Weight for anchor rode

[zoidberg]

The perfect rode would be fractionally heavier than water infinitely strong and chafe proof piano wire.

RORC racing fanatic Adlard Coles used a reel of piano wire for deep-water light breeze kedging, and wrote about it in one of his books. I used his idea on 'Triohe' during the 2003 Fastnet, but with Kevlar-cored cordage from the fibre-optic installation industry. We won our class against larger boats, which didn't....

So a chain size or two smaller than traditional and made of higher quality material is the best compromise.

That's advocated by Ozzie anchoring guru Jon Neeves, in these very pages.

However, if you have primarily fiber rode ( i.e a 'mixed rode' ) a kellet has several uses.... But, I would NEVER use a weight for that. I've learned that attaching a loop of old chain of the same weight (10 pounds or so is all we are talking about) is much easier to handle. Loop it twice to reduce the length.

My stowed kedge anchor has a short length of 10mm chain, then a long light fibre rode. That length of chain, looped around several times as above, then secured to the end of my main anchor's chain, ( softee shackle ) does as 'thinwater' suggests.

 

[thinwater]

I find 10kg of dive weights tied to the rode simple enough to handle. Whatever is at hand.

Not hard to handle, but it's a pain in the neck (back) to reach around the forestay, past the roller, and down to the rode on many boats. The chain loops avoid the need to reach forward and a foot below your feet. I don't even need to take it off the rope, I just let the rode out. I use this system on my Corsair F-24 mk I trimaran, and it is so easy. On the PDQ (avitar) I use all-chain rode.

 

[thinwater]

RORC racing fanatic Adlard Coles used a reel of piano wire for deep-water light breeze kedging, and wrote about it in one of his books. I used his idea on 'Triohe' during the 2003 Fastnet, but with Kevlar-cored cordage from the fibre-optic installation industry. We won our class against larger boats, which didn't....


That's advocated by Ozzie anchoring guru Jon Neeves, in these very pages.


My stowed kedge anchor has a short length of 10mm chain, then a long light fibre rode. That length of chain, looped around several times as above, then secured to the end of my main anchor's chain, ( softee shackle ) does as 'thinwater' suggests.

Why to the end of the chain and not further along the rope portion of the rode?

I'm not challenging you--I'm curious. I can think of several good reasons. I just want to know which reason you chose!

 

[zoidberg]

Nothing absolute and definitive. However....

In light and variable breeze, changing weak tidestream, that 'knot' of chain will be dragging around the floor. I wouldn't want rope to be dragging and chafing..
I run a textile rode forward, out through a toerail cleat, and back 'outside everything' to the cockpit. There I attach the main short chain and the anchor, which I deploy from the cockpit. It's easier to attach the supplementary 'kellet' of looped chain at that time and place, so it all goes over almost together.
I'm fond of using 'softee shackles' I've made up, and it's easier to pass one through a chain link then around the 'looped' chain-kellet.

There may, of course, be other considerations, but these save me faffing about on the foredeck when I don't need to.

 

[MM5AHO]

I don't think that's lead, rather more likely galvanized steel.
The loop is welded to the main block. Presuming that loop is steel, then its not welded to lead, that just doesn't work.
The weld appears in the picture to be to both the loop and the block, Probably then they're the same metal. The colour suggests galvanized. Galvanizing does look a little like lead, but I suspect this isn't lead.
And steel is almost half the density of lead.

 

[Mudisox]

As I have a catamaran, I always use a bridle of some length that lessens yawing. Having taken the weight of the boat on the bridle, I then let out more chain to make a bight under the bow which acts as a chum so no heavy lifting for me. The anchor winch does it's job. Also, it helps keeping the angle of the anchor chain down, when acting as a committee boat. The chain is no use sitting in the chain locker- put it to use.

 

[thinwater]

Nothing absolute and definitive. However....

In light and variable breeze, changing weak tidestream, that 'knot' of chain will be dragging around the floor. I wouldn't want rope to be dragging and chafing.. Excelent point. That is why I extend it with a 250mm sling. This is true of any kellet.

I run a textile rode forward, out through a toerail cleat, and back 'outside everything' to the cockpit. There I attach the main short chain and the anchor, which I deploy from the cockpit. It's easier to attach the supplementary 'kellet' of looped chain at that time and place, so it all goes over almost together. Makes sense. In fact, on my F-24 I deploy off one of the wing tramps, because I keep my primary anchor in the ama locker (won't fir in the anchor locker).


I'm fond of using 'softee shackles' I've made up, and it's easier to pass one through a chain link then around the 'looped' chain-kellet. Me too.

