Rocker and Overhang vs. Waterline Length

[leong]

Many of the race-oriented sea kayak manufacturers (for example; QCC, Kayakpro and Epic) make the claim that their kayaks are faster due to a higher waterline length to overall length ratio. They also implicitly or explicitly claim that rocker and overhang are overrated. For example from Epic:

“Our experience and testing have shown that long overhanging bows offer no benefit.â€

“A common misconception is that sea kayaks require extensive "rocker" or extended-bows to perform well in waves or rough water conditions.â€

“Epic kayaks have ample rocker but minimal extended-bow.â€

“With a plumb bow and full waterline length the bow gradually lifts as it approaches the wave and lands more gently. The longer waterline length gives a much more efficient hull and the kayak performs better in all conditions.â€

From QCC:

(with respect to overhang), “… sticking out there catching the wind or adding weight (serves) no purpose.â€

Although this is all probably valid with respect to speed for racing, the higher rocker and overhang of more traditional boats surely offer some other advantages. It’s easy to make a kayak with 1. a high waterline length to overall length ratio and 2. less rocker and 3. no overhang. Yet, most boats are designed with higher rocker and more overhang than, say, QCC boats. It can’t just be that the manufactures are building boats for the aesthetic beauty of overhangs and rocker at the cost of functional capability. In almost every case, extreme expeditions use kayaks with fairly high rocker and overhang; think of boats like the NDK Explorer or the Valley Nordkapp. I’m trying to determine the advantages and disadvantages of kayaks with more rocker and overhang versus those with a longer waterline length. The published literature only emphasizes hull speed, wetted surface area and tracking with respect to rocker, overhang and waterline length.

Obviously, for kayaks in general, the longer the waterline length the higher the hull speed at the cost of being harder to turn. For a given overall length, high rocker and overhang make it easier to turn a boat at the cost of a lower hull speed (due to a shorter waterline length).

Consider two cases for comparison: 1. Two kayaks with the same waterline length but with different rocker and/or overhang, and 2. two kayaks with the same overall lengths but with different rocker and/or overhang. Below are some possible advantages/disadvantages I can think of for both cases.

Case 1. Keep the waterline length a constant (say16 feet) and stretch the overall length of the boat from 16 feet to say18 feet via increasing the rocker and/or the overhang. The advantages/disadvantages of this hypothetical stretching are:

More cargo carrying capacity.

More playful??

Able to handle higher loads because waterline length increases as load increases.

Better handling in waves and rough water??

Worse tracking than it would have been if you also stretched the waterline length.

Less efficient due to more of the boat sticking out to catch wind and adding weight.

Less prone to pearling.

More aesthetic beauty.

Case 2. Keep the overall length a constant (say18 feet) and increase the waterline length of the boat from 16 feet to 18 feet by decreasing the rocker and/or reducing the overhang. The advantages/disadvantages of this hypothetical stretching are:

Faster top speed (higher hull speed due to increased waterline length)

Harder to turn and handle (less playful), but you can effectively increase rocker by leaning

More prone to pearling??

Better tracking

Harder to handle in waves and rough water??

More efficient due to less of boat sticking out to catch wind

Less able to handle increased cargo loads (as boat sinks waterline length doesn’t increase much)

Wetted surface area increases at the cost of more drag.

Less aesthetic beauty

Dear Reader: Are the two lists correct? Can you think of anything else that needs to be added to the lists above? What else needs to be considered?

[Paul Sylvester]

Comments only......nothing to add.

I used to think it was fun when the whole front of the boat would plough through the wave and you would get that wall of water on your chest pushing you back, now my boats with full bows (ndk) allow me to ride over more and get a cleaner ride......still get deck wash it just takes much bigger water.

Big water=more fun

go fast vs. rough water, different boats for all,

This is the arguement to buy more boats and you have covered it well

[jdkilroy]

Don't forget the more practical aspect of a kayak designed with some "overhang."

