Kevlar Valley Avocet Review

What an absolutely fabulous play-boat for day paddles! Not too shabby on a multi-day trip either--both in terms of load carrying capacity and cruising speed.  I am 6', about 180lbs, 32" waist, 33" inseam and have gone on a 4-night camping trip in this boat comfortably.  For longer trips, a Nordkapp HS and the Avocet complements Nordy extremely well.

When I first paddled the Avocet I was surprised at the small speed difference between it and Nordkap HS. There is a distinct difference though and I could feel how effortless the glide in the Nordkapp was at a pace where Avocet hit the wall.  It's just not as noticeable as I expected it to be given the 2' difference in boat length.

I was very pleased with the stability profile of the Avocet which I found to be more similar to my Nordkapp than to a boat in Avocet's class--NDK Romany.  The Romany has a distinctly stronger primary which beginners would relish. I found that Romany fought my attempts to put the boat on edge. When it comes to secondary, the Avocet is way more stable on the edge than the Nordkapp HS but comparable to Nordkapp H2O. However amply rockered the Nordkapp may be, 2' difference in boat length makes a huge impact in maneuverability and in tracking as well.  The Avocet quite literally turns on a dime!  Bow rudder turns with the blade at your knees is a thing of magic.  Neither of these two boats can be paddled comfortably without a skeg in wind and waves--not unless you desire an extreme practice in edging and sweeping on one side, that is.

I absolutely loved the boat in surf! In the Nordkapp, I slide off the face of the wave broach and the straight part of the ride is over. In the Avocet I can steer and keep the boat going straight! Makes for much longer and controlled rides. At 16' it's not a surfing boat by any stretch of imagination but at least I have a shot at some control in it.  And did I say it is much more fun in the surf? :)  I had a chance to paddle the Avocet next to Romany in 10' breaking surf.  This is not a conclusive evaluation but Romany felt even easier to maneuver and spin on the wave crest.  It may have been that the conditions were somewhat different.  On the other hand, Romany does have a flatter and more square hull under the cockpit so it may be that it planes noticeably better than the Avocet and rises higher out of the water during runs enabling the skipper to do more.

The cockpit of the Avocet fits me very well. I miss the tight fit of the ocean cockpit of the Nordkapp but not the getting in and out of it part :) Thigh braces are not as fool-proof method for being one with your boat but I have not gotten to installing any extra padding--have not found the need for it really.  In the Nordkapp I did that promptly after a 4-5' breaking wave sucked me right out of the OCEAN cockpit! I added about an inch on the sides in the upper thigh area for better contact with the boat. In the case of the Avocet, I am at the very top of the fit bell curve and the fit is tight enough (surprisingly, adding some 70lbs of load on top of my own weight, did not seem to overwhelm the boat's carrying capacity).  Can't complain about the back band--it's small and could be much improved but for my paddling style it more than meets the need.  I have a fancy white-water Immersion Research back-band sitting in my garage but have not felt the need to replace the simple back support of the Avocet yet.  My back feels quite happy.

The boat is extremely easy to roll compared to Nordkapp HS.  Given that the Nordy is quite easy to roll in it's own right, this is quite a compliment.  The boat is light, lifts itself out of the water due to the upswept bow and stern, the cockpit is low in the back and wide on the sides so that it does not interfere with the hip snap.

The boat is Pro Kevlar but weighs about as much as my light layup fiberglass Nordkapp. I don't quite understand how this is possible given that it is smaller boat.  A clue may be in the 1/2-inch thick layer of gel coat on the foredecks. I can see the thickness where the foot pump outlet exits on the top deck. It's thick! Could probably take a full tsunami!  It's also cracked because the front deck oil-cans under my weight.  The foot pump adds a couple pounds to the total weight of the boat too.

In summary, a perfect day boat and play boat sea kayak. Distinctly slower but much more maneuverable than Nordkapp HS. Fast enough for casual paddling. Big enough for a week of camping out of the boat.  No shortcomings that I can find.  I give it a 9/10 because no kayak should get a 10. They are all compromises of one kind or another.

Let me know if you have specific questions.

Vintage Valley Nordkapp HS review

There is a lot of confusing information in reviews of this boat on paddling.net! Nordkapp is one legendary name.  That one name covers several quite different models of kayak. When reviews below are talking about Jubilee or H2O it is easy to see that they are not describing Nordkapp HS. Jubilee or H2O are quite different from the original HS!

Unfortunately, reader and potential buyer beware, even when a review is about Nordkapp HS, there are several different kayaks with this name in existence. I have no experience with the current "Nordkapp Classic" with 'HS' designation; however, based on some earlier reviews in this section, I strongly suspect that even the "Nordkapp Classic HS" handles quite differently from the original Nordkapp HS.

I have paddled my 1987 Nordkapp HS for the past 4 seasons. The way to recognize this older model and to differentiate it from the new "Classic HS" look for:
- round rather than oval stern hatch,
- absence of a day hatch,
- no recessed cockpit coaming in the back,
- molded gelcoat rather than screw-in plastic recessed deck anchoring points,
- skeg control box behind the cockpit rather than in front of it, and
- hefty long square composite skeg,
- the older HS also had a hand chimp pump behind the cockpit.

From what I understand, the hull shape of my 1987 Nordkapp HS is the same as the original Nordkapp that was used for Cape Horn expedition.  It has a skeg which the original lacked. I have seen HS applied to the original Nordkapp multiple places so, if you are looking to get one on-line, make sure it has a skeg at all. Look here (http://www.ukseakayakguidebook.co.uk/nordkapp/art_nordkapp.htm) for an excellent coverage of the confusing Nordkapp family tree. Best I can tell, HS stands for 'Hatches + Skeg,' not 'Hull + Standard.'

I hope this will clear some of the confusion about the model. That being said, I had a chance to compare my HS to a 2000 American model with Jubilee on the deck and H2O on the manufacturer sticker. Way to go Valley--keep the nomenclature clear!  From what I understand, the original Jubilee had a round front hatch and '2O' in H2O stands for two oval hatches. The story goes that American distributors applied Jubilee stickers to boats that should have been designated as H2O. In other words, the comparison boat is most likely a purebred H2O or the most current version of the full-sized Nordkapp.

These two Nordkapps are very different boats. It is not easy to see the difference when they are on the ground or in the water. However, once hoisted on top of the car, the differences in hull are quite apparent. The newer boat has longer waterline, less overhang on both the bow and the stern, and considerably more volume toward the ends of the boat. The bow on the new boat does not rise up quite as much as on the old Nordy. Front deck in front of the cockpit is a bit higher and aft deck is lower on the H2O. H2O has less rocker—the difference is especially pronounced at the stern.

