Seakayaker’s newsletter came in the email yesterday. Take a look at this letter about kayak speed from a reader - the colors in the graph are hard to read on my screen, but look how similar these boats are at 4 knots!!
http://www.seakayakermag.com/2007/07e-newsletters/December/fastkayak.htm
It really is mostly about the engine. Time to get to the gym…
Alan
As regularly noted here…
Yup. There is little to no significant difference in drag among sea kayaks up to 4 knots.
The most common figure given for average cruising speed in a sea kayak is 3 knots. BCU 4* expects the ability to maintain 4 knots over a period of time. When paddling with Cheryl and moving at a brisk clip we are often moving at 4-4.5 knots (according to her gps). Though we were traveling at 6+ knots a week and a half ago heading up river from Catskill - riding the incoming tide 
However, as Sea Kayaker and others note, there are many other factors that are not included in the drag tests that affect the speed of a boat. These include yaw, windage, paddle, lumpiness of the water, winds, etc… These other factors can mitigate or magnify the drag figures.
Overall, the engine IS the most significant factor in the speed of a kayak.
Hull speed is a function of several
measureable properties. The most important of which is waterline length assuming all others are relatively equal. I don’t think that kayaks in general can be of a length long enough to make a VERY big difference, yet we all know that we have paddled some boats that are faster than others. In general, make it long, make it sharp, make it narrow, make the surface friction free, keep it low profile for windage, and these displacement hulls will bring their sweet spot up in the speed range. Where the sweet spot is in a kayak, is probably within 2 knots of each other over the entire range of boats. IMO
before posting
at least try and make an effort to read the original link
great graph
It would be interesting to see a close-up of the upper-right side of the graph. It looks like the lower curves are the long (racing oriented) models.
DIY
http://www.marinerkayaks.com/
Go to the “downloads” page, download the Excel spreadsheet, and plot to your heart’s content.
If 4 knots makes you happy …
Its a self-perpetuating myth that sea kayakers can only paddle at 3 - 4 knots. If that is satisfactory for you then that is fine. But, it is misleading that the graph only goes to 5 knots. This only serves to reinforce the slow-speed myth. Some of the kayaks displayed on the graph are designed to cruise at 6+ knots quite efficiently. Its too bad that they were cut off before they hit their sweet spot. Its also too bad that the text accompanying the graph would lead most paddlers to believe that 3 - 4 knots is all they should expect.
It is actually quite easy to average speeds of 5 - 6+ knots. You don’t need to be a racer or an incredible athlete. You just need to understand that significantly faster speeds are very easily attained if you want it. Its as simple as learning a good forward stroke and getting a sea kayak that has the capability to reward you as your technique improves.
It is often said that it is the engine not the boat. This is true, however 99% of the paddlers out there are getting their power from their arms - a very weak engine. Every one of them could increase their power 200 - 300% if they learned to use their torso muscles. If you suddenly had twice as much power, would you be satisfied with a kayak that sucks above 4.5 knots? No way.
It takes two important ingredients: The right technique and the right equipment. Having one without the other will only perpetuate the myth that 4 knots is satisfactory. Actually, there is a very important third ingredient: The belief that this breakthrough in speed and range is a possibility for you. Without believing, you will never commit to either the technique or equipment.
The vast majority of paddlers are either missing good technique, fast equipment or both. Because of this they will forever be locked in the sub 4.5 knot range. They are happy because they have been taught that this is all they should expect.
What is sad is that many who might have aspirations for significantly more speed and range will continue to be mislead by this large vocal majority. I am just one of many who can tell you that you can expect so much more from yourself and your equipment. If you want more performance than the masses, then I suggest listening to a few of the asses.
I did. How is my post not relevant?
Increasing waterline using the same horsepower will increase the hull speed of a displacement hull. The other factors I mentioned apply, but in the world of recreational kayaks you are not going to see BIG differences in speed, or if this is your beef, resistance at a normal speeds. Again, my opinion.
Graph should go to at least 7 knots…
– Last Updated: Dec-06-07 1:56 PM EST –
..., putting the divergence point more mid graph.
Some kayaks on that list are just coming into their own at around 5 or more, and for the more average among us (self included) it's still nice to see sprit potential/effort too. Quick sprints can come ion very handy sometimes, not matter what your average speeds. I look at it as a safety feature.
