Some anchor rode has chain at the end of
the rode near the anchor. The purpose of
the chain is to:
• Reduce the pulling angle near the anchor
by adding weight; the rode will lie more
nearly horizontal near the anchor and
help the anchor dig in
• Prevent chafing of the rode on rocks,
coral, etc. as it swings across the bottom
You will find the relative strengths of various
kinds and sizes of materials used for
anchor rodes in marine catalogs, at marine
stores, and in other reference books such
as Chapman Piloting–Seamanship and
Small Boat Handling.
Scope
In order to gain a nearly horizontal pull on
an anchor, the rode must be relatively long
compared to the vertical distance to the
bottom of the seabed (Figure 10-6). This
ratio (comparison) is called scope.
Vertical distance to the bottom
includes:
• The height of the boat’s bow from the
surface of the water
• The depth of the water
• Any anticipated change in water depth
due to rise and fall of the tide
The amount of scope required depends on
your anchor’s ability to hold in a particular
type of bottom, considering wind and
sea conditions and ratio of rope to chain
(Table 10-1).
Section 10: Anchoring 109
Figure 10-5. Rope plus chain
Figure 10-6. Anchor scope
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