Kayarchy - the sea kayaker's online handbook and reference


Paddling your sea kayak (7)

Advanced sea kayaking — fast-moving water & surf

Kayak in white water

When you're sea kayaking, waves are inevitable but strong currents and surf are optional. Some kayakers seek them out and play, others use chart and tide tables to avoid them.

Where there is a large vertical tidal range, all that water has to get from one place to another every six hours so there will be fast tidal streams, flowing like rivers in the sea. Tidal streams speed up when they go over reefs, through narrow channels and round headlands. If the average speed of the tidal stream is 2 knots or more then where it speeds up locally it can create isolated features similar to those in a river. At a headland projecting into a current of 3 knots there will often be features like a whitewater river.

Is it a whitewater day?

For a trip to a playwave at sea, consider taking whitewater equipment instead.

That means a short polyethylene kayak capable of doing eddyline turns, cross-current moves, going vertical (if the water's deep enough), surfing on stationary waves, and tricks such as 360s, flat spins, squirts and cartwheels. See Whitewater Playboats.

We would fit a full set of inflated buoyancy bags and take a strong paddle, a helmet, two or three friends who understand whitewater rescue, and some throw-lines. You can't really use a throwline from a kayak (there's a good chance of ending up wrapped up, upside down) but there's a handy rock alongside most playwaves so you can have somebody standing on it, ready to throw a rope to anybody who takes an accidental swim before the swimmer is carried away by the current. You may also want a chase boat, which is somebody in a kayak just downstream, ready to go after swimming kayakers or lost equipment.

Throwline for white water rescueA throwline is just a fabric bag containing some foam flotation and about 65 feet of floating rope, usually the same 7.5 mm (9/32") 8-plait braided polypropylene rope you would use for a towline. One end of the rope is attached to the bag and has a loop tied in for a swimmer to grab. Usually a 6 inch length of PVC tube is slipped over the rope before the loop is tied, to keep the loop open and make life easy for the swimmer. The rest of the rope is stuffed into the bag foot by foot, starting at the end that's tied to the bag. Never coil or bundle the rope outside the bag before stuffing it in, or it won't run out properly when you throw the bag.

Undo the neck of the bag, hold the other end of the rope and throw the bag to pass over the swimmer's head.. When you have thrown it, don't stand in such a way that you get pulled into the water when the rope tightens (sitting is better). Don't wrap the rope round your wrist or any other part of you because this may prevent you letting it go in an emergency. Make sure you can easily reach a knife.

If you're taking a throwline you probably also need a whitewater PFD with quick release "chest harness" belt, cow's tail and carabiner. Whitewater assessment and rescue are technical matters, and they are beyond the scope of this website. Before you visit any of the major whitewater play spots we mention in this section, we recommend you go on a course or get a specialist book.

The shape of fast water

The mythical headland of Reef Point represents all those thousands of places at sea where you can enjoy fast water in your sea kayak, with no need for specialist equipment. Here's a eagle's view showing the headland, the lighthouse and its driveway, and the rocks lying offshore. If it was a chart, it would also show lighthouse data, heights and depths. A chart, even on a large scale, would not show any tide race, overfall or back eddy because there's nothing here which would affect a ship or fishing boat.

Diagram of sea eddies 1

The current atlas says that when we arrive there will be a 3 knot tide running north to south, so we can be sure that there are back eddies and standing waves of interest to a kayaker. We can predict that they look something like the image below.

Diagram of sea eddies 2

The current speeds up when it is constricted by Reef Point and the islands. The large black swirls are back eddies, slowly rotating. The blue swirls are turbulent eddylines that separate them from the fast current. The white areas represent breaking waves where a very fast current pours through a narrow, shallow gap between islands, and foam being carried away down-tide.

Back eddies

Diagram of sea eddies 3Where a rock or headland sticks out into a tidal stream flowing along the coast, it will create a back eddy or counter-current. This is a horizontally-rotating area of fairly calm water downstream of the obstruction. It is separated from the fast stream by a turbulent "eddyline".

Just downstream of the constriction, the eddyline will be a distinct, narrow barrier between the fast stream and the back eddy. In the next 10 or 20 yards the fast water will slow down a lot, and the eddy line will become wider and less distinct.

For an experienced kayaker who knows (s)he will do a kayak roll after every capsize, it is really good fun to paddle in and out of these fast streams of water. A beginner can get the feel of a weak eddyline by sticking the front end of the kayak into fast water while nearly stationary. Crossing a narrow eddyline into a fast, powerful current takes some determination. The eddyline will resist a weak attempt to cross it, so you have to paddle hard and fast. You also need some technique. If you cross it at a coarse angle, the water in the fast stream will snatch at the underside of your kayak unless you have a raised upstream edge and a low brace. See Breaking In, Breaking Out.

Standing waves

Kayaker surfing small standing wave

A friendly standing wave is the perfect place for practicing your surf technique. On any rocky coast with a large tidal range you will find a small one every few miles. This one is in water about 3 feet deep next to a low rocky headland. All around, the surface is smooth and the current is about 1.5 knots, but at this point the stream pours over an underwater ledge and creates a standing wave just downstream. The current under the kayaker is flowing from left to right at about 8 knots.

When the tide is flowing most strongly round a headland or through a channel you will often find a standing wave to play on, and sometimes a second or even a third standing wave parallel to the first but a little further downstream. If you prefer to avoid standing waves, you can just go round them 10 or 20 yards away, or go past them at slack water when all will be calm. Slack water often corresponds with the time of local high water or low water, but not always.