If space on the sheet is an issue, drop everything under 3. Look how close they are, and the effort is light anyway, so who cares!
"locked in the sub 4.5 knot range"
Guilty as charged, but barely as I can consistently hold 4.3+ averages over 15-20 miles.
All it would take for me to get into the 5 knot+ average range would be to drop some weight and paddle more than I have been.
For me to see 6+ averages would take more serious training, and then an equipment upgrade once I had the engine in good enough shape to make use of it.
It has renewed my interest in…
… the Rapier 20, but only by a millimeter or two! L
Not worded well
I know what you are trying to say, but it’s technically incorrect. For a given cross sectional profile a longer displacement hull has the Potential to be paddled faster via longer LWL and resulting Hull Speed as the longer hull creates a longer wave period (translation).
BUT, the power has to be there to use this Potential. Example: 110 lb. low powered paddler will not be able to overcome the Frictional Resistance to achieve that Potential in a longer hull…even though it is there. That is why boats for smaller lower powered paddlers are usually shorter (14-16 ft.) not 18 ft. These folks are Faster in the shorter boats. Clearly there’s a balance here.
And if you know a way to eliminate skin friction let the Navy know OK! You’ll be famous!
I agree with you envyabull
BUT you are nor paddling the types of kayaks many of these folk are! You aint paddling a Brit coatal play boat at 6 knots all day long!! If you are, then you should have a gold medal or two somewhere.
Epic 18, Rapier, KayakPro Nemo, Seda Glider, etc. sure!! Good form and a wing, and you bet. These craft are designed for speed. Many touring kayaks are NOT. So you like tio go fast and use appropriate gear. That gear may not be much fun rock gardening or playing in overfalls surf etc. Many boats suitable for the latter are not designed for speed, rather efficiency in the 4 knot range along with excellent playfulness in big seas.
But yes, I agree with th gist of your post.
.5 knot
This info has been discussed many times, there’s an interactive table here:
http://www.unold.dk/paddling/articles/kayakvelocity.html
though it won’t have many more recent boats in it.
The point I always like to make is to look at what happens where the curves diverge. Trace horizontally between 4.5 and 5 knots, there’s only one boat here that’s easier to move at 5 than the slowest here is at 4.5. Just one, and that’s a pretty extreme boat. The situation gets even worse as speeds increase. So the boat by itself is only worth a tenth or two, for the kinds most non-racing people buy.
I also don’t see how pushing anything other than a racing hull over 5 knots sustained can remotely be considered “easy”. Those curves are shooting up really steeply after that point. There really is a wall out there for most of them, for all practical purposes. Just to go from 4 to 5 requires about double the force.
Mike
You too can play with this
Download this software and try…
http://www.blueheronkayaks.com/kayak/software/software.htm
Hi Greyak
Greyak, I would love to go for a paddle with you some time. I would be happy going 4.3 knots along side you just to chat about boats and paddling for a while.
I agree completely with you about a kayak’s ability to sprint well above one’s cruise speed. Besides the issues of safety there are other good reasons to have a kayak that accelates easily. Being able to make surf runs can increase your downwind average speed another level. Having more speed can help one get out of bad current faster. Longer, speedier kayaks also tend to be more seaworthy. Speed begets speed.
Did you notice that the kayaks shown in the graph were all described as high perfomance sea kayaks? I only consider 3 - 4 of those boats to be high performance sea kayaks.
What I find interesting about those drag resistance graphs is the left hand column that shows the drag in pounds. This is equal to the power a paddler must maintain to achieve the speed. The vast majority of paddlers achieving power mostly with their arms generates about 3 - 4 pounds of continuous thrust. If you extrapolate the faster kayaks out to 6 knots you will see that those who claim to maintain 5.5 - 6 knots are able to genereate 8 - 12 pounds of continuous power. They are not doing this with their arms. These faster paddlers use a good solid torso-rotation-based stroke to do this. So switching from an arm-based technique to a torso-based technique has the potential to more than double one’s continuous horsepower.
There are many arm paddlers out there who may want to look at those graphs and ask themselves which type of kayak would be more suitable for them once they learned a good forward stroke technique and doubled their power. In other words, buy a boat for where you see yourself in a year or two. If you want to paddle 5.5 - 6.5 knots, buy the boat better suited for that speed range and then work on the technique that will get you there.
