Before purchase must know .(Kayak)

Kayak stability: what you need to know

A kayak is a highly personal purchase - read the text in picture once again .
The way a kayak fits your body, your personality, your sense of adventure is unique.
The kayak you purchase, needs to fit your criteria; - not someone else's.
"What the rest of the world paddles is only important to the rest of the world."
A kayak that is easy to roll, is also quite easy to capsize,
- that may be a good hint regarding the kind of kayak you personally want.
Some people love to take pictures, wave at passing boats, watch birds flying overhead
and others just want to focus purely on paddling straight ahead, accumulating mileage.
Tipping your kayak could ruin expensive camera equipment, binoculars,
cause loss of prescription eyeglasses and/or anything in the cockpit.
Perceptions, connotations, preconceived notions, are all very, very real to paddlers.
They influence all decision making process and are neither right nor wrong - they just exist.
There is no best kayak; it's a myth, an illusion, a quest that cannot be achieved.
Conditions, skills, and objectives are never constant so it all ends up "touchy feely".
It comes down to what "feels right" for each individual paddler.
This can only be done by direct demo, on the water, in the cockpit of the kayak, paddling.
Try - before you buy. Make the effort, please. Ask the salesperson "Can I try it first ? ".
***___Stability___***
Every geometric shape you can imagine, has a center of gravity.
The amount of force needed or required to tip over depends on many factors.
A kayak can move in endless variations and combinations of the X, Y, Z axis
- all at the exact same time, with variable forces from various angles.

How a kayak "resists" movement is often described as its primary/secondary stability.

Various shapes of the kayak hull can modify, the amount of resistance, to the forces.


The paddler affects how the boat sits in the water. Humans are not rigid stick figures !.

Kayakers typically want to go somewhere, so cargo aka ballast is often involved.

A paddler will move the center of gravity upward, cargo will counteract - moving it downward.

Recreational kayakers often paddle empty, making a kayak "feel" twitchy, unstable, etc.

Influences on Stability in a Kayak

1) Water conditions

2) Boat shape

3) Boat loading

4) Skill of the paddler

5) The paddle

6) Wind

Re-read the text above - Q = What affects "secondary stability" the most ?  A = elliptical hulls

TopKayaker.Net: Kayak Instruction Articles

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Kayak Design Terminology Defined By Tom HolteyThere are quite a few terms used to describe the various hull shapes and other design characteristics that determine a kayak's performance and "personality". This list serves as a glossary and as a primer to help you understand these terms when you encounter them. You can use this list to judge a kayak's handling before you paddle it. These "tools" will also be handy in selecting a kayak that is right for you and your needs.

California Hull - Soft Chine

California Hull - Hard Chine

A California Hull is a hull shape that combines the elements of the flat hull and a round hull. (Largely attributed to Tim Nemier of Ocean Kayak fame.) This combination provides performance in tracking, speed (rounded center keel line), greater stability (flat hull) and performance in surfing waves (hydroplaning). California hulls can be found with soft chines (like a Scupper Classic) or hard chines (like a Scrambler).

Soft Chine

Hard Chine

Chine defines the shape of the kayak's side. Hard Chine indicates an angle between the side of the kayak and the bottom, possibly as much as a right angle, almost boxy. A hard chine boat tends to have greater primary stability and lesser secondary stability. This "edge" can also add performance in surfing, allowing the kayak to grip a wave face and carve a turn. Soft Chineindicates a smooth curved transition from side to bottom, giving the kayak a more cylindrical shape thus increasing speed. Soft chine kayaks tend to have greater secondary stability and lesser primary stability. Multi-Chine kayaks are somewhere in-between the two.

Fishform Hull

Fishform is a term to describe an asymmetrical hull shape that has stern with less volume (narrow) than the bow with greater volume (wide). This will allow the bow to ride over the swell and waves, improving surf zone performance.

Flare

Straight

Tumblehome

Flare Side kayaks have sides that are shaped upward and outward. This decreases the tendency for waves to wash over the decks and increases secondary stability. Kayaks with flare sides are not as easy to Eskimo roll. The opposite of Flare is Tumblehome. Kayaks with nether flare or tumblehome are called "straight side" and perform in-between the two.

