Wednesday, January 23, 2008


A wooden block, consists of one or more sheaves (pulleys). Each block has one or more steel straps which strengthen the block and support the sheave pin. Personnel may suspend the block or apply a load by means of a hook or shackle inserted in the top of the strap. The strap may continue through the block and form a projection, called the becket, to attach another line. The becket usually has a thimble to prevent chafing of the line. The front of the block is called its face and the sides of the shell are called cheeks. The opening between the top of the sheave and the block where the line is passed through the block is called the swallow. The breech is the opening between the bottom of the sheave and the block and serves no definite purpose. Line is never passed through the breech of a block except for a small tail line used to keep the block from bouncing on the deck. The entire wooden portion of a block is called the shell, it protects the sheave and line.