This question wants to know the difference between the objects downward force; its weight and its upward force; the displacement. The fact that the object is heavier than the water it displaces means it is negatively buoyant and to move it we must first make it neutrally buoyant.
Since we need to find the volume of air to be added to the lifting device we need all numbers converted to litres. the weight of the object; the anchor weighing 22 kgs must be divided but the type of water it is displacing. 22/1.03=21.36 (rounded to 2 DP)
This is the total volume of water that needs to be displaced to lift the anchor. Since we already have 18 litres of displacement in our favour already we subtract that from the total required, 21.36-18=3.36.
This is the amount I need to fill a lift bag with to remove the anchor from the bottom.
In Section Three of the Advanced Open Water Course Guide of the Instructor Manual, there is a really great quick reference great table. This includes which Instructor may conduct which Adventure Dives, what materials are required and the minimum age of participants in the Adventure Dive itself.
Think of this as the AOW Key Standards.
The Earth's rotation causes something called Coriolis Force. The deflection of an object due to this inertial force causes the Coralis Effect.
The Coriolis Effect is the reason the major currents in the Northern Hemisphere move in a clockwise manner and a counterclockwise manner in the Southern Hemisphere.
Semi-Closed Units generally supply one breathing mix at a time. The gas enters the breathing loop at a constant rate so oxygen in the mix may be replenished as the diver consumes it.
Excess gas must be constantly vented from the loop to keep the gas in the breathing mix correct. Inert gas and breathing gas cannot be separated making it inefficient in the oxygen reserve.
General Rules for the PADI RDP can be found under Table 3. It states that you must plan as if diving 4 metres deeper than actual depth.
This is a logical step to counteract the increasing amount of Nitrogen entering the body due to a higher breathing volume.
An example would be diving to the NDL at 18 mteres would mean a dive of 56 minutes. If planned 4 metres deeper than actual depth, 22 metres, the NDL is decreased to 37 minutes to indicate the increased amount of inert gas calculated to be in the diver's tissues.