Outfitting
The Dashews Windhorse with Smaller Drag
Devices and
Putting them to the Test
By Zack Smith
(excerpts from Zack's seminars)
My first contact with yacht designer and author
Steve Dashew came after he wrote an article
entitled
Drag Device Polemics in the May 2000 issue
of Blue
Water Sailing. He concluded that the
parachute sea anchor system “can work in gale
and moderate storm conditions, but may not be
suitable for use in huge breaking seas and winds
of severe storm strength.”
A New Theory
As a drag
device designer for parachute sea anchors, I
disagreed with him and submitted a response to
his article that essentially provided a basic
outline of the “Constant Rode Tension Theory”
that I developed from experience gained during
sea trials while designing the “Buckle” and
“Para-Ring” parachutes with Fiorentino’s
Research Team. This theory states that “Keeping
the rode taut is the key to successful parachute
anchor and storm drogue use.” Maintaining taut
rode often requires changing rode lengths,
adding weights next to the para-anchor and
balancing the boat with bridles sail and/or
through rudder position. I concluded by saying
that constant rode tension allows bow deployed
para-anchors to be used effectively in extreme
weather.
Larger vs. Smaller Para-Anchors
Four years
later, Steve, who still favored storm drogues
over the parachute anchor, surprised the folks
at Fiorentino when he acquired a Fiorentino
offshore para-anchor for his 83-foot (25 m)
trawler, Wind Horse. Steve followed Fiorentino’s
recommendation and opted for the 24-foot (7.3 m)
para-anchor despite the overwhelming industry
belief that “larger” is better. For example,
here are other approximate recommendations
published by other manufacturers for a boat like
Wind Horse:
Para-Anchors
Australia—
well over 30-feet (9.1 m),
Para-Tech—a minimum
of
32-feet (9.8 m),
W.A. Coppins—a
minimum of 32.9-feet (10 m).
Fiorentino’s Philosophy for Using Smaller
Para-Anchors
According
to industrystandards, a boat like Steve’s would
require a para-anchor approximately two sizes
larger than Fiorentino’s recommendation. Many of
Fiorentino’s online instruction videos
demonstrate how maintaining “constant force” in
the system is the “big secret” in maximizing the
performance of a drag device, thus permitting
the use of a smaller para-anchor.
Fiorentino’s
original formulas, as shown in the video,
demonstrate how to pay out specific lengths of
rode and/or to connect a small piece of chain
next to the para-anchor to minimize stretch in
the setup. If you minimize stretch, then force
generated from the para-anchor reaches the bow
of a boat faster to help maintain the bow head
to wind or in a hove-to position. Without
“constant rode tension,” rode becomes slack far
too long and the boat tends to bounce around
back and forth uncomfortably.
We have found a
slight advantage in using a larger para-anchor
as recommended by the industry. You typically
can omit the use of chain and be less exact on
how much rode you deploy since the larger
anchors grab more water that generate extra
force on the rode. However, our research team
discovered that certain wind conditions still
require rode length adjustment if one is to
maintain “constant rode tension” with their
para-anchor set-up in changing sea states. (In
the end, we choose to use smaller para-anchors
because they are easier to handle.)
Para-anchor and Storm Drogue Test
After two
years of e-mail exchanges about setting up
para-anchor and storm drogue sea tests, Steve
and I finally arranged to meet at Ventura Harbor in California at
noon, November 26th 2006. It wasn’t
hard to find his 83-foot (25.3m) trawler, Wind
Horse. It’s a very interesting vessel to look
at…sort of a destroyer/sailboat
combination…innovative and very cool. A number
of Dashew fans were there taking pictures of the
boat.
Setting Test Parameters
This was
the first time Steve had ever deployed a drag
device so his desire to test several of them was
very encouraging. Since engineering is second
nature to him, he quickly figured out the basics
of how both the para-anchor and storm drogues
worked. We decided to follow the test parameters
established from my previous sea trials
conducted with Fiorentino and other government
organizations. We first practiced deploying the
24-foot (7.32m) Fiorentino para-anchor from the
Wind Horse. Later, we conducted tow tests with a
Galerider, a Jordan Series drogue (stopping
drogue) and a Fiorentino Shark drogue. Steve’s
wife, Linda, helped us out by taking the helm.
Two reporters, Beth Leonard and Evans Starzinger
were invited onboard to observe the test.
Professional photographer Michael Munson, hired
by Fiorentino, photographed our efforts. Beth
Leonard also contributed photos.
At the start of the
testing, the Dashews and I had a good discussion
about the various aspects of packing, unpacking,
deployment and retrieval.
Sharing
information and ideas helped us work smoothly
through the tests.
We then headed outside
the breakwater when the reporters boarded Wind
Horse. Because the water was relatively calm on
the day of testing, we decided to concentrate on
ease of deployment and retrieval for the sea
parachute. We practiced using the same
techniques as demonstrated in my 2003 DVD
“The Complete Para-Anchor Set-Up.”
Type of Rode Used for the Test
When we
laid out the Fiorentino Para-Anchor on the deck
of the Wind Horse, Steve brought out a bag of
Spectra anchor rode, telling me he thought
lighter rode would be better for para-anchor use
because it was lighter and easier to handle.
