: Most Greenland kayaks don't have
: this kind of chine, usually the chine ends below water so the shape at
: waterline is much smoother (and less resistance I believe).

The chine stringer on many Greenland types dives in under the skin a ways back from the bow to accomplish a smooth transition. Easy with skin, harder in plywood. Twisted/tortured panels in S&G approximate this, and this is what I'm really talking about in regards to Henk's design. In strip, you can blend even more and lose a bit of the hard corner without really changing the feel and adding strength (or easily take it farther and really clean up and develop the form).

Some other designs simplify the bottom panels so there is little or no twist and terminate them at the knuckle (I'm not a fan of this as I think it makes for a poorer cutwater - but there are many historical examples as well as some "modern" kayaks that are good performers like the Betsie Bays, Duane S's purposely flat single bottom panel Mini Benny, and some of the Yost folders are pretty close to this chine configuration too [wood versions interestingly look a little less so), etc.

Examples can be found for anything in between these: Chines ending all the way forward or well aft of bow, and ending height anywhere from knuckle to bow tip, but regardless of termination point all share a relatively simple chine arc.

Henk's are the only ones I've seen with where the bottom panels arc gently up and then reverse back downward to a termination at the bow knuckle. I do think it gives an interesting look - and just about anything even remotely kayak-like can work well enough so I think he could follow this sort of design thinking happily for many years. Still, the tow tank/wind tunnel simulators in my mind and my carving/shaping/sculpting instincts both have fits with it. It just reads wrong to both my limited scientific understanding and to my more developed eye (the eye typically being the better judge for boat building anyway). If it were one or the other fine - but when they both agree then I'm pretty sure something's off. I don't expect Henk to care - or alter what he does based on my inputs. I only offer my thinking (although none of what I'm babbling about is really mine) as something to consider - and so I might learn something from everyone else's replies.

How about a bit more hands-on visualization since this is the building forum?

A. Imagine trying to replicate Henk's chines in SOF or Strip. It could be done of course, but would be a real PITA. That alone should raise some red flags.

B. I imagine sanding a small scale model of that hull in the direction of flow...

: The link is to pictures of one fast Greenland kayak. It's unconventionally
: high volume for a greenlander but the chines are usually placed. This is
: the kayak from which I took the Kaper values earlier. And actually those
: values dont do justice for this kayak - it starts to really shine above
: hull speed.

Do you mean on the PC or on the water?

The longer and skinnier they get, the less relevant hull speed is as any sort of performance indicator. It's still there, as is the steeper increase above that, but actual speeds are all about the paddler's skill and power. I would have to train long and hard to get the full potential out of my SOF!

Below is a non-computer example of the chines blending in. Again, I'm not claiming it's optimal or anything - just using it as an example. Going from 4 panel to 2 panel without forming any distinct panel intersections or edges, and keeping what edges there are farther back relatively well aligned with the water flow - or at least not running across it). It would be helpful to have another shot looking at the bow perpendicular to the keel to show how and where it fairs in a bit better, and an on water shot would show where this all lies in relation to the waterline - but I don't have either handy. Suffice it to say the bow remains a narrow V quite a ways back (farther than perspective in these shots indicates) and the transitions are very gradual.

Side notes on that particular SOF for context (aka - who cares? Feel free to skip - just rambling really): It looks Greenlandish but it's not really all that much like what most would consider a "Greenland" style hull to be. It's a full 6 meters long (19'8" with 18' LWL), has rather full ends, moderate overhangs, unpinched gunwales, it's swedeform (at deck and waterplane), and overall hull cross-section at widest point is more round than boxy. All tradeoffs to meet my design intent for a reasonably well mannered efficient 5mph+ cruiser (75-80% of hull speed in this case) over distance for 180-220 lb. paddler with minimal day paddling gear (and at couch potato fitness level - with decent rewards for me beyond that for dropping pounds and/or adding power) and an easy roller. The "traditional" appearance makes it sort of like what car aficionado's call a "sleeper" (I had a couple surf ski guys in it who were surprised by it's speed and stiffness). All of these features can be found on historical designs - just not all in one, and not too commonly on modern Greenland SOF interpretations (and replicas) used mostly for rolling, demonstrations, and paddling limited distances at lower speeds. Might get around to building one for that too someday. For now I'm more interested in taking lessons learned from this one and other kayaks and applying them to a new strip design (whenever I find time/space/$ to build).