[Rhodes22-list] Anchor Chain Question

[Roger Pihlaja]

Wally,

#1, you do not entirely lose shock absorption with chain.  The energy
absorption just changes to a different mechanism.  With nylon rode, shock
absorption comes primarily from stretching the nylon polymer after the
caternary curve is pulled straight.  With chain, shock absorption comes from
the energy that is required to lift the chain up off the bottom (potential
energy) + the viscous drag as the links of chain are pulled thru the water
as the shock load straightens out the caternary curve.  Note that both of
these energy absorbing things must happen before the boat or occupants would
feel any shock at all.  Yes, you will get more shock absorption with an all
nylon rode.  But, I've tried it both ways & the difference is not that
noticeable.  In 6 feet of water on 7:1 scope & assuming 2 feet of freeboard,
the rode length would be:

7 * (6 ft water + 2 ft freeboard) = 56 ft total rode

56 ft total rode - 22 ft chain = 34 ft of nylon rode

[Difference in Nylon Stretch] = {1 - (34 / 56)} * 100 = 39.3% less stretch
with 22 ft of chain vs. all nylon rode & most of this difference is made up
for in the alternate energy absorption mechanisms described above.

#2, when we cruise, we don't typically know in advance how crowded the
anchorage is going to be at the end of the day or what the sea-bed is going
to be like.  Typically, with a small sailboat, we arrive at a popular
anchorage after the big fast powerboats have taken all of the good spots.
So, quite often, we end up anchoring in the less desirable spots.
Fortunately, with the R-22's shallow draft, we can usually utilize
anchorages the big boats shy away from.  But, weather conditions,
overcrowding, a noisy party on shore, poor holding conditions on the
sea-bed, or any of a number of other factors may cause a change of anchoring
venue.  Also, when you are anchored off a deserted island 35 nm from shore
in the middle of one of the Great Lakes and the weather changes for the
worse, you don't have a lot of options.  There is nowhere to run to.
Therefore, your anchor(s) had better hold or you are in deep trouble!  In
addition, with an all nylon rode, sooner or later you are going to have
problems with some anomalous sharp object on the sea-bed.  People have been
visiting these anchorages for a very long time and some of them throw sharp
stuff overboard.  It's just a fact of life.  With chain, this sharp stuff on
the sea-bed, be it natural or manmade, becomes a nonissue.  Therefore, since
you have to have the chain on board anyway for safety's sake and the anchor
ALWAYS sets and holds better with the chain no matter what the condition of
the sea-bed; then, you might as well go ahead and use the chain.

My experience is that the chain is no more trouble to clean the mud off of
than the anchor itself.  You just dunk it a few times, or at worst, coil it
up in a bucket of water & let it soak for a while.  As far as I'm concerned,
it's all part of the game.

Hey, if you always sail in your own little cruising area, those waters are
small and protected, and the sea-bed has good holding in that location;
then, you probably don't need to use chain.  We like to range further afield
on bigger water that we've never explored before.  We have to be prepared to
deal with the sea-bed and prevailing weather as and where we find it.
You've evidently never dragged anchor in a storm.  Once that's happened to
you, it may cause you to rethink your anchoring technique.

FYI, have you checked your boat insurance policy regarding their coverage
policy on claims due to the owner's negligence?  i.e. - If you lost your
boat or caused damage to another boat while it was at anchor because the
anchor dragged on an all nylon rode and the instructions that came with the
anchor recommended the use of a certain minimum length of chain, what would
your insurance policy cover?

Bottom line, for us on Dynamic Equilibrium, the boat length of chain rigged
with each anchor is cheap insurance.

Roger Pihlaja
S/V Dynamic Equilibrium


----- Original Message -----
From: "Wally Buck" <tnrhodey at hotmail.com>
To: <rhodes22-list at rhodes22.org>
Sent: Saturday, March 19, 2005 11:45 AM
Subject: Re: [Rhodes22-list] Anchor Chain Question


