Sometimes you may feel sociable and want to raft up alongside a neighbour. This is fine, provided the weather is calm and there is negligible surge in the anchorage. But be sure you can cast off quickly if the wind or surge increase. It is very easy to smash lifelines, topsides and even masts as two yachts grind together.
The two yachts should be anchored at a safe distance from one another, then their anchor lines should be slackened off and the boats should be secured together. Two taut springlines led to the jib winches will hold the boats tightly, while the breast warps at bow and stem should be left relatively slack. Plenty of fenders are essential, while the masts must be staggered to prevent rigging tangles and costly damage.
Never raft up in anything but calm conditions and avoid doing so on one anchor. You will swing too much.
Rafting up. Note that the springs are taut, the masts an staggered, and the breast lines are relatively slack