Capn's Note: This study was recently redone, with new and improved results. The
results of the new study are at the end in an Addenda.
(Little Wing 16)
Yak Length WL WS Cp
Skua 17'4" 16.2' 21.2 0.556
LW 16 16'3" 15.9' 23.4 0.679
LW 18 18'4" 17.6' 25.0 0.675
Note: WS is wetted surface, Cp refers to prismatic coefficient. The Skua has the lowest wetted surface, even when compared to the shorter LW-16. Both wings have a higher Cp (see below*).
This analysis is full of BS - and it might just be mine!
On the other hand, it may not...
Now if you want a BJ with it, you'll have contact the RNC...
Little Wing sez: "Little Wing's design goal was to provide the performance of a racing kayak with the stability of a touring boat. This goal is accomplished by adding wings." Wowee!! Sounds like wings on an airplane - this yak must be REALLY fast...
They explain: "Little Wing's long and narrow waterline, and smooth, round hull allow her to glide through the water with minimal drag. Low drag lets Little Wing move faster as you paddle harder." - while at the same time - "Little Wing's patent pending shape gives her the robust amount of stability needed to handle rough conditions." Finally - "The wings stay out of the water when not edging, giving Little Wing a narrow waterline width, but as the boat is edged the wings gradually enter the water providing for increasing stability."
In other words, Little Wing would like you to believe that the sponsons only come into play in really rough conditions. Amazing! Can it be true?
Let's consider the LW 16 which claims a mere 17.8 inch waterline! Whew. This is equivalent to narrow, high performance racing surfskis. Now I can tell you from considerable experience with my 19 inch Mako XT surfski (19 ft x 19 in) that when you work with such narrow beam, speed comes with a considerable loss of stability. It took me an honest 3 months to reliably stay upright on the XT, and true 17 inch beam racing skis often take a year or more of intensive experience to stay upright.
So I do believe Little Wing's claim that their wide "wings" or sponsons (bow AND stern) are not in play short of "rough conditions or edging (turning)"?
No way. Even small waves and ordinary chop will cause considerable side-to-side rolling of narrow hulls. On a surfski you simply have to go with the roll and depend on loose hips, repetitive J-leans and the support of your paddle in the water to stay upright. On the Little Wing the sponsons will be forced into play. Constantly and in almost all conditions. The point:
Little Wing's claim (that their waterwings are not in play) is for all practical purposes, impossible. Now let's look at the numbers:
Perhaps the very most important number for the average paddler is wetted surface (WS), which is directly proportional to frictional drag, and - short of all-out sprinting - this is the number with which most paddlers should be concerned. The greater the wetted surface (WS), the more friction/drag, and the harder you have to paddle. And despite Little Wing's claim that their "wings" aren't touching the water, the numbers don't bear them out.
The Kaskazi Skua has the lowest wetted surface, and therefore the lowest resistance to paddling. Put another way, the Skua will have the fastest cruise, or will travel at most speeds with less effort. For the same effort, in most conditions the Skua will be faster than either Little Wing (and that's assuming their "wings" don't touch the water)...
Which they do - most of the time - which adds even more drag and turbulence. Furthermore, please note that Little Wing bases all their calculations on a 150 lb paddler and no cargo - unrealistic and self-serving. At least Kaskazi is forthright enough to list performance specs for both 231 and 363 lbs - realistic figures. And still beats both Little Wings. (Fortunately, in an attempt to level the paddlin field I was able to adjust Little Wings' specs for an estimated load of 231 lbs).
Think about it. The Skua has a waterline beam of perhaps 21 inches vs. Little Wing's claims of maximum beams of only 17.8 inches (for the 16) and just 17.3 inches (for the 18). Yet the Skua has the lowest wetted surface - how can that possibly be? The inevitable conclusion, for me, is that the "wings" ARE in play and add width and/or wetted surface. Both Little Wings have significantly more wetted surface, even after cheating by using just a 150 lb. load! Put a real paddler and gear in there and their numbers would really head south.
Bottom line: Little Wing's claim ("Low drag lets Little Wing move faster as you paddle harder") doesn't stand up to either real world paddling or based on their own numbers. The "wings" are in play by design, or in use - or both.
Still Little Wing continues with the hype and explains their chopped-off stern this way:
"The transom creates a longer virtual waterline length, making Little Wing perform like a longer kayak. The distribution of the kayak's volume along the kayak's waterline length is critical to its performance. The technical measure for this concept is the kayak's prismatic coefficient. The optimal prismatic coefficient is a debated number, but most agree it is between 6.2 and 6.7. Little Wing's prismatic coefficient is 6.4 while most kayaks have prismatic coefficient's in the low 5s."
Prismatic coefficient (Cp) is a measure of fullness, and it is a matter of great debate what effect it has on speed. At best its effect is relatively minor, and then only when approaching hull speed (sprinting) - a matter of concern mostly to racers, and even they will disagree about Cp, believe me. And it competes with many, many other factors.
This is where things get dicey. Little Wing wants you to believe (a) that speed is directly related to prismatic coefficient (Cp - refers to fullness at the ends of a typical kayak hull shape), (b) that there is an optimum range (6.2 - 6.7) which "most agree" on, and (c) that since "most kayaks" fall in the low 5's that the Little Wing is clearly faster.
What hogwash! Couldn't be more misleading. Let's parse this doodoo...
"Most" don't agree on any design factor. First of all, speed is a combination of two factors. The most important, by far, is frictional resistance or Wetted Surface, already discussed, and the Skua prevails. The second is wave resistance, which no one completely understands, but which is a very, very complex relationship among these factors:
Displacement, speed, BWL (beam waterline), LWL (length waterline), EWL (effective waterline length, LCB (longitudinal center of buoyancy), Cp (Prismatic Coefficient), Cb (block coefficient), Cm (midship coefficient), angle of entry and exit, and various form factors (like chines, "wings", etc.).
