Dave Gerr - Boat Mechanical Systems Handbook-How to Design, Install, and Recognize Proper Systems in Boats

(Rick Simeone) #1

seaplane patent anchors (Figure 22-17). The
stock is located at the crown and folds flat
for easier storage. As is often the case, tests
of the Northill’s holding power vary widely,
but many sailors who have used Northills
swear by them and claim their boats have
never dragged.
A modern variant of the Northill was in-
vented by Robert E. Pekny, and not surprisingly,


it is known as the Pekny anchor. This anchor
apparently performs as well as the Northill,
but I’m not aware of any companies manufac-
turing the Pekny anchor today.
GRAPNELANCHORS For small boats, such as
dinghies, the simple grapnel anchor is a com-
mon choice (Figure 22-18). The grapnel has
superb holding power, but only when it can
hook on something, such as buried logs,
branches, or rocks. The folding grapnel,
though, makes a very compact package and
conveniently will set as a lunch hook for
most very small boats (Figure 22-19). Grap-
nel anchors are also useful for dragging the
bottom to pick up lost anchor rodes and
such.
Because grapnel anchors primarily work
by hooking, they are particularly subject to
fouling and refusing to release. On any larger
grapnel or in any longer-term use, a buoyed
trip line to the anchor crown is recommended.

New Anchors
SPADEANCHORS One of the newer success-
ful developments in anchor design is the
spade-anchor form (Figure 22-20 and 22-21).
This works almost opposite from a plow,
digging down into the sea bottom. As you
would expect, the anchor flukes or blades
are configured roughly like a spade, usually
with a “roll bar” over the anchor to force itto
right itself and dig in at the correct attitude.

Chapter 22:Anchoring Systems, Anchor Types, and Anchor Selection


Figure 22-15. Bruce anchor proportions


TABLE 22-6. BRUCE ANCHOR DIMENSIONS (USE WITH FIGURE 22-15)


Dimensions,inches Dimensions, millimeters
Size Size
Weight, lb. A B C D E Weight, kg A B C D E
4 7.0 14.3 9.7 0.3 4.7 2 178 363 246 8 119
11 9.3 18.5 12.4 0.4 7.0 5 236 470 315 10 178
16 10.6 21.3 14.2 0.4 7.5 7.5 269 541 361 10 191
22 11.4 23.0 15.3 0.5 8.0 10 290 584 389 12 203
33 12.9 25.8 17.6 0.5 8.7 15 328 655 447 12 221
44 14.3 28.1 18.5 0.7 9.5 20 363 714 470 17 241
66 16.0 32.1 21.3 0.8 11.0 30 406 815 541 19 279
110 18.9 38.1 25.3 0.9 13.4 50 480 968 643 23 340
176 21.8 42.9 28.0 1.0 14.8 80 554 1,090 711 25 376
242 24.1 48.4 31.9 1.2 17.3 110 612 1,229 810 30 439
330 27.5 53.4 35.3 1.5 19.5 150 699 1,356 897 37 495
550 33.8 63.7 42.0 1.7 22.8 250 859 1,618 1,067 43 579

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