There may, of course, be other considerations, but these save me faffing about on the foredeck when I don't need to.

See above.

 

[thinwater]

As I have a catamaran, I always use a bridle of some length that lessens yawing. Having taken the weight of the boat on the bridle, I then let out more chain to make a bight under the bow which acts as a chum so no heavy lifting for me. The anchor winch does it's job. Also, it helps keeping the angle of the anchor chain down, when acting as a committee boat. The chain is no use sitting in the chain locker- put it to use.

Long term, in sandy locations, that could rub off the galvinizing. But as a committee boat, makes good sense. Fast.

 

[RichardS]

I don't recall seeing a snubber used on most ships?

Having you boat behave badly at anchor is poor seamanship.
How you avoid that is up to you.
Maybe the better seaman has more tools in the box and an open mind?

What has an open mind got to do with it? We're not talking about ships, this is Practical Boat Owner.

Are you prepared to go on the record on this forum and say under which circumstances you would advise that it is preferable not to use a snubbing line?

Richard

 

[Neeves]

What has an open mind got to do with it? We're not talking about ships, this is Practical Boat Owner.

Are you prepared to go on the record on this forum and say under which circumstances you would advise that it is preferable not to use a snubbing line?

Richard

We unfortunately use the word 'snubber to mean two entirely different items.

A snubber can be a short length of rope, of almost any dimension, method of construction and actual cordage type (as long as its manageable and strong enough) that is used to take the load of the rode (and the potential load) off the windlass. This snubber would have been traditionally attached to a Samson post (most of us need to find something else as Samson posts went to wherever sextants went). The snubber can be short - all it is doing is protecting the windlass.

The second snubber, or bridle, is used to offer elestacity to remove snatch loads and if a bridle it helps to manage veering. In order to reduce the impact of snatch loads it must 'stretch' and consequently is not as strong as the chain. The snubber also needs to be sufficiently long to offer the necessary stretch. Because this snubber is cycled, stretched and not stretched, it tends to be weaker than the chain and has a finite life span (consider it a consumable) and also needs a snubber as defined in the previous paragraph.

You thus need two snubbers, one that reduce the impact of snatch loads and one as back up in case your snubber fails.

If you are using lightweight chain then the need for the elastic snubber increases as you have sacrificed catenary (for less weight in the bow).

An elastic snubber 'works' because it absorbs energy, a catenary works because it absorbs energy (the same energy) and thus a long snubber can replace some length of chain deployed. If you deploy your snubber from the transom that 10m of snubber along the deck already replaces the need for you to deploy some chain, meaning your swing room in a tight anchorage can be smaller.

As an aside - some deploy lots of rode to offer a horizontal tension to the anchor. This is very old fashioned thinking but is valid for old anchor designs. If your anchor is a modern one, not much bigger than recommended for your yacht then it will be well buried and bury some chain. The tension angle on your anchor is not that defined by the scope but is defined by the angle subtended by the buried shackle. Your scope may lead you to think the tension is horizontal but the shackle angle can be high - if the anchor is well buried. If you want to minimise the shackle angle, use smaller chain, a smaller shackle and get rid of your swivel. The shackle angle is virtually independent of scope but is determined by the depth of burial of the anchor, the physical resistance of the rode (shackle, chain swivel) to burial and the shear strength of the seabed. I spent a lot of time setting anchors, digging them out and measuring angles - there is an article in the works (it will invoke plenty of controversy - and controversy can be useful). If this paragraph merits elaboration........?

Larger vessels tend not to veer as much as smaller slightly built vessels nor are they impacted so much by waves and larger vessels can afford to have more weight in the bow (heavier chain). There are no hard and fast rules. But most new AWBs are relatively light and more attention need be invested in a snubber or bridle than in, say, a traditionally designed, long keeled, heavy displacement yacht. Multihulls would conventionally have a bridle, commonly lacking in elasticity.

To me - the ideal rode is a very thin wire (piano wire) as strong as the chain it replaces and the energy absorbing component being provided by a thin strong piece of elastic cordage run up and down the deck (between blocks) (this gives length) and only a small portion outboard at the bow. The wire provides the tether to the anchor, the cordage provides the ability to absorb the energy. We are currently unable to reach this ideal - but smaller chain is one step in that direction. It is possible to source high tensile 4mm chain which, potentially, could be galvanised and replace 8mm chain, and 6mm replace 10mm chain etc - but for the 4mm chain - there is no windlass capable of handling 4mm chain (no gypsy) but maybe we need to think of drum windlass/winches. Wire rodes are perfectly acceptable - but do have issues (swage life being one)

How to: Dealing with Snatch Loads in an Anchorage

Anchor Snubber Tips

The art of snubbing, in the nicest possible way - MySailing.com.au

Anchor Snubber Shock Load Test - Practical Sailor

This next article is on how we, personally, arrange to increase snubber length without much of the snubber being forward of the bow. It is a bit multi-centric but has been applied to a monohull.