When landing on rocks or beaches or simply striking something inadvertently, the boat with the plumb stem will tend to take the blow more directly potentially causing (more) damage whereas the bow that sweeps forward as it rises will dissipate the impact by riding up and over the rock/beach etc.

Jon

[Nick Schade]

Take a QCC or Epic into a rock garden (assume it is constructed to handle abuse) and then take a boat with more rocker and shorter waterline length.

Shorter boats with more rocker handle better in situations where maneuverability is at a premium. You could actually say: "Long waterlines and straight rocker serve no purpose."

Some people like to cross long distances quickly and efficiently, others like to maneuver precisely in tight spots, many people end up doing some of each. Each paddler should choose their boats accordingly.

[EEL]

I think these discussions are fun, but I also think without professional training in hull design we are all wandering around in a dark room or are blind men describing an elephant.

There are so many factors that make comparisons based on length, width, rocker can easily be misleading.

For example, how full is the hull, what is the flare, what is the shape through the length of the hull, and difference in bow and stern rocker as opposed to curve of the "deadwood".

I once asked a paddler why he liked his Nigel Foster boat. He took a few minutes walking around the hull describing a variety of subtle and not so subtle attributes most of which are not mentioned when people describe sea kayaks and how they gave the boat the traits he liked. Later I found out he was a naval architect.

As to on expeditions paddlers only using traditional Brit style boats, that really isn't true, but easy to think so given the publicity given to some trips. Interestingly, Freya is using an Epic for her circumnavigation of Australia. I believe Morely used two different boats going around Vancouver. I belieive there are more differences that similarities between say a Nordcap, Explorer, and Greenlander let alone some of the boats used on major expeditions built in other countries.

As Paul suggests, horses for courses.

And great fun to talk about too.

Ed Lawson

[leong]

Take a QCC or Epic into a rock garden (assume it is constructed to handle abuse) and then take a boat with more rocker and shorter waterline length.

Shorter boats with more rocker handle better in situations where maneuverability is at a premium. You could actually say: "Long waterlines and straight rocker serve no purpose."

Some people like to cross long distances quickly and efficiently, others like to maneuver precisely in tight spots, many people end up doing some of each. Each paddler should choose their boats accordingly.

Agreed. But how about a kayak with low-rocker, short waterline length and no overhang. How would that boat compare in maneuverability to a more traditional kayak of the same waterline length but more rocker and overhang? That is, is it the the rocker and/or overhang that provides the maneuverability or is it strictly the waterline length (assuming similar prismatic coefficient).

Also, out in deep and rough water does the rocker and overhang help or not? The Epic pitch implies that it doesn't... from Epic: “A common misconception is that sea kayaks require extensive "rocker" or extended-bows to perform well in waves or rough water conditions.â€

[PeterB]

Agreed. But how about a kayak with low-rocker, short waterline length and no overhang. How would that boat compare in maneuverability to a more traditional kayak of the same waterline length but more rocker and overhang? That is, is it the the rocker and/or overhang that provides the maneuverability or is it strictly the waterline length (assuming similar prismatic coefficient).

Also, out in deep and rough water does the rocker and overhang help or not? The Epic pitch implies that it doesn't... from Epic: “A common misconception is that sea kayaks require extensive "rocker" or extended-bows to perform well in waves or rough water conditions.â€

What does “perform well in waves or rough water conditions†mean? , Go fast, and cover a lot of miles through waves and rough water? Maneuver, roll, scull , play, and be nimble in waves and rough water?

Regarding the difference between a low rocker, blunt- bowed boat and a traditional kayak with rocker and overhang : Wouldn’t it be better to go and paddle the boats, find out what happens?

I remember a college text book which described extensive physiological studies of ruby throated hummingbirds , the findings of which were that they were physiologically incapable of storing the energy required to migrate across the Gulf of Mexico, from the Yucatan Peninsula to the Gulf coast of Texas, without sustenance.

