UK winter diving – pleasure or purgatory?

By David Parker

When you mention going on a winter dive trip within the club, the responses are usually quite polarised, from “Yeah great, when and where?” to “Are you mad, I would rather stick hot needles in my eyes!”. 

For me, cold water diving does hold some weird pleasure, as yes, there is some pain, but also there is often the rewards of fabulous visibility and the warm glow that comes from the dopamine and serotonin release from cold water immersion. It also helps you keep the skills up because if you can handle your kit with freezing hands in 5 mm gloves, then it will be a doddle in 3mm gloves in the summer. 

The biggest reward from cold water diving is definitely the visibility as it is too cold for algal blooms and after dry periods the visibility can easily be 10 to 15 metres at inland sites. It is brilliant to go to a site such as Vobster and get a truly panoramic view out over the underwater seascape. It never ceases to amaze me that the attractions that you found (bumped into) in low viz and thought were miles from each other, are actually just a few metres apart! Or this could possibly be down to my poor navigation skills in low viz? And in the winter you don’t get that horrible thermocline at around 10m that is so noticeable in the summer in inland sites. 

For the purposes of this blog, cold water will be defined as anything from 5 to 9° Celsius which is the typical range you would experience in a UK inland dive site in winter. 

There are some obvious risks associated with cold water diving that you do need to mitigate if you are going to have a safe, enjoyable dive. Firstly it is recommended that you don’t try it until you have at least built up some experience in warmer open water diving. There are many factors for consideration that are covered in detail in the BSAC training on cold water diving, but the two biggest risks are as follows: 

• Hypothermia – if the core body temperature drops below 35° C then this is the start of Hypothermia and is a serious medical condition if not treated. In addition to having the appropriate kit to stop you getting too cold underwater, one of the keys to safe diving is to follow the principle of not to dive when you are already cold, so if you have not warmed up during the surface interval then it is probably not a good idea to do a second dive.
• Kit failure – with open circuit kit the act of breathing through your regs causes them to cool down and can result in a free flow if you are not careful. This risk is exacerbated by breathing heavily, or by using your octopus to inflate your DSMB. A free flow at the end of a dive with numb hands and little air reserve is not a good situation to be in.

Here are just few top tips on how to mitigate the risks and have an enjoyable mid-winter dip.

How to keep warm:

• Dive in a ‘dry’ dry suit, that annoying cuff leak in the summer translates to a freezing cold, numb arm in the winter
• Wear decent dive gloves, or consider using dry gloves
• Buy a good quality hood as so much heat is lost through your head
• Several thin layers of warm-when-wet thermals are much better than one thick layer (remember to do a proper weight check when you add more layers and not just guess and add on a few more Kgs to compensate – see NSDC Buoyancy tutorial video)
• Eat a proper, slow-burn breakfast such as porridge, the oldies may remember the Ready Brek ‘central heating for kids’ adverts which held a lot of truth. It is surprising how cold you get if you dive on an empty stomach
• Keep dive times short – 45 mins is about the max that is comfortable when the water is 7-8 degrees
• Keep your torch on to ‘be seen’ so your buddy doesn’t have to keep looking around to find you and risk getting a leak down their neck seal
• I was always told that cold water diving gives you an exemption to eat junk food during the break and never has a sausage bap and hot chocolate tasted as good as after a chilly dip! 
• If you do feel the cold then maybe look at buying a heated vest and/or socks suitable for diving. There have been huge improvements in heated garment technology over the last ten years and several club members swear by them
• Wear a hat and gloves when you are not diving and if the wind is blowing put on a windproof top to reduce the wind-chill effect
• Fill your wet gloves & hood with warm, not hot, water before you put them on for the second dive, or use spare dry gloves/hood if you have them

How to minimise the risk of a free flow:

• Try and keep your regs & first cylinder from getting too cold by not leaving them in the car overnight beforehand if frost is forecast
• Maintain good buddy pair positioning underwater to be close at hand in case of a free flow
• Slow down if you are breathing heavily underwater
• Use a crack bottle DSMB or inflator nozzle rather than your octopus reg to inflate your DSMB
• If you start to breathe in ice crystals this can be a precursor to a free flow and it is probably time to call the dive

UK winter diving isn’t to everyone’s taste, but the fabulous viz and feel-good effects can make cold water diving really rewarding, as long as you understand the risks and plan accordingly. And of course winter diving does earn you extra bragging rights, so when your work colleagues ask you “What did you do at the weekend?” a reply of “I went scuba diving in a lake” is likely to gain more interest than just “I sat in front of the telly”!