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From: David Straton (no email)
Date: Tue May 09 2006 - 19:45:32 EDT
I did a search and didn't find it. I did find this, though, which is
interesting. The Drag Device Database, which lists stories of
sea-anchors and drogues.
Cheers
Dave
Ahmet wrote:
> It may be worthwhile investigating the situation of the 2 Prout
> catamarans that were in the fastnet race. I am surprized that this has
> not been publicized more
> Ahmet
> www.sailnomad.com
------------------------------------------------------------------------
http://www.dddb.com/news.html
We plan on updating this section once in a while so please check back
from time to time -- don't forget to click the REFRESH button on your
browser to get the latest upload.
IN THE FOOTSTEPS OF K. ADLARD COLES
Adlard Coles and his era may have passed away, but his legendary
masterpiece Heavy Weather Sailing will always be a best seller. What is
so remarkable about Heavy Weather Sailing is that in it Coles laid down
a foundation for the methodical comparisons of different tactics used by
small craft. Coles was an enterprising seaman who knew sailboats inside
and out, but the ingredient that set his work apart was the systematic
way in which he compiled, documented, and analyzed case histories. Coles
avoided dogmatism. He stayed away from secondhand accounts,
unsubstantiated claims and idle speculation. He relied on real life
observations, evidence and data. He let the facts speak for themselves,
searched for compelling logic, and was quick to nail it down when he
found some. And yet he was slow to speak from a posture of certainty. He
kept his mind open, avoided overcompensation, and was willing to learn
new lessons. He understood the subject of heavy weather tactics to be
complex and did not wish to draw false inferences or jump to premature
conclusions. He purposely left many questions, in particular the one
relating to sea anchors and drogues, open to future resolution. We walk
in his footsteps.
GROUP SYMMETRY AND DISASTERS AT SEA
Symmetry-keeping, inertia and group linearity have been the cause of
many disasters at sea, even for naval ships. There comes a time when
every fiber in a seaman's body seems to be urging him to change course,
or break away, or heave-to. But he/she just sits there, paralyzed as it
were, letting nature take its course. Reflection will show that sailors
are more likely to succumb to this sort of inertia if they are involved
in a race, flotilla, or rally. Examples abound. Fastnet '79. The Queen's
Birthday Storm. Transat des Alizes. The disastrous Sydney-Hobart Race of
1998. The Caribbean 1500 Rally of 1998.
It is a lot easier for an independent-thinking cruiser to "break
symmetry" than it is for a crew participating in a race or rally.
Hypothesis: Everything else being equal, the herd mentality can increase
the odds of disaster, but independent thinking can reduce it.
Experience has shown that in offshore gales small differences in initial
disposition can produce huge differences later on. Indeed much of what
we call seamanship has to do with being able to act in advance -- taking
appropriate measures early. If one can't act early enough because of
peer pressure, or race or rally deadlines, the chance of disaster may
increase.
There is nothing wrong with yacht races or rallies per se, so long as
organizers recognize the pitfall and provide adequate
"symmetry-breaking" guidelines. But there doesn't seem to be any such
policy in force today. So, if you are about to participate in race or
rally, or go "buddy boating" with other cruisers, remember this: Group
sailing poses a danger in that the participants are under pressure to
finish the voyage together. This sort of pressure runs against the
cardinal rule of cruising safety, which is never leave according to
clock or calendar, nor have a deadline at the other end. If you are
participating in a rally and the barometer begins to fall, it may be
time to break symmetry and go your own independent way, irrespective of
what everyone else is doing.
NEW DATABASE FILES:
Science depends on a large number of observations from which reliable
patterns can be extracted. However in trying to compile a database such
as this, one runs into a paradox: Those who use drag devices for the
first time and run into problems will tend to send back comprehensive
reports; the veterans who use them routinely and don’t run into any
problems, won’t. To avoid a possible distortion, we need a broader
sample – a more balanced base of participation. If you use a sea anchor
or drogue in heavy weather PLEASE PARTICIPATE IN THE DRAG DEVICE
DATABASE, even if it was a routine event. It is easy to participate.
