Wednesday, October 3, 2018

Rips and Undertow explained

For many of us, after the calm of summer come autumn winds, and with the winds, rougher conditions along the coast. This is a time when it’s good to remember that hand in hand with the tumbling surf  comes the danger of undertow and rip currents that pull away from shore.

Powerful shore-break on Brighton beach can create undertow

Rips are formed by surf when white water tumbles down the face of breaking waves toward shore. That water then escapes along the beach to a deeper channel cutting out to sea through the surf line as a rip current. Beyond the break line, the current dissipates. Rip currents are relatively narrow and focused currents, that can flow much faster than a swimmer can swim. The water carried to shore by the surf will drain along the beach until it reaches a rip. You can often feel the sideways pull of this alongshore current against your ankles in shallow water, and by walking downstream locate the rip. If you pass the rip, you’ll feel the water flowing in the opposite direction.

Arrows show rip current. Look for breaks in the lines of surf and also moving water

Viewed from shore, the rip will appear as moving water with more confused wave patterns than the surf on either side, and with smaller waves. The scouring effect of the current gouges out a deeper channel. As the waves push in and slow against the current, they converge and crisscross and run off to either side, leaving a visibly calmer channel. Rips are most easily seen from elevation. Once you have located a rip, look for landmarks that will help you locate it from the water.
If caught in a rip, escape by swimming across the current. Once you are out of the current the surf will help push you toward shore again. You’ll be quickly exhausted if you try to swim to shore against the rip current and if If you do nothing, you’ll be carried beyond the surf, so swim across the current.
Launching through surf to sea kayak, or to go surfing, the rip can offer an easy way through the break. (You can also read more in my book The Art of Kayaking).In a rip the waves are smaller and more broken, and the current will help carry you from shore. The danger is that once you’ve been carried out, you’ll find the conditions more than you bargained for, and have difficulty returning to shore.

A rip can easily help carry you out farther than you might want

So, although paddling out against the surf can be exhausting, it’s best to locate and then avoid the rips to start with, at least you know how big and powerful the waves really are today. When battling through waves from the beach between rips, you can easily turn back when you choose, before you meet the biggest waves. If you find yourself beyond the break, waiting for a big set to ride the biggest waves, and you are comfortable with the conditions, then you might consider using a rip to make your paddling out easier.

A rip is not the same thing as undertow, although you’ll often find the terms misapplied. Undertow is caused by shore-breaks, rips are caused by surf. But the two sometimes work together when there is both surf and a powerful shore-break. Undertow is caused by the backwash returning down the beach after a wave has broken. In certain wave conditions beach cusps form as a series of scooped out hollows separated by spurs pointing seaward. Each beach cusp focuses the power of the shore-break into a tongue of water rushing up the beach which drains back into a narrow channel of rapid water often powerful enough to sweep a person from their feet. This focused backwash drags through the next breaking wave, so it can carry an unwary person beyond the shore-break into deep water.
Returning safely to the beach might require outside assistance: for example, a throw-line.

Beach cusps funnel backwash into jets that push out to sea as undertow

When a beach has both a sizable shore-break, and lines of breaking surf, you can find both undertow at the shore, and rips running out through the lines of surf. The undertow can feed a swimmer into current that runs into a rip. The rip can deliver the swimmer beyond the break into ocean current. People swept from a beach by undertow don’t always return.
Rips and Undertow are beach hazards. The Rips and Undertow Video Presentation takes about ten minutes and shows more clearly what is going on. If you find it useful, please spread the word, and be safe!

Wednesday, May 23, 2018

What makes a kayak side-slip?

A side-slip is a satisfying smooth sideways glide that makes use of your forward speed. You can use it to approach a dock or another kayak without turning.

Side-slip. Upright paddle, blade behind hip, blade face engaged

There are several factors key to success.

1) Start by paddling forward in a straight line

2) As you glide forward, position your blade upright in the water alongside your kayak in a neutral position. That is, so it does not grab the water with either the face or the back of the blade.

3) Position the blade a foot or so behind your hip, a few inches away from the side of your kayak.

4) Gently engage the face of the blade by rotating the leading edge (the blade edge nearest the bow of your kayak) just a few degrees out from the side of your kayak.

5) Your kayak will do one of three things: slide gently sideways, turn toward the paddle, or turn from the paddle. If it turns toward your paddle (as in a bow rudder) move your blade back. If you turn from the paddle (as in a stern draw) move your blade forward until you eliminate the turn.

6) Once you have found the perfect blade position for a side-slip, you'll notice that as your kayak loses forward speed it will begin to turn from your paddle. This will occur because your center of turning will move forward as your kayak slows. To prevent the turn, gradually move your blade forward toward your hip as you slow.

The side-slip is a draw stroke. If you start from standstill to draw sideways, you place your blade and pull your kayak toward it until the blade reaches your hip. When you are moving forward your center of turning/pivot point moves back, so you must position your blade behind your hip for the side-slip and move it gradually forward to your hip as you slow. To make a side-slip work in reverse, begin with your blade forward of your hip and gradually bring it back as you lose speed. You'll need to open the blade toward the stern by rotating the leading edge of the blade away from the hull by a few degrees. The leading edge when you reverse will be the edge nearest the stern.

You'll find more detail in my book "The Art of Kayaking"

The Art of Kayaking by Nigel Foster

Tuesday, April 10, 2018

Kayaking and the desert

Music breathes softly through the cracks between the spot welds of Ricardo Breceda’s magnificent desert sculpture as the hot breeze fills its cavernous body. In its escape, as from the bellows-filled bladder of Northumbrian pipes, the air makes music.

Ricardo Breceda's desert sculptures breathe with the breeze

Music is not the main purpose of Breceda’s sculpture, but as I move through the desert to stop at each massive monument I can hear the breeze playing across the surfaces.

Heavy metal guitar, but the desert music whispers

The sounds remind me of the diverse water songs I hear in my more usual environment paddling kayaks and canoes. Many of these sounds I create myself as I strive for efficiency. Maximum effect for minimum effort plays its own tune, a different one from maximum effort with indifferent efficiency.

An efficient stroke sounds different from an inefficient one

There’s the rush of water when I pull too hard and my blade drags through the water losing traction. There’s the quiet “sip” sound when I slice my canoe blade edge-first from the water after a stroke, a sound I hear from my wooden blade but not from my carbon one. There’s the plop of blade entry when the trajectory is poor.

A carved turn sounds different from a skid turn, an efficient stroke sounds different from an inefficient one. The slap of kayak against wave subdues when I tune from out-of-sync to in-sync paddle strokes.

A skid turn sounds different from a carved turn

When I listen I can hear these water sounds like the song between the metal plates of the desert sculptures, but it’s easy to miss their significance when there’s a lot going on. It's better to start listening on a quiet day.

Nigel Foster's newest book "The Art of Kayaking" explores how to get maximum effect for minimum effort, and this mantra has influenced his kayak and paddle designs.