Wednesday, 18 January 2012

Technical: Sea Kayaks

For my first semi-technical post I thought that the sea kayak seemed like a good starting point. The picture above shows a 'Quest' sea kayak hand made by British manufacturer P&H. I'm hoping by advertising it to the 4 and a half people who visit this page P&H might give me a free one ;)

Anyway, starting with general characteristics the front of the kayak (right) is known as the Bow, the rear is referred to as the Stern. Looking side on, the red stripe from bow to stern marks the Gunwale. Above it you have the blue Deck and beneath the white Hull

Unsurprisingly, as the hull is in the water it has a large effect on the way the boat performs. In general the longer the hull, the faster it will be and the better it will track as it increases the effective Waterline of the kayak. This can be modified with a characteristic called Rocker, you will have noticed that the Quest pictured above is not flat against the floor, by increasing the rocker (curvature of the kayak) we can make it turn more easily. This will however have a detrimental effect on the tracking, the kayak may also catch more wind. If you look at the shade on the hull you can see it looks quite rounded, this is called Chine. This affects how the kayak feels on the water, those with a hard chine (square edge) feel more stable but they will capsize suddenly if edged over. Those with a soft (rounded) chine feel more tippy generally but are more predictable on edge before capsizing.

The shape of the deck will also have some effect on how the kayak catches the wind, how it slices through big waves and also how easy it is to roll should you end up upside down, or just re-enter the boat should you have to wet exit.

Looking at the top picture again there are a number of features on the deck. Working from the bow to the stern these are:

  • Front grab handle - Used to carry the boats around.
  • Life/Grab Lines (Red) - Useful for grabbing the kayak if you are in the water and more importantly keeping hold of it, wind can quickly separate the kayak from the paddler. Tow lines can be attached to these should a paddler become tired or sustain an injury.
  • Compass Recess - For a deck mounted compass
  • Front Hatch - Used to store gear inside the boat and keep it dry, like camping stuff for Anglesey. There is an amazing amount of room in a kayak if you pack it well. Behind this (inside the boat) there will be a watertight Bulkhead separating the front storage from the cockpit.
  • Deck Bungees - Useful for holding maps / GPS / water pump etc.
  • Cockpit - Aptly named perhaps. The cockpit above is a keyhole shape, this shape makes it a bit easier to get your legs in. It does however mean you need better eyesight to see your map as the deck is further away! At the front of the cockpit there are two Thigh Braces, although you paddle with your arms your hips and legs do a surprising amount of work to control the kayak. There is another bulkhead behind the cockpit. The red rim around the cockpit is known as Combing, this is what you attach your spray deck to.
  • Day Hatch - For storing stuff you need access to but want to keep dry-ish! Food to refuel on the water for example.
  • Rear Bungees - for storing even more gear. However, if you self rescue from the stern putting gear here makes it more difficult to get back on and into the kayak.
  • Rear Hatch - for storing stuff as the front hatch. It's good to spread the weight around between hatched to maintain the handling of the kayak.
  • Rear Life/Grab Lines & Rear Grab handle - As previous.

To finish, the two most common forms of construction are roto-molded plastic (polyethylene - coke bottles!), and fibreglass (like the Quest above). If you're loaded you can also get Kevlar or carbon fibre constructions. But fibreglass is probably the easiest to repair.


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