Just fill out the DDDB form and send it along with a paragraph or two of
observations, opinions and suggestions. Your participation will help
balance things out, level the playing field, sharpen the focus and
increase our understanding of offshore safety. Thank you for your
participation.
The files listed below were submitted after the publication of the 4th
edition of the DDDB. For an actual copy of any of these files please
send a SASE to DDDB, POB 19, SUMMERLAND, CA 93067, U.S.A. Please specify
the file by its number (S = sea anchor, D = drogue, M = monohull, C =
catamaran, T = trimaran, P = power).
MONOHULLS USING SEA ANCHORS
S/M-42: Vessel name Never Monday, Out Island sloop designed by Morgan,
LOA 33' x 7 Tons. Never Monday was tethered to a 15-ft. dia. Para-Tech
sea anchor in a whole gale about 500 miles north of the North Cape of
New Zealand. "The boat was immediately brought bow into the waves..."
(Quoting her owner). Never Monday remained sea anchored for 64 hours,
the line chafing through just before the parachute could be retrieved.
"I may have second thoughts about deploying the sea anchor because of
the rough ride we experienced, but I feel that we were spared a complete
roll over by the fact that we were on a sea anchor," (quoting her owner).
S/M-43: Vessel name Blue Devil, Caliber 38' x 10. 5 Tons. This yacht was
participating in the 1998 Caribbean 1500 Rally when she ran into the
remnants of hurricane Mitch and her skipper deployed a 15-ft. dia.
Para-Tech sea anchor. Blue Devil was tethered to the para-anchor for 16
hours in F-9 conditions, her skipper reporting satisfactory results.
S/M-44: Vessel name Dragon, Hinckley 38’ x 11 Tons. This yacht also ran
into tropical storm Mitch while participating in the 1998 Caribbean
1500. Dragon was tethered to an 18-ft. dia. Para-Tech sea anchor for 36
hours in Force 9-10 conditions, her lady skipper, Pat Festino, reporting
satisfactory results. Afterwards Pat crawled to the bow and retrieved
the sea anchor by hand, a crewmember grinding in the rode on a cockpit
winch. “Foot by foot it came in. My journal says, ‘inch by inch.”
(Quoting her words.)
S/M-45: Vessel name St.Crispin’s Day, Hallberg-Rassy “Mistral,” LOA 33’
5” x 6 Tons. This yacht also ran into tropical storm Mitch while
participating in the 1998 Caribbean 1500. St. Crispin’s Day was tethered
to a 12-ft. dia. Para-Tech sea anchor for 36 hours in Force 9-10
conditions, her singlehanded skipper reporting satisfactory results.
S/M-46: Vessel name White Water, full-keeled wood sloop designed by
Sparkman & Stephens, LOA 38' x 10 Tons. White Water with family of four
on board was tethered to a 15-ft. dia. Para-Tech sea anchor for 15 hours
in a gale about 300 miles west of Vancouver, BC. In spite of being
partially fouled, the sea anchor did a very good job of holding White
Water's bow into the seas.
S/M-47: Vessel name Shag, cruising cutter designed by Lidgard, LOA 40' x
12 Tons. Shag was tethered to a 12-ft. dia. Coppins sea anchor for 63
hours in a whole gale in the Tasman. “Some waves broke on the bow but
did not put the boat at risk. Not much heavy water got back to the
dodger from the bow,” (quoting her owner). A 6-ft. length of chain
coming over the bow roller solved the chafe problem. “Plan B... was to
run with a Galerider off the stern. Very much a second best alternative
especially as we did not wish to approach the continental shelf in those
conditions.”
