[Rhodes22-list] Anchor Chain Question

[Steve Alm]

Lake Minnetonka, where I sail the most, is very weedy and as I mentioned
before, my Danforth isn't cutting it.  So I'm thinking about a plow.  The
Delta one-piece would only have to  be a 14 pounder for the R22, whereas the
CQR hinged shaft (more expensive) would need to be a 22--at least that's the
rating in WM.  Anyone have any experience with the Delta?  I understand
they're not the greatest in soft mud, but I'd keep the Danforth for that.  I
too plan on increasing my anchoring possibilities this year.  I like the
folding grapnel as well for its ease of handling and stowing, and I want to
find something for a sentinel that won't hook on the bottom.

Slim

On 3/23/05 3:11 PM, "Bill Effros" <bill at effros.com> wrote:

> Mary Lou,
> 
> Thank you for engaging in this discussion, it's been quite useful to me,
> too.
> 
> Wally's comments, also.
> 
> I prefer to sail on weekdays when there are almost no cruising sailboats
> on my side of the Sound, and plenty of  space to fool around.  Of
> course, I normally can't see my anchor either, so I pull close to shore,
> and drop the anchor where I can see what's happening.  It's
> interesting.  I recommend it.
> 
> At my mooring the only time the anchor line goes slack is when the
> direction of the current is reversing and there's no wind.  This is most
> likely to happen early in the morning.  There are thermals most of the
> rest of the time.
> 
> It's hard for me to believe that your anchor chain is actually holding
> you in place most of the time.  But if you honestly believe it is, I
> would suggest that you get a 10 or 15 pound mushroom anchor, vinyl
> coated, which should do a better job, and come up clean.  I would attach
> an all-line rode.
> 
> Please understand that in my heart I believe a rusty chain is stronger
> than a brand-new rope.  But in my head, I know it just isn't so.  Adding
> chain to line doesn't make the line any stronger.  In fact, it weakens
> the line at the point where the two are joined.
> 
> Modern line is monstrously strong.  The stuff just doesn't pull apart.
> It may chafe, it can age in the sun, it can rot; but if it's in
> reasonably new condition it won't fail from the amount of strain our
> boats and ground tackle are capable of exerting.
> 
> I still have chain on board, but thanks to this discussion, I think I'm
> going to try not using it for this entire season.  Instead, I plan to
> mix up my use of anchors, setting multiple anchors in overnight
> situations.  I'm going to put multiple all-line rodes of varying lengths
> in a container under a cockpit seat along with half a dozen different
> anchors.  Then I will select the appropriate rode and anchor for each
> situation.
> 
> I, too, have been relying too heavily on my Danforth anchor.  In an
> emergency situation, that would not be my anchor of choice -- I think a
> grapnel has a far better chance of quickly setting in a Hail Mary
> emergency.  I have 4 grapnel anchors of differing weights that would
> quickly go overboard in an emergency.  After that, I would dump my
> mushroom anchors, of which I have three of differing weights.  After
> that I would use my Danforth anchors, of which I also have three, again
> of differing weights, and currently all attached to rodes with chains
> segments.
> 
> Also, as I become more comfortable with all-line rodes, I plan to
> experiment with kellets, although I anticipate that multiple anchors on
> separate rodes will be both easier to handle, and more effective.
> 
> The Chapman I referenced is the 61st edition.  I mentioned it only
> because someone made a statement that no reputable reference had ever
> recommended an all-line rode.  The point made in the book is that for
> smaller boats an all-line rode is preferable to an all-chain, or
> chain/line rode in many circumstances.  Chain is preferable only when
> its weight won't upset the balance of the boat, or in instances where
> the boat and ground tackle are so large that the diameter of rope
> required becomes unwieldy, and the weight so great that a windlass is
> required.
> 
> The catenary, kellet, and shear explanations for partial chain rodes are
> never adequately explained to my satisfaction, and have not proved to be
> valid in my experience.  This year I'm going to put my anchors where my
> mind is.  I'll let you know how it turns out.
> 
> Bill Effros
> 
> 
> 
> 
> 
> 
> 
> Mary Lou Troy wrote:
> 
>> Bill.
>> A few more thoughts. You've raised some very practical points beyond
>> the theory. I've put a few practical observations below from our 10
>> years of experience anchoring on the Chesapeake. These points are
>> probably not "generalizable" (I can't believe my spellchecker accepted
>> that) beyond anchoring in a mud bottom in mostly shallow water.
>> 
>>> Let's start with John's explanation, which is well written, and
>>> pretty typical.  In order to make his examples work, he's got to
>>> anchor in 30 feet of water.  I have never anchored in 30 feet of
>>> water, nor have I ever paid out 200 feet of rode.  (When I first read
>>> explanations of anchoring like this I bought 300 feet of line on a
>>> single anchor rode, but most of it has never been in the water.)
>> 
>> 
>> We've only anchored in 25 feet of water once. It was notoriously bad
>> holding ground so we put out most of our 200 feet of rode. There are a
>> few places on the Bay where you get to anchor that deep. We are
