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Old 07-18-2014, 12:08 PM   #21
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I have a 30' boat w a 435' rode.
and a very handsome boat at that!
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The most advantageous weight that you can add to your system is not chain but in your anchor. .... One could add 50lbs of chain but be better off adding 10lbs of anchor...... I think adding anchor weight is far more effective.
I disagree. Having more chain is far superior. LOTS more chain. If my chain locker could hold it, I would have 300' of 5/16" there.

It is not the scope that 'makes' an anchor dig in. It is the catenary. The lower the angle the quicker and more substantially the anchor sets, and resets upon breakout. Rope needs WAY more length because it pulls so taut. Chain keeps more catenary in the equation.

I was towing the "Evilina M Goulart" a 90' old Grand Banks fishing schooner to her final resting place years ago. When we arrived at the inlet of the Essex River about 6 hours early, I decided to put down a hook and wait for daylight. (it was the tugs 'lunch hook'.) Mind you, this is a 60' tug, with the 90' schooner along side. I dropped a 55 lb danforth over the side. with 50' of chain. and a 100' piece of line. The schooner Captain looked at me incredulously and said: "You don't seriously think that little anchor will hold us do you?"

Yup. It held. Not because of the weight of the anchor. But because of the amount of chain that kept the line pulling almost horizontal to the bottom. I have pulled many boats off the beach that have snazzy hightech anchors at the end of the rode. with the atypical 6' or 8' plastic coated chain attached.
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Old 07-18-2014, 01:24 PM   #22
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+1 to what Bill said about adding hitches. Bowlines wont fail under load and are easier to untie when done but will come loose under pull then relaxing conditions of anchoring.
I highly doubt one would if properly snugged up in the first place...I rig hundreds of lines every year from towing to salvage to anchoring...and over 12 seasons in this boating business, I have never have had one come undone unless tied incorrectly or not sufficiently snugged when first tied.
They are pretty much the go to knot for everything we do in the assistance towing company I work for....and the last marine towing, barge, salvage business before this one.

edit: at least not as a temp rode...and if not temp..I would use something more permanent than a couple bowlines anyhow.
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Old 07-18-2014, 01:47 PM   #23
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Cappy With respect to your experience on a couple of occasions I have seen my rode ( once all chain and once half chain and rope) pull all the apparent catenary out. I really don't know how fast the wind was but I doubt it exceeded 40 knots because we all overestimate wind speed.
I guess only luck held the boat but it really made me wonder about my previous belief in catenary.


Here is an interesting paper on catenary.
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Old 07-18-2014, 01:55 PM   #24
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PS

YMMV but for an anchor I would leave a long tail on the bowlines and half hitch them. But then I don't see any reason to take unnecessary risk.
I do the same with lines to poles not because I don't know how to splice but because I don't like the permanence of splices. Never had a bowline come undone there either but for long term I add hitches as insurance.
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Old 07-18-2014, 02:28 PM   #25
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Knots reduce the strength of the rope by almost 50%. The breaking point is usually right near the end of the knots where the most bends and stress are.
A simple splicing of the two 3-strand ropes/lines will only reduce breaking strength by about 10%. If the line proves too much to handle in your locker, just cut the splice off and seize the ends again, You will only lose less than 1' per rope.
If you go the thimble and shackle route, check the breaking strength of the rope and the new shackles and try to get the shackle to exceed the breaking strength of the rope. You might find that what you thought was an adequate shackle may be way too weak.
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Old 07-18-2014, 04:01 PM   #26
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Knots reduce the strength of the rope by almost 50%. The breaking point is usually right near the end of the knots where the most bends and stress are.
A simple splicing of the two 3-strand ropes/lines will only reduce breaking strength by about 10%. If the line proves too much to handle in your locker, just cut the splice off and seize the ends again, You will only lose less than 1' per rope.
I agree, an end-to-end short splice will be near full line strength, but almost doubles the diameter. An end-to-end long splice looses a little strength, but is almost the same diameter as the line, so it will run freely through blocks and rollers. Either will be stronger and feed better than a knot. Definitely more tedious though . . . .

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Old 07-18-2014, 04:34 PM   #27
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I highly doubt one would if properly snugged up in the first place...I rig hundreds of lines every year from towing to salvage to anchoring...and over 12 seasons in this boating business, I have never have had one come undone unless tied incorrectly or not sufficiently snugged when first tied.
.
I mentioned the half hitches because I've seem bowlines come loose a few times over the years. Mostly in situations where they were wet. And yes them were tied correctly and tightly. The type of line can make a difference too from what I've seen.
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Old 07-18-2014, 04:40 PM   #28
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As I said...if temp, a naked bowline has always worked for me...then again I would not tie one in springy, cheap, three strand poly...or in fishing line...the knot was probably never designed for them.

The half hitches are at least a good measure to make sure the tag rend of the bowline isn't too short.

If I have to worry about a knot coming undone...I would always upgrade to something more permanent...especially in a situation like anchoring where the knots can't be monitored.

What would worry me even more in a line to line situation is chafe...especially in a sandy environment or with some of the new synthetic lines.
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Old 07-18-2014, 05:00 PM   #29
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Just get a bigger anchor and loose 0% rode strength.

And adding a significant amount of chain will weigh enough that you probably could double the size of your anchor instead. That should work much better than extra chain. You could/can change the anchor size and type to accommodate whatever bottom conditions and geography that may present itself. Lots of flexibility.

If I had 5/16" all chain (appropriate for my heavy 30' boat) rode and my 33lb anchor and switched to mostly chain how big of an anchor could/would I have. I think if you ran the numbers it would be very clear 10lbs of anchor is worth much more than 10 lbs of chain.
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Old 07-18-2014, 05:15 PM   #30
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and a very handsome boat at that!

