Interested in other perspectives regarding ‘negative rocker’ in canoe hull design. Having narrowed my search for an ultralight 12 foot canoe with a hung seat (do not enjoy sitting on the floor), I was informed by builder that one design embraced a slightly negative rocker to assist tracking in the relatively short 12 foot hull. My only experience in this regard relates to a new MR Serenade 13 that had negative rocker as a result of defect, not design. When the hull oil-canned, the shallow-v hull with slight rocker went negative by about an inch and a half, resulting in a noticeable speed decrease and difficult turning. I am admittedly not an expert in canoe design, and would normally give the builder the benefit of the doubt, but would appreciate any input before dismissing this canoe.
I don’t perceive negative rocker as a benefit, but maybe it can be, if the rest of the hull design works with it.
It’s hard to imagine that this could be a good thing overall, and making a canoe deeper at each end in order to track better seems analogous to adding training wheels instead of expecting the paddler to correct his own paddling deficiencies. What could be good about pushing a small portion of the displaced water aside twice instead of once? What could be better about using a shape that increases both the draft and the wetted surface area? I’d pass on that design for those reasons unless someone with real expertise can make a believable argument to the contrary.
Slipstream and the negative rocker for some strange reason works. Sweet boats that look like they ought not to turn but they do
We all thought the same thing looking at them on racks at a rendezvous but paddling was awesome
Thanks for that info Kayamedic.
kayakmedic, how would you compare them to their competition?
My homebuilt Wee Lassie has about an inch of negative rocker(not on purpose.) It is a bit hard to turn, but I figure in something so small and light that is the better side to be on. Speed seems fine.
Part of my problem is that I had an MR Serenade 13 in glass that handled like a dream, the hull was as stiff and solid as a rock and she handled like a dream. When I opted for the Kevlar version and the hull went negative, it handled like a completely different animal. I have paddled an OT Pack that has a rather ‘flexible’ Royalex hull and the floor comes up to meet you as soon as you get in. Well, the Pack was never known for speed and agility. I was hoping someone could convince me negative rocker wouldn’t be an issue, as the canoe I was considering had many other fine attributes, but my predispositions may get the best of me!
What is the name of the canoe with negative rocker in it by design? I’d love to take a look at it. I’m having a hard time coming up with an explanation why a hog-backed hull would not be awful to paddle.
Slipstream Canoes Very light craft. I did not paddle all the competition as they weren’t at the Solo Canoe Rendezvous. I have a Rapidfire which is faster and holds more and is more suited to big water aka Superior
A friend has a Slipstream Wee Lassie. She is a kayaker looking for a very light weight canoe for lake trips that require portages. It seems to move along well on our local lake. She notes that it is wet is the short period chop we get there. Powerboat wakes looked to be fine though the other night.
When you look at the Slipstream website and see a little 12 foot tandem I can see where the little front and rear mini-skegs could be a feature where tracking is a priority. I don’t even like straight keel boats so I don’t envision any negative rocker boats in my future.
In that size range it’s not unheard of to have seemingly strange design elements. The original Hornbecks had strong tuck at the ends. Cheeks actually tapering to needle nose
I think that “tuck and cheek” was a popular thing among some boat builders in the Adirondacks 100 years ago or so, and it might have been based on the mistaken idea that a delayed taper (which is initially a lot sharper at the entry) was good for efficiency. I seem to recall that my modern Adirondack guide-boat is a close copy of one of Rushton’s later model guide-boats, and it has that tuck and cheek feature, as does the “pack boat” which is a totally original design from the same company. I noticed the “cheekiness” of Hornbeck’s older pack canoes a long time ago (and it makes them immediately recognizable at quite a distance when on a car roof!), and I found myself wondering if Hornbeck was also copying an old Rushton design.
https://www.flickr.com/photos/11908573@N00/15333493080/in/album-72157648645325776/
Though the cheeky design is supposed to be slower than a more abrupt taper which lacks any reverse curvature, I haven’t found that it’s enough to notice on either of my boats that have it. Besides, “it looks fast and that’s all the matters.” Okay, no, actually, I’ve learned not to care either way, as I’m pretty happy with the way both boats perform.
GBG, interesting about the tuck and cheek, seems right that at low speeds the hydrodynamic difference is probably minor. Have you actually seen intentional reverse rocker, i.e. hogging, in a canoe? There are no under-hull photos on the Slipstream website.
@carldelo said:
GBG, interesting about the tuck and cheek, seems right that at low speeds the hydrodynamic difference is probably minor. Have you actually seen intentional reverse rocker, i.e. hogging, in a canoe? There are no under-hull photos on the Slipstream website.
No, I’ve never seen reverse rocker provided by design.
I did not intend to call out Slipstream specifically, but apparently its no secret to the community they employ negative rocker. To be fair, they say ‘slight negative rocker’ without specifying exactly how much (on the Impulse anyway). If it is part of some overall design enhancement (works well with the other aspects) I would appreciate hearing the theory. All I know from experience is one hull (MR Serenade 13) with a designed rocker of 1" bow and .5" stern, paddles like a dream and the exact same hull with 1.5" negative rocker at the center by defect, paddles like a barge! https://youtu.be/3dvW3xX7NNo
Bring the hull back to shape with a support from the center of the seat frame or the thwart behind the seat down to the hull. A rigid foam pillar narrow enough to get your feet past will work, or just a sturdy piece of wood. The paddling will improve. Sad Mad River is not the company it once was. No excuse for a Kevlar solo to oil can or distort.
Bill
Pete was basing his original boats on Rushton designs.
And the negative rocker is something that everyone thinks is a problem. It’s not really. Even my Peregrine had 3/4 inch negative rocker. That is a fact and certainly did not jibe with LDC website. Yet the negative rocker wasn’t an issue except going upstream on rivers
Bring the hull back to shape with a support from the center of the seat frame or the thwart behind the seat down to the hull. A rigid foam pillar narrow enough to get your feet past will work, or just a sturdy piece of wood. The paddling will improve. Sad Mad River is not the company it once was. No excuse for a Kevlar solo to oil can or distort.
Bill
I actually carved up a piece of minicell to tuck under the front edge of the hung seat, which worked somewhat, but you could still see some deformation between my brace and the front and back of the hull. Really, though, who wants to drop that kind of money on a new canoe and have to turn it into a Coleman? Just a very weak hull overall, but to be fair, Mad River took the canoe back for a full refund.