They are similar in a lot of ways so it's easy to get them confused.
There are two types of kayaks: open top (sometimes called sit-on-top) or enclosed hull boats. In either type, the paddler sits with their legs stretched in front of them and paddles using a double blade paddle (they don't have to flip it around to paddle on both sides). An enclosed boat may or may not have a spray skirt attached. A spray skirt fits around the paddler's waist and attaches to the opening of the hull, forming an almost watertight seal, this is useful in situations where there may be lots of waves or spray. Experienced paddlers may also be able to flip their boat right-side up if they have rolled over while wearing a spray skirt. Kayaks come with either a well defined keel, or none at all. If a kayak has a keel, it is used for flat water, to go straight with little effort. If a kayak has no keel it is used for quickly moving water where it is important to be able to turn quickly.
A canoe also has two types: a flat water boat, or a white water boat. The main difference is in the keel of these boats. Flat water boats have a very distinguished keel on the bottom to help them track straight in the water, white water boats have none. Another distinguishing feature of these two types of boats is the shape of the bottom. Flat water boats have flat bottoms and white water boats have curved, this also helps in turning. An easy way to tell if you're looking at a flat water or white water boat without flipping it over is to look at the center of the inside of the boat, if there looks like a dotted line running from each pointy end, then it's a flat water boat, that line is where the keel is. Canoes of either type are paddled with a single blade paddle, the paddler generally sits on their knees in the bottom of the boat (if they're smart) and NEVER on the seat (which causes the boat to be unstable).
Here's a few things that CAN but are not necessarily similar between the two types of boats:
- both can be paddled single or tandem (2 people)
- both can be used on flat water (lakes) or white water (rivers with rapids)
- you should wear a coast guard approved PFD whenever in EITHER boat (not just have one on board)
- in most states (not all), neither type of boat has to be registered
- both are generally not motorized (although some canoes have flat backs so a small motor could be attached)
- both can be made of advanced forms of plastic to be sturdy and lightweight
Here's a few differences:
- open top kayaks (those without spray skirts or enclosed hulls) are generally used in the ocean
- some kayaks can have attached rudders, that are used to turn the boat while paddling that are controlled through foot pedals (canoes don't have this feature)
- canoes can carry more than 2 people in some circumstances, there is a mathematical formula to figure out how many people can board a canoe, a general rule of thumb is that a 15 ft boat can carry 3 people maximum (kayaks will carry 2 max if they are a tandem boat)
- a single person can easily paddle in a tandem canoe, they simply sit in the middle and face the back and the boat will stay 'trim' (balanced in the water) but not a tandem kayak
- kayaks sit lower in the water, but have less 'drag' (boat touching the water) and are therefore paddled with less effort
- you will not find a metal kayak
- aluminum flat water canoes are common (and sturdy!)
- kayaks usually appear to be smaller
Hope this helps!
I'm a canoe and kayak small craft safety instructor for the Red Cross.