Initial Reports, Volume 206
Ms 206IR-103
Chapter 3, Table T1. Operation acronyms.

Acronym	Defininition	Comment

APC	Advanced Piston Corer	A coring tool
APCT	Advanced Piston Corer Temperature tool	An APC coring shoe with termistors for making temperature measurements 
BCR	bi-centered reamer	A bit used to open holes to a larger diameter than the bit diameter
BHA	Bottom-hole assembly	The bit, the thick-wall joints of pipe, and other parts that are at the bottom of the drill string
CADA	Cam-actuated drill ahead	A casing running tool made by Drill Quip
DDI	Downhole Designs, Incorporated	A company
DP	Dynamic positioning	A shipboard navigation system
EOP	end of pipe	The end of the pipe
FMS	Formation MicroScanner	A logging tool
gpm	Gallons per minute	A circulation rate for fluids out the end of the drill pipe
GPS	Global Positioning System	A satellite navigation system
GUATB-03C	Guatemala Basin site selected for drilling	Now known as Site 1256
LGH	Lower guide horn	A guide located below the moonpool that keeps the pipe from getting bent sharply at the base of the ship
mbrf	Meters below rig floor	Depth measured from the rig floor
mbsf	Meters below seafloor	Depth measured from the seafloor
PDR	Precision depth recorder	An instrument for estimating water depth
PFT	Perfluorocarbon tracer	A dye used for microbiological cotamination tests
RCB	Rotary core barrel	A coring tool
ROP	Rate of penetration	A coring or drilling penetration rate
spm	Strokes per minute	A circulation rate for fluids out the end of the drill pipe; 1 spm ? 5 gpm
SSR	Subsurface release	A tool used for connecting to and releasing from casing
TDC	Tapered Drill Collar	A tapered heavy-walled tubular that is part of the BHA
UTC	Universal Time Coordinated	A time standard
VIT	Vibration-isolated television	The camera that is lowered along the drill string
WHC	Wireline heave compensator	Reduces motion of wireline tools by compensating for ship heave
WOB	Weight on bit	The weight at the bit
WOW	Waiting on weather 	An operational delay caused by weather conditions
WOW	Waiting on whales	An operational delay in using the seismic guns because whales were in the vicinity
XCB	Extended core barrel	A coring tool