Although this is not my preferred choice for
rode, I do appreciate Spectra for its ease of
handling and low stretch characteristics.
The Para-Anchor deployment and retrieval went
off without a hitch. Steve noted in his log
posting a few days later on setsail.com that,
“Fiorentino makes what looks to our eye a very
robust, well-thought out piece of gear.” Of
course, Steve hopes to never have to use it!
More About Rode
Nylon is
currently the industry’s established standard
for rode used in drag device deployment, but it
can stretch easily creating significant slack in
the rode. Long periods of rode slack can cause
the drag device to lose its grip allowing a boat
to fall sideways to the waves. As the drag
device re-inflates the rode becomes taut very
quickly which generates a high rate of force
that can easily break equipment.
Traditional Nylon vs. Fiorentino’s
Deployment Rode
Fiorentino’s sea trials have been most successful in reducing shock loads
caused by oscillating rode when we use a braided
rode that has an outer Dacron cover to reduce
rope stretch and chafe, but an inner nylon core
to absorb shock loads. This is the same mix that
Fiorentino uses exclusively in its rode
manufacturing process. Research completed by our
team shows that the mixed rode is stronger than
rode that is all Dacron or all nylon, because
the combined fibers work together more
efficiently to keep the rode taut. The mixed
rode is heavier to use, but it does give sailors
the option of omitting the use of chain weight
attached to the para-anchor.
Regardless
of the fiber-type you choose for deployment
rode, I recommend sticking with braided rode
since it has less stretch and is easier to pack
than stranded rope. If you choose to use
stranded rode then we highly recommend that you
connect at least 6-feet (1.83 m) of chain to the
para-anchor to maintain constant force upon the
rode. Chain diameter should equal the deployment
rode’s tensile strength.
Lightweight Spectra
Fiorentino’s sea
trials demonstrate that lightweight rode like
Spectra can be made more effective, by adding
weight next to the para-anchor or storm drogue
to maintain “constant rode tension.” (View Tech
report FPA-124 and the Shark Manual for research
results on this subject). Weight added next to a
para-anchor contradicts the industry standard of
attaching weight at the boat end instead of the
anchor end, but Fiorentino’s reports show that
it’s a more effective way
of
keeping constant tension on the rode.
Shark
Drogue vs. Galerider and Series Drogue
After packing the
para-anchor we then went on to test my new Shark
Drogue, Galerider, and a Series (stopping)
Drogue. In an effort to maintain consistency
with previous drag tests that I conducted with
Fiorentino and others, I recommended that we set
Wind Horse’s speed to seven knots before
deploying each of the drogues. Again, the test
went smoothly. I think Steve was a bit surprised
by how well the small Shark Drogue performed and
how easy it was to use. In his Dashew Log of
November 28, 2006, published on setsail.com, he
calls the Shark Drogue, “A very welcome addition
to the heavy weather arsenal. The compact design
and ease of launching are big advantages.”
Today, I think Steve still believes that moving
the boat is probably the best policy for storm
tactics, but he’s decided to cover different
scenarios such as “What if the boat breaks down
or what if actively steering the boat fails?”
Steve now equips many of his power trawlers like
the Wind Horse with both storm drogues and
Fiorentino para-anchors. Steve sizes all
Fiorentino para-anchors according to the
Fiorentino’s size recommendations, lending
support to our theory that “smaller” may be
better.
Print this
Article
ADMINISTRATOR'S NOTE:
Our special thanks to
the Dashews for giving us
permission to attach a pdf file
of
their November 28, 2006 Dashew Log. If
you
have any questions about this article or you
would like to upload a response to this
website
please submit
your comments here.
Related Links:
Dashew
Drag Test Log:
This log provides the
Dashews' perspective on
the drag exercises
conducted aboard the trawler,
Wind Horse.
Fiorentiono Tech Report
FPA-124:
Technical Report FPA-124 offers a compilation of
drag tests by Fiorentino's research team detailing
the amount of force
placed on spectra flat rope
and nylon deployment
rode. several different
boat designs using various brands of storm
drogues
were used for comparison purpose. Test
results include Fiorentino's
perspective on the drag
exercises conducted
aboard the Dashews' boat
Wind Horse.Tech Report FPA-124 may be purchased as a
hardcopy for $79 by contacting
info@para-anchor.com or you can view the
report online for free.
Shark
Drogue Manual:
The
Shark Drogue Manual, written by Zack Smith,
inventor of the revolutionary Shark Drogue is a
must read for any sailor thinking about using a
drag device on his or her boat. The manual not
only details use of the
Shark Drogue, but provides information on the
pros and cons of various types
of drogues. Sailors
will also learn firsthand about Zack’s
pioneering “Constant Rode Tension” theory which
he developed after more than a decade of
sea
trials. In the manual, he not only explains his
copyrighted theory, but offers specific formulas
for putting it into use. Zack also shares specific amounts of
weights for reducing slack rode and
other
groundbreaking tips on how to avoid shock
loads
on your boat.
The Shark Manual may be purchased as a hardcopy
for $49 by contacting
info@para-anchor.com or you can print the
report as a pdf. for free.
Fiorentino's
Deployment & Retrieval
A free on-line video shot by Fox
Sports
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