What is very hard if not impossible to see, is that the hull shape under the cockpit is also different—H2O is a bit wider and has a more pronounced (albeit still soft) chine, while HS is skinnier and rounder.

Not surprisingly, HS and H2O paddle and quite differently. Stability wise, HS is has substantially lower primary and virtually no secondary. Taking pictures in the HS in anything but flat water is touchy. HS is very easy to put on edge; however, there does not seem to be any point at which the boat starts to resist the capsizing momentum and locks in that edge—it will just keep on going and capsize if you let it.

I agree with previous posters who claim that HS has no surprises in rough water. Surprises come when you expect that the boat will keep you up and it fails. With HS you are always in charge of staying upright—the boat will not do that for you. Some may consider this as a negative; however, consider this—when broached sideways or when current hits from the beam, there is no chine to grab onto and trip you over. Stability profile of the HS is neither good nor bad—it’s just unique.  I would describe it as smooth and gradual tipping profile without any peaks or abrupt changes.  Some people will like it some will not; some conditions will reward it while others will punish.

At nearly 18' Nordkapp is considered a fast boat. Unfortunately, with all the overhang and extremely low volume at the ends the effective waterline of HS is noticeably is shorter than H2O. HS has more rocker which further reduces its cruising speed. Unfortunately, it gets worse for racing fans: in waves, paddling side-by-side HS tends to bury the bow when going down a wave much quicker and more frequently than H2O which translates into further loss of cruising speed. In calm conditions, I can cruise at 4 knots all day in my HS, maintain racing speed of 5 knots for a marathon distance, and push the boat to a maximum speed of about 7 knots for a couple of seconds.

I have not noticed much difference in tracking and turning performance of these two boats. Nordkapps in general are quite bad in beam winds and require skeg. I would not recommend the original Nordy without the skeg for paddling in any wind. Manufacturers quickly noticed the problem and produced HM with a skeg permanently molded into the stern. HM is a beast that requires a lot of edge and effort to be turned and sacrifices all the benefits of Nordkapp’s rocker for maneuverability. HM has a cult following of its own.  I much prefer the original hull design with an optional skeg. You would think that HS would be easier to turn and more vulnerable to windcocking than H2O and it may well be that way. The reason for this difference between HS and H2O being small is, perhaps, in the fact that H2O is more comfortable on the edge and, due to its higher volume around the cockpit, may lift the ends out of the water more effectively when on edge.

Ocean cockpit is a thing of the past, in my opinion. I am 6’, with a 32" waist, and under 180lbs.  I used to have to wiggle quite a bit to get in. I added the recess to the back of the cockpit and lowered it by about an inch (see photo blog: http://picasaweb.google.com/Karovaldas/NordkappHSUpgradesJulyAugust2009#). Still, if I wear any boots, I need to wiggle to enter. Keyhole cockpits are much easier to enter and exit and, with modern materials for spray decks, they are just as watertight and reliable as the smaller and much less practical ocean cockpits. Ocean cockpit is a potential hazard when you need to get out of the boat fast--during landings on dumping beaches, for example. Capsizing is the only option for a quick exit. Re-entry repertoire is limited to re-enter-and-roll in all but the calmest conditions when you have a better than 50% chance of a successful scramble with a paddle used as an outrigger (unless you have a paddle float to stabilize yourself during a scramble).

Efficient forward paddling is limited by the inability to bend the knees but in this regard HS is probably little different from the H2O. Some people worry about getting stuck in the small cockpit after capsize. Fear not! Staying in is a much bigger problem :) I've been sucked clean out of the boat by waves as small as 4' and installed substantial additional padding around the hips and thighs to have good contact with the boat.

The original HS cockpit is only 15" wide. For me this means that my edging ability is limited by the side of the cockpit hitting my ribcage on extreme edge. C2C and hand-rolling is similarly hampered by this lack of space around the hips. The back of the cockpit is also too high for layback rolls. Even after I lowered it by 1", I still need to lift my butt of the seat for laybacks but I can now finally perform a hand roll. To be fair, my seat is only about 1" off the bottom.  Adding some to the seat height would provide better clearance for the hips.  As it is, with narrowness limiting your ability to do C2C and high aft coaming interfering with laybacks, forward-finishing roll is your best option in this boat.  Ocean cockpit provides excellent contact for the knees and will help with the hip snap.

My HS did not have a day hatch or a bulkhead behind the seat. It’s very convenient to have one for items you may need to access while on the water. Beyond comfort there’s a safety issue—since there is no bulkhead immediately behind the seat, in case of capsize the boat will take on an additional 5 gallons of water or so! Not helping is the fact that there is at least a foot of empty space between my footpegs (33" inseam) and the front bulkhead — that's at least another good 3 gallons of water and wasted gear storage space.
In place of the third hatch, Valley has installed an optional hand pump. Mine worked just fine even 20 years after the boat was manufactured. Unfortunately, its placement behind the seat made it quite useless in rough water. Balancing while pumping with my right hand behind my back is quite precarious in this tippy boat. It may be possible in the ocean where one has time between the waves; however, short wave periods of the Great Lakes' storms don't make it easy.  The end of the hand pump came when the straps of my PFD got caught under the handle when I was trying a layback roll.  I was stuck to the back deck.  Off with the hand-pump.

Skeg control box on my HS is behind the cockpit. Same issue as with the hand pump—in rough water, where you are more likely to need the skeg in the first place, balancing the boat becomes very interesting; especially if the skeg gets stuck. I have capsized once while trying to adjust the skeg and promptly moved the controls from the back to the front of the cockpit. The old-fashioned skeg is very nice, works well and does not vibrate at high speeds the way the skinny modern plastic skegs do; however, there is a price—the skeg box in the rear hatch is enormous and takes up quite a bit of storage space. Getting to the space behind the skeg box is difficult.

