Wednesday, December 22, 2010
Saturday, December 18, 2010
Monday, December 6, 2010
Tuesday, November 23, 2010
Thursday, November 18, 2010
Friday, November 12, 2010
Wednesday, November 10, 2010
Monday, November 8, 2010
Saturday, November 6, 2010
Saturday, October 23, 2010
Sunday, October 17, 2010
Monday, October 11, 2010
Saturday, October 9, 2010
Wednesday, October 6, 2010
Monday, October 4, 2010
Thursday, September 23, 2010
Thursday, September 16, 2010
Tuesday, September 14, 2010
Saturday, September 11, 2010
Friday, September 10, 2010
Thursday, September 9, 2010
Wednesday, September 8, 2010
Monday, September 6, 2010
Friday, September 3, 2010
A few more elements of tides that we need to understand are that the tides don't change like a switch going on and off. They gradually change, and that change is constant. In a normal situation you have 4 tides a day, as I mentioned previously. Two highs, and two lows. If you have four tides a day, and the changes are gradual then they must be fairly even in their dispersal throughout the day. They each last approximately 6 hours - give or take. In actuality tides occur about fifty minutes later each day, (Because it takes the moon 24 hours and fifty minutes to complete a cycle around the earth) which is why our tides don't occur at the same time each day. Tidal changes during that six hours start slowly, build to maximum strength, and then start decreasing in intensity. During the middle of the cycle when the most water is moving, you get the biggest change in tide height. This varying cycle generally follows the rule of twelves. During the first and sixth hours of the cycle 1/12th of the water will move. During the second and fifth hours 2/12ths of the water will move. And during the third and fourth hours of the cycle - the middle two hours - 3/12ths of the water will move.
The important aspect of this is that in the middle of the cycle you have the most movement of water, and at the ends of the cycle the least. In fact at the change of that cycle when we end the 6th hour of the high tide and start the 1st hour of the low tide, in that change over, we are in a period called 'slack tide', this is when the least water is moving.
So there are times when a lot of water is moving, and times when very little water is moving. It is important to know when those times are because while the water is moving vertically, it flows to new areas, as water always seeks its own level. When water flows through a narrow area - a constriction - it goes faster. Like putting your thumb over the end of a hose.
So when you create your float plan, look at the possibilities of water being constricted and a tidal current being created. If there is an area of constriction water will be flowing very fast through that constriction at the middle of the tide. Whereas very little water will be flowing there at slack tide. Plan your paddle accordingly.
For instance, if I am paddling out and back to the same point I want to paddle against the tide on the way out, and back with the tide - so when I am tired I am not also fighting the tide. The same goes for the wind. I would rather start my paddle heading into the wind, so I get a push coming back.
Or perhaps I have to transit an area of high tidal current, but its going to take me four hours to get to it. That means I need to leave the safety four hours before the slack tide, so I reach the area of high tidal current when the least amount of water is flowing through it.
An area like this is not very far from where I learned to paddle. It's an area called 'Hell Gate' and it is in New York State. Three bodies of water converge on a very small opening. The Long Island Sound enters the East river along side Manhattan Island. At the north end of Manhattan island The Hudson river joins the East river. The sound, the East river, and the Hudson river are all tidally influenced. Meaning the rivers reverse there flow when the tide is coming in - or flooding - and then the rivers flow takes over when the tide is receding - or ebbing. (In actuality the East river isn't a river, it is an inlet from New York Harbor, a large bay, and finally the Atlantic ocean.
So when the tide is flooding, water comes from the Long Island sound and floods into the east river. At the same time the Water is flooding the east river and Hudson river. This junction can become very turbulent with a fast moving tidal current.
Other things effect tides and tidal currents as well. The shape of the land surrounding the water, and the shape of the land under the water all will effect the tide, and tidal currents.
It's good to understand tides and tidal currents, but the best way to know how tides effect a certain area of coastline is to get knowledge from someone who paddles there all the time. Local knowledge is key. Seek out paddlers who know the area, and can give you information that can only be learned by putting a kayak in the water.