I disagree. Having more chain is far superior. LOTS more chain. If my chain locker could hold it, I would have 300' of 5/16" there.

It is not the scope that 'makes' an anchor dig in. It is the catenary. The lower the angle the quicker and more substantially the anchor sets, and resets upon breakout. Rope needs WAY more length because it pulls so taut. Chain keeps more catenary in the equation.

I was towing the "Evilina M Goulart" a 90' old Grand Banks fishing schooner to her final resting place years ago. When we arrived at the inlet of the Essex River about 6 hours early, I decided to put down a hook and wait for daylight. (it was the tugs 'lunch hook'.) Mind you, this is a 60' tug, with the 90' schooner along side. I dropped a 55 lb danforth over the side. with 50' of chain. and a 100' piece of line. The schooner Captain looked at me incredulously and said: "You don't seriously think that little anchor will hold us do you?"

Yup. It held. .
That's not surprising at all. If you said it held in 60 mph winds and in 50' of water I'd be impressed.

Cantenary may help an anchor set. But of course when you back down on an anchor to set it you have basically zero cantenary so I'm not 100% sold on that idea.

Tests have shown that snatching action as a rode comes tight over and over in a blow is more a factor in an anchor breaking loose then constant pull. So a rode made of line and chain gives you the best of both worlds with chain weight to add cantenary and line stretch that reduces the snatch loads on the anchor lessing the chance the anchor will break out.


But either way adding 50' of chain is not going to get him to the proper scope when starting with a 22 lb anchor and only 1/4 chain to start with. At least in my opinion. And there no reason for him to spend the money to buy enough chain to switch to an all chain rode just so he can anchor safely for 3 days in 75' of water.
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Old 07-18-2014, 08:22 PM   #31
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I anchored in 85' of water in Alaska but there was little wind. I was close enough to the beach on one side to require 3-1 scope or less. I used my 22lb Claw because of it's short scope abilities.

CaptBill,
For a 30' boat that is not heavy 1/4" chain is perfect ... Not too light or small. And no reason to buy more chain I agree but at 3-1 a bigger anchor would be more secure IMO. Instead of 40 lbs additional chain 40 lbs more anchor would give him a 62lb anchor. If the bottom's any good that should hold his boat at least in a 50 knot blow.
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Old 07-18-2014, 08:32 PM   #32
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The answer to any anchor question on this forum is your anchor is too small, it's the wrong kind and you don't have enough chain.
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Old 07-18-2014, 10:02 PM   #33
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The answer to any anchor question on this forum is your anchor is too small, it's the wrong kind and you don't have enough chain.

Lol

Says the man who sold me a bigger anchor

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Old 07-18-2014, 11:54 PM   #34
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"Says the man who sold me a bigger anchor "
That's right, now don't you need an even bigger one?
How about a shot of chain to go with that?
How about a nice balsa wood kellet to go with the chain? They're so much easier to handle than those heavy old cast iron and lead ones.
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Old 07-19-2014, 01:26 PM   #35
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I have dived my anchor line many times, and the chain is usually lying on the bottom (except 3-4' of the shackle end) even at fairly short scope if the tides and wind are moderate. I might opt for a longer chain only if I were going to be awake all night, say tuna fishing, but not to sleep on of for extended stays. I am a believer in a balanced anchor system with no knots or splices in the rode. As a former firefighter I use the figure 8 a lot. It is easy to tie and untie even in the middle of the rode, and won't work loose like some other knots when worked by waves and wind.
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Old 07-19-2014, 01:38 PM   #36
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1/2" three strand line is what is presently in place then simply splice an eye on that and then splice another eye in the additional line. Either hook together with a shackle or entwine prior to splicing the second eye. Should take about two minutes and creates an 80-90 % effective joining.
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Old 07-19-2014, 02:28 PM   #37
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The answer to any anchor question on this forum is your anchor is too small, it's the wrong kind and you don't have enough chain.

Well of course! And all those answers are the correct.
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Old 07-30-2014, 12:17 PM   #38
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I formed my opinions on the limited effectiveness of chain catenary from two sources.

1.). Hinz's book, "The complete book on anchoring and mooring". He had some interesting math that seems to show that while chain does have some incremental catenary effect, it's not much, and less than by word of mouth than we typically give it credit for.

2.) Standing on my bow in a fair breeze with 4:1 scope, and watching the anchor chain tighten up, go perfectly straight, then we would drag about 15 feet, the gust would die down and start the cycle over again. I was stern tied, heavy, with the wind on my side acting like a sail. It was just a cool little science project to see how obviously, immediately and simply was the relationship between scope acting to keep the anchor line parallel to the bottom and how easily an anchor can drag when that effect is momentarily overcome.
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Old 07-30-2014, 12:38 PM   #39
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. I was stern tied, heavy, with the wind on my side acting like a sail..
Unless the winds are forecast light, I don't stern tie. An anchor and rode performs much better IMHO when the boat is allowed to swing.

A few weeks ago when anchored in the Broughtons the winds were blowing 20 to 25 knots. A GB was anchored nearby, stern tied too so he could easily get Fido to shore. His anchor would not hold as the winds from the side kept breaking him loose . After noting we were swinging freely and not dragging at all he finally pulled loose from the stern tie and reset in deeper water, no problems after that as he swung freely.
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Old 07-30-2014, 01:22 PM   #40
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If you're going to also set a stern anchor and align perpendicular to the wind, I'd say all bets are off on how much anchor/chain/scope you're going to need. Seems contrary to any anchoring advice I've read. That provides maximum windage to the prevailing winds which will place maximum tension on your rodes, current notwithstanding.
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