Hurghada Days

[MATTBIN]

the air drops to the bottom of the cylinder when upside down?
Matt

[Jay]

Ok Paul - a more serious answer. Its probably to do with not having a reference point when lying on your back looking upwards. You are constantly adjusting your depth minutely through your breathing when 'right side up' and are using visual points of reference in doing this. Next time you are in deepish water with no visual points of reference (or any depth in Stoney!!), check your depth, then attempt to maintain your depth through normal breathing with no visual reference points then recheck your depth. I bet it'll have noticeably changed.

Do I win the prize?

[Gavin Yates]

Or could be this:-

As you're an ankle weight wearer (I think) your normal diving position will be head slightly above feet.

This causes you to fin slightly upwards as you go along - in effect being very slightly negative keeps you in position - hence you adjust your boyancy to reflect this.

When you swim on your back your diving position changes and you will start to sink unless you add a small ammount of gas to the BCD.

It's a theory .....

[Lou]

Or how about...

Your lungs are actually in your back, rather than your front.  When you roll over they probably lose about 0.3-0.5m of depth and just start you sinking.  Once you start of course it only gets worse...:)

Just as good as the rest!

In fact better than Gav's because he is suggesting that you fin to hover - subtract points from that man!!:shocked:

[PaulC]

Great thoughts guys!

Actually Gav ignoring the grave 'fin to hover' insult I don't wear ankle weights with a wet suit but fair enough I didn't make that clear. Jays (second) explanation seems the most likely but Lou's is more elegant - you share the prize at the moment (you will need straws). Any more takers?