Hi Terry, water temperature would of been between 14-16 degrees c. There was a noticeable on shore breeze, which I think lowered my body temp down before I even entered the water. I have swum in similar water but always in my wetsuit with a cap on too. We are enjoying the warmest and longest spell of warm weather in the UK for possibly four or five years. I can only assume this has affected my judgement! I must of confused Irish Sea with the Med.
On a serious note, I now understand that when your core body temperature goes into freefall, you had better have a back up plan. The sudden lack of coordination was a real shocker for me, and I can now see how even 'strong' swimmers can get into difficulty. Acclimatisation is the obvious message here. Hopefully my message may make somebody think twice before just 'going for it' in water that they are not yet ready to deal with.