I am surprised that no-one has told you to make a check list.
I made a check list to suit my own aircraft for when I was over the sea.
I assumed that should an engine fail, I would be at a sensible height over the water and would therefore have quite a few minutes before getting down to ditching level.
Making the list was good in itself as it made me think specific to my own aircraft.
After basic engine failure checks I listed in order the things that might get muddled. Things like get your position from the GPS and write it down, call mayday then remove headset and get the rubber helmet of the wetsuit on. Get the rubber gloves on. Make sure the location beacon is handy and clipped to you not the aircraft, deal with passenger, make sure the door is unlatched.
I can't remember all the things but I know that there would be plenty of time between cruising height and water level to do things methodically.
Getting down to water level will be the easy bit it is entering the water that it is all about. Your screen will likely come in and you may have problems getting out. If you prepare yourself for the cold shock and an upside down position you will be less surprised when it happens. Remember your engine will very likely try to take the craft down so getting out is important.
I have never been impressed by inflatable dinghies unless they get outside by themselves, can you imaging trying to heave one from the back seat of a PA28 for example and then it not being in the way when you try to get out. A full immersion suit is the only way.
So among your book of checklists have a 'ditching' checklist.
Off to Jersey...
