A mooring field should have vessel length and weight limits defined by the swing diameters, so as to mitigate against playing tag with the neighbor's vessel and in particular to maintaining a fairway through a crowded field. Always a PITA when someone is occupying a hole in the
water that was intended to be the pothole to
cruise through on the fairway.
In addition there are limits imposed so as to not exceed the holding capacity of the permanent
anchor and the tackle [heavy and light chain,
hardware and line] under worst case conditions in order as to not cause the moor to drag on the bottom or to break the
rode.
A 65' MT is likely pushing or exceeding the load limits of many mooring
equipment configurations during adverse
wind or swell conditions, and / or as to intended safe swing radii.
If I
recall correctly, a recommended
scope of mooring chain is not less than 2.5 to 3 times the
depth at high tide consisting of the riding [lighter] chain length equal to maximum
depth of
water at high tide with ground [heavier] chain the remainder. Note: The mooring chain could be longer, providing for a
scope of 3.5 to 4. The recommended length of the pendant line(s) from buoy to chock is to be about 2.5 times the height of the freeboard of the vessel. Never understood why the word pendant is pronounced pennant.
My understanding of the eco friendly mooring systems which do not have lengths of damaging ground chain can provide for yet shorter lengths of
rode from
anchor to buoy but by using stretchable floating line materials will stretch considerably in length under full loading [e.g., 12 to 17 feet], but their all in the swing radius can be made shorter than a traditional, non-eco friendly chain mooring system because the peak loading can generaly be lessened with their shock absorbing stretchy rode, at least up to the point of loading to maximum stretch.
Therefore, a mooring field provides for considerably great occupancy capacity than temporary
anchorages due to the shorter scope [e.g. 3:1 versus 7:1] and thus shorter swing radius. Mooring fields are generally intended to be comparatively "cozy" which coziness can be a bit unnerving when vessels sail and swing differentially from each other. But putting a long, high windage vessel in a spot designed to accommodate a shorter [lower windage] vessel is problematic.