When donning your cylinder at the surface and underwater, the primary difference is that you want to be:

When donning your cylinder at the surface and underwater, the primary difference is that you want to be:

• A. Negatively buoyant at the surface and positively buoyant at the bottom
• B. Buoyant only at surface
• C. Positively buoyant at the surface and negatively buoyant at the bottom
• D. Neutral buoyancy at all times

Answer: (C)

The idea here is to use buoyancy to make the donning process easy at the surface and then descend with control once underwater. At the surface, you want to float so you can dress and gear up without fighting to stay above water. Once you’re in the water and ready to descend with the cylinder on, you want to be heavier than the surrounding water enough to sink with the gear in place. In practice, that means you’re positively buoyant at the surface and become negatively buoyant as you go deeper, so descent is smooth and controlled. You can then use the BCD to dial in buoyancy at depth as needed. Being neutral all the time would make adjustments harder; being buoyant only at the surface would hinder descent; being negatively buoyant at the surface would cause you to sink before you’re ready.

The idea here is to use buoyancy to make the donning process easy at the surface and then descend with control once underwater. At the surface, you want to float so you can dress and gear up without fighting to stay above water. Once you’re in the water and ready to descend with the cylinder on, you want to be heavier than the surrounding water enough to sink with the gear in place. In practice, that means you’re positively buoyant at the surface and become negatively buoyant as you go deeper, so descent is smooth and controlled. You can then use the BCD to dial in buoyancy at depth as needed. Being neutral all the time would make adjustments harder; being buoyant only at the surface would hinder descent; being negatively buoyant at the surface would cause you to sink before you’re ready.