So there you have it, my honest assessment of the Nordkapp HS. It was my first real sea kayak and it was an excellent teacher. Before I knew better, I was an ardent advocate for this craft. My skills went up faster than they would have in a more stable boat, I am sure of that. The old HS is a great tripping boat with sufficient bracing recovery and balancing skills. It has good hull speed and is very maneuverable for a boat of it's length.  It also gains substantial stability when fully loaded. You will need to pack everything in small dry bags to fit through the round 7.5" hatches but I don't really see that a drawback. HS is great training platform for rough water and behaves very predictably in it. It will teach you balance and self-reliance. It will amply reward skills and, when it does not, you will only have yourself to blame. It is considerably less stable than most other boats in this class including its younger Nordkapp brothers (Nordkapp LV may be an exception but I have not paddled that boat recently). HS is also slower and less convenient than the modern models. On the positive side, you can snatch one for under $1,000 on the used market which is hard to find for any other fiberglass kayak model. For that price, it’s a good deal as long as you realize what you are getting and are willing and able to put up with the requirements that this boat imposes. It's a good boat, worthy of it's legendary name; however, it's not the boat I would choose if finances were not an issue.

Will It Float?

Years ago, or maybe just last Friday, there was a segment 'Will It Float?' on David Letterman show. They would toss all kinds of things into a tank of water and guess whether the objects would float. Some said it was not very funny, silly and pointless. Others opined it was fascinating, educational and taught scientific principles of answering questions through empirical research through an accessible comedy medium.

Kayaks, especially the sea kayaks, float--we know that, right? It's the ultimate sea-going vessel that, in capable hands, can challenge seas that threaten big strong supertankers. Just to confirm this, I've flooded the cockpits of multiple kayaks and once I even filled the entire bow chamber separated from the cockpit by a bulkhead. The horizontal machine that is a kayak turned into a vertical bobber fit to catch whales, yet, the kayak stayed afloat. I've filled my bulkheadless folding kayak with water and it floats thanks to structural sponsons.

But is a fiberglass kayak really just an 'unsinkable' Titanic in disguise? I already knew that it is no nimble sea creature with a cockpit even half-full of water but will it stay above if all compartments are filled? In other words, will it float?

Here's the answer.

No tricks, no weights just water in all four chambers. If this happens to you in deep water, the kayak will go to the bottom and you will remain without a ride home.

That being said, it took quite a bit of pushing, spinning, shaking and wiggling to force the air completely out of the kayak. This particular model--Valley Avocet--has upturned nose and tail which, as it turns out, trap just enough air to keep the boat on the surface. I wonder if that's an intentional design feature. I needed to push the bow and then the stern down deep under the water in sequence to get those last air bubbles out. Only then the kayak sank. So that may take care of an accidental loss of hatch covers.

Another likely scenario is hull breach. If a kayak is floating upside-down with air leaking through the bottom of the hull in all chambers, in theory, it will eventually sink. A typical kayaker would have something in dry bags in the hatches. Given how little fiber and resin differ in weight from water it seems to me that even a single dry bag would keep the kayak on the surface even if completely submerged.

None of these assurances should comfort a paddler, however. Yes, sinking the kayak is very unlikely but a water logged beast completely submerged under the waves is entirely useless as means of travelling or surviving on the water. I was just looking for something to do at a pool session other than work on the hand rolls.

So there goes our own little round of "Will It Float?"

Surfed b the Waves in Beverly Shores, IN

http://caskaorg.typepad.com/caska/2010/10/surfed-by-the-waves-in-beverly-shores-in.html

"Door Slamer 2010" Summer is Over

http://caskaorg.typepad.com/caska/2010/10/door-slammer-2010-summer-is-overbring-out-the-drysuits.html

Lake Michigan Crossing, 2010

On September 11-12 I crossed Lake Michigan with three other CASKA paddlers.  Here's our write-up on CASKA blog:

http://caskaorg.typepad.com/caska/2010/09/four-paddlers-cross-lake-michigan-by-sea-kayak-2010-trip-report-1.html

Meteorology Conundrum

http://caskaorg.typepad.com/caska/2010/09/meteorology-conundrum.html

Gales of September

http://caskaorg.typepad.com/caska/2010/09/gales-of-septnovember.html

Breezing through the Calumet Region

http://caskaorg.typepad.com/caska/2010/07/breezing-through-the-calumet-region.html

Tranquil Churchill Woods

http://caskaorg.typepad.com/caska/2010/06/tranquil-churchill-woods.html

“RULES OF THE ROAD” and Signaling Devices for Sea Kayakers

Outline for a clinic at WMCKA 2010 symposium

www.navcen.uscg.gov.mwv.navrules.rotr_online.htm

1. YOU are the Captain of your Ship—CONGRATULATIONS! "With great power comes great responsibility!"
   
2. Where do Navigation Rules Apply? International --> Inland --> State --> Municipal
   
3. What is a kayak under Navigation Rules? Where does it fit among others?
   
   1. Certainly a Vessel (any means of transportation), not excluded from being subject to the Rules
      
   2. Power Driven > Sailing > Fishing > Restricted in the Ability to Maneuver > Not Under Command
      
   3. Limited Maneuverability (speed) status is not explicitly granted to kayaks in the Rules; other vessels are required under law to consider kayak's limited speed when assessing risk of collision, but SO ARE YOU!
      
   4. Suggestion: Operate as if you are a Power Driven Vessel (any vessel propelled by machinery—paddle)
      
   5. Kayak is a Sailing Vessel when under sail
      
   6. Always remember that you are difficult to see and other vessels are not on the look-out for small craft when under way
      
4. Rules Abridged: Rights and Obligations = Good Seamanship
   1. Maintain proper look-out with eyes and ears and by any other available means
      
   2. Maintain safe distance and speed at all times
      
   3. Avoid collision with others. Other vessels need to avoid collision with you WHEN and IF they see you (limited visibility) and when and if they can (limited turning and stopping ability of big ships + shallow water)
      1. Take timely action
         
      2. Use decisive maneuvers—avoid small changes to speed and/or course
         
5. Right of the way (ROW) = the only time a kayak has the right of the way is when it is being passed by another vessel. Maintain course and speed—the other vessel has no right to cut you off. You should avoid collision if in danger when being passed and have the right to ignore the rule to maintain speed/course. Vessels limited by channels have the right of the way in areas of limited operational space
   
6. Interactions with Other Vessels—"stand-on"=vessel that will maintain course vs. "give-way"=vessel that should not cross in front of the other vessel by stopping, slowing, and/or turning:
   1. Open water=unlimited navigability:
      1. Overtaking: vessel being passed has ROW, overtaking vessel can pass on either side—keep course and speed unless in danger
         
      2. Head-on: neither of two power vessels has ROW, both turn to starboard/right to avoid collision. Sailing vessel has the ROW over power-driven, power-driven needs to turn to starboard/right
         
      3. Crossing: vessel on starboard/right has ROW if two power vessels; sailing has ROW over power
         
   2. Narrow channels=sides defined by sea walls or banks:
      1. Stay as far to starboard/right as safely possible—can use middle of channel if sides are not safe (rebounding waves)
         
      2. Do not impede vessels that can only navigate in the channel (sailboats only have ROW if limited by keel)
         
      3. Avoid crossing and cross fast, at right angles, and as a single group if many kayaks
         
   3. Fairways=shipping lanes and open water channels: treat as narrow channels with an additional challenge of knowing where they are (need current charts), cross fast in a group and with plenty of safety cushion. Safe distance in front of ship—need to get out of the way even if paddle gets broken, capsize, dislocate shoulder, etc.
      