S/M-48: Vessel name Ardevora of Roseland, Whisstock Ketch designed by
Steve Dalzell, LOA 55' x 22 Tons. Ardevora was tethered to an 18-ft.
dia. Para-Tech sea anchor in shallow water (25-100 fathoms), opposing
current and Force 9 conditions off the coast of Chile, her owner
reporting violent pitching/yawing motion and generally unsatisfactory
results. After 4 hours the rode parted from chafe and the yacht came
beam to the seas, her owner reporting a much more comfortable ride lying
ahull, but with a caveat: “Instinct suggests lying ahull is inviting
damage/disaster,” (quoting Ardevora’s owner). “I made mistakes and
miscalculations and so lying to our sea-anchor was an unpleasant
experience. However I believe that even if a sea-anchor is perfectly
set-up, lying to it would not be as comfortable as heaving-to.” (Compare
with file S/M-52 below).
S/M-49: Vessel name Okiua, custom ketch, LOA 41' x 11 Tons. Okiua was
tethered to an 18-ft. dia. Para-Tech sea anchor for 12 hours in F-8
conditions in steep coastal seas near San Clemente Island (off the coast
of California). After some trials and tribulations the sea anchor was
properly deployed and did a good job of stabilizing a chaotic situation.
“I can see it start to open and take hold, and this is a VERY, VERY good
feeling. The bow of the boat came straight to the waves and wind and
held great. Well, almost too great, as the next big wave came up under
the bowsprit, snapped away 2 planks, then traveled down the deck and
drenched me again…” (From the owner’s log.)
S/M-50: Vessel name Harmony, Passport 40’ x 12. 5 Tons. Harmony also ran
into the remnants of hurricane Mitch while participating in the 1998
Caribbean 1500. Her skipper deployed an 18-ft. dia. Para-Tech sea anchor
– “Deployment was accomplished by tossing the rode bag and sea anchor to
weather and everything worked beautifully. The boat just settled bow to
the wind and seas…. The ride on the sea anchor was good but rough
because of the steepness and confusion of the seas.” Harmony rode to the
sea anchor for 7 hours before losing it due to line chafe. Her skipper
said he would purchase another one.
S/M-51: Vessel name Illusion, Breekvelt (New Zealand) steel cutter, LOA
36' x 13 Tons. Illusion was tethered to a 12-ft. dia. Fiorentino sea
anchor for 10 hours in Force 8-9 on her way to Newport Beach,
California, from Ucluelet, Canada. Her owners reported satisfactory
results – “We had been in the [adverse] conditions noted on the reverse
side [of the DDDB form] for close to three days and were able to catch
up on some rest as we laid to our para-anchor.”
S/M-52: Vessel name Shiriri, Chadelle schooner, LOA 55' x 14 Tons.
Shiriri was tethered to a 12-ft. dia. Para-Tech sea anchor in shallow
water (35 fathoms) for 24 hours in Force 10 conditions just south of
Cape Mendocino, California, an area infamous for its chaotic sea states.
Her owner reported violent pitching up and down motion at sea anchor. 15
Hours into the deployment the engine went down because of a line around
the prop, and later the rudder quadrant sheared. Conditions were so bad
that a call had to be placed to the US Coast Guard. An hour before the
CG cutter arrived the rode chafed through and the schooner came
broadside to the waves, her owner reporting a much more comfortable ride
lying ahull, with the usual caveat – “I know that we risked a roll over
in those conditions.” (Compare with file S/M-48 above).
S/M-53: Vessel name Blue Cristal, Beneteau sloop, LOA 37' 7” x 6. 5
Tons. Blue Cristal was tethered to a 15-ft. dia. Para-Tech sea anchor
for 26 hours in Force 8-9 conditions on her way to Noumea from
Bundaberg, Australia. Her owner reported satisfactory results – “The
Para-Tech sea anchor worked very well… two other vessels in the area
tried to sail out of it… one ended up 75 miles off course and the other
ripped its mainsail and broke the forestay…”
S/M-54: Vessel name Supremacy, custom wood sloop, LOA 45’ x 12 Tons.
Supremacy ran into a whole gale on her way from New Zealand to Tahiti
and her retired owner deployed an 18-ft. dia. Para-Tech sea anchor.
