Steve, this is for you, so other readers need not follow it because it might be TMI. No debate that a 15’ 6" x 21" kayak moves forward easier than a 17’ 4" x 25" kayak. However, in reply to @kapungo, it’s important to note that a shorter kayak isn’t necessarily slower, it just has a lower speed potential than a longer boat. Longer doesn’t mean faster, and I agree that the narrower (and possibly lighter) boat is initially faster, but it can’t reach the same top speeds, which can be explained by belaboring the concept of hull speed, regardless of the way it’s calculate.
To reiterate, water cannot be compressed, therefore, it must be displaced to allow the boat move. The displaced water can only be deflected down, or get pushed aside, but it eventually flows back to fill the gap made by the passing boat to find equilibrium. How efficiently it does that depends on the hull form, the configuration of the chines, the width, draught, and to a somewhat lesser degree the texture of the hull (see archives about waxing the hull). It all influences efficiency, but it is the length of the hull that sets the speed cap of all displacement hulls (the hull speed formula fails to address specially designed hulls like the surf ski, race boats, and catamarans, otherwise, the simple hull speed charts are close enough. The accompanied charts show how when the hull length matches the wave length, it traps the boat between the bow wave and the water that fills the gap the passing boat displaced. The graph roughly represents how resistance builds as speed increases. There is a sweet spot where power output becomes exponentially greater than the increase in speed. To me, how fast I can go is less important than how much I benefit from the effort.
This topic is so theoretical it induces “ho hum” reactions. I only repeat it to emphasize the reason hull length is a limiting factor rather than a magical speed enhancer. A longer boat typically means a heavier boat, which if all things are equal, heavier means more displacement. My assumption is that two boats that are identical externally but with one weighing 20 lbs more means that the heavier boat will be slower. The reason- it displaces more water. Therefore it sinks deeper. Water weighs “about” 62.4 lbs or 8.34 lbs a gallon. If you consider that a boat must push that weight aside to move through water, the most efficient wedge design will push forward with the least resistance.
That brings the paddle into the equation. If the hull is designed to part the water more efficiently and ease the inevitable rush to fill the void, it’s only logical to conclude how a paddle that provides the most resistance is the most effective. As long as you don’t feel fatigued from lifting the overall weight of the paddle and your cadence allows you to control the paddle placement, you have a great paddle. However, supporting a heavy paddle for extended periods, swinging a high cadence, or have issues with accurate placement for a splashless catch, are reason to consider upgrade to a lighter paddle. Before you decide on a paddle, analyze the features of the blade and how it attaches to the shaft
Many paddles advertise a blade with dihedral, which balances the way water flows off the power face equal . . . The pause is intended to make you think. If the function of the paddle is resistance to push the boat forward, how much dihedral should a paddle have to move the boat. Technically, the answer is as close to zero as possible. Greater dihedral improves the balanced feel as the paddle “moves” through the water, but the ideal paddle doesn’t move at all. So the paddle you select should be the one you control best. If your paddle is fluctuating up and down, oscillating, cavitating where you feel bubbles, you’re dumping power. Asymmetric blade designs are intended to balance the way the blade contacts the water. The trapazoidal design should be more clipped brcause it catches at a lower angle, but for some reason, both high and low angle paddles seem to favor the same geometric shape, with the high angle featuring a wider but shorter blade with greater area to compensate for the lag during the transition from exit to catch. Greater blade area typically results in higher anerobic demands. That’s benefits full power sprints that can be sustained by an athletic person, but it seriously limits endurance. One caveate is that the closer you get to the hull speed of the boat, the less efficiently the hull will perform. So a longer boat simply extends the hull limit. At my personal level of conditioning, I can cruise in the 145 at around 4.75 mph and the 175 Tsunami at close to 5.0 mph over about 8.5 miles. I purposely avoid peak speed except to test the force of the waves. On moderate waves, I can repeatedly hit 6.4 mph to 7.1. Larger waves can drive my peak speed to 8.3 mph. That exercise allows me to assess the impact the waves will have when I reverse direction. My strategy, right or wrong, is based on assessing the conditions so I can tackle them most efficently. The focus is not speed, but continuity and efficiency. I’m confident that if I can reach a specific speed over 8 miles, I can sustain it for 20 miles, and my logs support it.