“But the birds, never having read the report, continue to do so every spring.â€

[Gcosloy]

Agreed. But how about a kayak with low-rocker, short waterline length and no overhang. How would that boat compare in maneuverability to a more traditional kayak of the same waterline length but more rocker and overhang? That is, is it the the rocker and/or overhang that provides the maneuverability or is it strictly the waterline length (assuming similar prismatic coefficient).

Also, out in deep and rough water does the rocker and overhang help or not? The Epic pitch implies that it doesn't... from Epic: “A common misconception is that sea kayaks require extensive "rocker" or extended-bows to perform well in waves or rough water conditions.â€

The shorter boat may perform as well or better maneuvering than the longer boat. While the shorter boat has little or no rocker it does have about the same water line length as the larger boat with rocker. All things being equal it should turn as well. However, it is when one puts both boats on edge that the shorter boat excels. Assuming that both waterline widths are similar the hull shape in the water redefined by the angle of heel now provides more virtual rocker over the longer boat. Witness the specs for the CD Gulfstream: a rather short expedition style boat with little rocker and super maneuverability on edge. Also quite a fast boat. The only downside I can see in such a design is the tendency to pearl, however that can be compensated for by increasing the volume in the bow's height, which is also true of the Gulfstream.

[leong]

What does “perform well in waves or rough water conditions†mean? , Go fast, and cover a lot of miles through waves and rough water? Maneuver, roll, scull , play, and be nimble in waves and rough water?

Regarding the difference between a low rocker, blunt- bowed boat and a traditional kayak with rocker and overhang : Wouldn’t it be better to go and paddle the boats, find out what happens?

I remember a college text book which described extensive physiological studies of ruby throated hummingbirds , the findings of which were that they were physiologically incapable of storing the energy required to migrate across the Gulf of Mexico, from the Yucatan Peninsula to the Gulf coast of Texas, without sustenance.

“But the birds, never having read the report, continue to do so every spring.â€

What does “perform well in waves or rough water conditions†mean? , Go fast, and cover a lot of miles through waves and rough water? Maneuver, roll, scull , play, and be nimble in waves and rough water?

Answer: All of the above.

Regarding the difference between a low rocker, blunt- bowed boat and a traditional kayak with rocker and overhang : Wouldn’t it be better to go and paddle the boats, find out what happens?

Answer: For sea kayaking, theory (kayak design) informs practice (paddle the boat) and practice informs theory. Besides, there is not enough time this century to try all the boats. It’s better to have some rules of thumb and valid theory to guide you in choosing what boats to try.

I remember a college text book which described extensive physiological studies of ruby throated hummingbirds , the findings of which were that they were physiologically incapable of storing the energy required to migrate across the Gulf of Mexico, from the Yucatan Peninsula to the Gulf coast of Texas, without sustenance.

“But the birds, never having read the report, continue to do so every spring.â€

Answer: A valid scientific theory would have predicted that the birds were capable of the flight. Remember: In science, theory informs practice and practice informs theory. I would hope that, based on the practice (what the birds actually did), the biologists would have revisited their invalid theory of energy storage and corrected it accordingly.

[Paul Sylvester]

Also, out in deep and rough water does the rocker and overhang help or not? The Epic pitch implies that it doesn't... from Epic: “A common misconception is that sea kayaks require extensive "rocker" or extended-bows to perform well in waves or rough water conditions.â€

The Epics have a full looking bow ( imo) and that fullness may give them confidence to make this statement. Don't they almost look like a surfski bow?

Not sure of the lenght of their long boats but if they are only 18' or so they may get acceptable lift in moderate conditions.

The lightness of the skis and Epics will keep them high also......

Rocker just helps in turning and correcting, I would not expect alot of rocker in a fast boat.

also, my 19 foot go fast boat is not the fastest in close 2-3' waves because the rear will catch the wave while the bow will bury in the next wave.

The ice cream stand in my town has 75 flavors, anyone seen any used Epics around? :^)

[EEL]

Answer: All of the above.

I am reminded of sign in diner.

Food: good, fast, cheap. Pick any two.