Supremacy was anchored to the surface of the raging sea for 120 hours
(five days), her owners indicating that she was riding well to the sea
anchor. However at a certain stage the cast aluminum rudder quadrant
cracked, one thing led to another, and a call was placed to the Coast
Guard, her owners deciding to abandon ship. In a letter to DDDB’s Victor
Shane, Jim Lott of the New Zealand Maritime Safety Authority wrote: “I
concur fully with the comments about cast aluminum [rudder] quadrants.
Frankly, I would not entertain the thought of one myself. It is hard to
beat cast bronze.”
S/M-55: Vessel name Virtuosity, Laurent Giles sloop, LOA 25' x 4 Tons.
On a bumpy passage between Cyprus and Rhodes, Virtuosity ran into a
Mediterranean gale and was tethered to a 12-ft. dia. Para-Tech sea
anchor for 11 hours. Her owner reported satisfactory results – “On
arrival in Rhodes we met two other yachts who were caught in the same
gale… one, a German yacht, capsized and was lucky to recover and make
safe harbour.”
S/M-56: Vessel name Morgan’s Cloud, McCurdy & Rhodes cutter, LOA 56' x
28 Tons. Morgan’s Cloud was on a passage from Bermuda to the Caribbean
when she was overtaken by a cold front. The yacht ran all day before the
gale but when the seas became ungovernable her owner decided to heave-to
under triple-reefed main, his tactic of choice. However, “at about 23:00
hrs. we were hit hard on the weather beam by a breaking wave that heeled
the boat to about 30-40 degrees…. The lulls would allow the boat’s bow
to fall off and then in the next puff she would reach off at as much as
2 knots before the action of the rudder lashed hard down would bring her
back up to about 60 degree off the wind, her normal heave-to attitude.”
To remedy the situation, her owner then deployed a 42” dia. Galerider
drogue OFF THE BOW (similar to the Pardey stratagem). “The drogue line
made an angle of about 130 degrees from the bow of the boat, so that the
Galerider was in the water behind and to windward of the boat.” This
took care of the forereaching problem, allowing the bow to stay 50-60
degrees from the wind with no tendency to fall further. (Experience and
creativity are the parents of seamanship.)
MULTIHULLS USING SEA ANCHORS
S/C-21: Vessel name Mutual Fun, Prout Catamaran, LOA 37' x BOA 16' x 6
Tons. Mutual Fun was hove-to to an 18-ft. dia. Para-Tech sea anchor in a
whole gale about 450 nm NW of Bermuda in Force 9 conditions for about 15
hours. “Once the anchor deployed, it was like sailing into another
world. No longer were we punching into the sea, but just riding over
them.... We were able to say 'time out' during a severe situation.”
(Quoting her owner).
S/C-22: Vessel name Stress Relief, Catamaran, LOA 33' x BOA 14' x 6
Tons. Stress Relief used a 12-ft. Para-Tech sea anchor four times in
heavy seas en route to Bermuda from Newport. Writes her owner: “First
Time, 5-25-97: 48 hours on the sea anchor, seasick. Second time,
5-27-97: water inside the salon -- hung on the sea anchor until
daylight. Third time, 5-30-97: radar fell off the mast & engine broke --
hung on the sea anchor until daylight. Fourth time, 5-31-97: genoa
ripped during the night -- hung on the sea anchor until daylight.”
S/C-23: Vessel name Laura Lee, Prout Catamaran, LOA 37' x BOA 16' x 6
Tons. Laura Lee used a 15-ft. dia. Para-Tech sea anchor to heave-to in a
gale en route to the Canaries from Gibraltar. “It is very important to
PRACTICE with this rig under windy but non-gale conditions as small
mistakes could be disastrous under gale/storm conditions! We had a
'dress rehearsal' a few days earlier in Force 7 and learned the
important lessons needed when the real thing caught us.” (Quoting her
owner).
