billvoss

Unless the pond closes (https://twitter.com/waldenpondstate) I expect to be there again this week. I hope you and your wife can make it.

Rob, Thursday is for surfing! Also known as practicing an occasional combat roll. I didn't mean to scare everyone off, just to adjust their timing. So far as I know, I was the only NSPNer present tonight. I missed you all. They say it is a bad sign when a social drinker starts drinking alone. After missing Walden and Surfing last week I was suffering so much rolling withdrawal I finally started rolling alone tonight. I wonder how long it will be until I'm rolling alone every day.

7/13/16 Wednesday July 13 at 2:50pm Walden Pond closed for visitor capacity Walden reopens at 5:30pm today, limited parking may be available https://twitter.com/waldenpondstate

I will try, but I am not certain I will be able to attend on July 6th. Have fun anyway. :-)

I plan to be there again tonight (6/29). Haven't missed a week yet! Posting because weather hourly forecast currently says chance of thunder drops from 30% at 5pm to <10% chance from 6pm on. See you there!

According to http://www.familykane.com/WaldenTempsPhp/ 5/28/2016: 68 F° (20 C°) For safety, you can probably wear most anything. For rolling comfort... well everyone knows what I'll be wearing.

Walden resumes this Wednesday! I sure hope to have some company. For further details see the NSPN Walden Calendar entry.

Congratulations to both of you!

Somehow April 1st seems appropriate. Have fun!

To be an ocean kayaker (the thread title), you need an ocean, a kayak, and a paddle. If your kayak is not a sit-on-top, you need a spray skirt [neoprene recommended] or equivalent. (Renting or buying used is recommended for people new to the sport.) If you are a beginner and go out with just that minimum, you may be written about in the paper, and discussed as an idiot in this forum. If you also aspire to be a prudent modern ocean kayaker, first you need education and companions. Both of which are available for free (via places like NSPN), or with paid lessons and guided trips (for example Charles River Canoe and Kayak). Reading Deep Trouble 1&2 (via the library or Amazon) is great winter preparation. Following the "three to sea" minimum rule is a good idea at least until you are near expert. For safety, first you need a PFD (ideally a high flotation model with 20+ pounds buoyancy, not a legal minimum 15 pound model) and a whistle. Next ideally you (or at least your group) needs ways of calling for outside help such as VHF radios (ideally DSC with GPS), possibly supplemented with PLBs, and cell phones. Your next investment is thermal protection appropriate for the sea temperature where/when you intend to paddle. If you are comfortable getting into the water at each put-in before each segment of your paddle, you are wearing appropriate thermal protection. Around here, if you want to be on the ocean more than about one month a year, you will want a drysuit. Adding a bilge pump and compass are cheap potentially very useful additions. (I bring a bailing sponge instead of a bilge pump when white-water kayaking, but I only bring a bilge pump when ocean kayaking.) I always wear a helmet that I can also use to pour water over my head (no vent/drains). It is a hat that stays on in the wind. A few times each year it takes a hit for me. I am in the minority, but definitely recommend them. Paddle floats have their own thread. I carried a foam float my first two years because my first instructor strongly recommended foam over inflatable because they don't require any time to deploy. He assumed the float would be used to assist a reentry by a paddler wearing marginal thermal protection. Later I switched to inflatable because I knew I would be wearing a drysuit, and I was unlikely to be using the float to assist me during a reentry (they have other uses). Dry bags are extremely useful. Charts and GPS systems so you know where you are. Tow systems to assist others in your group. If a new kayaker was going rent their kayak, paddle, spray skirt and PFD, and always travel with a group. My first purchases would be dry bags (for lunch and gear), a drysuit, a personal high-float PFD to which I would attach a whistle and cheap compass, a VHF radio, and a helmet. Probably in that order.

Dessert.

Succeeded in paying for a pool session. Went to get the waiver, which http://www.nspn.org/forum/store/product/3-haverhill-012316-saturday/ says is at http://www.nspn.org/forum/files/download/138-aca-pool-session-form/ However, that link gives a page does not exist error.

