misses an important nautical use for this term.
In wooden ship construction, a drift is an inexpensive fastener
used to hold large blocks of wood together permanently. They are
long (sometimes more than a yard long) wooden or metal rods, hammered deep
into both pieces of wood. They fasten together pieces of wood that
will never be separated through the lifetime of the ship: big keel
timbers, or planks edge-set to make rudders, centerboards, or hatches.
Drifts can be cut from lengths of soft metal rod (rebar would be nice if it weren't iron), with barbs quickly
knocked into the sides with a cold chisel. They can also be rough-cut
wooden dowels, without any special effort given to rounding off, although a broom handle will do in a pinch.
Installing a wooden drift (aka 'treenail') is literally banging a square peg into a round
Drifts are decidedly low-tech, but they work: Friction on the
sides of each pin holds the pieces of wood together snugly.
When the wood gets wet, it swells up and the drifts are held in that much
Several drifts can be set into a line, but always at the same angle.
It's geometrically impossible to set drifts at different angles before
putting the two timbers together, and while it is theoretically possible
to drill in from the other side of one of the timbers afterwards and set
another line of drifts at right angles to the first, the swelling of the
wood would then make the drifts tear the timbers apart.