Caribbean Compass Yachting Magazine January 2015

JANUARY 2015 CARIBBEAN COMPASS PAGE 36
Anchors… and Why
They Don’t Work
Many boaters new to the Caribbean are coming from marina life, and whether newbie
bareboaters or experienced racing sailors, anchoring is a skill yet to be acquired.
How many times in the Eastern Caribbean has one seen a boat come into a breezy
anchorage, drop the anchor, veer a hundred or more feet of chain — and immediately
drag off to the west Often the chain has piled up on top of the anchor. Then,
as the boat drifts off downwind, the chain straightens out. When a full load finally
comes on the anchor, it bounces across the bottom. It seldom digs in, but often
catches another boat’s anchor line and confusion ensues.
Getting the anchor to hold is like setting the hook when catching big fish. When
the fish hits the hook and the reel starts spinning, first the drag is set lightly, and
then set hard to set the hook. Similarly, when the anchor is dropped, the amount of
rode (either chain or a combination of chain and line) let out initially should be only
a little more than the depth of the water. Use the helm so the boat backs down head
to wind. Veer more rode as the boat backs down, keeping some tension on the rode
so it lays out straight and has some drag on the anchor, giving the anchor a chance
to dig in. When you have veered rode three times the depth of the water, tighten the
rode and finally make it fast. Hopefully the anchor has set. If it appears to be dragging,
veer more rode, then secure. If you still continue to drag, hoist the anchor and
try again.
It must be remembered that the holding power of the anchor is greatly influenced
by the angle between the bottom and the anchor rode. If the bottom is flat, a threeto-one
ratio is usually sufficient in normal 12- to 15-knot tradewinds, but as wind
increases more rode must be veered. The load on the anchor rode, caused by the
windage of the boat, goes up with the square of the wind’s velocity. Thus the load on
the anchor rode at 30 knots of wind is four times that of 15 knots. To keep a low
angle of attack of the rode to the anchor, if the wind is gusting 30 knots you will have
to veer rode five to six times the depth of the water.
If you are anchoring on a steep slope, to obtain a low angle of attack at the anchor
you will also have to veer rode five or six times the depth of the water. Conversely, if
anchored bow on or bow tied to a tree ashore, where the bottom is steep to, since
the stern anchor is pulling uphill you often will only have to veer one-and-a-half
times or twice the depth of water.
If anchored where there is a reversing current, it is necessary to put down a
Bahamian moor as is shown and described on the back of every Imray Iolaire chart.
Practically all the places in the Eastern Caribbean where you will need a Bahamian
moor are also noted there.
If you are anchored on chain and a swell starts surging the boat back and fetching
hard on the anchor, it is time to veer more chain or to rig a nylon line as a shock
absorber. Note that 3/8” chain has a breaking load of 3,640 pounds, but 1/2” threestrand
nylon line has a breaking strain of 5,000 pounds. Secure 1/2” nylon line to
the anchor chain via a rolling hitch or a chain hook, veer out the chain and the nylon
line until there is 50 or more feet of nylon out, secure the line, continue to veer
another 15 or more feet of chain, then secure the chain. The three-strand nylon line
will act as a shock absorber. If the nylon line breaks, all is not lost as you will fetch
up on the chain. Use plenty of chafe gear where the nylon goes through the chock.
Use three-strand nylon rather than braided nylon, as the three-strand nylon will
stretch more.
For many more details on anchoring techniques, see Daria and Alex Blackwell’s
Happy Hooking — the Art of Anchoring, available at Amazon.com.
Most experienced cruising sailors I know feel that three anchors are a minimum
number that a cruising yacht should carry. Iolaire carried seven, which seemed like a
bit of overkill until we were caught by Klaus, a late-season (November) hurricane. We
were anchored on the north side of St. Martin with two anchors out in a Y — all set,
we thought, as “hurricanes in the Caribbean go west”. However Klaus went northeast,
passing north of St. Martin. The wind clocked and veered eventually, making our nice
SEAWISE WITH DON STREET
As a boat pulls back on a stockless Danforth-type anchor…
…the tips dig into the bottom…
…burying the flukes
anchorage under the lee of St. Martin a deadly anchorage on a lee shore. As the wind
veered, our port anchor line went slack. All of the load came on the starboard anchor.
So we dropped another anchor underfoot, veered line from the starboard anchor of
the Y, and paid out line on the anchor we had just dropped until we had enough line
veered to set the third anchor so the load was again spread between two anchors. As
the wind continued to veer we did the same process again, dropping our fourth
anchor, veering line and again riding on two anchors. As the wind continued to veer
we repeated the process with anchors five and four, then with five and six.
—Continued on next page
TOSAKA