I'd be most grateful for any help regarding a lift bag calculation.
I wish to raise a 20kg grapnel anchor from the sea bed at 20 metres depth in salt water. I am happy with the calculation apart from working out the actual volume of the anchor. I have guesstimated the volume but I would be grateful if anyone has experience of calculating the volume of an anchor or has actual experience of lifting an anchor which they would be happy to share? I intend to use a 20kg lift bag. My guesstimate of the volume is 5 - 10 litres but I may be miles out hence this post.
If the object in Salt water 20 m, weighs 20 kg and has a volume of 5 L.
you will need a lift capacity of 15.6 kg (or 15.21 L) and the lift bag will use 257.15 L of air.
If the object in Salt water 20 m, weighs 20 kg and has a volume of 10 L.
you will need a lift capacity of 11.25 kg (or 10.97 L) and the lift bag will use 252.91 L of air.