I recently found this question in PaddlingLight’s inbox (BTW, I answer all questions that I receive. Sometimes they spark article ideas):
I am considering the Siskiwit SOF build. My son & I are about to skin a Sea Tour 17 Explorer, but I haven’t formed the cockpit yet. Can you enlighten me on the different cockpit shapes? I see round, oval and egg shaped with “arm rests”(?) at the narrow end.
So, what kind of kayak cockpit should you buy or build?
I personally like the egg shaped with the “arm rests” cockpit, which is called a keyhole cockpit. The “arm rests” are knee or thigh braces (depending on where they hit you) that help you stay in contact with the kayak. I like one that measures about 31 to 32 inches long and 16 to 18 inches wide. A round or small oval cockpit is called an ocean cockpit and it gives you lots of contact, but it’s hard to get into, especially if the kayak has a high rear deck or low front deck. A large oval cockpit, like you’d see on a recreational kayak, is easy to get into, but lacks contact. The keyhole attempts to give you best of both worlds, it’s easy to get into and has lots of contact. That’s the way I’d go.
Most ocean cockpits are either round, oval or elliptical in shape. The typical ocean cockpit size measures 16 to 20 inches wide and 21 to 26 inches long.
Pros: Because it’s small in size, your knees and thighs come into direct contact with the kayak’s deck, which can give you extra control over the boat and helps in rough water or during rolls. Some paddlers build a masik, a traditional deck beam spanning the width of the deck at the front of the cockpit opening, into their kayaks with foam or in a skin-on-frame with wood. This provides even more contact and control.
With a smaller opening, a spray skirt can also be kept similarly small. This helps prevent the cockpit from imploding in surf or other rough water situations. The small opening also keeps the deck closer to you, which means that your chart case is closer and easier to see, especially if you have failing eyesight but don’t need glasses all the time.
Cons: While the small opening of a keyhole cockpit has many advantages, it also has disadvantages. The primary disadvantage is the ease of entry and exit. To get into the cockpit, you need to sit on the back deck and slide your legs into the hole. If the difference between the height of the front deck and rear deck at the cockpit coaming is small, then getting in is even more difficult. This disadvantage can also make rescues difficult. For reentry and roll, I’ve found that I have to somersault into the cockpit, and for assisted rescues, I need to slide my legs in the correct direction instead of sliding in belly down and twisting. It requires different techniques.
Keyhole cockpits are generally pear shape measuring 16 to 20 inches at the widest point and 30 to 32 inches long. Near the front, they have thigh braces, sometimes adjustable.
Pros: Keyhole cockpits are easy to get into and out of. You can easily sit your butt down into the kayak’s seat and pull your legs in after you. Or get your legs out first and stand up. The easy of entry helps during rescues because you can slide in with your belly down, which is easier, and twist to sit upright. Boats with adjustable thigh braces also offer a custom fit that an ocean cockpit may not be able to offer. A keyhole cockpit also allows you to slide a leg up during the day to help stretch your legs.
Cons: The larger cockpit gives less contact than an ocean cockpit, and it also has a larger sprayskirt which may more easily implode in surf or rough water. Modern neoprene skirts mitigate this issue though. The length of the cockpit keeps your chart further away unless you get a skirt that has clips for a chart.
Large and wide opening often oval or squarish in shape. They often measure 20+ inches wide and 36+ inches long.
Pros: Easy to get into and out of. If you’re not going to wear a sprayskirt, you may get a nice tan.
Cons: Little to no thigh contact offers little control over the cockpit. Your chart sits far away from you. Even neroprene skirts — if you can find one this big — may implode in rough water. These large cockpits are designed for kayaks that should be used on warm, calm lakes.