Let someone responsible know exactly where you are going and tell them how long you’re going to be.
Never swim alone and keep an eye on your swimming buddies.
Conditions at a normally safe location can change from day to day. Also, know your limits. If you have any doubts about safety don’t enter the water.
If you start to shiver, or lose control of your fingers, while swimming, get out and warm up. Wimp suits – sorry wetsuits! – will keep you warmer in the water, although for aquabuddhist purists they are a ‘no no’. A wetsuit, particularly a triathlon wetsuit, will also make you more buoyant and help you swim crawl faster. The additional buoyancy, however, will make breaststroke more difficult. Wear a latex swimming cap, the thicker the better; a lot of heat is lost through the head. Use ear plugs to keep cold water out of your ears.
Warm up quickly after your swim. Get dried and dressed briskly, putting on warm clothes. Once dressed, have a warm drink.
Consider the security of your belongings on shore. It may be worthwhile hiding your keys under a rock or in the branches of a tree, rather than leaving them in your pockets; that way if someone steals your clothes you can still warm up in the car.
Know how you will get out before you enter the water.
Think about wearing aqua shoes; it’s very easy to cut numb feet on sharp rocks unknowingly.
Who says you can't be sexy in a wetsuit?.
Avoid blue-green algae; it can cause a rash and irritation of the eyes. It is most common in late summer on the downwind side of loughs. It is recognisable as a green scum.
Don’t swim with a major open wound. Cover minor cuts with a waterproof plaster to protect against Weil’s disease, an illness caught from infected animal urine. If you develop flu-like symptoms or become jaundiced within two weeks of swimming (particularly in slow-moving water close to farms or where a high rodent population is suspected) go to your doctor.
Treat currents with respect. Is the current faster than you can swim? In fast-flowing rivers, where you intend to swim with the flow, decide where you’ll get out before you get in and plan how you’ll become reunited with your clothes.
When swimming in a tree-lined lough, consider tying something conspicuous (perhaps a spare towel) to a tree that will be visible from the water; from a distance it can be difficult to identify where you left your clothes and got in.
In the sea
Keep within coves and bays; they are sheltered from the currents that may run past headlands.
If unexpectedly caught in a rip, a localised current pulling you out to sea, don’t try to swim against it. Instead, swim parallel to the shore until you’re out of the rip, then head for shore.
Fast flowing water is inherently dangerous.
Several of the contemplations in this book involve jumping. Always check the depth before jumping, even in places where you’ve jumped before; depths can change and new underwater obstructions can appear. Keep your legs together on entry and allow your knees to flex underwater; this way, any unforeseen encounters with submerged objects will be less jarring. Also, keep your head up and your arms close to your body.
Avoid obviously polluted water. For more information on water quality see the Northern Ireland Environment Agency's website.
Don’t swim near rocks in fast-moving water.
Weed scares some people (although I enjoy swimming through it). If you encounter weed, stay high in the water and kick as little as possible. Your limbs are less likely to become entangled if you crawl rather than breaststroke.