Yes, Teribus, "2-6-heave" is a ubiquitous chant used *nowadays* / recently to coordinate effort. Anyone who has worked around ships since the later 20th century has heard it, and probably also heard the "guns" explanation, though people invariably cite no source. Can you date it? I would be obliged if you could. At some point was it a chant only heard in application to moving a cannon in and out of position (as, for example, it's used in demonstration at the U.S.S. Constitution in Boston, MA)? If so, when and why was it adapted for any and all combined-effort tasks? Was it Sail Training International (for example) who decided this military call would be a good one to work into their revival of seamanship, while simultaneously leaving all the chanties behind? (And did they --whoever they were-- not experience dissonance by saying "heave" when they were *hauling*?) And so what about the 1-2-3 and the haul-in-haul-2-belay attested for the 100 years from Falconer to Smyth? Chopped liver?

The OP is talking about 1825.