A few playwaves have an international reputation. For example:
• The Sechelt rapids, Canada. In the Skookumchuck narrows, north-west of Vancouver. Usually fairly friendly.
• The Falls of Lora, Scotland. North of Oban at the mouth of Loch Etive. Standing waves, turbulence of all sorts. Often creates whirlpools more than 3 feet deep which local kayakers like to play with. Sometimes unfriendly (the Falls, not the kayakers). www.fallsoflora.info
• The B-tches, Wales. Between Ramsey Island and Pembrokeshire. Sometimes downright unfriendly. See Example Of A Hole.

With the right swell, tide and light winds you can find friendly deep water playwaves in some other tide races and tide rips. In Scotland there are the Grey Dogs between Scarba and Lunga. Welsh sea kayakers go to Holy Island off Anglesey to surf in tide races off Penrhyn Mawr and North Stack.

Diagram of standing waveA friendly standing wave looks and sounds friendly. It isn't very high, it has a fairly gentle, glassy slope on the upstream side, and the crest is probably not breaking. There is no long twisting tail of boiling turbulence downstream. If it was in a more accessible location, probably there would be lots of 10-year-olds jumping in above and being carried down through it. Beginners and intermediate sea kayakers can surf on the upstream face, do break-ins and break-outs (see next page) and try high-speed ferry glides from one side of the wave to the other. A ferry glide along the face of the wave is called a high cross. Good fun, and good practice especially if there is a convenient back eddy in which the inexperienced can be retrieved and put back in their kayaks.

Let's say the wave is a bit bigger and more turbulent, the crest is breaking but you are sure this is not a hole (see below), and you are feeling adventurous. You are sitting in the back eddy alongside the top of the wave. You have not been put off by the roaring noise or the mist of spray, and you are giving serious thought to sprinting across the eddyline and dropping into the trough in front of the wave, to see what it's like to surf it. Not such an odd ambition - we do it all the time! Just be aware of the turbulent tail snaking away downstream. If you capsize, the turbulence may mean that your first attempt at a roll is unsuccessful, so hang in there and try again. Keep an eye on each other, because anybody who goes for an accidental swim will be carried off downstream very rapidly.


Standing waves are usually fun. Holes are seldom fun, and can be genuinely dangerous.

Diagram of whitewater holeThey may look similar (a ramp of fast water leading down to a stationary wave with a pile of foam). The big difference is that in a hole, a lot of the water in the foam pile is flowing upstream. Holes are a frequent feature of whitewater rivers. River kayakers generally avoid them by going to right or left, but the occasional safe one will attract playboaters. Before they play, they will set up safety cover so that there are people on dry land holding throwlines, and a chase boat to retrieve anybody who goes for an accidental swim.

Holes are quite rare at sea. They exist where a strong current pours over a ridge of rock, and they appear and disappear as the current changes speed and direction and as the tide rises and falls. One which is large enough to be a danger to ships or boats will be marked on the chart as an overfall. See Overfalls & Tide Races.

We give some pointers here, but please don't approach a hole unless you have the experience to assess whether it is reasonably safe, how to set up safety cover, and whether other members of the group have the necessary skill to approach it without going for a bad swim.

A hole is created where water pouring over a ridge of rock plunges down deeper on the other side, making a hole in the ocean. Not just the crest but the whole top half of the wave breaks continuously in a flurry of white foam. If the top half of the wave is pouring back upstream so that it is difficult to get a kayak through it or over the top, it may be called a stopper, keeper or hydraulic.

The diagram above shows a big hole with a lot of water pouring down the ramp and a tall stopper wave. This particular one is actually not too hostile, most of the time. Click here for a photo.

If you are tempted to play, it is best to inspect an unfamiliar hole from the side while standing on dry land.

The kayaker in the diagram is using a faster but unsafe technique by inspecting from above while seated in his kayak. An experienced whitewater kayaker will often do this. Usually the water at the top of the ramp is shallow, which means the water above the ramp is horizontal and flowing quite slowly. It is often possible to approach in your kayak from upstream until you can look down the ramp, paddling backwards all the time. This kayaker has been over-confident, definitely doesn't like what he can see in front of him but may have left it a bit too late to paddle backwards.

If he goes down the ramp, his kayak will go under the foam pile, where all the water is flowing downstream. The kayaker will be hit in the chest and face by a powerful current flowing back upstream. If he paddles as hard as he can down the ramp, leans hard forward to reduce the impact, plunges his paddle deep into the water beneath his kayak (because that at least is flowing downstream) he should get through. But he may not, and that is why it is called a stopper.

If you try to punch through a stopper and don't make it, after a second or so the water will turn you sideways and you are in for a memorable ride. You will capsize unless you raise the upstream edge of your kayak, and you will probably have to do a low brace on the downstream side. Getting out of a small hole is usually easy, just paddle forwards or backwards, but see Stuck Sideways In A Hole.

Small holeHoles come in all sizes but in each case water is constantly recirculating, flowing back upstream.

This is a small one, revealed only by a band of foaming white towback across the kayaker's path, and it makes hardly any difference to the kayak's progress. But if you drop into it sideways it will stop and hold you.





    Go to next page for:
Example of a hole
Holes & sea kayaks
Stuck sideways in a hole
Dangerous holes
and the new topics of:
Breaking In, Breaking Out
Ferry Glides
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