Symmetry vs. Asymmetry

I paddle swift streams here in Florida with lots of sharp turns. Down with the flow and hard paddle back into it. Usually I use a Bell Merlin II or a Swift Osprey, both asymetrical designs with differential rocker. Latey I have been thinking about picking up a symmetrical design such as the old Bell Wildfire. Any thoughts about current performance differences and the trip back up? Thanks,


Asymmetrical form, in theory, increases hull speed by moving the water out of the “hole” a little more gradually than symmetrical hull forms.

It should be noted that ICF sprint boats are less radically asymmetrical than USCA cruisers.

Rocker differential is another matter. Rocker tends to increase hull speed by reducing wetted surface. ICF sprint hulls have quite a bit od rocker carried well under the hull.

Modern touring boats have differential rocker for handling purposes. The bows have adequate rocker to enable turning and reduce wetted area. Sterns are skegged to compensate for paddlers’ tendency to not stack their hands and to carry the blade behind their bodies. These flaws introduce sweeping components at the end of each stroke, and reduced stern rocker limits the sterns ability to yaw towards the paddle.

Using a straight shaft, careful attention to a vertical paddleshaft, a stroke parallel to the keel line, not the rail, and isolating the stroke forward of the knee frees the paddler from needing that skegged stern.

One can then dominate a hull with increased rocker, bow and stern; paddling the inside circle and catching every eddy.

Have both…
and paddle similar streams and rivers. I had the Merlin II first and at the time I started using it my skills were not as good as they are currently. The Merlin tracks a little less effortlessly and turns not bad. The Wildfire I obtained after I started haeavily into FreeStyle technique and it is just more fun to turn than the Merlin. At this point and for that specific type of paddling, if I had to choose only one it would be the Wildfire.

Stroke mechanics
rather than hull shape seem to be the determining factor. I guess my thought was the symmetrical hull might facilitate turns into the current with less actual forward length to swing around.

symmetrical rocker for turning
After eleven years with a WildFire (symmetrical rocker) and a year and a half with a RapidFire (skegged stern), I prefer the increased maneuverability of symmetrical rocker. But the RapidFire is faster because narrower, and I have fairly fast kayakers for friends, so I’m sticking with the RapidFire. It’s maneuverable enough for my kind of paddling, just not as much fun to turn – the sticky stern doesn’t like to slide around.

I don’t see any reason that a symmetrical, narrow, long boat couldn’t be as fast as the RapidFire and almost as maneuverable as the WildFire. Every once in a while I ask Charlie to build one for me, but he hasn’t done it. Yet.

– Mark

Water dripping on stone
I guess the water5 always wins in the end.

chop wood carry water?

make an asymmetrical canoe
with more rocker aft, and it will turn even better than a symmetrical one…

Oh, but than it is probably not called a touring design anymore but a whitewater canoe :wink:

Dirk Barends

good point
My last use of “symmetrical” should have been “symmetrically rockered.” I don’t mind a little width asymmetry, but I like to be able to slide the stern around.

So to restate my wishlist: 16’, 27", 10", deck, symmetric rocker (3-4"), asymmetric width, strongly arched bottom, lots of flare, large cockpit, kneel/sit adjustable-height seat. I’m confident it doesn’t exist, but it sounds like Charlie is weakening, so who else wants one?

– Mark

A number of years ago I used to do the same kind of paddling here in Michigan almost daily, including sections of river fast enough that you’d fight hard for every foot of upstream progress. I had all 3…Merlin II, Osprey and Wildfire.

On one upstream stretch the Merlin would cruise at 2.7 mph by gps aginst 2.3/2.4 for Osprey. The Wildfire is significantly slower than the Osprey for same fairly hard ongoing effort.

When running upstream through a spout…fast current through a break in a rock wall, the Merlin has the best ability to drive through, but could become almost uncontrollable if pushed off course by current. The Osprey is much more controllable. The Wildfire loves current and just settles down in current and responds to your paddle easily - no matter what and much better even than the Osprey. You can get perpendicular to fast current and easily straighten it out.

Over time I used my Wildfire very little because I really did need the upstream efficiency of the other boats. The Wildfire does not take extra muscle cruising…it’s always effortless…just cruises slower on flatwater or upstream. It cruises better with a bent shaft since the boat could not decelerate as much between strokes. Downstream it’s the best because you can just spin and play and eddy turn and go crazy. In whitewater the boat gets calm - like more stable than on flatwater - it’s amazing.

For downstream river work and freestyle I always felt that the Osprey was way better than the Merlin II.

Overall I do love them all; I’ll never get rid of my Merlin II, I have a Loonworks Aria that’s basically a wood/canvas Wildfire, and I’d get another Osprey in a minute if I had the room, money, and wife’s pemission…preferably in Champagne or Killarney green - with cherry trim.

==> just my two cents

“more stable in whitewater”, etc.