All of them. Prismatic coefficient simply can't be separated out.
Worse yet, these calculations assume the relatively standard shape you think of, i.e. a pointed bow, gradually widening to a maximum beam somewhere amidships, then narrowing again to the stern. Beyond the fact that you simply cannot make such a simplistic blanket statement regarding speed and prismatic coefficient, it is important to note that Little Wing's unusual shape (which begins to approximate TWO hulls joined in the middle), it should be obvious that the usual single hull formulas may begin to fail.
Let me give you just one example, Cm (which plays a part in determining Cp, BTW). Cm is the Midship coefficient and measures the relationship of the maximum sectional area of the hull (usually midship, ergo the name), the waterline beam, BWL (also usually midship) and the kayak's draft. With the Little Wing their claimed waterline beam MAY be midship, and the design has not one but two maximum sectional areas (the wings) which are NOT midship. This is a problem, and only one of many.
And again, it assumes the "wings" never touch the water. For as soon as they do - and I contend this is MOST of the time - you can throw ALL of the calculations out, if you haven't already.
Little Wing counts on the ignorance of most folks, and I have no doubt that many real experts would take great issue with these simplistic claims. But hey, that's marketing. Just like the myth of light hull weight for speed and that of the superiority of (expensive) ultralight paddles, the claim that you can have your cake (speed) and eat it too (stability) is simply too good to be true.
One final note: I know a good bit about marketing and it is no accident that Little Wing calls em "wings" and not sponsons (marketing), focuses on Cp (perhaps the only spec favorable to the design), bases their calculations on a mere 150 lbs (to reduce wetted surface) and last, avoids comparisons with the big gorilla, wetted surface. Their "unique marketing proposition" might otherwise fail.
Will I spend big bucks based on such a flimsy proposition? And just when is Little Wing gonna get around to submitting their design to Sea Kayaker (who has the expertise to rip apart their data and claims, and would perform honest sea trials with paddlers of varying weights)? They've had years to do so. Trust me, not gonna happen anytime soon...
In closing, do check out ALL the photos from Warrencraft's site and you'll not find a single one without their "waterwings" IN the water (and most were taken in relatively mild conditions). I rest my case...
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* Wetted surface analysis extrapolated from data from Kaskazi and Little Wing.
It is some months later, and having gained much experience with Kayak Foundry and Freeship, I decided to revisit this study, using improved methods. Here's the results:
LW16 CJ16 LW18 CJ18 Skua
Length 16' 3" 16' 3" 18' 4" 18' 4" 17'4"
Beam 23.7" 23.7" 22" 22" 22.5"
Beam at Paddler 20" 23.7" 20" 22" 22.5"
Paddler Wt. 150lb 150lb 150lb 150lb 150lb
Cargo Wt. 0lb 0lb 0lb 0lb 0lb
Boat Wt. 32lb 32lb 36lb 36lb 33lb
WL Length 15' 9" 15' 9" 17' 6" 17' 6" 16' 3"
Wetted Surface 20.9 19.9 22.5 20.3 19.0
Wetted Surface Scores:
New Study Old Study
1. Skua 19.0 sq ft (150 lb paddler) 21.2 sq ft (at 231 lb)
2. CJ16 19.9 (150 lb) ---
3. CJ18 20.3 (150 lb) ---
4. LW16 20.9 (150 lb) 23.4 (adjusted to 231 lb)
5. LW18 22.5 (150 lb) 25.0 (adjusted to 231 lb)
Kayak Foundry (v. 1.51) was used:
(1) to create designs matching LW's length, beam, and paddler/cargo/boat weights to produce reasonably comparable conventional designs. These were named the CJ16 and CJ18.
(2) to create a Skua lookalike that reasonably matched the Kaskazi's length, beam, waterline length and paddler weights - indeed the lookalike exhibited slightly more wetted surface (and drag) than reported by Kaskazi. This error was induced purposely so as to slightly favor LW (and to shut up Great Asses and wannabees). The design waterline was then adjusted to match Little Wing's target paddler weight of 150 lb. This was done in part to confirm the earlier study, and also for a real life comparison to both the LW and CJ designs.
The earlier study was based on adjusting LW's published specifications (based on an unrealistic paddler weight of 150 lb) to match Kaskazi's published specs (based on a more realistic displacement of 231 lb). This was done by noting the difference in wetted surface between Kaskazi's specs published for 231 lb and 363 lb., and applying the same surface/lb relationship to extrapolate LW's specs to a 231 lb paddler.
The later study did just the opposite, adjusting Kaskazi's specs to reflect LW's 150 lb paddler. However, this methodology was much more satisfying as I was able to create a Skua lookalike with Kayak Foundry that reasonably matched Kaskazi's published performance and drag specs. The model was created to give LW a slight advantage. For further confirmation two more models, the CJ16 and CJ18 were created using LW's primary dimensions.
The results were not unexpected. The Skua, CJ16 and CJ18 conventional designs all outperformed both LW's. I was especially pleased to note that the originally reported advantage for the Skua was closely confirmed by the later, more scrupulous study, with both studies agreeing very closely in percentage terms for the Skua's advantage.
It is my opinion that the LW's deficits are much greater in reality than on paper since, as noted, the "wings" are frequently and substantially in contact with the water much of the time. These sponsons are not insubstantial and will intermittently add much more wetted surface for extended periods in comparison with conventional designs in the same conditions.
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