I suggest going to Nick's site and maybe One Ocean kit site and look at the specs and design theory pages. Check out the online stuff Johnathan Winters has written about design. Studying what is available on these sites will give you something to think about. Nick has a variety of boats for different uses and specs on them as well as drawings. See if you can discern why the hulls for different uses vary as they do. Then ask yourself question like, "Why has the Coaster style boat never been popular on the East Coast, but is considered the gold standard of rough water play boats on the West Coast." or "Why are Nigel Dennis's boats more popular than Nigel Fosters?" or "Why do people still paddle Anas Acutas or little SOF boats?"

Then think about what you currently like in a boat, what you think you might like in a boat, and what you do in you boat and perhaps what you expect to use if for most of the time.

Then paddle as many boats as you can with an emphasis upon boats that paddlers similar in size and skill to you who paddle their boats as you tend to use yours.

This process might lead you to form some views/ideas that enable you to form a decent opinion of whether a given boat is likely to work for you. And what works for you might be the opposite of what would work for me.

Fun to talk about, but it really is horses for courses and riders for horses.

Ultimately have to ride the horses and courses to to know.

I suspect designers of good boats could tell many a tale of how they had to tinker and tinker and tinker to get a hull right after applying all the theory initially. FWIW, Brian Shulz had such a tale on his Cape Falcon site at one time.

Ed Lawson

[leong]

I am reminded of sign in diner.

Food: good, fast, cheap. Pick any two.

I suggest going to Nick's site and maybe One Ocean kit site and look at the specs and design theory pages. Check out the online stuff Johnathan Winters has written about design. Studying what is available on these sites will give you something to think about. Nick has a variety of boats for different uses and specs on them as well as drawings. See if you can discern why the hulls for different uses vary as they do. Then ask yourself question like, "Why has the Coaster style boat never been popular on the East Coast, but is considered the gold standard of rough water play boats on the West Coast." or "Why are Nigel Dennis's boats more popular than Nigel Fosters?" or "Why do people still paddle Anas Acutas or little SOF boats?"

Then think about what you currently like in a boat, what you think you might like in a boat, and what you do in you boat and perhaps what you expect to use if for most of the time.

Then paddle as many boats as you can with an emphasis upon boats that paddlers similar in size and skill to you who paddle their boats as you tend to use yours.

This process might lead you to form some views/ideas that enable you to form a decent opinion of whether a given boat is likely to work for you. And what works for you might be the opposite of what would work for me.

Fun to talk about, but it really is horses for courses and riders for horses.

Ultimately have to ride the horses and courses to to know.

I suspect designers of good boats could tell many a tale of how they had to tinker and tinker and tinker to get a hull right after applying all the theory initially. FWIW, Brian Shulz had such a tale on his Cape Falcon site at one time.

Ed Lawson

Been there, done that. But it doesn't answer the fundamental question I posted from Epic: “Our experience and testing have shown that long overhanging bows offer no benefit.†Is it true? Is it hype? Perhaps there is no answer.

I'm working on a possible explanation which is related to how the overhangs are often in the water when the conditions are rough. But, because of the non-linearity of the Navier-Stokes equations, it's difficuult to arrive at a stable numerical solution.

[rick stoehrer]

Been there, done that. But it doesn't answer the fundamental question I posted from Epic: “Our experience and testing have shown that long overhanging bows offer no benefit.†Is it true? Is it hype? Perhaps there is no answer.

I'm working on a possible explanation which is related to how the overhangs are often in the water when the conditions are rough. But, because of the non-linearity of the Navier-Stokes equations, it's difficuult to arrive at a stable numerical solution.

oooh boy....engineers with too much time on their hands and a caffeine jag ....ahhh, the ole non-linearity of the navier-stoke equation? of course. just plug that into the xp eradicator, factor in the heisenberg uncertainty principal and then have that cat (or is he in the box) hit the big red easy button and while fibonacci is running those #'s for you, YOU can order the boat fabrication material...i suggest unobtainium - which as you know, has a greater strength to weight ratio than even my imagination...oh wait...better have my wife along, she can use her laser beam eyes (but maybe all women have this power? to cut us right down to size?) to cut through the unobtainium...but since the delivery date on that has been pushed back to julember 42nd you have plenty of design time.

sooo....,happy hot stove/cold weather musings!

