hard chine vs. soft chine

Why are soft chine designs so much more common? Have demo-ed many kayaks lately. Hard chine boats handle (turn) so much easier. It’s like having two hull shapes in one boat. Other than the increased wetted surface arguement, can anyone think of any other detriment to hard chine boats. Are hard chines more susceptible to broaching?

1 Like

Funkier Secondary Stability

– Last Updated: Jun-19-06 9:21 PM EST –

Soft chines give a more forgiving secondary stability. In most boats you can feel the boat at first resisting the lean and then increasing the tendency as you aproach the "Aw Crap" zone.

Hard chine boats tend to have a very strong secondary but only in the "sweet spot". Its very easy to overdo it and end up wet.

My Take
In the beginning hard-chine boats were easier to build and were refined for thousands of years. They handled well without rudders. With the advent of modern materials and molds people started building soft-chine boats just because they now could. True they are a little faster but most are dependant on add-ons to control them. Hard-chines are more of a paddlers boat… GH ducking…

more than hard versus soft
Besides purely hard chined (Anas Acuta, Legend, Vela, etc) and soft chined (Outer Island, classic Pintail and Nordkapp, etc) there are many boats that fall between in their hull section.

Actually most of the boats whose handling I like best are neither purely soft nor hard chined.

My Romany is what NDK calls ‘modified hard chine.’ More precisely, it is soft edged hard chine. My Aquanaut is softer chined than my Romany. It looks soft chined when on the car next to my wife’s Explorer, or next to my friend’s Chatham 18, but next to another friend’s Outer Island it looks rather hard chined.

It think the softer chined boats tend have broader more gradual secondary. Sometimes wholly soft edged soft chined boats seem to have no hang point on their secondary (e.g. Sirius).

There are so many factors that impact a boats performance/personality that thinking in terms of hard versus soft chine is probably not worthwhile.

I don’t have the range of experience with different kayaks that some here do, but your answer matches my own feedback.

One thing I prefer about soft chines is how waves roll smoothly under the boat. With hard chines, there is definitely more of a slapping-smacking effect, and it is clearly audible also. Has an abrupt feel that I don’t like. Soft chines and free-moving hips feel more…fluid.

Construction Methods and Aesthetics

– Last Updated: Jun-20-06 12:55 AM EST –

Chine shape has very little to do with all the performance things people claim. You can get any mix of primary and secondary stability, tracking, turning, or whatever with soft or hard chines - if all else is equal. Any one doubting this should look at Nick Shade's example of otherwise identical boats in both hard and soft chine versions:

hard chine: http://www.guillemot-kayaks.com/guillemot/node/45/draw
softer chine: http://www.guillemot-kayaks.com/guillemot/node/29/draw

As he says: "The performance is almost identical. Modeling shows minor differences in stability, but they are below my threshold to detect on the water."

The trouble is, people are not comparing the same boats like this. They are comparing very different boats - and assuming the differences have to do with the chines. Except for a very slight differences in the computer calculations - there should be no perceptible difference. Even the drag difference of the slight larger wetted surface with the chines is very minute (again, with otherwise identical hulls).

The differences people feel are due to other factors like how flat the bottom, how much or little flare to the sides, how much rocker, etc, etc. The overall cross section shapes matter - and chines are a very small part of the overall cross section.

Many "hard chined boats are relatively flat bottomed and have slab-like sides. The result is fairly box like cross section. Adding some degree of radius to the corners of that box will not do much to it's overall performance. Not all hard chined hulls are boxlike. My SOF in cross section is closer to round than square (more on this stuff here - scroll to end of post to see cross section drawing at the widest and flattest point of the hull):


Choice of chine shape is primarily about construction methods and materials. Not so much about the limitations of the materials either, but rather their strengths.

Skin on Frame and Stitch and Glue plywood panel boats naturally are hard chined. The hull shapes and performance characteristic of these types can vary widely - and there are no "hard chine" performance qualities specific to these types.

Rotomolded and composite boats tend to have softer chines because flat panels and sharp edges are not desirable/optimal on a molded shell. To get the most strength you want flowing compound curves, like an egg. Molding something flat is a a poor use of the technology. Again, there are no performance qualities specific to these types.

