Hull speed comparison?

16 foot glass VCP Avocet versus 17 foot 2 inch glass VCP Skerray. Conditions would be average ocean swell and small surf. Paddler would be 195 lbs. I find them very simular speed wise. Moderatly fast and able to keep up with most long boats at a touring pace. That said I have read many comments claiming the Skerray to be a slow boat. The early Valley promo all says it is a fast boat. I do not yet have a GPS and am curious about other paddlers experiances with these two kayaks. Thanks in advance.

Chuck

Avocet vs. Skerray

– Last Updated: Nov-27-05 9:37 PM EST –

I've paddled both boats quite a bit but don't have any GPS data about speed or effort required to paddle at certain speeds. My sense is that the Avocet is "faster" (i.e. easier to paddle at speeds above 4.5 knots). This would probably be due to the narrower beam (width of Avocet is 22" Skerray is 23"), more rounded hull shape (vs. shallow arch for the Skerray). (Does the Skerray have more rocker than the Avocet? My sense is that it does -- the Skerray definitely tends to weathercock more easily.) Rocker may be a third reason for the Avocet being slightly faster -- despite being about 14 inches shorter than the Skerray.

Neither are especially fast boats when compared to other similar kayaks. A listing of Water Resistance vs. Speed for 105 kayaks shows the Avocet to rank 75th in efficiency at speeds between 4 and 5 knots. See http://www.unold.dk/paddling/articles/kayakvelocity.html
The Skerray is not listed here unfortunately. At slower speeds, the Avocet ranks much higher on the list in terms of efficiency. At 3 knots, the Avocet ranks 23rd.

Happy paddling!

Effort / Rocker
Thanks… interesting list. The Skerray appears to have more rocker than the Avocet. The Skerray has slower acceleration but seems to be easier to keep at speed once you get there. (fishform?) The Avocet is better all around especially the tracking.

Often
at slower speeds wetted surface is dominant factor (less wetted surface = less resistance) and at higher speeds waterline becomes dominant (longer = less resistance)



The Avocet is faster than most 16 foot boats of its type such as Romany, Meridian, Chatham 16, etc…

the list
does the list simply go by beam/lwl? I can’t imagine that would provide an accurate desription of water flow or surface area.

Sea Kayaker Magazine explanantion

– Last Updated: Nov-28-05 10:23 AM EST –

Here is the link to the Sea Kayaker explanation. Note the bottom of page 2 and the top of page three for explanation of how they calculate resistance.

http://www.seakayakermag.com/PDFs/Kayak_Reviews_Info.pdf

Splitting hairs
Paddled Romany, CH16, and Avocet and find VERY little real world difference in speed. Hardly worth discerning in MY mind. All three are good boats that handle sea and wind well. None are fast, all are fast enough. Anyone who cares about flat water speed would be better served by another type of kayak.

True, but
my Romany sure throws a much bigger bow wake than my friend’s Avocet.



I’ve paddled an Avocet and a Romany and can feel the greater resistance when pushing the Romany.

16 ft boats
I agree but was strictly speaking about typical NE offshore conditions of moderate swell with 2 to 3 foot wave height. I paddled the Chatham 16 a few times. Great handling kayak but I found it to be much slower than the Avocet and tuff to keep up a fast pace with. I was surprised that the list did not include the Impex Montauk which is a very fast 16 foot boat. My wife has one.

Chuck

Buy what you feel best in
I think the reality is simply that you like the Avocet for whatever reason, and you should buy it. To say that any one of these boats is WAY faster than the other two is lost on me, as I have use of all three. My preference is not important. They are all good, so buy the one that does it for you subjectively and paddle the thing often. All are slow as HELL, so get past the speed BS. All are very capable coastal fun boats that will be a blast in big conditions. The Impex boat is likewise excellent, but not, faster to any significant degree. Look, if you want to go fast paddle a lot, stay fit, become skilled, and you’ll cover ground in any boat. If speed is your primary focus on flat to moderate water, none of these products is appropriate.

