Extending my anchor rode

I currently have 50ft of 1/4 inch ht chain with 300ft of 1/2 inch 3 strand rope. I have the possibility of having to anchor in 75ft of water for 3 days. Thirty foot boat aprox 10,000lbs plus. Main anchor is 22lb Bruce. If that is the case I will need to add to the rope. What knot would you use to add rope? A better way to add rope to my 350ft total???? I normally would not need to anchor this deep.
Thanks
Jim

Well you could by another anchor line that has a thimble on it and just tie your old line to the thimble with a bowline with the tag end locked off with a couple of half hitches.

Or you could add a thimble to the end of your current anchor line and join the two thimble ends together with a shackle, carabiner or swivel.

When we would fish for tuna overnight in 120 ft sand bottom, we only used 300 ft of 3 strand and 20 of chain. If we needed to anchor off the lump in 200 ft, we would add a 300 ft section stored in a Rubbermaid tub with a simple shackle. Never dragged with a standard danforth. 30 ft lobster boat about 12K#.
50 ft of chain and 300 ft in 75ft, you should be good in decent weather and bottom.

Been reading about the Zeppelin Bend in the other forum... seems like maybe an option. Don't know whether the knot folks would recommend for this scenario, though...

Or could just go bowline-to-bowline (in lieu of another rode with thimble), although not sure what end strength of that might be.

-Chris

I'd be nervous about using knots in that situation. I vote for thimbles spliced in the ends joined by a shackle.

HopCar said:

I'd be nervous about using knots in that situation. I vote for thimbles spliced in the ends joined by a shackle.

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shackle with a wire tie or safety wire...

Bowline to bowline is great but not pretty.

Any line to line know often suffers from chafe between th elines versus knot preaking.

While assistance towing , I use pretty much bowlines for all high stress situations. I have had the line melt to itself without the bowline failing.

When I need to add temporary length to my rode I use bowline to bowline. Maybe not pretty or go through a windlass, but it's rock solid and easy to remove later.

Ken

another vote for two bowlines I would add a few stiches through the bitter ends fixing them back to the main line so they can not pull lose. this is ugly and will not go through a windless but will not fail and comes apart when you no longer need it.

Thanks for the response. I was thinking Bowline to Bowline also but wanted to be sure. I was thinking of weaving the bitter ends back into the rope so that the knots would not pull loose.
Jim

just put a few stiches in bitter end back to main rode easy to remove at later time.

" I was thinking of weaving the bitter ends back into the rope so that the knots would not pull loose."

Stitching would relieve my concern over using knots. Watch for rope to rope chafing. It can happen fast under a load.

Double sheet bend. Simple, and safe.

I would add a 50 pound weight at the end of the chain, about 3' away from the rode. It acts as a 'sentinal' adding scope angle, without actually increasing the length of rode.

However, it is NOT to be used in a blow, or if you are in a LOT of current. The proper thing to do, would be to add 25 or 50' of 5/16 or 3/8" chain from the anchor to the 1/4"

Do you have a storm anchor you could 'borrow' the extra chain from? then you just have to use seizing on the shackles to put it together.

No the proper thing to do is just what he is trying to do. Which is increase the length of his rode to get more scope. Anything else is just a band-aid.

Ummmm. I think adding more chain (and heavier) would accomplish the same thing...... Unless more chain does not increase scope. I guess it depends upon your point of view.

If one is having difficulty deciding 'which knots' to use to marry two rodes together, it is far easier to screw two shackles and seize them than describe how to properly marry two lines.

Scope is the ratio of the length of the rode to the depth of the water, adding 25-50' of chain will help only slightly. And since he is talking about anchoring in 75' of water, the only way to get to the correct scope is to add a whole lot more line rode or way more chain than 50'.

Chain is proportionally WAY more effective if you have to 'short scope'. Even one or two others mention using complete chain at a 3:1 scope as enough. More chain is far superior to 'lots' more line. Of course just my opinion. It seems to be borne out over 35+ years of observation and practice. But, of course, I learn new stuff every day.

With a complete chain rode you can go as low as 3:1. (Preferably 3.5:1). When mixing rode (not talking about a short piece for bottom abrasion) as the OP has mentioned adding more chain is FAR more preferable.

There are many 'documented' Internet tomès on the lack of suitability of sentinels on rodes. But none of them document a chain rode. Chain is completely different than a fiber rode. More weight down low is the solution.

Yes but he only has a 22lb anchor and 50' of 1/4 chain. 3-1 scope in 75' of water with all chain is still 225' feet of chain. So adding only 25-50' is not going to get him there.

Plus he mentioned staying at anchor for 3 days. If it was a very protected anchorage, I had a larger anchor and the weather was supposed to be stable for that whole time I might be comfortable with that little scope. Otherwise I'd want as much as I could get.

He's got 300' of line now. And line is cheaper than chain to buy. Especially if you only need it for a one time or once in a while thing.

I have a 30' boat w a 435' rode. Only 20' of chain. I'm a fan of long rodes for safety/emergency situations and as most here know not a fan of lots of chain. 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. And Jim your'e halving one of the best anchors in the world for short scope anchoring I'd strongly suggest getting a 33lb claw of your choice. I recently bought a 33lb Lewmar for less than $100. Go down to the store and lift a 22lb and a 33lb ..... huge difference. And in your case you can continue to use your 22lb for every day use if you pull by hand or ? Don't know what the rest of your anchoring system is but you talk about adding chain for holding at short scope. I think adding anchor weight is far more effective.

Cappy,
If you really get into a strong blow the chain will be pulled out almost straight and it's effective catenary advantage is lost. Chain is great for bottom abrasion and setting anchors but for maximum holding increasing holding power is best accomplished by using a bigger anchor. He could also choose a higher performance anchor that has been tested superior at short scope like a Manson Supreme. In that case Jim could probably increase his holding power at 3-1 scope with a lighter anchor. I have a 15lb Supreme but it actually weighs 18lbs and I'm sure holds better than the 22lb Claw. Not many of the newer anchors perform well at short scope though. And of course if Jim is pulling by hand and can afford it the Fortress is probably the anchor to have especially if he's anchoring in really soft stuff.

+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.

manyboats said:

I have a 30' boat w a 435' rode.

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and a very handsome boat at that!

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.

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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.

bayview said:

+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.

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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.
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.

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.

Catenary & Scope In Anchor Rode: Anchor Systems For Small Boats

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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.

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.

Tony B said:

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.

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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 . . . .

+1

psneeld said:

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.
.

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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.

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.

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.

cappy208 said:

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. .

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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.