dan_f

Hi Sue, I'm sure those are nice binoculars, but they are a bit on the big size for daytime use. Google "binocular exit pupil". You will only use the light gathering power of those big lenses at night when your eye is dark adapted, and then only if you are pretty young and your pupils open that wide. I like a waterproof binocular like 8x25 or 8x30 for daytime use in a canoe or kayak. They are easy to carry and provide as much light as your daytime pupil can take in. If you are on power boat and plan to be out at dusk or in the dark those big binoculars will be great. Best, Dan

This short article plots a number of kayak drag force curves and shows that many boats have nearly identical drag forces at speeds less than 4 knots: http://www.seakayakermag.com/2007/07e-newsletters/December/fastkayak.htm

Hi Leon, I should have rounded to the nearest watt since my conversion factors were rounded off. My question for you is how much sustained power a strong kayak racer actually produces?

Well Leon, I'm afraid that we've both (once again?) overestimated general interest in physics problems. Your paddler can paddle at 5 knots with 4.213 lbs (force) of drag, producing a power output of 21.065 lbs-knots. With the same power in the new boat the paddler can go 5.5 knots against 3.830 lbs of drag. It might be fun to convert this strange unit of power to one that is more familiar: 21.065 lbs-knots =48.7 watts if I haven't goofed. This isn't too far off what I might expect since on a bicyle we can generate about 125 W. In reality a strong paddler can probably produce double or triple the power output of the hypothetical paddler in Leon's example.

Another hint - the amount of energy that the paddler supplies is: Energy=Force*distance. The amount of energy that the paddler supplies to go a certain distance against a constant drag force is independent of the amount of time that the paddler takes to go that distance, However, we all know that it matters if we supply that energy over 10 minutes or 20 minutes, so just matching the drag forces on the two boats and reading off the corresponding speeds is not the right answer. We must consider power, the rate of energy expenditure per unit time. If you were confused by my equation above, speed and velocity are equivalent here.

Hint - assume that paddler output power is constant. Power = Force*velocity. Leon told you force=drag.

Hi All, My thanks also to David. A great day and company! I posted two pictures: http://danielfabricant.com/pictures/Misc_Kayak/Rowley_River_1.jpg and for Katherine: http://danielfabricant.com/pictures/Misc_Kayak/Rowley_River_2.jpg Best, Dan

I'd like to join in - prefer longer route, but either is ok. Best, Dan

No takers, so chores win out. Paddle cancelled. Dan

Oops - that's Sunday the 12th!

I am planning to launch from Pavillion Beach in Ipswich and paddle to the end of the Rowley River and return. Leaving 1 pm, and high tide is around 3 pm, so the current will assist both ways. Please reply to this post if you plan to join me because I might adjust plans if I'm solo. This is around 12 miles round trip. Another possibility would be to take Fox Creek to explore Essex Bay. Best, Dan

Thanks Barry, this is very helpful! Dan

Although I drive over the Mystic River every day I've never paddled on it or explored it. I was thinking about paddling down river to the harbor tomorrow (Monday the 6th). Does anyone have a recommended put-in or advice? If anyone is interested in joining in, company is most welcome. Thanks for any comments. Best, Dan

No interest so decided to make other plans. Dan

I was thinking about launching from Pavilion Beach around noon and heading through Fox Creek for a leisurely paddle around Essex Bay. High tide is around 2:45pm so Fox Creek will be passable in both directions. This would be an outing for those planning to underachieve on Saturday. Dan F