Anchor rode.

[Neeves]

Thank you Neeves, "Boomerang" ordered.

Lucy, You need to read my Boomerang article, above. I don't know what Viking offers in the way of installation instructions - if any (I've only heard they have a Boomerang as part of their portfolio and not actually checked to see if it is true). I think all the installation instructions are in the article. You can vary the number of links between Boomerang and anchor - if space is at a premium. If the anchor gets to the point where it is turned by the Boomerang and the extra links simply allow time for the anchor to settle down from its gyrations. The more links the better. We find have marked out rode so when we know when the Boomerang will hit the roller itself and we stop, for a few seconds, as the Boomerang come over the bow roller - this allows the anchor to settle down and then we can restart. Modern windlass can be very fast and you don't need a wildly gyrating anchor whipping onto the bow roller. Its dead simple to install you just need to check that there are no twists in the chain from where it 'enters' the gypsy through to the anchor itself - so check that all the links aligned vertically - stay vertical and don't slowly twist. The long of the Boomerang should be near the windlass and the short of the Boomerang near the anchor. You don't need fancy shackles for the Boomerang but you still need a decent shackle on the shank as this is the one that might be side loaded.

If you have any issues PM me or start a new thread.

Jonathan

 

[Bristolfashion]

"...problem with lateral forces IS dealt with by having ...." Nothing personal, Bristolfashion, but I despair at the abysmal standard to which English Grammar has descended. They don't seem to teach it properly any more.
I constantly see and hear plural verbs thrown mistakenly into main clauses whenever a plural appears in a subordinate clause.
( Apologies for thread drift)

Oh come on, I like pedantic irrelevancy as well as the next man, but this is obviously a simple typo. Not a mistaken is/are, but a missing "s". We are not producing great literature here, but mostly prodding away on phones and the like.

If you review my body of work (ok, a bunch of posts on the forum), you will find some fine old usage of the language with a close attention to the rules, but I'm not going to run over it with the red correcting pen before pressing "post reply".

As had been pointed out previously, you have an incorrect capitalisation in your "Grammar"(sic) lesson!

 

[Bristolfashion]

It is possible to buy Imperial chain, G43, in the UK - so I was really just questioning.

I confess some amazement that the gypsy will accept both 7mm and 6mm chain to metric specifications. But if you have been assured this is the case then even though it must be true - I'd double check by taking the gypsy in and trying it. Once you have a length of chain - its yours! unless you buy the chain from the people who defined the gypsy and assured you it fitted both 6 and 7mm. Some gypsies are more forgiving than others

I've never seen 7mm chain so I am talking from total ignorance - but hey its the internet why should ignorance come into it

But I would check - its simply too expensive if someone has made some slick comment (like me!)

Jonathan

Sage advice - most of the winch gypsies here that run 6/7 mm seem to indicate, "Dual 6mm DIN766, 1/4" G4 or BBB, 7mm DIN766" or similar.

I am considering DIN 766 7mm as well as your comments on 6mm.

One Lofrans winch gypsy will only run ISO standard 7mm, (as well as the range of 6mm chain) which is not so readily available.

From previous experience, I found a long 8mm nylon snubber on our 6/12 set up worked well.

 

[Neeves]

Sage advice - most of the winch gypsies here that run 6/7 mm seem to indicate, "Dual 6mm DIN766, 1/4" G4 or BBB, 7mm DIN766" or similar.

I am considering DIN 766 7mm as well as your comments on 6mm.

One Lofrans winch gypsy will only run ISO standard 7mm, (as well as the range of 6mm chain) which is not so readily available.

From previous experience, I found a long 8mm nylon snubber on our 6/12 set up worked well.

As I mentioned here I've only ever seen 6mm and 8mm metric chain - I have heard of 7mm. I recently discovered you can source 4mm high tensile, I think G120, but I have not found anyone making a gypsy. Being tedious . I don't think there is a 1/4" G4, G4 is metric. BBB is an old imperial standard and would be a different link size to G43 and imperial G30 ---- though maybe at 1/4" or 6/7mm it does not matter. If you ask your windlass supplier for their gyspy spread sheet you will find there are some strange overlaps but you will also find they need to stock a huge range of gypsies - which part explains why they are so expensive.

8mm nylon would be excellent, if you could source 8mm kermantle (from a climbing gym or from a rock climbing club) it might be better, but I suspect difficult to source (so don't lose any sleep over it, stick with the 8mm you have been using).

Our usage started of using all sorts of rubber devices, nylon rope etc etc - we then re-cycled 2 x 15m x 12mm kermantle from a gym (liked it) went to recycling 2 x 12mm x 30m from a gym (needed to find a 'high) gym), then bought 2 x 30m of 12mm and after a short period are retiring the 12mm in favour of 2 x 10mm x 30m. I have had the end of our new rope specially sewn with an extra long loop or eye with a long sewn overlap (kermantle is impossible to splice and difficult to knot with anything that looks neat.