>> usually anchoring in 5 - 6 feet of water mid-tide. Tidal range on our
>> part of the bay is usually around a foot.
>> 
>>> In practice, I would be happy if I could anchor in 10 feet of water,
>>> pay out 70 feet of rode, + my 22 ft. boat = 92 feet x 2 = 184
>>> feet...I would need a circle greater than 184 feet in diameter with
>>> no other boats encroaching to be sure we would not foul each other's
>>> rode or bump in the night.  (John's circle would be larger than a
>>> football field.)  I've never been in a busy anchorage where boats
>>> stayed a football field away from each other.
>> 
>> 
>> We also routinely anchor in crowded anchorages. Even in 5 feet of
>> water we sometimes do not get 142 feet (5 feet of water + 2 feet of
>> freeboard x 7 = 49+ 22 feet of boat = 71 x 2) between boats.
>> Fortunately most boats swing with the tidal currents and you don't
>> need that kind of distance. If it's windy enough to overcome the tidal
>> currents most boats swing with the wind - same effect. We try to have
>> enough distance to allow for variations in how boats swing.
>> 
>>> In fact, in most busy anchorages you are lucky to get a 100 foot
>>> circle.  22 feet of boat, 28 feet of rode, 7 foot depth, 4:1 scope.
>>> If this is the way you are anchoring, then your 16 feet of chain
>>> represents more than 50% of the rode--however it weighs only around
>>> 10 lbs, and would not be sufficient to create a catenary shape
>>> between your bow and the anchor.  If you actually anchor in 30 feet
>>> of water, your 16 feet of chain would still weigh only 10 pounds, and
>>> could still not create a catenary between your bow and anchor.
>> 
>> 
>> In reality, most of our 16 feet of chain ends up flat on the bottom. I
>> see the muddy evidence every morning. Catenary effects would only come
>> into play as the wind picks up. After a particularly windy night we
>> will have a lot of mud embedded in the chain - mud that helped us stay
>> put. After a 35-40 knot t-storm I was glad to see all that mud on the
>> chain the next morning. We rode that one out with the engine running
>> in case we needed it to take the strain off the anchor. Fortunately we
>> didn't ever need to put it in gear but the pop-top enclosure and the
>> bimini create a frightful amount of windage in a storm.
>> 
>>> When I look around my harbor at hundreds of anchored boats what I see
>>> are very short scopes, no catenary shape, a straight line between the
>>> anchor and the bow, no chain on the bottom, constant pressure on the
>>> flukes of the anchors, and very little drifting.
>> 
>> 
>> Do boats in your harbors generally turn with the wind or the tide? I
>> expect your conditions are routinely more extreme. We rarely see a
>> straight line between the anchor and the bow. We sometimes see a boat
>> with all chain where the chain drops straight from the bow to the
>> bottom. We know he didn't set his anchor there because we watched.
>> Having spend many a minute watching the rode as our boat swings at
>> anchor, I am certain that the pressure on the flukes is not constant.
>> Having hauled many a muddy anchor and chain in the morning, I know
>> that the chain spent a lot of time digging in the mud - it wouldn't do
>> that if there was a straight line between the bow and the anchor. The
>> Chesapeake waters are not clear enough to see the anchor even in 5
>> feet so I have to go by other evidence.
>> 
>>> I think everyone should anchor in a manner that allows them to sleep
>>> in the night, but I find it interesting that so much of what we read
>>> turns out to be wrong in practice.  As Wally has mentioned, the
>>> biggest benefit of the all line rode is that it comes up clean.  It
>>> is much easier to handle and store, and it is light enough so that
>>> even a child can haul it on board.
>> 
>> 
>> I don't want my anchor and chain to be clean. I want it dug in so that
>> the chain is part of the system that holds the boat in place. If I
>> were anchoring for lunch I might consider an anchor with no chain but
>> most of our anchoring is overnight - and we have two people on board -
>> one to man the tiller and motor - one to haul anchor and wash down the
>> chain and rode. If we were single handing we'd be setting and/or
>> stowing anchors differently.
>> 
>>> Anchoring on coral is a frowned upon practice in most places that
>>> still have coral.   Danforth anchors are the wrong type to use on
>>> rocky bottoms.  Again, like Wally, I have never seen abrasion on my
>>> all line rode.  I don't think line abrasion is a valid reason to use
>>> chain.  I don't think either the chain or the line spends much time
>>> on the bottom.
>> 
>> 
>> My only experience is with the Danforth. We have yet to find a rocky
>> bottom on the Chesapeake. We'd have to learn all over again somewhere
>> else. Our chain spends a lot of time on the bottom. When we had the
>> shorter chain the first 3 or four feet of rode where it was attached
>> to the chain would occasionally have a lot of mud as well.
>> 
>>> I was surprised to find on our boats that all line rodes worked just
>>> as well as chain/rode combinations.
>>> Bill Effros
>> 
>> 
>> It's interesting to hear your experiences and observations because
>> they are so different from mine. I'll file them away in case we ever
>> come sailing on Long Island Sound. I've forgotten - which anchor do
>> you routinely use?
>> 
>> Mary Lou
>> 
>> 
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