Page 79 - Buck Tilton - Outward Bound Ropes, Knots, and Hitches 2 ed.

Bring the working end back out and over the

standing part and then through the loop created.
Tighten by pulling simultaneously on the working
end and standing part.

Two Half Hitches

AN ADVANCED VARIATION OF THE HALF HITCH THAT

CREATES A MORE SECURE KNOT

Two half hitches bind a rope to an object or another rope
with twice the security of a single half hitch. Security is lost,

however, if the load is not applied at a right angle to the
object. The knot is a half hitch tied on top of a half hitch. It

does not have to be constantly loaded, but when it is, the
load needs to be constant, or else it will work loose. A

favorite among campers, two half hitches may be useful in
climbing and boating.