[PeterB]

Regarding the difference between a low rocker, blunt- bowed boat and a traditional kayak with rocker and overhang : Wouldn’t it be better to go and paddle the boats, find out what happens?

Answer: For sea kayaking, theory (kayak design) informs practice (paddle the boat) and practice informs theory. Besides, there is not enough time this century to try all the boats. It’s better to have some rules of thumb and valid theory to guide you in choosing what boats to try.

I remember a college text book which described extensive physiological studies of ruby throated hummingbirds , the findings of which were that they were physiologically incapable of storing the energy required to migrate across the Gulf of Mexico, from the Yucatan Peninsula to the Gulf coast of Texas, without sustenance.

“But the birds, never having read the report, continue to do so every spring.â€

Answer: A valid scientific theory would have predicted that the birds were capable of the flight. Remember: In science, theory informs practice and practice informs theory. I would hope that, based on the practice (what the birds actually did), the biologists would have revisited their invalid theory of energy storage and corrected it accordingly.

Good response! Sorry if I came across as anti-science, I guess I was emphasizing the “practice informs theory†over “theory informs practice “;

If the long and short of it is: how do boats with a blunt bow & no rocker paddle compared with traditional/British style boats with rocker and overhang , I would still say: “let practice inform theoryâ€, and paddle the boat:

To avoid paddling every boat on the planet:

In this neck of the woods it’s easy enough to try out “traditional/ British style†boats.

As to the other kind: QCC and Epic are the most obvious examples of this design. QCC’s are a bit hard to find in this area, but Epics are here and there : I think Charles River Canoe & Kayak might have them . Maybe you can rent one and take a spin around Cape Anne on a bumpy day, see how it does.

You might like to talk to Ken Fink, from Maine. He’s big on the Epic 18 and has used it extensively, not just racing, but as his everyday go-to boat.

My impression of the Epic 18 was from the Peaks Island race two years ago; it was a bumpy/windy day, enough to call off the afternoon race to Outer Green: my impression of the Epic 18 : not one’s first choice for paddling in conditions, but it does okay, and you can definitely cover miles fast.

[leong]

Regarding the difference between a low rocker, blunt- bowed boat and a traditional kayak with rocker and overhang : Wouldn’t it be better to go and paddle the boats, find out what happens?

Answer: For sea kayaking, theory (kayak design) informs practice (paddle the boat) and practice informs theory. Besides, there is not enough time this century to try all the boats. It’s better to have some rules of thumb and valid theory to guide you in choosing what boats to try.

I remember a college text book which described extensive physiological studies of ruby throated hummingbirds , the findings of which were that they were physiologically incapable of storing the energy required to migrate across the Gulf of Mexico, from the Yucatan Peninsula to the Gulf coast of Texas, without sustenance.

“But the birds, never having read the report, continue to do so every spring.â€

Answer: A valid scientific theory would have predicted that the birds were capable of the flight. Remember: In science, theory informs practice and practice informs theory. I would hope that, based on the practice (what the birds actually did), the biologists would have revisited their invalid theory of energy storage and corrected it accordingly.

Good response! Sorry if I came across as anti-science, I guess I was emphasizing the “practice informs theory†over “theory informs practice “;

If the long and short of it is: how do boats with a blunt bow & no rocker paddle compared with traditional/British style boats with rocker and overhang , I would still say: “let practice inform theoryâ€, and paddle the boat:

To avoid paddling every boat on the planet:

In this neck of the woods it’s easy enough to try out “traditional/ British style†boats.