> Roger,
>
> I agree chain has it uses. However there is not much need for chain when
> anchoring in Bill's local waters. I suggested he use chain when on the
coast
> or traveling to areas with unknown bottom. If I were traveling to
different
> waters I would bring my chain but experience has taught me it is not
needed
> for my local hang outs.
>
> Not using chain has nothing to do with lack of physical ability. I am
quite
> fit; I just don't like hauling up chain coated with red mud/clay. More
> importantly my boat holds quite fast without chain. I have learned a few
> things spending a hundred plus nights on the river. One lesson learned; I
> don't need chain. I check for chafe but I don't have any. No worries.
>
> I typically anchor in 6 feet of water in coves surrounded by trees and
> hills. Very much like the area Bill sails locally. If a heavy storm rolls
in
> I could quickly rig second anchor if needed. My single cheap anchor has
> always held just fine. This includes riding out summer thunderstorms and
> winter Noreasters.
>
> Your tip sheet is good advice but it does not apply to all bottoms. If you
> want to mess with chain even in areas that don't require go for it. Me I
> would rather not have to re-dip the anchor a mess of time to try to clean
> off stubborn red clay. A bunch of folks at my marina told me the same
thing.
> "Oh it will not hold, you will chafe problems." Guess what? They were
wrong!
>
> So I am off to the lake for the night. And no I will not have a single
link
> of chain with me!
>
> Wally
>
> >From: "Roger Pihlaja" <cen09402 at centurytel.net>
> >Reply-To: The Rhodes 22 mail list <rhodes22-list at rhodes22.org>
> >To: "The Rhodes 22 mail list" <rhodes22-list at rhodes22.org>
> >Subject: Re: [Rhodes22-list] Anchor Chain Question
> >Date: Sat, 19 Mar 2005 10:24:18 -0500
> >
> >Gentlemen,
> >
> >The following quote is taken from the SAFE ANCHORING TIPS sheet supplied
in
> >the package by the NAV-X Corporation when I bought my Fortress anchor:
> >
> >
> >5: ANCHOR RODE: Use a short length of chain and three strand nylon rope.
> >The nylon rope is very elastic and greatly reduces the shock loads on
your
> >boat and your anchoring system.  The chain protects the rope against
chafe
> >from the sea-bed and also provides a more horizontal pull on the anchor
> >when
> >it is just beginning to set.  If you normally anchor in 25' of water or
> >less, use 6' of chain.  For greater depths, add 6' of chain for every 25'
> >of
> >depth.  For example, use 24' of chain if you anchor in 100' of water.
> >
> >
> >Note that the tip sheet cites two reasons why you should use chain: CHAFE
> >RESISTANCE against "stuff" on the sea-bed  +  WEIGHT at the anchor end of
> >the rode to help make the pull on the anchor more horizontal, especially
> >when the anchor is just beginning to set.  When cruising, I usually don't
> >know in advance how deep the water is going to be where I'm going to
> >anchor.
> >In addition, even on a supposedly pristine sand or mud bottom, you just
> >never know when your nylon anchor rode is going to find a piece of broken
> >glass or an old sharp piece of metal.  Therefore, on Dynamic Equilibrium,
> >the anchors are rigged with one boat length of chain.
> >
> >1/4" Hot Dip Galvanized Proof  Coil chain weighs 0.63 lbs/ft, so 22 feet
of
> >this chain weighs about 13.9 lbs.  If you are worried about this amount
of
> >weight on your boat or have trouble retrieving it, well God bless you.
For
> >me, it's cheap insurance.
> >
> >Roger Pihlaja
> >S/V Dynamic Equilibrium
> >
> >
> >----- Original Message -----
> >From: "Bill Effros" <bill at effros.com>
> >To: "The Rhodes 22 mail list" <rhodes22-list at rhodes22.org>
> >Sent: Saturday, March 19, 2005 9:30 AM
> >Subject: Re: [Rhodes22-list] Anchor Chain Question
> >
> >
> > > Bill,
> > >
> > > As I understand the function of chain, its primary purpose is to
prevent
> > > line abrasion on the bottom.  If you don't have a rough bottom you
> > > really don't need chain.  As soon as you set a Danford type anchor you
> > > have pulled the chain off the bottom, and the chain and line should
stay
> > > off the bottom, putting all the pressure on the anchor flukes and
> > > causing them to dig strongly into the bottom.
> > >
> > > If you have sufficient scope, the pressure on the anchor is horizontal
> > > within the design specifications, and it should reset itself as needed
> > > if the boat slowly swings around it due to wind or current shifts.
When
> > > you are ready to retrieve it, you move the boat over the anchor and
pull
> > > vertically, and the anchor releases.  (You can pull the boat over the
> > > anchor by hauling in the line, but it's much easier to motor over, and
> > > pull just line straight up until you get to the anchor, which in our
> > > case should weigh less than 10 lbs.)  The beauty of the Fortress
anchors
> > > is that they are both lighter and stronger than conventional anchors.