If someone buys a kayak that hits the wall at 5 knots then they will never paddle at the speed of the ocean. Instead they will join the masses that think 3 - 4 knots is all one should expect, and that is what they will get.
Old news
http://www.janes.com/defence/naval_forces/news/jni/jni061117_1_n.shtml
… and that’s what’s public. Th supercavitating bullets are interesting too.
A quote from a drag reduction patent I came across: “The need for reduction in frictional drag has long existed. Means for reducing frictional drag include laminarization, air cavities and air films, riblets, magnetohydrodynamics, microbubble ejection, polymer ejection and moving walls.”
Form
My assumption is that in a typical sea kayak (not a racing boat) proper form gets you just a few tenths more speed, what it, and dedicated practice, mostly gets you is the ability to maintain that speed for a much longer period of time. For even the really good people that’s still going to be less than 5 knots.
Mike
high performance sea kayaks
"Greyak, I would love to go for a paddle with you some time. I would be happy going 4.3 knots along side you just to chat about boats and paddling for a while."
You’re on my list of people to visit on my super paddling road trip - scheduled to happen sometime after my Lotto win!
“Did you notice that the kayaks shown in the graph were all described as high performance sea kayaks? I only consider 3 - 4 of those boats to be high performance sea kayaks.”
Well, SK does need to promote it’s advertisers! Maybe the rest have “performance layups” or other “performance features” L
“What I find interesting about those drag resistance graphs is the left hand column that shows the drag in pounds. This is equal to the power a paddler must maintain to achieve the speed…”
Yep, so in my simplified math that means I can take the curve for a kayak I paddle and know my average speed from - find the drag value for that kayak at that speed - and assuming no huge stability/comfort differences - can plot that value on other kayaks’ curves to see what they might do for me at my current sustainable effort levels. Pointless exercise at 3-4 knot range, gets a tiny bit more interesting above that, but above that the stability and outfitting issues begin to have increasing influence on actual maintainable speeds.
As you say, if you can sustain higher output levels the choice of appropriate boats and what you get out of them changes more significantly (again, assuming ability to handle them).
While I agree on core power vs. arm power, I think you may be exaggerating that 100% thing. First, it would take much less than that for most to get into the 5+ and even 6+ knot range - unless they insist on doing it in a rec boat. Second, while it may be hard to find excellent core paddlers outside K1 and A and B list ski paddlers, it’s also pretty hard to find 100% arm paddlers in sea kayaks who are not newbies or very rare occasion paddlers.
“If someone buys a kayak that hits the wall at 5 knots then they will never paddle at the speed of the ocean. Instead they will join the masses that think 3 - 4 knots is all one should expect, and that is what they will get.”
Yeah, not much open water bump milking going on in a Pintail, though such kayaks are fun in the light surf play, rock gardens, and tide races they were designed for).
Sort of assumes it’s really the kayak’s wall and not just the paddlers. Hull speed difference between 15’ and 18’ LWL is only half a knot. For the kayaks you’re talking about, and the core paddlers who paddle them - regularly exceeding hull speed is common. However, few few in a 15’ LWL kayak are doing near that (5.19 knots) with any regularity or for any length of time. 80% is doing pretty good.
That half knot penalty at the upper end on paper is huge for fitness/racing types, and of interest to fast touring wannabe types like me, but is still pretty inconsequential to most sea kayakers.
I have a design in mind - and if I ever get it to paper/screen I’ll run it by you. I think you might like it. Sort of splits the difference between these camps - and so would likely sell well to neither - but I’ll build it anyway someday (unless someone brings something really close to it to market in the US before then - and there are a couple here now I still need to try that might also put me off the idea or change it yet again. If I ever find a ski I can make friends with and devote seat time to - that might sideline it too - but this design would have a much shorter learning curve than a ski, at least for me.
Just one of a dozen projects on the far back burner. After picking brains on the road trip, a good bit of the Lotto money would get thrown down the rat hole of a paddlesport business startup!
The sort of “really good people”…
… you speak of are probably coaching and guiding and so can’t really set their own pace. Some even doing multi-day trips or longer expeditions where pace is adjusted for all day exertion.
Do you really think 5 knots to be unrealistic (in a hull optimized as you mentioned) for such paddlers on their own doing day paddles, or in sea kayak class races?