A diver weighing 170lb / 77kg displaces 3 cubic feet / 85 liters of water. What additional weight is needed for neutral buoyancy in 33ft / 10m of seawater?

To determine the additional weight needed for neutral buoyancy, we first need to understand that neutral buoyancy occurs when the weight of the diver plus their equipment is equal to the weight of the water they displace. Here’s how to calculate it.

The diver weighs 170lbs and displaces 3 cubic feet of water. The volume of water displaced can be converted into weight by using the fact that seawater has an average density of about 64 pounds per cubic foot. Therefore, the weight of the water displaced by the diver can be calculated:

Weight of displaced water = Volume of water displaced × Density of seawater

= 3 cubic feet × 64 lbs/cubic foot

= 192 lbs

Now, to achieve neutral buoyancy, the total weight of the diver must equal the weight of the displaced water. The diver weighs 170lbs, and to find out how much additional weight is needed, we subtract the diver's weight from the weight of the water displaced:

Additional weight needed = Weight of displaced water - Diver's weight

= 192 lbs - 170 lbs

= 22 lbs

Thus, the diver needs an additional 22 lbs for neutral buoyancy in 33ft of seawater. This calculation confirms