7. Darkness: powerful white light exhibited in sufficient time to prevent collision course; single constant white light will signify a sailing vessel or a stationary small boat to others
   
8. Limited visibility: generate a sound warning every two minutes with at least 0.5 mile audible range
   
   
9. Signaling devices—devices to attract attention:
   1. Hand and paddle signals
      
   2. Sound signals: Whistle, Air Horn, or Fog Horn for warning and communication
      
      1. One short blast = right/starboard (two long one short if passing on starboard)
         
      2. Two blasts = left/port (two long two short if passing on port)
         
      3. Three short blasts = backing/stern
         
      4. One long blast = warning/announcing location
         
      5. Five short blasts = imminent danger
         
      6. One long + one short blast = passing on starboard/right
         
      7. One long + two short blasts = passing on port/left
         
   3. Navigational Lights: required to display in order to alert other vessels
      
   4. Strobes: recognized call for help on inland waters; widely used in international waters but not technically legal there
      
   5. Flares—3 required at night
      
      1. Aerial
         
      2. Hand-held
         
      3. Light, smoke, dye
         
   6. Brightly-Colored Rescue Bag—when inflated can be used to increase visibility and aid in search and rescue
      
   7. VHF Radio—"Mayday", "Pan-Pan", "Securité"; distress, help, warning. Also to communicate to other vessels and Coast Guard
      
      1. Channel 9 = recreational boat hailing
         
      2. Channel 13/14 (listening only) = bridge-to-bridge, port operations, visibility reports
         
      3. Channel 16 = emergency hailing
         
      4. Channel 22a = Coast Guard
         
      5. Channels 68/69/71/72/78 = recreational boat-to-boat
         
   8. Family Two-Way Radio (FSR)
      
   9. Emergency Position Indicating Radio Beacon (EPIRB)/Personal Location Beacon (PLB) —to initiate rescue—Satellite Personal Tracker (SPOT)—alert Coast Guard or communicate with shore
      
   10. Cell Phone (dial *CG to reach Coast Guard within range of antennas)/Satellite Phone
       

Comments emphatically solicited.

SAFETY EQUIPMENT for Sea Kayakers

Outline of a clinic at WMCKA 2010 kayak symposium:

1. What is Safety?:
   1. "Getting out is optional, coming back mandatory!"
      
   2. #1 killer of sea kayakers = exposure to elements: cold, lightning, heat
      
   3. Avoid collision with other vessels, people, and property
      
2. Before paddling:
   1. Body:
      1. General conditioning and flexibility
         
      2. Safe application of paddling skills
         
      3. Know your personal limits—endurance, power, medical conditions
         
      4. Stretching for warm-up and cool-down
         
   2. Head/Knowledge:
      1. Skills—technique, group dynamics, navigation, rules of the road, signaling, and rescue
         
      2. Risk assessment/Prevention—people, equipment, environment
         
      3. Practice what you know—intentions mediate between knowledge and action
         
      4. Leave a Float Plan behind (http://www.seakayakermag.com/PDFs/Float_Plan_cs3_0909.pdf)
         
   3. Equipment:
      1. Serviceable functional condition
         
      2. Match for environmental challenges at hand
         
      3. Know what to bring or leave behind—use a checklist (http://www.seakayakermag.com/PDFs/Gear_List_cs3_0909.pdf)
         
3. On the Water:
   1. Flotation:
      1. Boat—bulkheads/hatches (spare) or float bags, sprayskirt, sea sock, sea wings, pod cockpits, bailing device (pump)
         
      2. Self—PFD, paddle float, quick-self-inflate deck bag
         
   2. Propulsion: Paddle with spare and paddle leash, sail, diver's fins
      
   3. Fuel (for body): food, snacks, water, warm drink or soup
      
   4. Clothing:
      1. Temperature—dress relative to potential and consequences of immersion (wet/drysuit, layers, head/neck protection, cotton bad in cold climates but great when it's hot, gloves/pogies), storm cag
         
      2. Protection—PDF (body), helmet (head) , footwear (feet), gloves (hands), sun protection (skin)
         
   5. Communication: learn paddle/hand signals, VHF radio, whistle/fog horn, other signaling devices (mirror, handheld and aerial lights/flares, smoke, dye)
      
   6. Navigation: compass, timer, GPS, pre-marked charts, navigational lights, notebook, kamal
      
   7. Rescue: tow rope, perimeter lines, VHF radio, signaling devices (light, smoke), paddle float, sea anchor/drogue, first aid, repair kit, bail-out survival bag, bright clothing, reflective tape
      
4. After the Paddle:
   1. Shelter/Fire
      
   2. Food/Water
      
   3. Means of summoning help or getting out on your own
      
   4. First aid kit/Boat repair kit
      
   5. Stretch and warm down to prevent injury
      
5. Discussion: "What is the MOST important article of safety equipment?"
   

Comments required!

My Review of REI Hoodoo 3 Tent - '09 Special Buy

Originally submitted at REI

The Hoodoo 3 is a full-featured, lightweight tent that optimizes convenience for 3 persons with ample headroom, 2 doors and generous storage.

REI Hoodoo 3 Tent - '09 Special Buy

Versatile Big Tent

By Haris from Chicago, IL on 5/19/2010

 

4out of 5

Gift: No

Pros: Fly Works Well, Easy To Set Up, Windproof, Waterproof, Comfortable

Best Uses: Backyard, Beach, Car Camping

Describe Yourself: Avid Adventurer

What Is Your Gear Style: Minimalist

I've owned this tent for two seasons. We bought it as a replacement for Alps Mountaineering Orion 3 tent because it shaves off over 4lbs of weight from that, otherwise excellent, tent. An additional benefit is much easier set up. Not having to thread the poles through holes in the fly helps a lot. HooDoo set up is somewhat different from the other tents I used and requires some learning which may intimidate some of the less technically inclined. Once you understand how things go together (and they are color coded) it's quick and painless.