As to the other kind: QCC and Epic are the most obvious examples of this design. QCC’s are a bit hard to find in this area, but Epics are here and there : I think Charles River Canoe & Kayak might have them . Maybe you can rent one and take a spin around Cape Anne on a bumpy day, see how it does.

You might like to talk to Ken Fink, from Maine. He’s big on the Epic 18 and has used it extensively, not just racing, but as his everyday go-to boat.

My impression of the Epic 18 was from the Peaks Island race two years ago; it was a bumpy/windy day, enough to call off the afternoon race to Outer Green: my impression of the Epic 18 : not one’s first choice for paddling in conditions, but it does okay, and you can definitely cover miles fast.

Actually, I have raced the old Epic (not the new 18X with integral rudder) twice on flat water at the weekly Charles River races. My times were comparable to my Falcon 18; but I think I might have done better if I were more used to the Epic.

But, as I've been trying to say over and over again, my question is more theoretical: All I want to know is if there is any validity to statements such as: “Our experience and testing have shown that long overhanging bows offer no benefit.� If the statement is valid, then why are overhanging bows part of most boats?

No time for Navier-Stokes today Rick ... the options market beckons.

[scamlin]

While not really addressing Leon's on water handling question, one functional advantage of overhang, bow and stern, is it is less likely to foul on seaweed. Not a big issue on the east coast, but on the west coast (CA and Vancouver Island) it can be a significant problem: bull kelp will stop you cold. The sloped shape of the keel tends to ride up and over while paddling forward and back; the higher point of the bow/stern is less likely to get under the kelp. You can imagine similarly riding up over other objects in the water: float lines, cables, underwater rocks and beach bottoms (when surfing). As mentioned above, the raked bow is becomes really important in rough shore or dumping surf landings as you can paddle straight in and ride up onto enough shore to scramble out quickly.

More to Leon's point, while the Epic/QCC assumption that "longer waterline length = higher hull speed" is accurate in principle, my understanding is that below, say, 4 kts, "wetted surface area = friction" is a more important factor in the speed of the kayak. You could argue that shorter boats are in principle faster--or at least no slower--for a given effort if paddled less than about 4 kts. Of course there are a lot of other factors as mentioned in previous posts, but it suggests that focusing only on waterline length is relevant only when paddling near hull speed, which for most kayakers (e.g. racers and fast expeditioners) is above 4 kts.

There was a link posted a few months ago that plotted curves for a large number of kayaks of a considerable range of waterline lengths, and the theoretical speed (if I remember correctly) was almost identical up to about 4 kts and only then did the usual suspects (such as the Epic 18) diverge. (I'd welcome help from anyone who can provide the link.)

That said, at least one well-regarded designer (Matt Boze of Mariner Kayak) suggests that:

"The raked and flared ends increase the effective waterline length allowing a faster top (hull) speed without the extra wetted surface (frictional drag) at normal cruising speed that longer waterlines suffer. " http://www.marinerkayaks.com/ (See also under Model History Boze's description of the Coaster mentioned above).

It appears he is saying is that as a kayak approaches hull speed, it is sitting in a trough; as the ends tend to bury, the waterline increases, thus effectively increasing hull speed. Hmmmm, not sure the angle of the hull wave really lengthens the waterline all that much, but it could.

I still think Leon's question is valid, but my non-technical hunch is that the advantage of overhang, if there is one, is secure, predictable handling in rough, choppy, roiling seas where the reserve bouancy of the overhang dynamically comes into play by increasing floatation as the boat ends get buried in the waves. The simple-minded idea is that, other things being equal, your boat is better off on top of the water rather than being buried in it, especially in dicey situations. That said, I remember one well known kayak designer telling me his boats had a steadier ride precisely because they had narrow bows, designed to knife through waves rather than bob up and down over them them (albeit with a wetter ride as Paul S. points out).

Definitely a winter topic when we all have too much time on our hands. Beats shoveling.

[djlewis]

...That said, I remember one well known kayak designer telling me his boats had a steadier ride precisely because they had narrow bows, designed to knife through waves rather than bob up and down over them them (albeit with a wetter ride as Paul S. points out).