Monday, August 30, 2010
Friday, August 27, 2010
Wednesday, August 25, 2010
Monday, August 23, 2010
Friday, August 20, 2010
First, and probably most common material for a kayak is plastic. I had the opportunity to go to a factory near me, to see plastic whitewater kayaks and recreational kayaks manufactured. Plastic kayaks are made from plastic powder, which is poured into a mold, and then placed in a very large oven. The oven is on a gimbal, and moves the mold every which way, after heating the mold to around 500º (If I recall the temperature correctly)
Plastic kayaks are relatively inexpensive, incredibly durable, but comparatively, fairly heavy.
The next most common material for kayaks is fiberglass, and it is the generally preferred material for a high performance boat. More expensive, a bit lighter, a bit stiffer. For all practical purposes each boat is hand made, though I am sure that someone can fill in the blanks of how they are manufactured.
These are, by far the two most common materials for kayaks. There are of course wooden kayaks, skin on frame kayaks, folding kayaks - which I tend to think of as skin on frames younger cousin, and high end carbon/kevlar composites, but the majority of paddlers use Fiberglass or plastics.
Like everything in kayaking there are trade offs of each, and because of the popularity of fiberglass and plastic those are the two I want to focus on.
As I said, the plastic kayaks are incredibly durable, and less expensive, and since a lot of high end fiberglass manufacturers are making plastic versions of their high end boats, it makes it very easy to start with one of these kayaks.
If you do manage to damage your plastic kayak they are not easy to repair. I have seen kits for plastic repair, but I suspect there is always a scar, whereas Fiberglass is easy to repair, and maintain, and repairs often leave no scars whatsoever, though they are a bit more fragile.
Having paddled both extensively, I can say that there is a responsiveness to fiberglass that is incredible. Actually responsiveness isn't the right word. It's a feel. This isn't an accurate description, but some say that paddling plastic kayaks, the boats 'feel dead'. I don't know what that means, but when you paddle both you will understand the expression. There is a snappiness in fiberglass that isn't present in plastic. Plastic kayaks have a 'thud' to them when they come down over a wave. It is really very hard for me to describe.
The big argument between the two is the inherent stiffness that the fiberglass kayaks offer, over the relative softness of the plastic.
And this brings me to my email exchange with the editor of Sea kayaker magazine. It was just before I bought my current kayak, I emailed him to suggest a story idea. The idea was this, since Sea kayaker does all sorts of tests on kayaks to determine drag, and speed, and the like, I felt they were in a position to discuss materials and all the benefits and drawbacks. Over several emails we exchanged ideas and information - in all fairness he gave information, I gave questions! He talked about the stiffness of fiberglass, and how that translates to speed. He talked about the plastic kayaks tendency to gouge, and its effect on speed. The flex of the side of the kayak when you push on your foot braces which he thought would be a big drawback of plastic boats efficiency, and I thought the flex of the paddle blade and shaft would be a big loss of power. (According to Sea Kayakers tests we were both wrong, as the flex of the kayak at the foot braces, and the flex of the paddle shaft are both non-issues.)
After a number of emails I asked what I really wanted to know. In testing, with all conditions being the same, what are we really seeing in actual speed difference between plastic and fiberglass. His response was this, 1% or 2%. I cruise at around 4 knots. 2% of four knots isn't much. So don't let speed be your overall judge in deciding what types of kayaks to paddle.
The outcome of the email discussion was published in the 25th anniversary edition of Sea kayaker magazine.
I have only owned plastic kayaks. Mainly due to cost, but durability is also a factor for me. I started kayaking the shores of Long Island, New York which are essential rock piles. I didn't want to worry about my kayak, so plastic it was.
Of course I haven't mentioned my current kayak, which is thermoformed plastic. Using plastic in sheets, the kayaks are manufactured similarly to fiberglass kayaks. I currently feel that it is the best of both worlds. It doesn't have 'the dead feeling' of plastic, and is lighter than most fiberglass kayaks. You repair it very similarly to fiberglass, but it is priced between fiberglass and plastic. I am curious how the kayak will age, but thermoformed kayaks have been around for quite some time with various names -airalite, and ultralite being the most popular.
So you need to think about use, and care, and cost of the kayaks you are looking at, but most importantly you have to paddle kayaks to get a feel for the different boats. I am a firm believer that once you start paddling different kayaks, just like the paddles, one will sing to you. One will feel just right. One will be 'the' kayak.