The poles don't fit together very well one folded. There are a couple small sections with breaks on each side I have to guess and try which side to open every time I fold them. Somewhat annoying. I guess I could just mark the right ones once and for all but that would be work :)

Love the horizontal walls--makes the interior feel so much bigger!

HooDoo 3 is a bit smaller than the Orion 3 and has just enough room for 3 20"-wide sleeping pads. With three people, there's very little room left for gear. I miss the overhead mesh storage compartment of Orion 3 but HooDoo has smallish pockets in each corner of the tent.

Vestibules were larger than other tents when I compared them on-line; however, my Orion 3 has substantially more vestibule space.

We used this tent as a shelter on the beach and during our son's outdoor swim meets--set up the ground cloth with the rain fly without the tent. Works very well and is easy to set up.

Although it could be used as such, I would not classify this as a backpacking tent. There are many of the same size that are much lighter but, of course, they normally cost more. I've used this tent for car and kayak camping with great success.

(legalese)

Into the new decade

Last weekend I gathered a bunch of friends from various walks of my life to inaugurate the fifth decade for me.

Before the party I was really eager to show of the standing waves on the mighty DuPage river. It rained the night before so, with the vast basin on this river, I was hopeful. The gauge was not showing much rise. And there wasn't much to show for the rain, as it turned out...

On the positive end, when the water is not high enough to generate the waves, a kayak in capable hands can make it up the stream throught he drop/constriction. And we had six capable hands...

Thanks to Eimly and Pierre for helping me smoothly transition into the new decade. I hope that it will be full of paddling.

Paddle on and paddle hard!

Empirical Feel for the Paddle Length

My first paddle was made by Canon. It had a fiberglass shaft and nylon blades. It's 230cm long. I got it to propel myself in a barge of a kayak: the folding Folbot Greenland II double. That's a beast with 34" of beam and 17" cockpit height. Folbot recommended 260cm for that boat but 230cm worked for me as long as I but a few inches of padding on my seat and was able to clear the coaming.

Since then I slimmed down. First came a single Folbot Cooper with a 24" beam. After that an old Valley Nordkapp HS—my slimmest boat at 20.5". With slimming boats and increasing appetite and skills, my paddles shrunk too. First I got an all-fiberglass 215cm Lendal, then another Lendal shaft to go with the fiberglass blades—a carbon bent-shaft 210cm. For the past 6 months I've been paddling a loaner 210cm all-carbon Werner Ikelos.

All along the way, "shorter is better and more efficient" has been the word.

This past weekend, I went for a paddle on a shallow rocky West Branch of the DuPage river. For the first time in years I've brought out my 230cm fiberglass-plastic Canon weapon. Just wanted to see how it feels and what difference 20cm in length really makes. Did not really want to bang up the primary guns against the bottom either.

First impression—the paddle felt very comfortable and efficient for casual stroking. The weight was not noticeably different from my fiberglass Lendal and the paddling was not any harder due to extra length. Very quickly I noted that the shaft was not as stiff as Lendal or Werner. It felt more like a Greenland stick as it obviously flexed with every stroke. I kinda liked that… I also liked the longer reach at the beginning of the stroke. It seemed like I could put more into each stroke and apply more power if I wanted to. So I decided to want to…

That's where things started to break apart. First, it was hard to maintain a high angle stroke as the blade went too deep under water and was harder to take out of the water. There was also no way I could generate high-frequency cadence with the longer shaft. Even though the blades on this Canon Heritage paddle had much lower surface area than my Lendal Kinetic or Werner Ikelos, the longer shaft increased the arm of the lever to the point where even these smaller blades quickly exceeded my available power. So while a fresh 4.5-knot touring pace with a stroke somewhere between a high and a low-angle felt very relaxed comfortable and efficient, sprinting with this paddle was awkward. Shorter paddle definitely has an advantage here regardless of the blade size.

Then I tried maneuvering strokes. I loved the extra extension on the stern ruddering strokes. Put the paddle parallel to the boat and work the throttle to see-saw from a pry to a draw. The boat responded wonderfully. Longer blade gives greater leverage and since the loads during ruddering are relatively low on intensity, extra length is an advantage. Something makes me think that the speed and power involved in surfing would most likely overwhelm the hands wielding a longer weapon.

Extra length does not work so well on bow rudders either. I immediately got lost with upper hand somewhere in the sky, lower blade deep under water and the amount of strain on the body noticeably greater than with a shorter paddle. Positioning the blade was also more lethargic, fine control more elusive. This could be, in part, due to the fact that I have not used this paddle for a long time but the difference was so stark that I tend to dismiss this argument of disuse.

Sweep strokes with a longer paddle—you guessed it—are more efficient. Here the more power and leverage you have the better. Since the blade is farther away from the boat, both the turning and the supporting momentums benefit.

In summary, longer paddles have come in disrepute lately. After a few hours of paddling a low-tech cheap long paddle, I could see no prohibitive disadvantages to using it for casual paddling. Some maneuvering strokes and bracing may be a bit slower with the longer paddle; however, this lag is more than compensated by the additional leverage that a blade gains when it is used farther away from the hull. As long as the blade is not too big, a longer paddle seems perfectly appropriate for a non-technical paddler. Lower paddling angle is also known as less demanding on the upper body strength and seems more appropriate for people who are less physically fit.

Except for the stern rudder and sweep strokes, a longer paddle will most likely interfere with technical paddling strokes and intermediate-to-advanced maneuvers. Acceleration is sluggish, bow rudder is awkward, braces are slower, draw strokes seemed less efficient due to sinking blade. It also seems like a longer paddle would be more of a hindrance than help when rolling in rough water. Extra leverage will be nullified by the difficultly of maneuvering the blades into proper position.

At the end of the day, I expect that longer paddles will be back in vogue in the next decade or so.

Standing Waves on the Mighty West Branch DuPage River

With the water about a foot above average, there are some surfable standing waves on the normally placid West Branch of DuPage river just north of Butterfield Rd. in Warenville.

About four of them are progressively longer from the first one with all of 2' to the last one that's probably good 6-8' long. They are not steep, hard to get on to, reside in swift current artificially produced by strategically placed boulders that constrict the flow. The water is about a foot deep on either side.

It is a pretty good place to practice surfing as the set-up is completely unforgiving.  I clocked the average drift speed at 5.5 knots with the GPS.

PS Here's a picture of the spot from the other side at an average flow.

When it is that low, I can paddle through the constriction.  GPS speed with average water levels was just a hair over 3 knots.

THE TALE OF TWO BOW RUDDERS?