Flat Hull

Flat Hull kayaks have greater primary stability, but less secondary stability. This will provide a stable ride, but when the kayak is leaned to maximum it is more likely to tip. A flat hull kayak will also turn more readily, but not track as well on a straight path. Flat hulls increase hydroplaning. (The kayak lifts out the water and skims the surface when it reaches "planing speed".) This is a common hull shape for wave skis and surf kayaks (much like a water ski or surf board) and is often used in combination with skegs/fins for directional control.
A Keel Strip is a ridge running the length of the hull, or most of it, providing directional stability, keeping the kayak on a straight path. Sometimes this is found as a long indention, or a reverse keel.
Primary Stability is the initial feeling of steadiness. On calm waters a kayak with good primary stability will feel solid and comfortable to beginners. A flatter hull with hard chine often has good primary stability. This provides a steady platform suitable for fishing, wild life viewing & photography. In rough conditions, and extremes of lean, primary stability can fail, allowing the kayak to capsize when tipped to the maximum.

Rocker

Mild Rocker

Straight Hull

Rocker is the measure of the curvature of a kayaks hull from bow to stern. A kayak with a lot of rocker will rock from front to back, like a rocking chair. This allows for greater manuverability (turning) because the bow and stern have less resistance against the water. However this prevents the kayak from tracking well (going in a straight line). A kayak with no rocker (straight hull) will track very well, as the bow and stern have much resistance in the water. This of course will prevent easy turning. Kayaks withmild rocker are somewhere in-between.

Round Hull

Round Hull kayaks, from side to side, torpedo shaped, have increased speed with less resistance to the water when moving forward. This decreases primary stability and can increase secondary stability. This is a common hull shape for surf ski racing kayaks.
Secondary Stability is the feeling of security when the kayak is leaned to the maximum. A kayak hull with soft chines, flare sides and round hull often creates good secondary stability. Secondary stability typically is only felt when the kayak is leaned, so a kayak with good secondary stability and poor primary stability will still feel tippy to a beginner, even on flat water. Secondary stability is ideal for rough conditions, extremes of lean and for Eskimo rolling.

 
Sponsons

Sponsons act much like the flare sides by increasing stability when the kayak is tipped. Typically the sponsons are above the waterline and dip into the water then the kayak is leaned. This increases the width of the kayak when tipped, adding stability. When the kayak is on an even keel the sponsons are out of the water, decreasing the width and thus improving speed and glide. They can also deflect spray from the decks. (This feature on sit on tops is largely attributed to Paul Cronin of Heritage Kayak fame.)

Symmetrical Hull

Symmetrical Hulls have the same taper of shape front and back. The center of the kayak is the widest point and the width gets narrower toward the stern and bow equally with a bow and stern of the same shape. This will increase the kayak's maneuverability. An Asymmetrical hull has a bow and stern of different shapes, called Swedeform or Fishform.

Swedeform Hull

Swedeform is a tem to describe an asymmetrical hull shape that has stern with greater volume (wide) than the bow with less volume (narrow). Sometimes this is coupled with a longer bow section, and a cockpit placed further aft. This will increase speed and tracking while decreasing manuverability. A narrow bow will cut or spear through the swell and waves.

Straight

Straight Side kayaks have neither Tumblehome or Flare. No extra stability, water sheding or improved Eskimo rolling is provided.

Tumblehome

Kayaks with Tumblehome have sides that are curved upward and inboard. This increases the tendency for waves to wash over the decks. Kayaks with tumblehome are easier to Eskimo roll. The opposite of Tumblehome is Flare. Kayaks with nether flare or tumblehome are called "straight side" and perform in-between the two.

V-Hull Kayak

V-Hull kayaks have a shallow v shape when looked at from front to back. The v shape provides better tracking (straight line paddling) acting much like a keel, but decreases primary stability.
Volume refers to the internal capacity of the kayak and is sometimes expressed in gallons. It is a way of measuring the displacement or buoyancy of a kayak and can be linked to the kayak's carrying capacity.
© 2002-9 Tom

OUR #1 MOST POPULAR ARTICLE 
How To Choose A Sit-on-top Kayak
by Tom Holtey, ACA Open Water Instructor,
Guide, and Author of "Sit-on-top Kayaking, A Beginner's Guide"

There are now sit-on-top kayaks designed for virtually every possible use in mind, so when purchasing one it is important to ask yourself some questions. Once you've read through this article visit our Interactive Kayak Research Tool to type in your criteria and find links to the kayak that is right for you:

• What will you use this kayak for?
  Will you be surfing, fishing, diving or touring and camping?

There are kayaks specifically designed for riding ocean surf and others that can surf and cruise. Surf kayaks are typically short, rockered, and slow on flat water.

