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

Chapter 23: Anchor Rode

Formula 23-1. Sizing Mooring and
Docking Cleats

Bow mooring cleat size (in.)= 4. 5 +

(0. 18 × WL, ft.)

or

Bow mooring cleat size (mm)= 114. 3 + (15×
WL, m)
Docking cleats (midships and stern) size
(in.)= 2. 2 + (0. 2 × WL, ft.)
or

Docking cleats (midships and stern)

size (mm)= 55. 8 + (16. 7 × WL, m)

Chocks are specified as one-half the cleat

size.

Larger is always better.
Example:For a 32-foot (9.75 m) DWL
boat, you would get

Bow mooring cleat size (in.)= 4. 5 +
(0. 18 × 32 ft. WL)= 10. 25 in.; use 10-in. cleats

or

Bow mooring cleat size (mm)= 114. 3 +

(15× 9 .75 m WL)= 260 .5 mm;

use 280 mm cleats

Docking cleats (midships and stern) size

(in.)= 2. 2 + (0. 2 × 32 ft. WL)= 8. 6 in.; use

9- or 10-in. cleats

or

Docking cleats (midships and stern) size

(mm)= 55. 8 + (16. 7 × 9 .75 m WL) =

218 .6 mm; use 220 or 250 mm cleats

Cleats are measured across their maximum
length, end to end. Chocks are measured
with reference to the size of their inside
opening.

Yale Brait

Though traditional three-strand nylon is

excellent and is standard for anchor warps,

it does have drawbacks. One is that, particu-

larly after getting wet and drying out repeat-

edly, nylon three-strand can become stiff and

difficult to coil or stow through a pipe into a

rope locker. The other is that, good as it is at

stretching and absorbing energy, it would be

nice to have even more stretch to absorb

more shock.

Yale Cordage has a relatively new nylon

anchor line called Yale Brait. It is of eight-

strand plaited construction, which remains

supple and soft and thus compacts easily

and into a considerably smaller pile than

standard three-strand nylon. You can see in

Figure 23-12 that Yale Brait will stow in

roughly 45 percent of the volume required for

standard three-strand nylon. Yale Brait also

has plenty of surface area to work well on

windlasses. Further, Yale Brait has 75 percent

more energy absorption (shock absorption)

than even the already-stretchy standard

three-strand nylon.

Attaching Rope to Chain

Since—except for the very smallest dinghies

or for temporary kedging—the anchor warp

is attached to chain, this attachment must

be done properly. There are just three

acceptable methods:

1 .Tie the rope warp to the chain or

anchor at an anchor shackle using an

anchor bend or an anchor bowline

(Figure 23-13).

2 .Put an eye splice with a thimble in the

end of the rope to attach to a shackle.

3 .Use a rope-to-chain splice.

TABLE 23-13. YALE BRAIT NYLON ROPE

Diameter Weight Breaking Strength

inches mm lb./100 ft. kg/m lb. kg

(^3) / 8 ̋ 9 3.4 0.051 3,700 1,679
(^1) / 2 ̋ 12 6.2 0.092 6,300 2,858
(^5) / 8 ̋ 16 10.3 0.153 10,400 4,719
(^3) / 4 ̋ 18 13.5 0.201 16,200 7,350
(^7) / 8 ̋ 22 19 0.283 22,000 9,982
1 ̋ 24 23.7 0.353 27,000 12,250
Formula 23-1.