I am in love with the bow rudder but I don't know her name! There, I said it. To me it's the sexiest most efficient and effortless move in a kayak. More than that, the way the boat spins under you when motions align just right feels almost magical. The turning momentum seems to perpetuate itself. It's like the boat starts to give back what put into it.

For a decent free skill description and illustrations of the stroke with moving images see this Atlantic Kayak Tours web page. Search also for "Bow Rudder" among these videos by Doug Cooper if you'd like to see a short movie of the skill in action. If you don't have them already Doug Cooper and Gordon Brown's books are great resources for updating your kayaking skills. They both also contain good consistent descriptions of the Bow Rudder. Gordon has a DVD companion to the book out as well.

Gordon Demonstrates cross-bow rudder

Then, there's another detailed and well-illustrated description of the skill by the same name by Derrick Mayoleth. You may not even notice much difference between the two versions but, in my opinion, what separates them is so critical that two different names should be used to label them. Derrick's is the way the bow rudder looked when I met her but she is definitely not the one I fell in love with. Yet, it is the skill as illustrated by Derrick that seems to fit the name. That stroke actually attempts to pull the bow in the direction of the blade. Applying the same name to the turning maneuver presented by Atlantic Tours, Brown and Cooper (ABC) seems to me like a long stretch. More than surface semantics, both of the words in the name obscure the little ABC gem from the sights or well-meaning students of the sport. What's your name, darling?

Derrik demonstrating lean-forward bow rudder

ABC version of the 'so-called' bow rudder is neither done at the bow nor is it really a ruddering stroke. ABC way, the active blade is planted perpendicular to the surface of the water at the paddler's knees, next to the gunwale. The placement is much closer to the kayak's longitudinal center of gravity than its bow. Furthermore, there is really no reason to move it in that direction in principle. If anything, I am curious it if wouldn't work even better applied a foot aft. The live blade placement is distinctly different in the forward-reaching skill as illustrated in Derrick's post. Here the paddler needs to lean distinctly forward and advance the rudder toward the bow. The body rotation in the two versions is in the opposite directions. For ABC you "face the work" on inside of the turn with maximum torso rotation. In the alternative, you are rotated with the opposite shoulder facing the bow as the outboard hand extends as far forward as possible.

The term 'rudder' in the name implies that the paddler should be trying to concentrate the action on the end of the boat. After all, 'rudder' is a steering contraption always found at the (rear) end of the boat. Substituting 'bow' for 'stern' does nothing to the implicit suggestion that the stroke should be performed as far away from the center of the boat as possible. The first term in the name—'bow'—does the same thing: it tells you to reach for the bow with the paddle.

Atlantic Kayak Tours version of bow rudder

The role of the active blade in the ABC incarnation is not intended to move or anchor the bow. Here the paddle in the water serves the role of a pivot point around which the kayak swings–bow moving in one direction stern in the opposite. In that sense, although it is clearly meant for turning the boat, the move feels more like a draw-on-the-move or a side-slip than a rudder. Cooper gives an apt analogy when he writes that bow rudder should feel like a runner grabbing on to a stationary post with one hand and spinning around. The forward-reaching version of the bow rudder emphasizes anchoring the bow, releasing the stern so that it could slide around. Leaning forward, weighing the bow, taking the weight from the stern, and sticking the blade near the bow to anchor it are mobilized to that end. The ABC version treats bow and stern on equal terms. Instead, it capitalizes on finding the most efficient pivot point on which to spin the kayak around its longitudinal center axis not unlike a table-top. The paddler remains fully upright throughout the turn.  Finally, the lower elbow is fully extended in the former and tucked into the pelvis in the latter--seems a bit safer to me.

I am yet to confirm this in the field, but I would guess that the ABC way would not work quite as well as the lean-forward version for turning into the wind. In practice, I only know that I can easily turn 180° or more on calm days but was barely able to do 90° with strong beam wind using ABC. The latter is much more efficient at producing quick radical changes of direction in tight quarters will less body contortion … not to mention it looks much more elegant and also makes your legs shake with excitement J

So what do you think—are these two different versions of the same skill or two different skills? Are we doing those who are learning the skills any favors by misdirecting their attention from the knee toward the bow and toward ruddering instead of pivoting and spinning? How about something like "gunwale swing" or "beam spin" instead? The way the kayak dances alongside the planted blade could almost pass as a dos-á-dos dance move. Whatever you call it, give them both a try and see if it changes your relationship as much as it did for me. Whatever you decide, I'll always go to my spinning version to get a smile on my face and a tingle in the belly.

While we're at it, how about a cross-bow bow rudder that is initiated by bringing your paddle across the deck rather than the bow, has the blade planted at the cockpit rather than the bow, and uses the paddle as a pivot point rather than a rudder? Any takers?

Is Visibility Statute or Nautical? Decide for Yourself

In a kayak, it's often good to know the distance to some destination or object. The human visual system is pretty bad at this task. I can easily recall many instances of paddling for hours without any apparent gain on large distant targets. It always feels that progress should be faster…

Kayak navigation books such as Burch or Ferrero provide some help. They give a simple formula for calculating distances at which objects with given elevations above the sea level will be seen. The range of visibility in miles is equal to the square root of elevation as measured in feet. For example, a light house 100 feet above the sea level will be visible from 10 miles away. The formula is for an observer at the sea level.

In a kayak, you are not at sea level. For an observer in a kayak cockpit, you can add 1.5 miles to the visibility range of an object as derived from the formula. One-and-a-half miles is the square root of the eye-level elevation above the surface of the water. On average, paddler's eyes are just over two feet above the surface. Here are some immediate applications—if you can see beach goers feet as they walk close to the water, you're roughly within 2 miles off-shore. That's 1.5 plus a little bit added for the elevation of the beach. Two kayaks will lose sight of each other when they are separated by three miles—one-and-a-half miles of visibility from each side.

This is where I got tripped up. The formula for the visibility range is supposed to give you statute, not nautical miles. Burch, then, suggests that the visibility range as determined this way is underestimated by about 15%. What this means is that 10-mile estimate for an object with 100' of elevation should actually be 11.5 miles instead. Funny, that just happens to be the distance in nautical miles. So what is going on here? Exactly how much off is the square root approximation?

Time to dust off high school trigonometry books. First, let's track down the mathematical solution to the problem. Then, we will have grounds to decide if the limits of visibility are statute or nautical and how precise they are.

Generalized shape of the Earth is basically a sphere. For our purposes, the sphere can be further reduced to a circle. An average radius from the center to the surface is approximately 3,440 nautical or 3,959 statute miles.