Avocet/Skerray

– Last Updated: Nov-29-05 1:16 AM EST –

Hi,

My understanding is that the sea kayaker list uses naval architecture software to predict these drag figures. This does give a useful guide but some factors do need to be considered alongside the results.

Firstly; compared to the sailed and powered vessels these programs are usually used for our kayaks are very small displacement hulls therefore even very small errors in scanning in the kayaks profiles results in (relatively) large variance in drag results.

Secondly; as several have already pointed out the effects of theoretical drag on real world cruising speed is hard to quantify. As an example a couple of years ago (whilst at P&H) I set out to objectively test our range of kayaks for speed, I used a flat time trial course, a hart-rate monitor to ensure equal sub-maximal exertion and a gps to record average speed etc. I always tested pairs of kayaks doing alternate runs in each and averaging the results. Despite repeating the test on different days and at different exertions levels I could not find significant variance between the Capella RM (The original not the fatter and slower new version) and the composite Sirius (ranks 54 & 39 on the web listing)

Add wave action, windage, individual trim of the kayak (all of our centres of gravity differ not just up and down put forward and back) and this make computer modelling very difficult. In fact a couple of scientists set out to design the fastest racing kayak using computers, the result “Godzila” on paper was the fastest ICF legal kayak, To the best of my knowledge it hasn’t changed the sprint world. I guess I just feel there is no substitute for real world testing!

Relating this to the Avocet/Skerray, on a theoretical level there is going to be very little difference in hull speed because the Avocet has far less overhang in the ends and thus it’s waterline length to total length ratio is better coupled with being narrower the Avocet possibly just edges it. In real world performance the Avocet will feel livelier, less boat to push around and is undoubtedly the more playful boat, the only area the Skerray really scores over the Avocet is in loading capacity.

From a totally biased perspective the Avocet is one of the liveliest 16’ kayaks on the market.

newer designs are better
Though the classic Valley boats are wonderful and striking, I believe the newer Valley hulls to be better mannered and performing designs.



It may be heresy, but I’d take my Aquanaut over a Nordkapp (especially older versions) any day.



Most I know have more use for an Avocet than a Pintail.



Of course then there’s the Anas…

I once did a very unscientific…
… comparison of a number of boats. I set an approximate 1 nm quiet water course and ran it both ways to equalize for wind. I did not use a heart rate monitor, but strove for a consistent pace that left me a bit winded but not exhausted. I think I was pretty successful at getting a consistent pace – I repeated everything at least once to check for it. I realize this was highly unscientific, without a GPS or heart rate monitor. It was also very specific and limited conditions, type of paddling and range of boats.



I compared composite boats – Explorer, Diamante, Ellesmere and Andromeda, and a rotomolded Avocet.



Bottom line – I was amazed at at the consistency. All the composite boats came within 2% of each other. But the roto Avocet was 10-12% slower!



One more test. I tried the same thing with a GP, at which I am quite a bit less skilled than a spoon paddle. That came out a consistent 5% slower in a the Diamante and Avocet. I’m pretty sure that could be correctred by better GP forward stroke technique.



Y M W! V --David.

There are two different skerrys
Hi, I have both boats, in glass. The glass Skerry would be faster, in my opinion. The confusion often lies in that the Skerry RMX or RM has a LOT

more rocker than the glass version. They are different enough to have different names. The glass boat, while still easy to turn, does not respond at all like the plastic boat that will almost spin in place, and is slower as a result. That said, the volume of storage it much greater in the Skerry over the Avocet. Both will keep up fine in a group. It often seems the once you get your paddling stroke down, the difference is more or less the that one will scrub off speed sooner when you stop to coast a little more than the other, soon you don’t even notice.

(Then there’s the Skerry XL, supper tanker, it’s no slug for it’s size though)

Aj

Skerray RM
The rotomolded Skerray (RM) appears to be smaller in volume than the glass Skerray. Is this so? I haven’t paddled either, but have seen the RM up close and the glass Skerray on cartops, and there appears to be a difference in volume as well as rocker. The Skerray RM , which I think is no longer in production, is one of the few plastic boats with an ocean cockpit. It looks like it would be a great boat for surfing & rock garden play where hull bashing is certain to be involved…