Running the Lines on the Multihull Bridle - Practical Sailor.


But going back to the beginning of this, rambling, discourse - if you use a snubber for its elasticity - you also should use, its good seamanship, a short snubber to protect your windlass in the event the snubber fails. We have broken 2 snubbers in 20 years - it does happen (carry a spare). You can use the short snubber as your chain lock for when you are on passage to secure the rode, should for example, the clutch 'fail'. You can use the short snubber for those occasions when the anchor is so deeply buried you need wait for it to break out (takes the load of the windlass). If you windlass fails the short snubber can be used to hold the chain when you swap attachment points for the rope as you use the halyard winch to retrieve the anchor etc.

Jonathan

 

[coopec]

We unfortunately use the word 'snubber to mean two entirely different items.

A snubber can be a short length of rope, of almost any dimension, method of construction and actual cordage type (as long as its manageable and strong enough) that is used to take the load of the rode (and the potential load) off the windlass. This snubber would have been traditionally attached to a Samson post (most of us need to find something else as Samson posts went to wherever sextants went). The snubber can be short - all it is doing is protecting the windlass.

The second snubber, or bridle, is used to offer elestacity to remove snatch loads and if a bridle it helps to manage veering. In order to reduce the impact of snatch loads it must 'stretch' and consequently is not as strong as the chain. The snubber also needs to be sufficiently long to offer the necessary stretch. Because this snubber is cycled, stretched and not stretched, it tends to be weaker than the chain and has a finite life span (consider it a consumable) and also needs a snubber as defined in the previous paragraph.

You thus need two snubbers, one that reduce the impact of snatch loads and one as back up in case your snubber fails.

If you are using lightweight chain then the need for the elastic snubber increases as you have sacrificed catenary (for less weight in the bow).

An elastic snubber 'works' because it absorbs energy, a catenary works because it absorbs energy (the same energy) and thus a long snubber can replace some length of chain deployed. If you deploy your snubber from the transom that 10m of snubber along the deck already replaces the need for you to deploy some chain, meaning your swing room in a tight anchorage can be smaller.

As an aside - some deploy lots of rode to offer a horizontal tension to the anchor. This is very old fashioned thinking but is valid for old anchor designs. If your anchor is a modern one, not much bigger than recommended for your yacht then it will be well buried and bury some chain. The tension angle on your anchor is not that defined by the scope but is defined by the angle subtended by the buried shackle. Your scope may lead you to think the tension is horizontal but the shackle angle can be high - if the anchor is well buried. If you want to minimise the shackle angle, use smaller chain, a smaller shackle and get rid of your swivel. The shackle angle is virtually independent of scope but is determined by the depth of burial of the anchor, the physical resistance of the rode (shackle, chain swivel) to burial and the shear strength of the seabed. I spent a lot of time setting anchors, digging them out and measuring angles - there is an article in the works (it will invoke plenty of controversy - and controversy can be useful). If this paragraph merits elaboration........?

Larger vessels tend not to veer as much as smaller slightly built vessels nor are they impacted so much by waves and larger vessels can afford to have more weight in the bow (heavier chain). There are no hard and fast rules. But most new AWBs are relatively light and more attention need be invested in a snubber or bridle than in, say, a traditionally designed, long keeled, heavy displacement yacht. Multihulls would conventionally have a bridle, commonly lacking in elasticity.

To me - the ideal rode is a very thin wire (piano wire) as strong as the chain it replaces and the energy absorbing component being provided by a thin strong piece of elastic cordage run up and down the deck (between blocks) (this gives length) and only a small portion outboard at the bow. The wire provides the tether to the anchor, the cordage provides the ability to absorb the energy. We are currently unable to reach this ideal - but smaller chain is one step in that direction. It is possible to source high tensile 4mm chain which, potentially, could be galvanised and replace 8mm chain, and 6mm replace 10mm chain etc - but for the 4mm chain - there is no windlass capable of handling 4mm chain (no gypsy) but maybe we need to think of drum windlass/winches. Wire rodes are perfectly acceptable - but do have issues (swage life being one)

How to: Dealing with Snatch Loads in an Anchorage

Anchor Snubber Tips

The art of snubbing, in the nicest possible way - MySailing.com.au

Anchor Snubber Shock Load Test - Practical Sailor

This next article is on how we, personally, arrange to increase snubber length without much of the snubber being forward of the bow. It is a bit multi-centric but has been applied to a monohull.