Any line that just touches the outside of the circle can be used to mark the range of visibility—objects whose height is above the line will be visible, the ones below will be obscured by the horizon. Another line can be drawn from the point where the visibility line touches the outside of the circle to the center of the Earth. This line will have two known properties: (1) its length will be Earth's radius and (2) its angle to the visibility line will be 90 degrees. The Earth's radius and the visibility line can be viewed as two sides of a right triangle. The hypotenuse of this triangle is equal to the Earth's radius plus the elevation of the object above the sea level. What we have here is a simple case of Pythagorean Theorem with two known sides of the right triangle. We can solve for the unknown third side. In our context, a² = c² - b²
can be written as Visibility² = (Radius + Elevation)² – Radius².


Plugging in the numbers and plotting the results of this equation we get the following picture. If the result of the square root solution is read in nautical miles, then it underestimates the actual distance by 6%. In statute miles, the distance is underestimated by just over 18%.

There it is clear as day: mathematically, the square root of elevation (measured in feet) is much closer to geographical visibility expressed in nautical rather than statute miles.

So why, then, is the formula is presented as offering the solution in statute miles? I don't know the answer to this one…

Here are some thoughts. Mathematical solution gives the distance at which the top of the object will reach the line of visibility. So the question is if you be able to see the top as soon as it reaches the line? To me, it depends. If the object is a mountaintop, the answer is most likely "No!" The tip of the mountain will have to get above the line at least somewhat to be seen. A mountain that is 400 feet above the sea level will reach the line of visibility when the distance is 21.3 nautical miles or 24.5 statute miles. Square root formula tells you that, when you first see the tip of the mountain, you are 20 miles away. By the numbers, when you are actually 20 nautical miles away, the mountain is already 47 feet above the line of visibility. When you are 20 statute miles away, the mountain will extend by 133'. When will you actually see the mountaintop? I don't know but, personally, I would rather be closer than I think I am. To me, nautical mile interpretation is a more conservative one and seems to be more appropriate.

If you are paddling at night and it is a light that you're looking for, you will see the glow well before it reaches the theoretical line. The moment the actual light emerges from beneath the horizon will be determined more precisely than in the previous scenario. Again, if the height of the light is known, it's square root is more appropriately interpreted as the distance in nautical, not statute, miles.

What do you think?

New Blog

This new blog will contain stories about paddling in Mid-West with the base in Chicago-Area and other paddling-related stuff.  I am currently working on a write-up of a week-long circumnavigation of Isle Royale completed in August, 2009.

Rules for Tides: Thirds, 50/90, Twelfths

Confused yet? I was! So I decided to work it out for myself once and for all. In the process, I found a way to inject some method into this madness. I have not seen the rules differentiated this way anywhere in the literature so I hope this will help clear things up for folks.

If you know the definitions for these rules, you can readily skip the next section and find the disambiguation in the Q and A part. The Math section will go into the mathematical details of how I figured this for myself. If you are a math type, you may find several hours of amusement therein. If you're not, it is likely to confuse you right back to where you started or worse.

DEFINITIONS

Here's a typical example of two rules mixed up into one: "The Rule of Thirds states that relative to the total maximum current speed, the current jumps 50% the first hour, 90% the second hour, 100% the third hour.  The current then decelerates to slack in the same order."  You can find this on page 90 of Sea Kayaking: Rough Waters (2007, Heliconia) by Alex Matthews.

Let's ask Gordon Brown—a recent kayak reference volume from a highly reputed BCU coach. On page 168 if his Sea Kayak (2006, Pesda) book he gives this for the Rule of Thirds: "… over the period of the first hour the current will flow at one third of its maximum rate …, for the second hour it will flow at two-thirds and the third hour at … three-thirds."  Hence the ubiquitous 1:2:3:3:2:1 abbreviation of the rule which stands for 1/3 of the max current rate in the first hour, 2/3 in the second hour, 3/3 during hours three and four, and then down to 2/3 in the fifth hour and 1/3 during the last hour of the cycle.

The 50/90 Rule gives you "… the speed of the current at the end of each hour." Starting from slack, the current will flow at 50% of its maximum speed at the end of the first hour, 90% at the end of the second hour and full 100% or maximum speed at the end of the third hour.  It will then slow down in the same steps: 90% at the end of the fourth hour, 50% fifth and back to slack at the end of the 6-hour period.  The full Rule of 50/90 should be stated as 0/50/90/100/90/50/0.

I could not find a reference to the Rule of Twelfths in Brown's volume so let's go to page 178 of David Burch's Fundamentals of Kayak Navigation (1999, Globe Pequot): "The rule of twelfths [is a] method of determining the tide height between high and low waters." In the six-hour period that separates the low and the high waters, the overall level will rise/fall 1/12^th of the full tidal range in the first hour, 2/12^ths in the second hour, 3/12^ths in the third hour. We know from the 50/90 Rule that after three hours the current reaches is maximum speed and starts to slow down. For the rest of the flood/ebb cycle the rise/fall of the water will be 3/12^ths in the fourth hour, 2/12^ths in the fifth and 1/12^th in the last sixth hour.  Here's a crown jewel or you: the Rule of Twelfths is also frequently presented as 1:2:3:3:2:1—same as Rule of Thirds! Fonfusing? Well, yes, you should be!!!

Burch also has definition of 50/90 Rule on page 226 as a "rule to estimate the effect of changing tidal current on net progress." Upon a quick scan, he does not seem to have the Rule of Thirds in his authoritative reference guide but there is a table in his text which gives "the constant current speed that is equivalent to the changing current of the cycle."

All of these definitions help me separate the Rule of Twelfths from the other two. Rule of Twelfths is about the height of the water while 50/90 and Thirds are both about the current. Horizontal and vertical dimensions.  Burch helps some by introducing the term 'net progress' but I think he has it associated with the wrong rule!

Q and A

Q: Are rules of Twelfths, Thirds, and 50/90 all dealing with the same thing? And, if so, can they be used interchangeably?
A: No! and No!

Q: I've heard that the Rule of Twelfths is different from the rules of Thirds and 50/90?
A: Yes! The Rule of Twelfths is about the rise and fall of the water levels at various stages of the tide while the latter two deal with current. Think VERTICAL versus HORIZONTAL dimension.

Q: That helps. So the rules of Thirds and 50/90 are basically interchangeable then, right?
A: No they are very different, although I've frequently seen write-ups using the two without distinction.