Any kayak can be a fishing kayak, but most kayak makers now have an "angler model" of their popular "regular models" that sport rod holders and other "fish friendly" accessories. Any kayak can be outfitted with fishing gadgets. Look for boats with easy to reach storage spots and a bit extra stability.

If you are planning to Scuba dive from a kayak an extern cargo well, or tank well, is best. (Some large hatches can handle a tank too.) Double check the fit with your gear. An internal cargo hold is handy for mask, fins and snorkel. Just about any kayak will do for snorkeling, tank well or no.

Touring is a pursuit that requires one to cover distance on a kayak. Look for longer sleeker models with space for a day's worth of cargo. If you plan to go on a kayak expedition you will need a kayak that can carry a week or so worth of cargo. Look for many cargo hatches with larger openings, as well as a longer sleek hull. See also: Packing Your Sit-on-top Kayak For Camping & Touring

• Will you paddle it alone, or take your spouse, child or dog?

If you plan to paddle solo most of the time be sure to get a solo kayak. Two person kayaks that claim to go both solo and tandem do so, but at the cost of loosing solo performance. It would be worth it to rent a tandem kayak, sometimes named "Double," "Triple" or even "Quad", for the few times you need to bring a buddy, rather than struggle with a boat too big and wide for most of your solo paddling.
If you plan to go with a partner, both in the same boat, most of the time, then a tandem is the way to go. The few times you may go solo will be ok despite the extra bulk. Most tandem kayaks are heavy and require two to lift it easily. (FYI: For expeditions two solo kayaks can carry more cargo than one tandem.) See also: "Tandem Sit-on-top Kayaking: How To Avoid A Mutiny"
There are now some tandems and "semi tandems" that are ideal for riding a child or dog. Some solo kayaks that have large cargo wells can carry a small child or dog, but never an additional full grown adult.

• Think about your desires and goals.
  Are you looking for action or adventure, exercise or solitude?

If you like action look for a kayak that is made for white water rivers or riding ocean surf. If it is adventure and exploration you desire get a touring kayak that can cover a lot of territory and bring into the wilderness.
Any kayak can be used for exercise, in fact a short slow moving inefficient kayak may help you burn more calories than a sleek racing kayak, but most folks who like fitness also like speed and competition that will require a long sleek kayak.

• What is your primary goal?

Decide what is most important to you and target kayaks that support that goal. Let other side interests take a back seat. Almost all kayaks can be used for almost all pursuits. Some kayaks just do much better at one task than another.
No kayaks do everything well. So choose the kayak that will do the best on your primary interest.

• What design of kayak hull and shape is best for your needs?

For an overview of kayak design and hull shapes read our article Kayak Design Terminology Defined
Address these questions with those who are helping you to make your purchasing decision. A salesperson at a kayak shop can be very helpful, but also seek a second opinion from a kayaking friend, club member, an instructor, Internet forums or from magazines and books.
When you have narrowed it down to a few top kayaks models, try them on the water in a safe environment, focusing on the test drive. Most shops will help you do this. Take your time and make your choice carefully. At the very least test-sit some kayaks on the show room floor to ensure that they will fit your leg length and feel comfortable for your body shape and size. (Tip: proper backrest accessory adjustment makes a big difference in comfort. See also "Demo Daze" to get the most out of a kayak demo event.)
Things to consider in choosing the best kayak for you are:

• Stability: Don't pick the most stable, as you will learn to balance quite quickly, and a very wide stable kayak may hold you back in your development.
• Speed: The wind in your hair is a nice feeling, and having a good hull speed can also make for safer kayak when the elements are against you.
• Capacity: Most kayaks will carry most people. But pay special attention to the weight capacity if you are planning on a heavy load: that means you plus your gear.
• Performance of the boat in the specific conditions you will be in.

Generally speaking:

• Longer will be faster 
• Shorter will be more maneuverable 
• Wider will be more stable

There are several classifications of kayaks. Take note of them so you can be informed when shopping for a boat that fits your needs:
Touring, sometimes called Sea kayaking is the endeavor to cover distance and explore. Longer sleeker boats, typically about 14 to 17 feet are considered touring kayaks.

Seat and back comfort for long hours on the water and the ability to store cargo are important features; however, backrests and hatches can be added at any time. See article: Backrests, Knee Straps & Paddle Leashes

Recreational kayaks are smaller and shorter. While all kayaking is "recreational" the term refers to a more relaxed and causal attitude toward kayaking fun. Some times called "rec boats" these kayaks have limited capabilities and should be used only as intended.

