[Chip-skiff]

At a very basic level the difference is mechanical -- rowing uses a lever based on the thole pin / oarlock, paddling doesn't.

Actually, paddling with a double-blade one uses the hand on the side with the blade in the water both to move the paddleshaft and as a fulcrum (which moves with the shoulders) so the lever analogy applies. That hand pulls back while the offside hand pushes forward. (Which increases the swept area somewhat.) To hold one hand still while moving the other would be hard— and awkward.

[meuritt]

I think that most of the difference in speed here is due to the displacement hull speed of each craft.


Dave, fellow piper here.

I just ran the numbers, guessing about water line length
http://www.sailingusa.info/report_speed.htm

I don't generate enough power on any of them to reach hull speed.

but it is a bit of an apple orange comparison. With rowing (not sculling) the muscles are all used in unison, and, as Thorne points out, has the advantage of a lever.

The kayak paddle OTH is lighter and I have a higher cadence and use different muscles, rotating the torso for one big difference, and alternates, right side, left side.

Also in the answer is the HP/pound ratio, the fastest of my three is also the lightest, lifting over the waves easier, and with the best glide in flat water.

A larger blade in the water will offer faster acceleration, but not higher speed. Speed is in large part a cadence issue, in my experience. Being heavier, a larger blade may contribute to fatigue.

With my paddles I've selected a bit smaller blades and shorter overall length, increasing cadence. I am hoping to make a Greenland style paddle this year to see where the extreme of small blades and light weight takes me.

clear as mud

Mike
San Rafael

[George Roberts]

"Who does the 500 km race?"

At one time there was a more or less annual paddling contest on the Missinaibi River about 750K (450 miles).

As I recall it was fast and dangerous. Mostly stupid people showed up to contest. (I did it twice.)

[skuthorp]

Uncle Duke, when I paddled the marathon in the late 1970's and early 1980's there was a section through a swamp and forest that they don't use now because people got lost trying to find a 'short cut'. Also because of the drought there is not the water and flow there once was. This last race was the last under the aegis of the Red Cross for various reasons, but I understand another organisation is looking at taking it up.
It's a canoe and kayak race only, but allows for 'team entries' some of which work as a sort of relay with several different crews in one boat on any given day. This is popular with school entries. This was not the case when I was a paddler. I also participated as paddlers land crew, and in the safety organisation.
Technique is all in such a race, if you do not get it right you can do permanent damage. I coached a couple of crews too, and mental discipline is a major factor in just finishing the race. It was the sort of event in which you find out things about yourself you didn't know before. When it's 45C and there's a bushfire breath northerly gusting up the river you wonder what the he** you are doing, but you look back with some satisfaction on the achievement.

[Dan McCosh]

The leverage of rowing is similar to a bicycle--converting short motion, high power, to long motion, low power in exchange for speed. Paddling is limited by the length of a reasonable oar, hence can't keep up.

[ingo]

There is a simple experiment to test the efficiency. Since speed depends to much on the shape of the boat, you better go to the dragging force at a pole. Just bind the boat to a pole and measure the maximum force. This can be done with a role to lift e.g. a large bucket with water. If the rowing boat can lift more water, it is more efficient.

[P.I. Stazzer-Newt]

The Sydney olympic results suggest that there is very little in it.

Mens Coxless 4 - 2,000 meters
1. Great Britain (J Cracknell, S Redgrave, T Foster, M Pinsent) 5:56.24

Mens K4 (1000 meters)
1 Hungary (A Vereckei, G Horvath, Z Kammerer and B Storcz) 2mins 55.18secs

So the Kayak went half the distance in a little less than half the time.

[Dan McCosh]

There is a simple experiment to test the efficiency. Since speed depends to much on the shape of the boat, you better go to the dragging force at a pole. Just bind the boat to a pole and measure the maximum force. This can be done with a role to lift e.g. a large bucket with water. If the rowing boat can lift more water, it is more efficient.

This is pretty much backwards. To stay with the bicycle analogy, a bike in top gear would measure with less, not more, force when static. Regardless, it would be faster when pedaled at speed.

[ingo]

This is pretty much backwards. To stay with the bicycle analogy, a bike in top gear would measure with less, not more, force when static. Regardless, it would be faster when pedaled at speed.

The question was not about the effience of a special type of boat (of course there are faster and slower ones) but of the principal difference between rowing and paddling. This experiment can decide it.

And a bike in top gear will (nearly) exactly give the same measure in this experiment. For example the weight of the bike ist not important nor the wind resistence.

[Nicholas Scheuer]

I used to row a 21-ft Dovekie using a pair of 9.5-ft oars.

Upon purchasing the Dovekie I removed the canoe paddle used in previous smaller sailboats from the Dovekioe's inventory.

The paddle would have been useless for propelling the Dovekie more than a few yards. We often rowed several miles at a time, when the wind wouldn't blow.

As a teenager I used to paddle canoes tens of miles a day with the Explorer Scouts, including one expedition into the Quetico, so it's not like I don't know how to use a canoe paddle.

Moby Nick

[Chip-skiff]

The comparison in my example was drawn from near-identical inflatable cat tubes: 16-inch diameter, same length/waterline, different cones on the rear. Also it was drawn from a single trip, rather long, on a single river.

So I think some of the potential variables (hull form and speed, displacement, etc.) are moot. Oars, in my case, were more powerful but not necessarily the best choice for enjoyment.

Yet the comments by Thorne and others point to a parallel truth: some hull designs are better suited to oars and some to paddles.

[Woxbox]

I'd say "Which is more powerful" is the key to the question. If by power you want to know how much force one can pull with for a short period, then the oars will win every time because they can be set up to be efficient levers.

But if you want to know which is best for a particular person for an extended trip, then I think it's more the person than the boat. When they developed the first human-powered airplane, the first thing they did was study humans as motors. And they found that the limiting factor is the heart and lungs, not the muscles. (And aerobic excercise was born.)

So whatever horsepower you can develop, you can put that energy into rowing or paddling, and the result will depend on all the specific details of the craft. The Blackburn challenge is an interesting study, where people race each other in a variety of craft. The paddled boats don't do badly at all against the rowed ones.

[Ian McColgin]

To repeat, on a sustained basis the healthy atheletic human can produce about one tenth of a horsepower sustained. By sustained, let's say an hour or ten.

So, power in the boat is entirely the function of how efficiently you get the human power into the water. Screw leverage - rowing does it because you can get more of the muscle power and more of the biomass into the stroke. if you want speed, go with the longer oar and narrower vessel. If you want load capacity, go with 3:1 or so and slow guts.

[seanz]

The Sydney olympic results suggest that there is very little in it.

Mens Coxless 4 - 2,000 meters
1. Great Britain (J Cracknell, S Redgrave, T Foster, M Pinsent) 5:56.24

Mens K4 (1000 meters)
1 Hungary (A Vereckei, G Horvath, Z Kammerer and B Storcz) 2mins 55.18secs

So the Kayak went half the distance in a little less than half the time.

Well, that settles it then......
:D

Except that the rowing 4 would have had sliding seats and it is easier to be faster over the shorter distance and the kayak had the shorter distance.
No, there's only one solution......Tug-of-War. Kayak vs Dory. It'd be a great event at this years Wooden boat show. I volunteer to row the dory........if someone comes up with the money for the ticket.
:D