How to create an instant hurricane mooring
Having watched scores of people drag anchor over the years
even though they have an abundance of highly touted ground tackle while other
boats hold their ground, it has become obvious to me that technique is the clue
to anchoring in severe conditions.
|Hurricane Erin, La Forza at hurricane mooring
August 1, 1995
We survived Hurricane Erin
without a scratch while others were not so fortunate. Corinne and I had anchored
our 32-foot catamaran La Forza at the head of Nigh Creek, a tributary
flowing into Hopetown Harbor in the Bahamas. We had the eye of the storm pass
just to the south of us, leaving us in the dangerous semicircle throughout the
entire ordeal. Below are my considerations on preparations for surviving a
severe storm in an anchorage, in my priority order:
1. The number and proximity of
other boats, especially unattended or charter boats -- It is other boats
breaking loose from their moorings or dragging their anchors that historically
are most likely to cause damage to you, to others, and to themselves. Those are
the likely boats to have inadequate ground tackle and insufficient personnel to
properly prepare and monitor them.
A person who cruises
extensively has long exposure and maximum opportunity to develop workable
techniques. Charterers and charter boats may not share this learn-by-experience
opportunity, and this was proved once again during Hurricane Erin, when the
majority of boats that broke free or dragged were unattended or charter boats.
Hurricane Luis did the same to Simpson Lagoon in St. Marteen when a charter
company moved a fleet of fifty boats from Tortola into Simpson Lagoon trying to
avoid the storm.
2. Protection from the expected
wind and wind shift -- The closer you are to the eye of the storm, the more
drastic the wind shift will be. If the eye passes directly overhead, you will
experience a 180-degree wind shift. Being at the correct shore of an anchorage
to obtain the maximum protection from the expected winds is a learned technique.
A radio receiver is a staunch
ally, but study and understanding of how a storm works is still essential.
Official and unofficial radio nets are on the air transmitting valuable storm
location and wind direction data. Except in the most remote areas, there is
usually a hurricane net of fellow boaters on VHF radio. During Hurricane Erin we
obtained storm information on ham radio, a local VHF net, and Silbert Mills'
reports from Admiral's Yacht Haven in Marsh Harbor. Silbert has a
state-of-the-art satellite tracking computer system that shows the storms, and
he was glad to share that information with us.
|Hurricane Erin, La Forza at hurricane mooring
August 1, 1995
3. Possibility of storm surge
-- During Hurricane Erin we experienced about a five-foot storm surge at the
head of the creek in which we were anchored. The main harbor surged a bit
higher. I suspect this was the primary factor in tearing loose so many boats
from their moorings. We had sufficient scope to protect us, and by the manner in
which the bridle was tied, were prepared to quickly increase scope if it became
4. Bottom conditions and
holding power -- I put the bottom last, because that will be the item you will
have the least power to control. Therefore, prepare to take alternative actions.
For instance, when we anchored in the creek during Hurricane Erin, had I found
the creek bottom solid rock or coral, a place where no anchor can be expected to
hold reliably, I was prepared to run long warps to mangrove strong points on
shore or drop lines to the bottoms of dock pilings. Always drop your line to the
bottom of the piling. Driven pilings are weaker than they appear, and the
leverage from a line fastened near the top can easily snap them off. Being in
close enough quarters to reach these secure points is a true advantage.
5. Be the first in the
anchorage and leave plenty of time to prepare -- Corinne and I moved to the head
of the creek two full days before the storm hit. While others were still
speculating on which way the storm might go, we were digging in for the blow.
Better to have been prepared and the storm not show up than frantically lay
anchors at the last minute in a compromise location. We also ran our water-
maker overtime and filled every possible container in the event we were trapped
in the creek after the storm and the water was contaminated.
Sizing up the situation I
determined that a good star mooring assembled from anchors was the solution.
This mooring type is well known in commercial circles and is described in the
Society of Naval Architects and Marine Engineers (SNAME) literature. The dredged
bottom of the creek was not conducive to reliable holding; therefore, lots of
scope was called for. Excessive scope has the very negative problems of allowing
too much swing and exacerbating any tendency to sail on the anchor, not
something you want to do, especially in a very close area. Many modern boats,
especially fin-keel, spade rudder, dinghy underbody configurations are notorious
for anchor sailing.
I built a three-anchor star
mooring out of my main anchor, a Delta 22, and my two FX11 Fortress anchors. The
Delta, with six feet of 3/8" chain and a 5/8" rode was laid out toward
the northeast, the most exposed direction and the direction from which the
highest winds would come. The two Fortress anchors, each with fifteen feet of
1/4" chain and 1/2" rodes, led out at approximately 120 and 240
degrees respectively. The three anchors formed an equal angle mooring at the
intersection of the three rodes and the bridle.