White water kayaks are for running rapid rivers. There are very few models to choose from in the SOT style. White water kayaks do poorly for distance on flat-water rivers and lakes. River running requires special training to be safe, take a lesson.

Wave skis and surf kayaks are for use in the surf zone for riding breaking ocean waves. They often have a flat planning hull, sometimes with skegs or fins, like a surfboard. There are numerous models and sizes of wave skis designed for every paddler height, weight and skill level.

Surf skis and racing kayaks are very long, slender and sleek. They are the fastest of all kayaks, used in competitive races and by fitness buffs. They can be quite tippy and take some time to lean. Some surf skis fit only a certain length of legs, essentially coming is "sizes".
(In some paddling communities the terms "surf ski" and "wave ski" are transposed and/or interchangeable.)

Inflatable kayaks come in all kinds, from touring to recreational. They are best used by those with limited storage space and by travelers. Pay special attention to the quality of design and material, there are many pool and beach toys that appear to be kayaks, but they are really toys. You can judge that by the cost in most cases, with costly kayaks being quality dependable boats that perform well with safety.

Other "kayaks" may include such craft as bike boats with foot peddle power, specialized sailing rigged kayaks, twin hull catarafts and "concept sculpture kayaks" that look like sharks or crocodiles. There is also an assortment of kayaks made specifically for the small frames of children, proving a craft suitable for them to get "adult like" performance from a kayak.
Practical Considerations:
Check to make sure that your cargo will fit in the hatches or on the deck. Not all kayaks have large hatches, or much internal storage space.
Consider paddler(s) weight and that of your cargo and compare it to the kayak's capacity. Most manufacturers supply specifications on each boat. Some boats come with hatches; others can accommodate a later installation, while quite a few kayaks do not have any hatch possibility.
Also consider how you will transport this kayak. A kayak cart that straps your kayak's hull for transporting over-land can come in handy.
Any car can carry any kayak with the proper roof rack system. You do not need to buy or have a large SUV to carry a kayak or two. You can put a couple touring kayaks on a sedan or wagon, and you have don't have to lift them as high.
Don't make the mistake of choosing a small kayak, easy to lift onto your car, if your safety and enjoyment will be compromised. There are roof rack systems that assist you in lifting heavier models.
Roof racks can be very simple and inexpensive, or very high quality. Make sure that the rack is secure, and that the kayak tied to it is also secure. Some roof racks are made only to fit certain cars. Other racks will fit all cars. Make sure the rack is the right kind for your car, by researching them carefully. Regardless of what system you choose, good quality tie-down straps are essential. Be sure to follow the roof rack and accessory instructions to the letter.

The paddle choice is just as important as the kayak choice. It is not uncommon to think the performance of a kayak is poor, when the paddle is the problem. The more you intend to use the paddle or the greater you will depend on it, the higher the quality should be. See "How To Choose A Kayak Paddle"
How To Decide On Gear:
Choose your accessories with care. All of the United States require by law that a Life Jacket or PFD (Personal Floatation Device) be on you or within reach. Make sure it fits, does not restrict paddle movement, and it is appropriate for your size. Special designs are available for women, children and even dogs.
Other accessories to consider to make the most of your enjoyment of the sport are: (Links take you to our TopKayaker Shop departments)

• Knee Straps 
• Paddle Leash 
• Back Rest 
• Bow Line 
• Dry Bags 
• Safety gear

Take a look at our Safe Kayaking Check List for more considerations.
When you are far from home and in rough conditions you will be depending on your gear. The best quality gear will then be essential. However, if you will be using your kayak just once in a while for short distances, then a lower quality purchase will be sufficient. Apply this evaluation to all your kayak and accessory purchases. Some shops will let you try the accessories that you are considering along with the kayaks that you are test paddling.
We wish you well in all your choices as you embark on this exciting, fulfilling sport. Happy paddling!

Tom

TopKayaker.Net: Buyer Research Tools & Articles For Kayakers

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How To Choose & Shop For A Kayak Paddle
by Tom Holtey, ACA Open Water Instructor,
Guide, and Author of "Sit-on-top Kayaking, A Beginner's Guide"

The paddle is an important purchase decision, right up there with the kayak and the PFD. Your paddle is the tool you use to make everything happen while paddling, and in some ways is more intimate a connection than the kayak or the life vest. Also, you must consider that you will be lifting the paddle with every stroke.