Running the Lines on the Multihull Bridle - Practical Sailor.


But going back to the beginning of this, rambling, discourse - if you use a snubber for its elasticity - you also should use, its good seamanship, a short snubber to protect your windlass in the event the snubber fails. We have broken 2 snubbers in 20 years - it does happen (carry a spare). You can use the short snubber as your chain lock for when you are on passage to secure the rode, should for example, the clutch 'fail'. You can use the short snubber for those occasions when the anchor is so deeply buried you need wait for it to break out (takes the load of the windlass). If you windlass fails the short snubber can be used to hold the chain when you swap attachment points for the rope as you use the halyard winch to retrieve the anchor etc.

Jonathan

Well I have a substantial Sampson Post as the manufacturers of my winch stated that I shouldn't use the winch as a samson post As you can see the samson post is bolted to the deck but there are X2 SS angle irons (2 in X 2 in) running for and aft and bolted to the transverse bulkheads as well.

The bow rollers are quite heavy and I'm sure you'd destroy the yacht before the bow roller. (They used a 1000 tonne press to bend the SS although I think 250 tonne would have done it. People in Europe may wonder why I have gone so heavy but it is the recommendation of Alan Lucas who points out that to the North of Australia there are uncharted anchorages which you may need to leave in a hurry. If the anchor gets snagged it may be necessary to get back and open up the throttle and drag the anchor out)

I've got more reading to do before I fully understand the purpose of a snubber but I think I should use one as I believe it would use the weight of the yacht as a shock absorber to avoid shock loads on the boat and anchor. Is that logical thinking?

 

[Neeves]

I was not denigrating Samson posts, far from it - I was saddened by their demise. They have disappeared from modern (high) production yachts and have commonly not been replaced by anything. In between some slightly older production yachts had a bow cleat roughly in the middle of the foredeck, which one might hope was suitably reinforced, but even this has become scarce - offering a nice clean, trip free deck but with no central point of securement for the snubber that could be used to protect the windlass. Some yachts have horn cleats behind fairleads at the bow, but these are commonly a bit too far offset from the centre line to replace the central horn cleat or Samson post (though it is easy to use both of these bow horn cleats to knit up something to act as the securement point for a short snubber).

Coopec - you bow looks significantly substantial - but you might want a plate on the bow between windlass and bow roller to protect the deck against abrasion from the chain - I don't know how much clearance there is between chain and deck - but most chain slaps the deck on retrieval. I might also attach a chain lock, better than a short snubber. You could bolt it to the Samson post plate. I do like the twin bow rollers, they are consigned to the same thinking of removing the Samson post - and, to me, a serious cruising yacht needs to be able to handle more than one anchor. (We regrettably have only one bow roller - but overcome the deficiency by using aluminium anchors).

I would certainly use a snubber. The yacht itself will take all sorts of punishment, especially with a bow structure like yours - it looks bullet, if not shell) proof. But the snubber not only protects the yacht (and crew) from any snatch loads but more importantly protects the anchor. If you snatch load the yacht your anchor enjoys the same, identical, snatch load and reducing that impact will make your anchor more secure. The snatch is absorbed by the elasticity of the snubber (that energy is transferred to the snubber stretching - and if there is nothing to stretch (and not enough catenary) you and the anchor will feel the knock (it can be like hitting a brick wall). At low wind speeds your yacht might not yaw nor horse (in seas/swell) but if you are caught out in an anchorage with high winds you may yaw and then you will value the snubber. Yawing is not only caused by yacht characteristics. Yawing might develop simply from wind shear (think of how aircraft can veer when landing in high winds), and then any yacht will yaw.

Jonathan

 

[coopec]

Jonathan

Thanks for that.

I could easily Sikaflex some heavy nylon strip to the deck to stop the chain from abrading the decks. (Sounds like a good idea)

When you mentioned "chain stopper" I became confused and thought you were talking about a Devil's Claw. When I did a little research I found they were two different things. I had planned to use a Devil's Claw but I may change my mind after doing further research (such as this thread)

Chain Stopper Vs Devil's Claw - Cruisers & Sailing Forums

 

[Neeves]

A chain lock, Lewmar can supply, is a gate that can stop and hold the chain. It is, or can become, an integral part of the bow roller assembly. In your case it can be bolted to the plate for your Samson post and could be as strong as everything else you have there. It will hold the chain and take any snatch loads off the windlass. It will also secure the chain in case the clutch slipped, scattering 100m of chain + anchor over the seabed in 1,000m of water (should the attachment at the bitter end fail) - might be embarrassing (and expensive). We actually use something like a devils claw because our bow roller is 'contained in' an aluminium 'U' shaped beam which is also structural (it supports or part attaches our cross beam (which holds the forestay) to the bridge deck and I am reluctant to drill holes in it for a chain lock. So our devils claw, its from the lifting industry, is held on a short dyneema stop attached to holes, as supplied at commissioning, in this 'U' shaped beam.