S/C-24: Vessel name Dream Hunter, Kurt Hughes catamaran, LOA 45' x BOA
24' x 6 Tons. Dream Hunter used an 18-ft. dia. Para-Tech sea anchor to
heave-to in a gale about 80 miles ENE of Punto Del Este, Uruguay. There
being a current in the region, the cat was pulled 24 miles UPWIND (!) in
the 36 hours that she was hove to. “Tendency to yaw was eliminated by
lowering the boards halfway. No problems with deployment -- flaking the
long rode is essential. Used rubber chafe guards. Once the sea anchor
was deployed the ride was so smooth and controlled that crew of 3 slept
for 12 hours!” (Quoting her owner).
S/C-25: Vessel name Kapal, Roger Simpson catamaran, LOA 42' x BOA 24' x
5 Tons. Two days out of St. Maarten, Kapal had a close encounter with
Hurricane Jenny (November 1999) and her owners deployed an 18-ft. dia.
Para-Tech sea anchor. Kapal was tethered to that sea anchor for 44 hours
in winds of up to 60-knot winds. “We are very happy with the result and
certainly very glad we didn’t go through the eye of Jenny (30 nautical
miles in diameter).”
S/C-26: Vessel name Sanyassa, Prout catamaran, LOA 35' x BOA 16' x 6
Tons. On her way to Fiji from New Zealand, Sanyassa ran into a nasty
blow and her owner decided to deploy an 18-ft. dia. Para-Tech sea
anchor. Difficulty was encountered in setting the sea anchor in those
conditions, but “once the parachute was deployed all problems ceased,”
(to quote her owner). Sanayassa was sea-anchored for 24 hours in Force
7-8 conditions, her crew managing to get much-needed sleep.
S/C-27: Vessel name Mango Mi, Chris White catamaran, LOA 42' x BOA 23' x
7 Tons. Twenty-one days out of Mexico and 350 miles from Hawaii, Mango
Mi found herself in confusing seas piled high by 28-35 knot trade winds
blowing over the unlimited fetch of the Pacific. Suffering from fatigue
and worried about the prospects of surfing down 15-20 foot seas at 17
knots, her crew decided to deploy an 18-ft. Para-Tech sea anchor, in
their own words, “to park it and get some sleep.” Deployment went off
without a problem and soon Mango Mi was anchored to the surface of the
sea, facing into the waves. “We lay at anchor for 20 hrs. and got some
much needed rest. We drifted 8. 3 nm towards our destination.” (Quoting
her owners).
S/C-28: Vessel name Catapult, aluminum catamaran, LOA 40' x BOA 23' x 7.
5 Tons. Catapult was tethered to an 18-ft. dia. Para-Tech sea anchor for
three days when her crew ran into adverse conditions in the Tasman Sea.
“The wind did not ever get to a steady 40 but there were rather large
seas as is commonly the case in the Tasman. The boat rode OK but I did
not enjoy the motion and my crew and eventually I got sea sick.”
Difficulty was encountered in retrieval but the skipper came up with an
idea: “I tied the boat end of the sea anchor line to a couple of large
fenders and tossed it free so that the whole sea anchor rig and line
were floating free. We then motored up to the trip line buoy…. The
recovery from the moment of picking up the trip line buoy was a piece of
cake.”
S/T-22: Vessel name Friends, Walter Greene trimaran, LOA 35' x BOA 29’
6” x 3 Tons. Friends ran into a nasty blow with large and confused seas
60 miles off the New Jersey coast. Her skipper deployed a 15-ft. dia.
Para-Tech sea anchor, but the 50-60’ of nylon rode snapped almost
immediately. It is difficult to ascertain what happened, but the
relatively short 3-strand rope is suspect. 3-Strand nylon tries to unlay
under extreme loading -- the “torque-wave” associated with extreme
dynamic loads can create a hockle or local stress point, resulting in
failure at that point. From the owner’s report: “Rope was wrapped around
Harken winches (3 times); rode went slack and tensed suddenly; rode
snapped right near winch… the strands were somewhat fused together.” The
solution would be to use a no-torque braided nylon rode instead. See
also illustrations on the Wave Rotation page of this website for a
possible explanation.
