PART SEVEN: ANCHORING SYSTEMS
designed and inadequately fastened chocks
out there.
Figure 23-10, a closer view of the moor-
ing line failure, shows that the chock is
poorly formed with rather industrial sharp
edges. It also shows that it was so weak and
poorly fastened that it broke in half, with half
falling off the boat completely! This is wholly
unacceptable. Had the nylon mooring rodenot failed due to the interfiber abrasion, it
would soon have chafed through and failed at
the broken chock. By the way, though
Figures 23-9 and 23-10 concentrate on a small
area, the damage to this boat was extensive
due to running aground after the mooring line
parted. The vessel was a total loss. Note also
the failures on the anchor roller. We’ll review
anchor rollers shortly.Sizing Mooring and Docking
Cleats and Chocks
When specifying or inspecting mooring cleats
and chocks, be sure they are of a strong, very
well-rounded form and are securely through-
bolted to strong backing blocks with back-
ing plates. When fastened through cored
decks, compression tubes and/or epoxy an-
nuluses must be used, or the core must be
locally removed and the resulting solid-glass
region considerably built up and reinforced,
with large backing blocks and backing plates
underneath. Alternatively, the foam or balsa
core may be replaced with solid marine ply
(well saturated with resin) or, better still,
G-10. G-10 can also be used for annuluses.
Give careful thought to avoiding chafe on
the mooring and dock lines, and be sure to
specify and draw in chocks to accept the line
where it goes over the deck edge. Mooring
and docking cleats should be of the four-hole
pattern for maximum strength and stability.
Size mooring and docking cleats by
using the Formula 23-1.Figure 23-10. A
broken chock and
a failed anchor
roller (Courtesy
Chris Wentz)
Figure 23-11. A sharp chockFigure 23-9. A
failed rope anchor
rode (Courtesy
Chris Wentz)