Each process takes best advantage of its materials. Some composites do have hard chines - but this is more to get a desired look - with such design embellishments being used to elicit a certain feeling in the target customer. In other words: "styling". I doubt you'll ever get VCP to admit that about the Anas or Q-boat, or CD about the Caribou, as their performance jargon about "Greenland" and "hard chines" is a more powerful marketing tool than the styling itself (and some designers really do believe their own BS). If the customers enjoy the product - this marketing hype actually adds to their experience - so it's not really a bad thing.

I have round hulls, very soft chine, soft chine, and hard chine kayaks. I like 'em all - but not because of chine type.

It is mostly which design is appealing
to your eye. There is much speculation as to which hull design does this or that and I haven’t seen much of it to be true. Paddle a kayak and see if it has the handling characteristics you like. How a kayak performs has more to do with many other hull characteristics than hard chine or round hull.

Hard chine vs Soft chine
Smoother ride.

When people refer to hard chine and soft chine they are usually refering to a round chine boat and not the softened hard chine boat in Nick’s drawing. If you just soften a hard chine, yes, you won’t see much differerence.

Many if not most of all commercial kayaks are designed on the computer these days and the speed of the hull is of prime importance. The computer model starts out with the ultimate shape which is a half circle for a hull. Many boat designers have just felt there was no need or benefit for hard chines that would ultimately slow down the hull speed. I do agree with the other poster in that I too find way smoother & greater secondary in the round chine boats. I do own three hard chine boats and enjoy paddling them.

Outer Island
The Outer Island is a good example of the nuanced, fluid and confident feel possible in a truly soft chine boat. I marvel at my friend’s Outer Island. This boat rolls easier than any other boat I’ve paddled, yet has thouroughly reassurring stability - initial to final.

for the same reason
fish aren’t hard chined. Water doesn’t flow smoothly around corners.

So many other factors
My Vela is a single hard chined, then rather round on the bottom, wiggles around more than the Explorer LV but has fine secondary so no big deal. The Explorer has the modified hard chine of the Romany series.

But the biggest diff that matters between these two boats isn’t in the chining. It’s in the fact that the Vela has a pretty tight bow and really needs the skeg to hold the fading stern in wind, and the LV has a pretty loose bow and is more equal in how the front and back get kicked around in stuff (especially if I trim the bow a little heavy). From the paddler’s seat, the latter stuff is much more noticeable than the chining. If I still had the Squall, which was a fully round-chined boat, I’d be saying that the boat’s overall stiffness in turning and in handling waves was much more of a factor in its diff’s from my present two boats than anything else.

well put
and then ya got yer ‘multi-chined’ marketing machine!


It handles waaayyyy different 'cuz it has many chines!


steve (designer of many different chines)

"chines for maneuverability!"…AARRRRRRRGGGGGH

Extreme Differences in Extreme Condition
One thing that makes a surf boat a surf boat is very hard, sharpe, low chines.


Hard chines gives a lot more control on a steep wave face, but are much less forgiving than soft chines.

You can really tell the difference in big, steep, short interval swells and/or breaking waves.

Regarding your last question, I have owned a fully soft-chined kayak (CD Squall), a sharp-edged, hard-chined kayak (Shearwater Merganser 16 S&G), and a soft-edged hard-chined (medium-chined?) kayak (WS Tempest 165). I still own the latter two kayaks and enjoy their different traits.

But surprisingly, the rounded Squall was absolutely the most susceptible to suddenly broaching, despite being hard to turn without pronounced edging.

The Merganser is easier to turn in calm water but harder to broach; possibly this is due not so much to type of chines as to the very sharp keel line. (Note: this is a MOVING turn, not sitting still and spinning around in circles, which it resists.) Once broached, though, it is like the Squall–somewhat hard to get back on track.

The Tempest 165 will broach if I sit passively but I can always feel it coming and easily prevent or control it. Even if it does broach, it is much easier to correct than the other two kayaks. So, despite the fact that this boat still has a little of that hard-chine slap from beam waves, it is my favorite. I never feel like I am fighting this one.

If you’re looking for a boat to buy, don’t get too hung up on what kind of chines it has. Paddle it and feel it.

Hard Chine Fish…
There are a few but they are not very fast… Then again all fish have rudders.


Greyaks treatise
should be a permanent pearl here.

Skegged fish handle better

I forgot about that. The Vela does have more of a tendency to catch on a wave face and be less forgiving about what I do next than the LV.