I'm a anovice kayaker. I got my first kayak last Christmas and fell in love with the sport. To date I have only done local rivers and lakes. The rivers I have been on don't really qualify as whitewater, although I have found myself in some pretty tight spots with serious rushing water. My goal is to expand m kayaking skills this summer, and try out a few larger and faster rivers. I decided to learn a few of the terms in order to be prepared for whatever lies ahead.
Whitewater rafters and kayakers are notorious for speaking in their own language. When you first get involved in rafting and kayaking, it is easy to feel intimidated by your lack of understanding of the lingo. Below is a list of basic terms you will need to know on the river. The list is not comprehensive, but will give you a great source to start sounding as if you know what you're talking about.
CFS (i.e. the flow) -- CFS stands for "cubic feet per second" and is the method of choice to describe the flow of water in a river. The flow is measured by gauge stations set up by the United States Geological Service (USGS). A cubic foot is roughly the size of a basketball, so if a river is running at 30,000 cfs, about 30,000 basketballs worth of water are passing by that gauge every second.
Class -- Stretches of river and their corresponding rapids are generally described by a class system with 1 being the easiest and 6 being unrunnable. Some large rivers in the west use a 1-10 rating system. The rankings of rapids is subjecting and based on the experience of the boaters, the water level, the consequences should something happen, the type of craft, and many other factors. Refer to guidebooks and knowledgeable boaters to determine the class.
Dumptruck -- When everyone falls out of the boat, but the boat stays upright.
Eddy -- When water flowing downstream hits an obstruction like a rock, the channel will move around it, creating an empty space behind the object. The river will fill in that area by flow upstream just behind it, creating an eddie. Eddies are fantastic tools because they can keep you out of the current, provide some gentle water to rest in or deal with an emergency, and can even help turn your boat in big rapids. To "eddie out" means to leave the main current and enter the eddie to stop or slow the boat.
Eddie Fence -- When water flowing downstream meets water flowing upstream it creates and eddie fence (also known as the "Eddie Line"). These typically have strange currents, and very powerful fences can even flip boats. Be aware that a swimmer can be caught in a fence, causing them to be pulled downstream or deeper into the river channel.
Flip -- When the boat turns over. It is possible to do a dry flip, where you jump out of the boat as it is turning over and manage to land on the bottom of the flipped boat without ending up in the water. This requires perfect timing and a lot of luck.
Flood Stage -- Every river section is different based on how steep it is, the type of rapids, the land it cuts through, and the flow. A small creek surrounded by high canyon walls may be at flood stage when it is running 1,000 cfs, while a large river like the Mississippi that runs through open marshland can flow over a million cfs without a ripple. Know the level of the section you are running and what flow it is recommended that you run it.
Gnarly -- A feature that is particularly troublesome, as in, "wow, that gigantic keeper hole is gnarly."
Hole -- Holes are the most notorious features in rivers. Similar to an eddy, when the river flows over a rock or other obstruction, the water rushes to fill in the space just behind the object. This creates a hydraulic. Holes can be very small or house-sized, and can often flip boats. There are several different types of holes:
Flushing Hole -- A flushing hole pushes water to the downstream edge of the hydraulic and generally will not hold you.
Keeper Hole -- A keeper hole has water flushing into the center of the hole from its edges. It may hold a swimmer or a boat for a long period of time and can be extremely dangerous.
Ledge Hole -- A ledge hole is a particular feature created by an obstacle with a sharp dropoff on the downstream side. These tend to be keeper holes and may resemble low-head dams.
Lateral -- A wave or hole that sits at an angle against the current. This can confuse new boaters because you will need to be at an angle to the current to hit these head on.
Pile -- The pile is the white, foamy mess at the crest of a wave. If you want to surf, look for a wave with a big pile to make it easier to stay in the trough.
Pillow -- Formed by water pushing up against an obstacle, creating a mound.
Pool Drop -- A type of river where rapids are spread far enough apart that a large pool of flat water sits below the rapids. These pools are a great place to recover should something go wrong above.
Put-In -- The put-in is where the river trip starts.
RDTFM -- "Right Down the Friggin' Middle." A way boatmen might describe their proposed route through a rapid.
River Left/River Right -- The sides of the river are determined by the boatman facing downstream in the main current, the right side being on her right. Downstream is always based on the main current. If you are floating upstream in an eddy (i.e. opposite the main current), river right and river left do not change.
Rooster Tail -- When water flows against a rock or obstacle with a sharp point on top, it may fling off that top creating a splash that resembles a rooster tail. Finding these from the scout can be a great way to identify where you do not want to be as they provide a good marker when you are in the rapid.
Scout -- Before you enter a large rapid, you may want to take a look at it first. This is called the scout. Pull your boat over to one side of the river and hike downstream to find a good view of the rapid. Look for where the current is pushing, large obstacles to miss, and multiple plans in case the first one does not work out.
Surf -- If a hole or wave is strong enough, it can keep a boat in its trough for an extended period of time. This can happen passively if you are caught unexpectedly in a hydraulic. When it happens actively, it can be one of the most fun aspects of river running. Kayakers especially love to surf and call it playboating. Experienced kayakers can use the water to do flips, 360-turns, and other tricks.
Strainer -- A strainer is anything that water goes through but a person (or boat, or other object) does not. This can be low hanging branches or shrubs on the side of the river, natural dams, driftwood, and clumps of rocks. Strainers are extremely dangerous and should always be avoided.
T-Up -- To hit a hole, wave, or lateral at a perpendicular angle. When you hit the obstacle with just your bow or stern, there is less surface area to create resistance. On the other hand, hitting them broadside gives the obstacle a lot more of your boat to push against and you are more likely to flip.
Take-Out -- The take-out is where the river trip ends. The take-out is always downstream from the put in (no, the boat does not run on tracks).
Tongue -- A tongue is a smooth "v" that generally represents the calmest route to enter a rapid.
Wave -- A wave is the nicer cousin of the hole. It can be formed on top of a hole when the water gets high enough, or just from gradient changes in the river bottom. As water flows over the submerged obstacle creating the wave it speeds up. When it hits the slower water below, it creates a wave.
Wrap -- When the boat becomes pinned against an object. Often requires a rope system or letting air out of the tubes to get the boat off.
Knowing these terms will help you feel more involved as you learn to whitewater raft or kayak. You can also do research on terminology directly relating to the boats and to safety gear. Like all activities, the sky is the limit to the knowledge you can amass on whitewater boating. Now that you are talking the lingo, you can start learning the more complicated aspects of the sport.