A heaving line knot is used to make lines easier to throw. It is tied by making a bight, then wrapping the working end around a bunch of times. When you get to the end of the working end, put it inside the bight and tighten by pulling on the standing part. One caveat is that it can be easy to pull apart.

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  Make a bight
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  Wrap the working end around
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  Put the end through the bight
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  Tighten by pulling on the standing part to close the bight
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