MONOHULLS USING DROGUES
D/M-20: Vessel name Cinnabar, cutter designed by Robert Perry, LOA 40' x
11 Tons. Cinnabar towed a 42” dia. Galerider drogue in a gale about 75
nm NE of Bermuda in 40-knot winds and 18' seas, the owner reporting
satisfactory results. The drogue was deployed to stabilize the attitude
of the yacht in a wind-current conflict situation, exacerbated by severe
--60-knot -- squalls. Microburst activity can't be ruled out. The drogue
was deployed for 12 hours, the yacht reported to have traveled about 12
nm in that time.
D/M-21: Vessel name Mary-T, Cheoy Lee Offshore 40' x 10 Tons. Mary-T was
one of the boats in the 1994 Queen's Birthday Storm off New Zealand. She
did not have any purpose made drag devices on board, but was able to
jury-rig something out of her spare sails, shackled to a ground anchor.
The makeshift device was “no good off the bow,” to quote her owner, but
fared better off the stern before being lost due to chafe. Like many of
the other sailors that went through the Queen's Birthday Storm, the
skipper of Mary-T emphasized the important of PRIOR PREPARATION: “We are
amazed at the variety of boats and techniques that were used with
success and no discernible pattern apart from strong boat and
preparation. Preparation BEFORE the storm counted more than what you did
in the storm.” (Words of wisdom indeed.)
D/M-22: Vessel name Glenyon, CSY cutter, LOA 44’ x 23 Tons. Glenyon was
a participant in the 1998 Caribbean 1500 and towed a 42” Galerider
drogue when she ran into tropical storm Mitch, her owner reporting
satisfactory results. The drogue was deployed for 24 hours, the yacht
traveling 25 nm in that time.
D/M-23: Vessel name Starlight, Ericson sloop, LOA 38' x 9 Tons.
Starlight was returning to Annapolis from Bermuda when she ran into a
gale in the Gulf Stream. When she began to surf uncontrollably at 9. 5
knots her owner deployed a Para-Tech Delta-72 drogue. This “slowed the
boat to around 5 knots, and steering was easy.” (Quoting her owner.)
However the rig was lost when the towline chafed through. The drogue was
deployed for 8 hours, the yacht traveling about 40 nm in that time.
D/M-24: Vessel name Moonlight of Down, Camper Nicholson sloop, 35’ x 8
Tons. Moonlight of Down was on a passage from Cocos Keeling to Rodriguez
Island (in the Indian Ocean) when she ran into gale conditions and
ungovernable seas. Her owner wisely deployed a 36” dia. Galerider drogue
“to stabilize the situation.” The drogue reduced her speed from 6. 5
knots to 2. 5 knots. The Hydrovane (self-steering) was then adjusted to
put the wind/waves on the port quarter, and the towline adjusted to
position the drogue at the back of the following swell. “The use of the
Galerider to steady the vessel running in hard Trade Wind conditions was
most successful due to the increased comfort of ride and the re-assuring
feeling that you were not likely to broach.” (Quoting her owner.) The
drogue was deployed for 43 hours, the yacht traveling 73 nm in that time.
D/M-25: Vessel name Egress II, Discovery cutter, LOA 42' x 15 Tons. On
her way to New Zealand from Tonga, Egress II ran into heavy weather with
40-50 knots winds and 20-ft. seas. Her owner deployed a Jordan Series
Drogue with 145 cones, each 5 inches in diameter. “We did not feel any
jerk as we slowed from seven to one knot,” (quoting her owner). Egress
II was tethered to the series drogue for three days, drifting 100
nautical miles in that period. “We were very happy with our series
drogue’s performance in a storm and wish to send a ‘thanks’ to Donald
Jordan for his unique answer to a longstanding sailing dilemma.”