> > >
> > > Bill Effros
> > >
> > >
> > >
> > > William E. Wickman wrote:
> > >
> > > > You are right Wally.  It is all mud and clay with the occasional
rock
> > > > cropping here.  I think I may cut my 20 ft chain in half and carry
the
> > > > resulting pair of 10 ft lengths for use when I go to the coast.
> > > > Bill W.
> > > > --------------------------
> > > >
> > > >
> > > >
> > > >
> > > > ----- Original Message -----
> > > > From: rhodes22-list-bounces
> > > > Sent: 03/19/2005 06:57 AM
> > > > To: rhodes22-list at rhodes22.org
> > > > Subject: Re: [Rhodes22-list] Anchor Chain Question
> > > >
> > > > Bill,
> > > >
> > > > I agree with Bill here. I started out using about 8 feet of chain.
For
> > > > my conditions I quickly found out that I don't need any chain. I
> > > > anchors in fairly shallow coves with red clay bottom. It has never
> > > > been a problem. The chain seemed like extra hassle and weight.
> > > > Everyone told me this was going to be a big problem. It has worked
> > > > just fine and I spend a bunch of nights anchored. I would guess your
> > > > conditions up river are much the same. If you plan on towing your
boat
> > > > to the coast I would suggest chain but don't see any need on the
> >river.
> > > >
> > > > Wally.
> > > >
> > > >> From: Bill Effros <bill at effros.com>
> > > >> Reply-To: The Rhodes 22 mail list <rhodes22-list at rhodes22.org>
> > > >> To: The Rhodes 22 mail list <rhodes22-list at rhodes22.org>
> > > >> Subject: Re: [Rhodes22-list] Anchor Chain Question
> > > >> Date: Mon, 14 Mar 2005 19:04:01 -0500
> > > >>
> > > >> Bill,
> > > >>
> > > >> I've got the Fortress FX11, and I think it's a terrific anchor.  I
> > > >> also have the smallest Guardian anchor, which I store in a pouch,
> > > >> unassembled, and I've been very happy with that one also.
> > > >>
> > > >> I think those people know a lot about anchors, and I would be
> > > >> inclined to follow their recommendations.
> > > >>
> > > >> I have several lines with differing amounts of chain on each, and
> > > >> several with no chain at all.  I find I always go for the no chain
at
> > > >> all, because I've never had any trouble with it, and it's so much
> > > >> easier to handle.
> > > >>
> > > >> The trick to anchoring (as with so many other things) is practice.
> > > >> Try setting your anchor when it's not critical.  See if you have
> > > >> enough navigation skill to be able to determine if your anchor is
> > > >> dragging.
> > > >>
> > > >> When it's really blowing you shouldn't be on our boats in the first
> > > >> place.  Anchoring and praying is not the answer.  If you are
trapped
> > > >> in a situation like this, and can't get to shore, head for open
water
> > > >> and heave-to.  Practice heaving-to, too.  Work with the elements,
not
> > > >> against them.
> > > >>
> > > >> The guy who developed those anchors recommends setting 2 at 180
> > > >> degrees apart and tying both off on the bow.  Then neither one will
> > > >> have to reset if current or wind shifts.  Differing lengths of
chain
> > > >> will  not matter, longer scope can be set because the boat will
> > > >> rotate in a much smaller arc relative to other boats.
> > > >>
> > > >> Avoid anchor overkill.  That goes for the chain, too.
> > > >>
> > > >> Bill Effros
> > > >>
> > > >>
> > > >>
> > > >>
> > > >> William E. Wickman wrote:
> > > >>
> > > >>> I just got my nifty Fortress FX7 anchor.  The instructions that
came
> > > >>> with
> > > >>> the anchor said to use a short length of anchor chain (6 feet of
> > > >>> chain if
> > > >>> anchoring in 25' of water or less, and add another 6 feet of chain
> > > >>> for each
> > > >>> additional 25' of depth).  Their claim is that chain anchor rodes
> > > >>> lack the
> > > >>> shock absorbancy of nylon rope when the wind increases.  This
advice
> > > >>> runs
> > > >>> contrary to what I have been reading in the Rhodes FAQ that most
of
> > > >>> you are
> > > >>> using around 20 feet of chain.  So, does the Fortress require less
> > > >>> chain
> > > >>> because it is so light?  What gives?  I presume that these anchor
> > > >>> guys know
> > > >>> what they are talking about, but...
> > > >>>
> > > >>> Also, since I have 20 feet of chain that I use with my gbi anchor,
> > > >>> what are
> > > >>> the dynamics of using shorter chain on a second anchor when
setting
> >two
> > > >>> anchors?  Does it really matter?
> > > >>>
> > > >>> B. Wickman
> > > >>>
> > > >>> __________________________________________________
> > > >>> Use Rhodes22-list at rhodes22.org, Help? www.rhodes22.org/list
> > > >>>
> > > >>>
> > > >>>
> > > >> __________________________________________________
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> > > >
> > > >
> > > >
> > > > __________________________________________________
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> > >
> > >
> >
> >
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