anchoring and marlinspike seamanship 233
wash galvanized or stainless thimbles and anchor rode with fresh water at the fi rst
opportunity. Dry thoroughly before coiling back down into the anchor locker.
Nylon composite. It’s best not to use plastic thimbles with heavy ground
tackle, because they fl ex a lot under load. Limit them to light-duty jobs such as
anchoring the dinghy.
Bronze alloy. Top-of-the-line bronze thimbles with keepers off er the best
combination of strength, resistance to saltwater deterioration, and chafe protection.
Th ey are the Mercedes-Benz of rope thimbles—superior to all other types!
Chafing Gear
In heavy wind and sea, your anchor rode saws like the devil in the chocks, and
many a boat has been lost from inadequate chafi ng gear. Wrap chafi ng gear around
the rope part of the rode where it passes through chocks or over the rail. Use old
hose, canvas, or—in a pinch—duct tape. Nylon line elongates under load, so you
want chafi ng gear that moves with the line. Inspect your chafi ng gear frequently,
and add more if necessary.
Most foredecks have two bow cleats. Lead the bitter end of the rode across
the deck to the far cleat for a better fairlead. Change the chafe point in the chocks
every now and then. Simply take in a little slack or ease off a bit of rode, then
reposition the chafi ng gear to the new contact point.
Horizontal Loading: Th e Secret to Drag Prevention
Whether ground tackle holds or drags depends on the relationship between the
anchor shank and the rode. To see this in action, try this experiment. Find an area
of sand or soft dirt. Attach a 20-foot piece of line to the shank of a small anchor. Set
the anchor on the ground, bend over so you are in line with the shank, and pull in
the line. Watch the fl ukes of the anchor. Even if the anchor rolls onto its side, as long
as you keep a horizontal load on the anchor, the fl ukes try to dig into the ground.
Now let the line out again. Th is time, stand up and place some tension on the
line; walk toward the anchor and gather line as you go. Th is simulates a vertical
load. Note the angle between the line and the shank. As the line gets shorter, it pulls
vertically on the end of the shank. Th e fl ukes rise, break out of the seabed, and drag.
Th is demonstrates why you must do everything possible to keep only horizontal
loads on your anchor. Vertical loads not only result in dragging but place enormous
strain on deck gear such as cleats and windlasses.
SCOPE SOLUTIONS AND CAREFUL CALCULATIONS
We can easily ensure that we have this horizontal alignment by putting out enough
scope, which is the ratio of rode to a combination of three factors: water depth,
tidal range, and bow freeboard. Th e average scope for a combination chain/rope