We don't use the devils claw as a chain hook as they can be inordinately difficult to release if the claw itself is under tension - (be warned). Our claws come from the lifting industry and are precisely made and need to be well aligned to release (which also means they do not fall off inadvertently).

In your case I'd use something like the Lewmar chain lock, I think Maxwell make something similar - as your arrangement lends it self to the addition (as if you planned it). But they need to be well secured and many bow roller assemblies and arrange,ents don't lend themselves to a retrofit - and short strop with hook or claw seems more appropriate (and is easier to install and cheaper).

For the sacrificial strips, nylon, stainless plate (which might remove the chain gal) or a teak strip might be possible.

You have plenty of room between bow roller and windlass and can I suggest you consider a Boomerang (instead of a swivel or manual re-alinging of anchor).

How to boomerang your anchor right back at you - MySailing.com.au

If you know anyone locally you could have one cut from duplex stainless, or make one yourself (which is what I do) but don't make it from 316 (or mild steel) the dimensions are based on using a HT steel.

And as I've allowed your thread to drift I'll compound the impertinence and offer you a bit more, uncalled for, advise:

Know how: Ground Tackle

Jonathan

edit

Maxwell call them 'chain stoppers'

Winch Accessories

 

[RichardS]

But going back to the beginning of this, rambling, discourse - if you use a snubber for its elasticity - you also should use, its good seamanship, a short snubber to protect your windlass in the event the snubber fails.

Jonathan

Whichever definition of snubber one uses, I'd still be interested to hear when "good seamanship" would suggest that it is better not to use one, as proposed above?

Richard

 

[Neeves]

Whichever definition of snubber one uses, I'd still be interested to hear when "good seamanship" would suggest that it is better not to use one, as proposed above?

Richard

I'm with you Richard, I cannot imagine any reason not to use one, sorry not one, but both. Its not difficult, its not expensive it has a number off benefits, I cannot think of a downside.

So - I'm with you.

How can it ever be better not to use one?

Jonathan

 

[zoidberg]

I'm thinking 'coopec's assembly of ironmongery, in Perth WA, is what may be described in Antipodean as 'like a brick-built dunny'. I'm sure Clive James would have appreciated its architectural merits.

I may have missed it, but I didn't see an 'ole for a rode retaining pin through the cheeks of the bow fitting. That may be a conscious choice, but I've found such very convenient when anchored in short chop.... and even when motoring with the anchor on the bow roller.

 

[coopec]

I'm thinking 'coopec's assembly of ironmongery, in Perth WA, is what may be described in Antipodean as 'like a brick-built dunny'. I'm sure Clive James would have appreciated its architectural merits.

I may have missed it, but I didn't see an 'ole for a rode retaining pin through the cheeks of the bow fitting. That may be a conscious choice, but I've found such very convenient when anchored in short chop.... and even when motoring with the anchor on the bow roller.

There's "Coastal Cruisers" and "Blue Water yachts" Mine is meant to be a blue water cruising yacht.

" Production boats are designed for light wind/light seas cruising while blue water boats are designed for rougher seas, bigger air and longer trips. A blue water boat has larger tanks and a heavier displacement. Production boats have a lighter displacement and are designed for coastal and bay cruising

Blue Water vs. Production Boats — Dave Townley Yachts

If you are sailing across the top of Australia you could be 500 km from the nearest port and if you get into trouble you have sort it out yourself.

Someone on this forum said in Europe you are basically "Day Sailors"?

 

[noelex]

I could easily Sikaflex some heavy nylon strip to the deck to stop the chain from abrading the decks. (Sounds like a good idea)

When you mentioned "chain stopper"

This photo shows our chain stopper and chain guide. It may give you some ideas.

If you have the room and the deck strength, a chain stopper is a helpful addition. It provides a releasable one way clutch for the anchor chain.

 

[coopec]

This photo shows our chain stopper and chain guide. It may give you some ideas.

If you have the room and the deck strength, a chain stopper is a helpful addition. It provides a releasable one way clutch for the anchor chain.

Thanks Noelex.

Up til now I thought Id use a Devil's Claw but I will have to do more research for sure.