Hi Rob, The uncompleted transaction shows up under Orders. NSPN Message Board | Store | Orders Shows Order #1319 as Pending On the far right are PayNow and Cancel Invoice buttons. When I click PayNow it takes me to Checkout Step 2 (Confirm & Pay) When I then click the "Place Order And Pay" button I stay on the Checkout Step 2 page, but the content changes to. ! There was an error processing the payment. Please try a different payment method or contact us for assistance. with a red background. There is also a Confirm & Pay button with a gray button, when I click "Confirm & Pay" the screen simply refreshes. We still have time, I'm trying to purchase 1/23/16. One of the rare afternoon pool sessions. -Bill Voss P.S. When I tried to PM you I got: Maintenance in progress We're sorry, but this website is currently unavailable. You can try again by clicking the button below, or try again later. Try again I'm not certain if that was a software issue, or just bad timing. Though the "Try again" button did not seem to do anything.

Tried to buy a pool session, it failed with an error about processing my payment. Probably because it neglected to ask me how I wanted to pay.

My first winter as a beginner, I greatly enjoyed reading and was greatly influenced by: Sea Kayaker's Deep Trouble: True Stories and Their Lessons from Sea Kayaker Magazine Paperback – May 22, 1997 For the video crowd, I was surprised to greatly enjoy Justine Curgenven's “This is the Sea” series. Nobody who knows me will be surprised to learn I'm requesting even more rolling videos on my X-mas list again this year!

Hi Leon, I think we may both remain unconvinced on precisely how to define the Power required for fast current, though we both seem to reach the same conclusion in everything but magnitude. Last night as I tried to fall asleep, I thought about the results for slow current. Would the paddler always win if the current was a fraction of a knot? One subtle advantage the paddler has over the poler is the paddler can select from a wide range of paddles. The largest wing paddle money can buy is certainly not always the best choice for all possible race distances and paddlers. Just like the most aggressive gear on a bicycle is not always the most efficient choice. The poler is normally in the situation of riding a fixed speed bike, with no option to change the gearing, even in the shop. If that fixed gear works well for that poler in that race, great. Otherwise, too bad. However, if the poler could pick the current for the race, the poler would be in the same situation as a fixed speed cyclist who could pick the grade for a race, or chance his cycle's gearing in the shop. The poler and paddler always tied in a zero current race. I assume the paddler is already always selecting the best paddle for each race. If zero current was a harder than optimal gear for the poler, then by selecting the right current, the poler might be able to improve their bio-mechanics enough to win! Unfortunately, I don't have enough experience poling to know if zero current poling is ever a harder than optimal gear for a poler. Enjoy another day in the sun Leon. -Bill

My turn Leon, I still maintain you need to credit the punter with the benefit of the current. Expressed another way, the current provides some of the power to both vessels. Expressed another way, you can not use one frame of reference (the ground) for one vessel, and another frame of reference (the water) for the other vessel when comparing the power required to win a race relative to the ground. I assert power can be defined as how much force it takes to move something over a distance, divided by the time it takes to move that distance. You can use any frame of reference you want for distance, so long as you use the same frame of reference for both vessels. As I originally posted, the punter must push at Still Speed + Current Speed (S + C) against the ground, which becomes impossible for a human for large values of C. However, it is impossible because the punter must push the POLE so fast. The punter must only accelerate the punt to S relative to the current for all values of C to tie the paddler. Yet the same poler who supposedly can not generate 5*100,004 pound-knots would easily generate 5*200,000 pound-knots in your example if the speed of the current was doubled! In your Piscataqua River example, put the two ropes into tension so they act like beams. The supertanker's rope is now tied to a second large ship pulling on the rope so it overtakes the supertanker extremely slowly. The bridge is now tied to a stationary anchor. Your ferry attaches an electric motor to the stationary rope and the motor starts spinning and generating electricity. You have in essence a short duration hydro-electric plant! That electricity is because of the power contributed by the current. Disconnect from the stationary rope and connect to the supertanker's rope, the motor does not spin. Now apply a current so that the motor pulls the ferry down the supertanker's rope at 1 knot relative to the rope (4 knots relative to the ground) towards the supertanker. Note how many watts are required to achieve that speed, and the motor's RPMs. Disconnect from the supertanker rope, adjust the motor's gearing so the same motor RPM would pull four times as fast as before. Apply the same wattage as before with the motor connected to the stationary rope. I believe you will find that the motor achieves the same RPM and the ferry achieves the same 4 knot speed relative to the ground as before. The power (watts) required is the same in both cases to accelerate the ferry to 1 knot relative to the current. As a thought experiment, suppose my young nephew throws a toy, and applies enough force to throw the toy 10 feet in 6 seconds across a waiting area. Later, while riding in a jet plane going 600 miles an hour, the nephew applies the same force causing the same toy to travel approximately 1 mile and 10 feet down the aisle in 6 seconds. I can tell you that my nephew contributed the same amount of power in both cases, but the jet definitely contributed way more, allowing the second throw to easily win a "Distance in 6 seconds race!" I hope this will convince you. Respectfully, -Bill P.S. I'm very jealous of your play between posts. Between health issues and contractor hell, I haven't made it out on the water since September 7th, though I'm looking forward to a pool session this Saturday on December 5th.