– Last Updated: Apr-12-08 12:35 AM EST –

All of the boat characteristics you described are actually quite explainable by how each boat moves though still, unmoving water. This stuff is pretty fun to take note of, at least for me. I'm certain I've seen similar things to your observation of the Wildfire being "more stable" in whitewater, and in my cases it has always been a result of a boat which is "more tippy" in flatwater simply responding to its surroundings the same way when the water got rough - except that instead of offering little resistance to being tipped by the paddler, it now offered little "purchase" for the water to grab onto to make the boat tilt with the waves, so it feels more solid than a "stable" boat would feel in in the same situation. In either flat water or rough water, the basic action of the hull relative to the surrounding water is essentially the same, but it is perceived differently if the paddler's frame of reference changes. My brain may be funny that way, but I'm always thinking analytically about little details like that, and it's one of the more unusual joys I get from small boats.

Anyway, for what it's worth, I also have a Merlin II and have noticed the same things you pointed out. The speed can be an advantage for upstream travel, but the same general resistance to making quick turns that the boat provides on flat water becomes very evident when going upstream and becoming slightly off-course. It can be a major pain to pull it in-line again, whereas a more "turny" boat isn't affected by little "blows" of turbulance or getting sideways to your proper orientation so it's a lot more easily controlled. This is another case where the frame-of-reference thing comes into play. In a situation where the Merlin II gets off-course going upstream and is hard to pull back where you want it, if you were to map out your course and speed *relative to the water itself* when that happens, and not relative to your actual progress (as compared to the locations of the riverbank or strainers), the maneuver would plot out the same as when trying to make a really hard turn at high speed on still water. When someone is "pulling the carpet out from under you" (the river current) it's easy to lose sight of that (especially since on the river, variations in current speed from one spot to the next complicate the issue!).

One big advantage I see in having symetrical rocker is when some of your boat-handling involves backing up. A boat with a skegged stern may be harder to turn when going forward than a symetrical boat, but when backing up, it turns too easily to the point of being squirrelly. A symetrical boat will handle the same going backwards as forwards, though you may need to shift your weight forward a little bit when back-paddling to attain the same trim (and handling) relative to your direction of travel as you have when paddling normally. Of course, in my own paddling, going backward isn't as clean as it ought to be, but I'm working on it. More fun stuff.

this sounds like
a RapidFire kind of canoe designed by John Winters?

I would buy one instantly, if I could get one here!

Dirk Barends

I agree
I agree with the comparisons of the Wildfire,merlin,and Osprey-having owned all 3.I still have my Osprey,which should say something.I think it’s the best compromise solo boat out there.It would be my last boat I got rid of.Twisty narrow streams in a Merlin always seemed more a chore than a pleasure to me,but in more open water+++.


Twenty years ago, when solo canoeing was new and the hottest game on the water, Cold Run Canoe often taught weekend intro courses.

Inevitable, folks preferred to start in Sawyer and WeNoNah sit down boats. Then they progressed to BlackHawk pedestal boats for more finite control and better maneuverability. By Sunday afternoon most were in cane bench seats, kneeling when needed; sitting when convenient.

I think we go through a similar trajectory with hull form. Beginners need high Length / Width ratios and skegged sterns to arrive at a destination. Over time the need for those training wheels fades as paddle sensitivity increases.

Very few hulls are made with significant, symmetrical rocker because the pool of paddlers able to enjoy them is small. So it goes.

on the other hand,
what you call a skegged stern can be a great help against severe weathercocking from an asymmetrical so called swede hull-form. This can save you a lot of energy when traveling on open waters.

Dirk Barends

Bob, my old Merlin II was good for going upstream but a chore to turn quickly in downstream situations. My most fun lately has come from paddling the Kestrel in twisty mangrove tunnels and cypress creeks. You wouldn’t think the boat was so maneuverable from the specs but it is. Have you tried your Kestrel in these environments? Just wondering what your thoughts were for comparison purposes.

is very difficult for me to use in those areas. The Osprey is about the best for that habitat. The Kestrel is a great boat on the flats but again turns poorly for me. The Merlin II is more comfortable with the flats also although turning is better than the Kestrel. Just my impressions.


This discussion illustrates the old problem of terminology when discussing hull shapes.

Universally in drafting, 3 views are shown, the Plan, the Elevation, and Sections. The Plan is a direct overhead or birdseye view. The Elevation is a direct side view, often in naval architecture known as a Profile. Sections are views of a hull in slices. It’s like viewing a loaf of sliced bread from the end, then removing each slice and viewing the shape of each succeeding slice. Each slice could be a designated section view.

In discussing hulls, symmetry typically refers to the shape in Plan. Usually this is limited to three shapes, symmetrical, fishform, and Swedeform. Fishform hulls are larger in the bow sections, Swedeform in the stern sections. The terms symmetrical and asymmetrical should be limited to shapes seen in Plan.

The Elevation or Profile view is often shown with a Baseline for context. It is like placing your canoe on a long table top at eyelevel and viewing the shape from the side. The tabletop would be the Baseline and the shape of the hull bottom is often referred to as the Keel line. Rocker can be measured by the gap between the Keel line and Baseline. Differential rocker can be noted in this view.

Section may be taken at any intervals desired, but often in canoes at each one foot along the length. It is a series of drawings, often superimposed showing the hull shape at any designated interval.

Hoped this helps more than confuses !

I’ve never tried
the Osprey or Wildfire but would love to.

Merlin II
I totally agree with you…fun stuff.

I think you must be paddling against some fairly swift current to experience difficulty controlling the Merlin II.

I’ve been pinnede against obstacles at least twice in mine due to a combination of fast spring currents and stupidity/bad judgement…but good learning experiences.