Kayak Design Notes
Length
There's two lengths: the length on the brochure and the actual waterline length: the length of the boat as she sits in the water.
The brochure one is for useless bragging, the latter is for designing.
Reasonably speaking, the practical length for a touring kayak is 15-16 feet.
My dad's kayak is a Wilderness Systems Pungo, which is 12' long and 29" wide. Weighs 49 lbs. I'm pretty sure they're not considered 'touring' kayaks, more general purpose. They'd be slower and fatter but more stable in non-wave waters and can turn / spin quicker.
Width (beam)
This is how wide it is at the widest part, which, for kayaks, is basically at your hips so it has to accommodate your personal width needs.
The upper boundary is defined by your paddle's clearance and stroke. Obviously something too wide is simply hard to reach side-to-side. There's stability concerns at both extremes, but that can be its own heading.
The other boundary is about displacement: the amount of water you're shoving around your shape: too wide and you've got a lot of drag to contend with. This is why some boats are called 'fast' or 'slow' - the ratio of length to width defines how sleek the craft is. called L/B ratio.
Seemingly, there's just good ratios that have been tested and tried over time? There's some arcane magic here to figure out. We can obviously just look at the number ratio but it doesn't necessarily scale well when you move up and down lengths. Certain lengths just have certain ratios.
11 is a sleek sprint kayak, 6 would be a stubby little thing.
Weight / Volume / Displacement
Since we have the luxury of designing these things for custom use, we're going to want to make the kayak for our specific weight + a tiny margin of extra for our lunch and stuff.
We want the wetted surface area - the part in the water - as low as possible to reduce drag. That means we want a design to be perfectly buoyant for our weight, which defines the displacement.
There's a ratio for this, but it's actually not super important if we're simply designing around our weight itself - that's just the driving variable and it is whatever it is.
the maximum displacement speed of the kayak is approximately 1.34 times the square root of the waterline length in feet. For example, the maximum displacement speed of the 16-foot kayak is 5.36 knots and that of a 25-foot waterline length is 6.7 knots.
Cockpit specs
There's two formats for cockpit location: with the main weight forward of middle and aft-ward of middle. These are, for whatever reason, called Fish Form and Swede Form respectively.
They have pros and cons, but long story short, you want aft-ward / swede form for boats like this.
Seems like the maximum is 55% distributed to back, so the center of gravity shouldn't be past 55% of the waterline length, which is to say: you're going to be pretty much in the middle + back a smidge.
Construction
Vinyl ester resin is tougher and absorbs less moisture than polyester resin
Epoxy comparisons: http://www.oneoceankayaks.com/Epoxresl.htm
Cloth comparisons: http://www.oneoceankayaks.com/Abrasion.htm
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