D/M-26: Vessel name Swift Cloud, Brooke cutter, LOA 37' x 6 Tons. In
June 2002 Swift Cloud left New Zealand for Rarotonga and ran into a
Force 10 storm. Her singlehanded owner deployed a homemade series drogue
consisting of 30 cones, each 10 inches in diameter. “At 45 knots the
drogue held Swift Cloud stern to, but an angle of about 20 degrees to
the wind. At 60 knots she was taking wind and sea dead astern. The ride
was a little like being on a bungee – I could feel her accelerate as a
sea approached, but as she went up the face of the sea the forward
movement would slow and then reverse.” (Quoting her owner.) The stern of
the yacht took a beating, however, water coming in through the
companionway “as though from a shower nozzle.” The self-steering gear
was carried away when a weld failed, “but the boat was kept well under
control.” Swift Cloud was tethered to the series drogue for 60 hours
during which time she drifted in circle of about 20 miles radius.
EMERGING PATTERNS?
NYLON 3-STRAND: The use of 3-strand rope for tether or towline is now
discouraged. 3-Strand nylon will try to unlay and torque (spin) under
load, leading to hockles and/or stress points that can fail. It may even
deform under extreme dynamic loading as the force tries to travel the
full length of the rode at the same time that the coil is trying to
unlay (untwist). The solution would be to opt for a neutral (no-torque)
nylon braid instead.
AVOIDING HIGHLY LOCALIZED BOUNDARY CONDITIONS: Would you park your car
in the middle of a narrow battle zone, with bullets whizzing by and
mortar shells exploding all around? There may be a moral in this for the
mariner because sometimes it is possible to sail out of narrow “battle
zones” in a matter of hours; or better yet, avoid them altogether. If
the choice were between deploying a sea anchor in shallow water, say,
over the Cortez Bank, or in deep water only 10 miles away, which would
you choose? We have a number of files now where sailors have set sea
anchors in shallow coastal battle zones and complained of a very rough
ride – uncomfortable pitching up and down motion. Examples would be file
S/M-48 where a sea anchor was deployed in 25-100 fathoms in a contrary
current off the coast of Chile, and file S/M-52 where one was deployed
in 35 fathoms of the coast of Mendocino, California, a narrow area
infamous for chaotic sea states.
It goes without saying that shoals, underwater ledges and continental
shelves have a destabilizing influence on wave shapes, in some places
exacerbated by underwater geography, strong currents, funnel effect,
and/or some other local boundary condition. In the Bass Strait between
Australia and Tasmania, for example, mature waves traveling the whole
fetch of the Southern Ocean suddenly “pile up” and get squeezed over the
continental shelf, creating havoc and pandemonium in certain conditions.
Bearing such things in mind, the wise and prudent seaman will anticipate
conditions ahead of time and try to avoid a situation in which he has to
park his ship right in the middle of a “battle zone.” Remember, if you
deploy a sea anchor in a shallow “battle zone” you will be stuck there
until the battle is over, even if deep water is only a few miles away.
Granted, one can’t always choose, but one should always be mindful of
bottom contours and the depth of water under the keel. On any ocean
passage one should try to anticipate the exact day on which the keel
will cross the boundary that separates deep water from shallow, just in
case there’s a storm brewing. (It helps to clearly mark continental
shelves, shoals and currents on your charts.)
FOOD FOR THOUGHT: “To every thing there is a season, and a time to every
purpose under heaven,” (Ecclesiastes 3:1). A time to use a sea anchor,
and a time to use a drogue. Everything else being equal, it might be
time to tow a speed-limiting drogue to sail safely out of a battle zone.
Conversely, if you are approaching a continental shelf and the forecast
is “Force 10 Imminent,” it might be time to deploy your sea anchor and
park the boat until the storm passes on and it is safer to sail onto
shallower water. The words of John Armstrong, owner of Shag (see file
S/M-47 above), are indicative of this sort of hard-gained seafaring
wisdom. Having assessed the situation, having considered all of his
options, Armstrong decided to deploy the sea anchor in deep water,
writing the following: “Plan B... was to run with a Galerider off the
stern. Very much a second best alternative especially as we did not wish
to approach the continental shelf in those conditions.”
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