Use a Midshipman's hitch (also called Taut-Line Hitch)

This is typically used to secure an awning or tent line to a peg, and it is adjustable.

For your application, make the loop part large and loose. Then pull on B, near the eyelet to tighten the load, then slide the knot down until everything is tight.

See: http://www.animatedknots.com/midshipmans/index.php

Use a Midshipman's hitch (also called Taut-Line Hitch)

This is typically used to secure an awning or tent line to a peg, and it is adjustable.

For your application, make the loop part large and loose. Then pull on B, near the eyelet to tighten the load, then slide the knot down until everything is tight.

See: http://www.animatedknots.com/midshipmans/index.php