The Greenland paddle relies on cant to direct the flow of water in a controlled fashion. Cant doesn’t improve the power transfer, it just augments control, and the “typical” symmetric design offers technical advantages for rolls, sweeps, and braces. If a paddle tends to fatigue you and the technical advatages aren’t critical, you might be adequately served by using smaller square inch blade.
So if I understand the question that @kapungo asked, it was related to comparing the speed in a 12’ boat to the relative advantage of paddling a 14’ boat. The data I logged over the years is limited to only four kayak models, with all being Wilderness Systems products with similar build and identical seats. Several points make the WS brand desireable for my kayaking needs, starting with:
*reasonable pricing (retail prices ranged between $999 through $1,599);
*each model has the unique multi-chine hull design which is responsible for the incredible primary stability and very predictable secondary stability; I rarely ever feel the need to brace in under any conditions and find that balance is easy, even when encountering breaching waves from the side. The last thing I want in a kayak is the need to fight it
*the seat system when I was shopping was rated as one of the most comfortable seats available, and still is rated highly; the adjustable high back seat offers great comfort for long hours in the boat, although it is less suitable for reentry compared to a backband;
*the roomy cockpit and high front deck is amply proportioned for a large paddler. The Pungo has the lowest deck at 14", but the cockpit is an open design; the 125 is 15", the 145 is 16" and the 175 is 15.75"; the Pungo is my favorite kayak. Even though I don’t paddle it anymore, it is the go-to kayak for guests because it’s so forgiving. Although I paddled it in open water and crossed the bay multiple times, it’s fast, but not as sea worthy or controllable as the Tsunami.
*rocker is minimal and tracking is very controllable through edging, except for the 175, which requires rudder input to control weather cocking as winds approach 10 mph; turning isn’t an issue for me since I value tracking over turning, but my trips tend toward touring in active open water. Although each model handles the open water of the Upper Chesapeake Bay, the Tsunamis are best suited when conditions are flagged Small Craft Advisories. Then the 175 is the best performer. I don’t go out or will get off the water if Gale Force Conditions are warned. I don’t wear a spray skirt, so I’m not comfortable with winds gusting over 30 mph.
140 Duralite Pungo (14’ x 28", 43 lbs, 400 lbs)
125 Tsunami (12’ 9" x 26", 52 lbs, max cap 300 lbs)
145 Tsunami (14’ 6" x 24.5", 58 lbs, max cap 350), and
175 Tsunami (17’ 6" x 24", 69 lbs, max cap 400).
I also own two rudder equipped 140 Tsunamis, and a rudder equipped 145. Unfortunately, I can’t fit in either model because the clearance needed for the rudder movement limits the extent of leg room, but that is not a problem with 175. Relicatingbthe 145 seat ti thecrear baba scant 43 mm upset the balance and made the kayak uncontrollable when following waves push the boat over 6.4 mph.
To emphasize our previous conversations, I am not a technical kayaker and believe you have far greater boat handling skills than I’ll ever pursue or achieve. I believe you’re also a far stronger paddler who is capable of reaching greater speeds and distances. I base that on our conversations, the behavior of your paddle that we both have adequate experience with., and your experience with paddles from a Taiwanese snow shovel, many styles up to the Kalliste, which has a blade area that may be insufficient for your powering strategy.
When assessing the design factors that contribute to hull efficiency, you have to consider how the hull floats, how it reacts when pushed through water, and how to propel the boat with a paddle which involves not only propulsion but control as well.
I’ll warn that perception is a poor method to assess performance, although it is the primary way to judge stability, comfort, and a sense that you are connected and able to control the boat. The reason for the inadequacy of perception is the conflicting forces and sensations that you’ll experience on the water. That includes:
*proximity to stationary object, land, other paddlers and the movement of floatsom on the water surface, which all create an illusion (for ex: witness the perceived size of the moon on the horizon vs. when it’s directly overhead, and measure actual speed when paddling alone, as compared to paddling into the wind when bracketed by other kayaks in line abreast. The higher the wind, the greater the resistance and the slower your speed. If you add a contrary tide combined with a river outflow which accentuates the waves, the sensation is exhilerating and reminiscent of a scene of speeding PT boats in the John Ford classic, “They Were Expendable”. I’ve had adjacent paddlers remark how fast we were going but didn’t have the heart to tell them we were going 1.5 mph faster when the wind was to our back and the tide in our favor.
