A splice is a method of permanently joining two ropes or forming a loop (eye) by unlaying and interweaving their strands. Unlike knots, which can significantly weaken a line, a properly executed splice retains up to 90–95% of the rope's original strength, making it ideal for high-load applications like rigging and mooring.

Common Types of Splices
Eye Splice: Creates a permanent loop at the end of a rope, commonly used for attaching lines to shackles or cleats.

Short Splice: Joins two ropes together by interweaving their strands; it is stronger than a knot but results in a thicker section, roughly twice the diameter of the rope.

Long Splice: Joins two ropes together with a minimal increase in diameter, allowing the rope to pass through pulleys or blocks, though it may be slightly weaker than a short splice.

Historical Context: "Splice the Mainbrace"

In the Royal Navy, the mainbrace was a crucial, heavy rope used for trimming the main sail. Because it was rarely spliced (usually replaced), repairing it was a difficult, high-skill task often required after damage in battle.

The Term: "Splice the Mainbrace" became a command for the crew to receive an extra ration of rum, usually for completing this dangerous task or to celebrate a special occasion.