While it is best to try a paddle before you buy one, this is hard to do even if you have good access to a full service paddle sport specialty shop. On-Line shopping is a viable alternative, provided you have researched your choices and carefully sized yourself for a paddle. Even a paddle purchased after an on-water demo can eventually feel like it needs an upgrade, so you may end up with two paddles in the long run; however, it is always good to have a spare.

Shop Prepared With Basic Paddle Knowledge:

When selecting a paddle there are several considerations. First, determine the type of paddling you will be doing. There are paddles designed specifically for touring, white water, surfing, or multi use. They come in different weights, shapes and lengths.
TOURING PADDLES:

(asymmetrical style shown)

Touring paddles usually have a long, skinny, asymmetrical blade. They are often lightly built for greater efficiency on long trips. Many take apart into two or more pieces for storage.
WHITE WATER PADDLES:

 
  (asymmetrical style shown)

White water paddles are built heavy duty to withstand the ruff and tumble river environment. The blade shape is usually symmetrical, but not always. They have a shorter and wider blade.
SURFING PADDLES
Surfing paddles are similar to white water paddles but are often built a little lighter and usually have a short asymmetrical face that is not too large.
MULTI USE PADDLES:

Multi use paddles incorporate design elements of paddles made for different disciplines. The general outcome is a generic paddle that does a little bit of every thing, but exceeds at nothing.
Next determine your style:

 

• Are you an aggressive power paddler?
  Look for a larger blade and a more symmetrical shape.

• Are you a long distance or easy going paddler?
  Look for a paddle with a long skinny shape for greater efficiency.

• Do you do a little bit of every thing?
  A multi use paddle may be for you.

If you are a person who is not particularly strong, you should look into finding a paddle that is made of lightweight materials.This will cost more but be worth every penny out in the field. If you find yourself dealing with some wind where you kayak, a feathered paddle would be the best choice. Feathered means that one blade is positioned so that it cuts through the air on the up stroke.
Finally, what size paddle should you get?
The shaft is the part of the paddle that your body needs to "fit into." Unfortunately, manufacturers size paddles measuring from blade tip to blade tip. This wouldn't be a problem if all blades were the same lengths.
Imagine this: Two shafts, the same length. Place a pair of long blades on one shaft, a pair of short blades on the other. This will produce two paddles of different lengths, but the same shaft fitting the same person:

Joe Kayak's Paddle Selections: All have the same shaft length but different size blades:  Low-stroke angle Touring-Distance-Ease of use Mid-stroke angle Recreation-General Purpose Paddle High-stroke angle Surfing-Whitewater-Power paddling

Manufacturers commonly label the measurements of the paddle in centimeters. A paddler, depending on their personal height and kayak's width, may want, for example, the following three sizes for different disciplines: a 240 cm for touring, a 220 cm for surfing and a 200 cm for white water, all with the same shaft length from blade throat to blade throat.To fit the paddle to you, place the center of the shaft on the top of your head, holding the shaft with both hands in a paddling grip. You should kind of look like a body builder posing. Your elbows should be bent at 90 degrees square, making a rectangle of two long sides (the shaft and your upper arms) and two short sides (your lower arms) with your head in the middle. A mirror or buddy can help you. Your hands should be no more than two grips to the end of the shaft, the beginning of the blade, and no less than one grip.
These are not rules carved in stone but guidelines for you to base your decisions on. Bear in mind that a wide kayak will require a longer paddle than a narrow kayak, so adjust your choice accordingly. Also, it is recommend that you test paddle an assortment to find out what you feel comfortable with. If you are unsure of your choice, don't despair. Paddles are like shoes, they will wear out faster than your kayak. You will want to have a spare or a loaner paddle. And eventually you will want a different paddle for every occasion.

In A Nut Shell:

• Consider price versus performance when shopping for a paddle. If you are planning frequent, long distance or remote trips you should try to get the best possible paddle. This will often mean spending a bit more. Look for light weight and durability.
• If you are planning short trips close to home, that do not occur very often, a lower quality paddle will do. You certainly will enjoy a higher quality paddle but if you want to save a few bucks this is an option.
• If you loan your equipment to others, an inexpensive "loaner" paddle can be helpful. If lost or broken, it will not ruin your friendships, and save wear and tear on your quality paddle.

MORE RESOURCES:
If this article was helpful please take a look at the current selection of paddles at Tom's TopKayaker Shop: mid-priced, children's and high-end touring paddles.
    If you are looking for a specific brand we do not carry, use the below banner link to buy online at REI. REI carries the other brands we most often recommend.