*the sensation of actual wind and perceived wind (for ex: paddling at 4 mph into an 8 mph wind gives the perception of a 12 mph breeze, while paddling with the wind at your back cancels the felt wind, then a side wind still offers another impression.
*level of exertion which varies with conditioning, and largely depends on how you encounter wind, waves, tides, and currents.
*the testing intervals and parameters have to be the same, the conditions need to be repeatable, and the sample large enough to show that the results aren’t spurious (for ex: testing for maximum speed can’t really be relevant to assess glide or how long it takes to get up to speed).
Several methods can offer valuable data:
*measured distance in a timed interval. Although that might be valid for the specific distances, it’s hard to extrapolate the findings to other boats or how the speeds translate to longer trips.
*GPS is best, primarily because it automatically measures speed, calculates average speed reasonably well, records the duration and distance of the trip, and usually has a clock to tick seconds or at least one minute intervals to count off cadence. I use both the GPS, as well as a phone app that revords speed on a graph to reflect the speed fluctuation. That serves as a black box for post-trip analysis. One thing I notice when viewing speed graghs of other paddlers is wide fluctuations that reflect a range of 2 mph between the high and low speed, or around (+/- 1 mph) above and below avg speed. I believe the best value of a GPS is the ability to bracket your speed to stay within a range of (+/- .2 mph) of your avg speed, which is the best I can seem to manage due to the GPS limitations. The reason I believe condensing those speed spikes has a great benefit is because the graphs show it takes more energy to get up to speed than it does to maintain it. My belief, based on experimenting with various paddling techniques, is that the closer you get to hull speed, speed gains become exponentially harder. If you’re a serious paddler, you probably hit a consistent pace. Rather than trying to go faster, its more beneficial to feel out your boat’s sweet spot. That’s where your power output seems to net the best result. If you’re at the boat’s sweet spot, you might have to put out 10 times more effort to gain an addition 1 mph of speed. Whwn the extra effort elevates your output to anerobic, the consequence will be a drop of 1 mph below avg speed, which depletes energy reserves. It takes at least 3 times more energy to just get back to the avg speed. My best strategy results when I plateau at a sweet spot that lets me predict an avg speed at the outset. If I go outside of the (+/-) .2 mph range and hit .5 mph, the sustainable speed drops below the avg speed for at least twice as long. It takes less energy for me to stay as close to the sweet spot as the GPS allows. Which brings me to cadence and paddles. I select a paddle that allows me to remain aerobic for efficiency and to keep a high enough cadence to sustain the glide. A cadence of 72 to 80 spm allows me to sustain the glide with 20 additional strikes per minute than one stroke every second. The increased cadence helps to manage tracking by alternating the power effort on each side of the boat. The way I look at it, the yaw rate is reduced by half with an 80 spm compared to a rate of 50 spm.
*heart rate monitors and oxygen sensors are probably the best tools to track how you use energy. They offer an accurate window to assess exertion. When coupled with indicated speed, you can correlate performance with actual effort to reach speed.
I’ve also compared my data to stats that @Craig_S shared with me about paddling his 175 Tsunami, 170 Tempest (17’ x 22", 57 lbs, max cap 325 lbs), and the fiberglass 180 Tempest (18’ x 23, 64 lbs, 400 lbs). His stats included some observations about his son’s race performance in the the newer model of the 145 Tsunami (14’ 6" x 25.5", 59 lbs, max cap 350 lbs) and the 170 Tempest (17’ x 22, 57 lbs).
Although we are virual opposites in our paddling technique, we approach the process in a similar fashion. My advice to Craig is to keep doingbwhat he’s doing. Rather than tell you what I think, I’d rather explain why I think it. That way you can accept, reject, or assimilate the info without having experiment.
If anyone got this far and feel cheated, I apologized. If you think its too long, I suggest you scroll down to determine how much of your life will pass before reachung the point. If anyone has questions, DM me to save the innocent bystanders who just want take in the wonders out there.
