‘Swell’ is the term used to describe a series of mechanical waves found in the sea or lakes set up by distant weather systems. While chop is generated by local winds, the size of swell is coming from far away.
Swimmers most often encounter swell in the sea. While sea swimming can be an enlivening way to experience the wilderness of our waters, big swell, when the surface of the water is turned into a series of peaks and troughs, has an undeniable effect on the way you propel yourself through the water.
When planning an open water swim in swell, bear in mind:
Check weather and swell forecasts, looking especially for wind strength and direction. White caps on waves will typically start around Beaufort 4 (13-18MPH). A direct on-shore wind will generally cause a rougher water state than an off-shore wind.
There will be times when the water may be too rough – everyone has different conditions that they feel safe in, so listen to your instincts.
Choose your swim spot with the conditions in mind. If your location is facing right into the swell, see if you can find a spot that faces a different direction, offering greater protection. For example, on a small island you can always go from the lee (protected) side of the island.
A key issue that swimmers often overlook is getting out safely. Whether you exit on a beach or onto a boat, this can be the trickiest part of a swim. If you don’t feel comfortable in the conditions, or in getting out, save your swim for another day. Preparation wise, nothing beats experience in the conditions. The more exposure you give yourself, the more confident you will feel.
Look for an entry spot which avoids any objects, natural or manmade, such as rocks, groynes or piers. Avoid any places with rip currents or locations that have heavy boating traffic or are near boating lanes.
Two dangers are: waves ‘dumping’ on the shore, which can make it hard to get your feet down and walk out without being hurt (if the beach is pebbly dumping waves are particularly dangerous); and shelved beaches where there is a huge suck back by the retreating tide – making it hard to get out of the path of the next breaking waves and onto dry land. Be aware that the shape and force of waves and suck back can alter dramatically as the tide comes in and out within the course of a swim – it is always worth talking to locals.
Swimming in a group is good for safety and motivation. One trick when swimming in a group is to keep those swimmers who breathe to the left on the right side of the group and vice versa. This ensures that all swimmers can keep an eye on the rest of the group, reducing the risk of separation. Ideally, never swim alone, but if you do, explain your swimming plan to the lifeguard or let someone know your plans (where and how long you expect to be in the water) and arrange to call them when you finish.
Be aware that it can be hard to see each other in swell – not only can the water quickly move you apart from other swimmers, the troughs and peaks can hide you from each other. Talk about this before you get in and make a plan.
Ultimately, the sea is an awe-inspiring body, and one in which we are privileged to swim. With the right considerations, swimming through mountainous oceans can be exhilarating – an embodiment of the changeable face of nature, which makes our swimming so truly wild.