Perhaps you should have stopped with "Andy and Bill are quite right" Leong. I don't think your formula applies. By the way, my first read of your description was that 5 pounds of drag existed when traveling at 4 knots. Not that 5 pounds * 4 knots was the appropriate formula, since we all know that drag increases exponentially, not linearly as speed increases. However, back to my main objection. The punt's drag is predominantly a function of the punt against the water, not a function of the punter's pole. Just because the punter is pushing on the ground does not negate the benefit of the current. So you still need to credit the punter with 5 pounds times 2 knots in your (power = force * speed) formula example. If the punter requires exactly the same amount of power to match the kayaker on still water a 4 knots, the punter does not require 50% more power to match the kayaker's speed when both have a 2 knot current assist. Consider this mind experiment. Old manually powered ferries hauled on a stationary cable to move the water craft. Assume the ferry and the kayak achieve the same speed in races over still water. Now repeat the race going down current. If the ferryman is manually pulling directly on the cable, the situation is almost equivalent to the punt. However, equip the ferry with gears like a bicycle, and assume the friction losses from the gearing are the same in current as in still water. Then I believe the ferryman and the kayak will still be essentially tied going downstream. The difference is that now the gearing can be adjusted so that the ferryman uses the exact same aerobic output at the exact same cadence in any reasonable current. So the ferryman does not suffer from current moving faster than the punter can pole. Regarding going upstream. The NH AMC White Water group includes some canoe poling enthusiasts. Though I have not poled a canoe, my understanding is that the huge advantage of poling is that it is practical to pole upstream in current too fast to paddle upstream. I believe a combination of poling upstream and paddling downstream was used by fur traders in America before motorized transport was invented. So you are on the right track there Leong. I also agree with your analysis that if the speed of the current exceeds the vessel's still water race speed, the poler will certainly beat the paddler, since the paddler is washed downstream.

Of course, I looked at your answer, then jazzed it up to make it look like you had copied off my answer.

The punter and the kayaker always tie on still water because they are friends, and neither wants to risk their friendship by beating the other. That will not change in current. However, if they have a falling out, and physics controls the outcome... In still water both achieve speed S relative to the ground, and relative to the water. In a down river race we also have current speed C. Current speed will actually vary being slower near the river bed. Neglecting minor affects such as air resistance, the kayaker should achieve speed S + C in a down river race. The punter previously pushed at speed S against the ground not the current. As current moves the punt down river the ground moves the wrong direction like a treadmill. So to tie the kayaker the punter must now push at speed S + C against the ground. As current speed C increases, this becomes more and more challenging and eventually for high values of C becomes impossible for human muscles. The water resistance against the punt required to tie the kayaker has not changed. However, the water resistance and inertial effects on the pole itself will change during different poling stages as the pole is forced to move faster than was required in still water, and different parts of the pole move through water moving at slightly different speeds relative to the ground. Pretending to be a physicist, my bottom line is that though both will make better speed over ground as C increases, the kayaker will benefit more as C increases. For small values of C the race will be very close. As a white water kayaker my answer is that as C increases, the river becomes more turbulent eventually capsizing both craft. The punter swims; while the kayaker rolls up and wins!!!!

No, I was just teasing the bearded wonder because of his Pink Stars post.

Congratulations. Did you know you were being assessed?

Congratulations Cathy!

Darn. It seems the season is ending. I'm going to show up a little early today with my WW kayak, and hope somebody (Sea or WW) shows up who likes to roll. Since I was the only sea kayak person who showed up last week, and I have a conflict next week, I think today is the last of the weekly Wednesday evening at Walden practices for 2015. It has been fun. -Bill