Editing Wetsuit (section)

==Buoyancy==
{{see also|Buoyancy compensator (diving)#Variable volume type}}
Foamed neoprene is very buoyant, helping swimmers to stay afloat, and for this reason divers need to carry [[Diving weighting system|extra weight]] based on the volume of their suit to achieve neutral [[buoyancy]] near the surface.<ref name=Williams2003/> Buoyancy is reduced by compression, and is proportional to depth and the amount of gas in the bubbles, and scuba divers can correct this  by inflating the [[Buoyancy compensator (diving)|buoyancy compensator]]. Breath-hold divers do not have this option and have the handicap of reduced buoyancy at depth due to lung gas compression in addition to suit volume loss. The suit also loses thermal protection as the bubbles in the neoprene are compressed at depth.<ref name=Monji1989 /><ref group="note">Non-foamed solid neoprene has a thermal conductivity between 0.15&nbsp;Wm<sup>−1</sup>K<sup>−1</sup> and 0.45&nbsp;Wm<sup>−1</sup>K<sup>−1</sup> depending on type, not very different from water – {{cite web |url=http://physics.info/conduction/ |title=Conduction |first=Glenn |last=Elert |year=2008 |work=The Physics Hypertextbook |access-date=April 27, 2014}}</ref> 

Measurements of volume change of neoprene foam used for wetsuits under hydrostatic compression shows that about 30% of the volume, and therefore 30% of surface buoyancy, is lost in about the first 10&nbsp;m, another 30% by about 60&nbsp;m, and the volume appears to stabilize at about 65% loss by about 100&nbsp;m.<ref name="Bardy2005" /> The total buoyancy loss of a wetsuit is proportional to the initial uncompressed volume. An average person has a surface area of about 2&nbsp;m<sup>2</sup>,<ref name="Gallo 2017" /> so the uncompressed volume of a full one piece 6&nbsp;mm thick wetsuit will be in the order of 1.75 x 0.006 = 0.0105&nbsp;m<sup>3</sup>, or roughly 10&nbsp;liters. The mass will depend on the specific formulation of the foam, but will probably be in the order of 4&nbsp;kg, for a net buoyancy of about 6&nbsp;kg at the surface. Depending on the overall buoyancy of the diver, this will generally require 6&nbsp;kg of additional weight to bring the diver to neutral buoyancy to allow reasonably easy descent. The volume lost at 10&nbsp;m is about 3&nbsp;liters, or 3&nbsp;kg of buoyancy, rising to about 6&nbsp;kg buoyancy lost at about 60&nbsp;m. This could nearly double for a large person wearing a farmer-john and jacket for cold water. This loss of buoyancy must be balanced by inflating the buoyancy compensator to maintain neutral buoyancy at depth.

There is also a buoyancy loss due to gas loss from the bubbles over time, and the neoprene also loses flexibility with time, and tends to stiffen and shrink. This tendency is exacerbated by frequent use, deep dives, and exposure to sunlight.<ref name="Monji1989" /> The "compressed neoprene" and "crushed neoprene" used for [[hot water suit]]s and [[dry suit]]s, is permanently reduced in volume by intentional hydrostatic compression during the manufacturing process, specifically to reduce buoyancy change with depth, at the cost of reducing insulation.<ref name=Barsky />