Was that Frank Goodman of Valley? I know that my Aquanaut -- with its concave, knife-edge bow waterline -- definitely rides wetter than, say, an Explorer, and is really smooth through the water, hence faster. Just intuitively, it also makes sense to me that knifing a bit into rough water makes it more stable and steady.

[leong]

There was a link posted a few months ago that plotted curves for a large number of kayaks of a considerable range of waterline lengths, and the theoretical speed (if I remember correctly) was almost identical up to about 4 kts and only then did the usual suspects (such as the Epic 18) diverge. (I'd welcome help from anyone who can provide the link.)

Scott, Here are two relevant links:

http://www.kayakshops.com/kayak_speed.htm

http://www.seakayakermag.com/2007/07e-news...r/fastkayak.htm

[Nick Schade]

Been there, done that. But it doesn't answer the fundamental question I posted from Epic: “Our experience and testing have shown that long overhanging bows offer no benefit.†Is it true? Is it hype? Perhaps there is no answer.

I can't answer whether there is a benefit, however I would say that overhang-or-not, makes a difference. And, where there is a difference there is an opportunity for a benefit.

If you paddle in a certain manner and a given design works very well for you when paddling in that way, it is very possible that changing the design will not afford any benefit, but that doesn't not mean that changing the design would not be of benefit if you want to do something different.

There are lots of ways to achieve most design goals. For example you can make a boat maneuverable with added rocker or by making it respond well to leans (or both). If you can make a boat turn well without leaning, some people may consider that a benefit, as there are situations where leaning makes you more vulnerable. But, then if you don't feel the lean is making vulnerable, then you may say it is of no benefit.

[EEL]

I can't answer whether there is a benefit, however I would say that overhang-or-not, makes a difference.

Would you describe what the difference would likely be?

Ed Lawson

[wilsoj2]

Derek Hutchinson asserts the overhang increases the waterline in lumpy seas making the boat more efficient.

I once read that the 'clipper' bows of Greenland boats was so the boat would ride over rather than crash into ice. I find this true of many obstacles when paddling my sea kayaks.

I find rockered boats more maneuverable than those with straighter keels. My Nordlow and Romany are joys to throw around.

I am somewhat unsettled with the way an Explorer slaps down and shudders after cresting a wave. I would imagine an Epic 18 or QCC700/800 would do so to an even greater degree. My Nordlow and Aquanaut seem smoother moving through lumpy seas.

[wilsoj2]

A couple of pertinent videos from Epic:

[Gcosloy]

A couple of pertinent videos from Epic:

Quite a dramatic difference. However the Brit design boat seemed like more fun. Another test might show the Brit design superior and that is in beam seas where maneuverability helps keep the boat on track. Also I suspect that the same would be true for following seas and surfing. My Chatham 16 pitches and slams in oncoming sea but is wonderful in all other respects, possibly the best long boat surfer I've seen.

[Michael_Crouse]

Interesting videos, but they are advertisements. I bet Valley or P&H has a video showing how badly the Epic is in the same conditions. Of course their is the whole "who is paddling the boat" argument. I bet if you put me in the Epic and Greg Barton in a Keowee he would leave me in his wake, even in rough seas.

[leong]

A couple of pertinent videos from Epic:

The Epic 18 used in the video has a water-line length of approximately 18 feet; the conventional kayak looks like it has a water-line length of about 15 feet (I'm guessing, perhaps someone can identify the conventional boat). Perhaps the longer water-line length (and not the lower rocker or less overhang) of the Epic accounts for most of the superior performance shown in the video.

A better comparison might be between two kayaks of the same water-line length. For example, the water-line length of my Falcon 18 is about 16 feet and the overall length is 18 feet. The water-line length of the Epic 16 is about 16 feet and the overall length is also about 16 feet It would be interesting to see a video comparing two such kayaks (i.e. of comparable water-line lengths) plowing through waves.