The bridle consisted of one
1/2" line from the starboard bow fastened to the three anchor rodes with a
rolling hitch. The three anchor rodes were fastened to a cleat on the port bow
and safe-teed to a central cleat on the deck. That meant that the left side of
the bridle consisted of three anchor rodes and the right side of the bridle
consisted of a single 1/2" line. The length of the bridle sides were about
sixteen feet, or the beam of my boat.
At the center junction of the
bridle and the three anchor rodes, I fastened a very heavy kellet (a weight
sometimes called a sentinel, angel, or bouncer). I scrounged around the
waterfront and found a cement block that weighed about fifty or sixty pounds. I
tied it to the junction with a separate line, being careful to avoid any
possibility of chafe.
For all practical purposes, La
Forza was anchored to this huge cement block, which rested on the bottom in
six feet of water, and the cement block was anchored to the three-anchor star
mooring. La Forza has virtually no tendency to anchor-sail, and with the
scope to the kellet being 2.6:1, it prevented any possibility of anchor-sailing.
Short scope in and of itself
will moderate anchor-sailing. That is why boats have so little tendency to do it
on a mooring. The mooring I constructed had not only provided very short
operational scope but also was the most incredible shock absorber I have yet
|These boats didn't stay put - Charles E. Kanter
Before the storm reached us, my
anchor rodes were protected from errant propellers because my anchor lines lay
on the bottom, held there by the heavy kellet. During the storm, it was obvious
that the kellet principle was what kept us from dragging. When we retrieved our
anchors after the storm passed--judging by the way they were set--it seemed
obvious that the kellet principle worked so well that the anchors had so little
tension on them that they never dragged nor even dug in to their maximum.
At the height of the storm
there were recorded 120-knot winds. In our protected location, we were buffeted
by 60- to 70-knot gusts. The kellet held the vessel weather-cocked into the
wind. The lack of scope from the deck to the kellet did not allow the vessel to
anchor-sail at all. La Forza would fall straight back, with no tendency
to veer or fall off. As the boat fell back, we could watch the cement-block
kellet rise up, but never quite get to the surface. When the gust subsided, the
kellet would gently sink back to the bottom, the forward movement of the boat
moderating its action.
Time after time we would get
the full brunt of the wind, but each time the forces were absorbed by this
exceptional shock absorbing system. This meant that scope between the closest
anchor, the Delta, and the kellet never went beyond about 10:1. Figuring that
each degree beyond the Simpson-Lawrence scope design parameter of 3:1 markedly
increases the holding power, it can be assumed the anchor never came close to
its potential holding power.
Previously I had experimented
with a kellet made from a canvas bucket with a rock in it. At that time its main
purpose was to keep my anchor rodes down to protect them from the propellers of
the small boats buzzing around while anchored. Now, I am going to construct a
kellet made from a two-foot length of four-inch PVC pipe with a section of chain
running through it and filled with a mix of lead weights and cement. I will
supplement that weight with jury rig weight or water-filled canvas buckets if
An interesting idea for those
with chain rodes is to attach a canvas bag at the junction of your chain and
bridle and fill it with the balance of chain from your locker. Simple, easy, and
For monohulls, especially those
with chain rodes, a good extra-heavy duty bridle/snubber can be made using two
docklines, one on either side of the bow in bridle fashion as a substitute for
your usual snubber. Shackle or tie them with rolling hitches to your chain or
rope rode. Do not trust an ordinary chain hook under these circumstances unless
it is moused.
Lead the lines through chafing
gear fixed securely to the boat, back to your primary winches so you can adjust
them without leaving the cockpit. Leave a large bight of slack in your anchor
rode between the bridle attachment point and your deck cleat or samson post.
Adjusting often will help lessen chafe and allow you to increase scope for tidal
surge. If you have those common bow chocks (called skene chocks), you must take
extraordinary preventive measures against chafe. Those chocks act like knife
blades in survival conditions.
Fasten your anti-chafe material
to the boat, not to the line. A piece of two-inch vinyl pipe makes good chafe
gear. Lead the lines through the pipe in order to avoid slitting them, which
will destroy their effectiveness in survival conditions. That way your snubbers
can stretch and contract, and you can adjust them right through the anti-chafe
materials. Better still, replace those marginal chocks with good quality roller
chocks and eliminate the worry altogether. Using docklines as snubbers leaves no
direct chafe points between the boat and the anchor rode. Therefore, if the
snubbers do chafe badly, you do not compromise your anchor rode.
The use of a kellet is not new
technology. It is ancient history, well documented in authoritative reading such
as Earl Hinz's Anchoring and Mooring, Chapmans, and SNAME. My contribution to
this technology is the manner in which I attached it to a three-anchor mooring
and to the greater weight I used.
There are commercial gadgets
available, such as the Rode-Rider, which allows you to run a weight up and down
your rode using another line. There also can be a myriad of alternatives to this
Prepare now. Knowledge is the
key to survival.