Q: But you said they were both about the current. What is the difference between them, then?
A: Think of it this way: Rule of 50/90 is used to estimate current speed at the end of each hour of the six-hour tidal period. The Rule of Thirds, on the other hand, is used to calculate distances that the current travels in full one-hour increments or drift. The first one describes the speed of the current at a single point in time, while the latter helps estimate what happens to an object affected by the current over a period of one hour.

Q: Wait, wait ... I don't get it. Is there a graph for this or something?
A: Great idea! Let's try a graph.

• Rule of 50/90: instantaneous speed of the current observed at each of the six hours in the tidal period ON THE HOUR.
  
• Rule of Thirds: cumulative distance the current travels DURING THE ENTIRE LENGTH OF EACH OF THE HOURS in the six-hour tidal period.
  
• Rule of Twelfths: cumulative change in the height of the water DURING THE ENTIRE LENGTH OF EACH OF THE HOURS in the tidal period.

Q: I think I get it but can you give an example?
A: We need to have some input information before the illustration can work. Let's say that High Water (HW) is at noon and Low Water (LW) is at 6pm. Reference materials specify that between noon and 6pm the water level will drop from 12' to 0' above the chart datum and the maximum ebb current speed will be 6 knots.

     The Rule of Twelfths will tell you that from noon to 1pm—the first hour of ebb tide—the water level will drop 1/12^th of the total change in water levels between HW and LW. Since 1/12^th of 12' is 1 foot, the water will drop from 12' to 11' between noon and 1pm. Between 1pm and 2pm the water will drop an additional 2/12^ths—that's 2 feet. At 2pm the water height will be two feet less than 11' or 9'. By 3pm the water will drop another 3/12^ths and will stand at 6'. Then another 3/12^ths by 4pm = 3'. Another 2/12^ths by 5pm = 1'. The final 1/12^th will drop the water level to 0' at 6pm.

     The 50/90 Rule helps estimate current speed at the top of the hour. At noon the speed is 0% of maximum—that's slack. At 1pm the current will pick up to 50% of its maximum flow or 3 knots (6*50%=3). At 2pm the current will flow at 90% of its maximum level or 5.4knots (6*90%=5.4). At 3pm 100% = 6 knots and then back to 5.4 knots at 4 pm, 3 knots at 5pm and another slack at 6pm.

     Finally, we can use the Rule of Thirds to estimate how far the current will travel during each of the hours of the tidal period. Between noon and 1pm the current will travel 1/3^rd of the maximum current speed or 2 miles (nautical). During the second hour of the ebb—between 1pm and 2pm—the current will travel 2/3^rds or 4 miles. Between 2pm and 3pm the current will drift the most or 3/3^rds = 6 miles. Then back in descending order—by 4pm another 6 miles of drift, by 5pm another 4 miles and, finally, by 6pm the drift will add another two miles.  Don't read the following mathematical sentence in italics if you understand the differences between the rules—it may confuse you. For those who are not afraid of math, drift or distance traveled by the current is the same as AVERAGE current speed during the hour.

Q: That's great but my current speeds are in kilometers per hour.  Can I still use the Rule of Thirds or 50/90?
A: Absolutely!  Only the units of measurement change in the Rule of Thirds.  Instead of nautical miles you will get kilometers.  If the speed of the current is given in MPH, then you get distances in statute rather than nautical miles.

Q: Wait, I just lost it again, I use the Rule of Thirds to estimate what and 50/90 what?
A: 50/90 Rule is for estimating the current speed on top of each hour in the 6-hours tide cycle. Rule of Thirds is for estimating the distance that the current will carry an object during each of the 6 hours in the cycle. If you want to know when the current will get too fast for you paddle against, use 50/90 Rule. If you want to know how far you will drift with the current use the Rule of Thirds.

Q: How precise are these estimates?
A: Glad you asked! These are all rules of thumb. As all rules of thumb, these ones describe idealized situations. Time between HW and LW will not be exactly 6 hours. For diurnal tides it will be around 12!  Divide the time between HW and LW into six equal intervals and you can still use the rules.  Tidal flow is influenced greatly by shoreline dynamics and other factors on Earth as well as in the skies. Importantly, peak current speed normally lags somewhat behind the the midways between HW and LW due to friction.  It is not uncommon to find that slack is mismatched with HW by hours.  Use these rules as guidelines.

Q: Why doesn't Burch reference the Rule of Thirds and why does he have that complicated table to calculate drift? He is the ultimate authority in the field of kayak navigation after all. That makes me uncomfortable with the Thirds Rule.
A: Well, it probably should. Burch probably thought that the rule of thirds is too far off the actual estimates for the drift that are obtained mathematically (see the last section for details). It estimates almost 10% too much for the first hour and is off by between 3% and 5% during the remaining two thirds. Quite a gross approximation if you ask me but would you rather use 26/70/96 rule?

DA MATH

For the present calculations of floods I used the following sine function to get the flow throughout the tidal cycle:

Flow = MaxFlow * sin(2*π*Period^-1*Time)

where Flow is the proportion of maximum current speed or actual current speed, Period is the length of the entire tidal period or 12 hours for tides and Time is the clock variable. MaxFlow constant can be used to set the output to the actual speed of the current.  When MaxFlow=1 we get proportion of maximum flow or the speed of the current when maximum flow is one knot.  A constant can also be added to Time variable.  This constant will allow one to manipulate the Y intercept.

  

Here are the results that this function yields:



Note how the numbers of 50% and 86.6% fit the 50/90 Rule pretty close.

The numbers don't work nearly as well for the Rule of Thirds. Mathematically the drift/average current speeds are 25.6%, 69.9% and 95.5% rather than 33.3%, 66.7% and 100% predicted by the rule.  For 6 knot max current, the Rule of Thirds will predict 1*6/3 + 2*6/3 + 3*6/3 = 2 + 4 + 6 = 12 nautical miles of drift.  The actual average current speed over the three-hour period is 0.713 so over the the entire 3-hour period the drift would come out to be 3hr*6knots*71.3% = 12.8 nautical miles.  Numbers are reasonably close when added up but deviate from the ideal scenario when taken hour by hour.

The average speeds for each of the one-hour intervals can be obtained by integrating the area under the harmonic curve for each hour. In this exercise they were calculated using simulated data instead. A theoretical dataset was generated using the above harmonic function with 1,000 data points for each hour. That's roughly one data point for every 3 seconds.  A simple average of all speeds was used.

Let me know if this helps clear things up or if it is useless.  Suggestions for improvement?  E-mail karovaldas@gmail.com.  I am especially curious about the graphical representation of three rules.