For those with bigger yachts - I arranged for an acquaintance to have some, (2 x 30m) 14mm specially made, with a long sewn eye at one end of each length for a 50' cat - so ask your rope maker (its used by the military (in boring colours ).

Long to me would mean starting at yacht length and then going longer.

If you start, or finished your long snubber at the transom you then have a deck length of elasticity before you progress beyond the bow, run it through the stanchion bases. So on a 33' yacht you could have about 10m of snubber 'on deck' and maybe simply a metre beyond the bow. If you have more than 11m of rope you could simply coil it at the transom and if the wind gets up - simply deploy a bit more as the conditions dictate (which is simplistically how we use 30m). Instead of your 11m of rope being subject to 35 knots of wind you actually are sharing that elasticity over, say, 20m.

If 6mm fits your gypsy then I'd look seriously at G70 (plus a long snubber). Less weight in the bow, more space in the locker (or some combination of more space vs more length), lower power needed - and if the windlass goes down - 6mm is a breeze to hand retrieve. 6mm still offers challenges - how to find shackles strong enough that fit both chain and anchor - if you go that route, start a new thread (so everyone can contribute) and I'll describe the option we have found. Or - I'm more than happy to provide the exact same detail in a PM.

Noting we have a cat - if you, or anyone else, wants to know about our snubber developments, which could be and has been adapted for a mono (and how we use 30m without it looking silly), send me a PM with a email address and I'll send a pdf.

And dump the swivel, they don't actually swivel (except with human intervention) a Boomerang works - all by itself + some help from Isaac Newton.

Jonathan

 

[NormanS]

Jonathan, in post 21, you mention that your boomerang has a long leg and a short leg. What's that all about?
My bent link, which as you know, is merely a bit of half inch round bar with a bend in the middle, with an eye on each end, doesn't require such sophistication. You know it works, and you've copied it.

 

[Neeves]

Interesting you should comment now - the article on the Boomerang was published a good few years ago and I've linked it frequently - anyone could read that article and make their own - there are no secrets, the article only needs a simply google search. Its 'open source'.

Actually Norman I noted your 'Bent Link' but effectively copied the Oscalutti version (which has adorned many yachts in the Med for decades)., and is similar to yours but the bend is about 1/3 along the length. The Oscalutti version is made in Qingdao by a company specialising in stainless for the leisure marine industry (I know the owner, or manager there quite well). I did not like the idea , or yours or that of Oscalutti, of using rod, see below.

If you look at an anchor shank - it is simply a Boomerang, or a 'Bent Link' with a fluke. All the Boomerang does is the same as the shank - it turns the anchor right way up - but does so before anchor actually arrives at the bow roller. I think the bent shank concept goes back to the CQR, or maybe Bruce and significantly optimised by Gordon Lyall at Simpson Lawrence with the Delta (and copied by everyone ever since)..

The Oscalutti version also has a swivel in it, which makes no sense at all. It also has a fork at one end and people place the fork over the shank (and the fork bends).

I believe there is a much older version in America called a Banana 'something' which I have never actually seen but it has been described to me.

I like the simplicity of your link but I wanted to 'make' something that anyone could make on their kitchen table. So wanted something that could be made using a drill and angle grinder. Bending 1" rod (see below) and welding were both rejected. Welding was rejected as though many can weld I'm not sure they can weld to a sufficient quality to secure the third largest investment they make, after choice of wife and purchase of home.

My design demanded cutting from a high tensile steel plate, Bisplate 80, drilling with a decent drill and then a bit of filing. I admit you need to find a sympathetic galvaniser (based on stories from the UK, sympathetic galvanisers are more common here). One reason for use of plate and the disadvantage of using rod is that when a modern anchor buries it drags down chain. The rod has a larger surface area than a bit of high tensile steel plate and rod inhibits the ability of an anchor to set but HT plate actually has a lower resistance to burial than the chain itself (I've measured all of this). So plate actually enhances anchor performance. Additionally as the plate buries with the plate vertically it acts in a minor way to reduce the impact of veering, a sort of vertical fluke, (again Ive measured it). So I would not want to be critical - but plate is a better medium than rod.

If you think all of this is rubbish - consider that everyone now introducing a new anchor always, without exception, uses a thin shank. Why - because a fat shank reduces anchor performance. Look at an oil rig anchor, they have rejected the shank used by Bruce and now fabricate their shanks (including the modern rendition of the Bruce) - engineering strength but minimising any thing that inhibits burial.

The design was copied, in consultation with me, by the Cruising Yacht Club of Victoria, I think they made around 20 units (and I was involved as I supplied them the drawings as a file) and helped them have the units Armorgalv coated, copied without attribution by Anchor Right and now (who asked permission) by Viking Anchors. Viking Anchors also took note of an article I wrote in Practical Sailor on anchor design An Inquiry into Anchor Angles - Practical Sailor and acknowledged my article(s) - as opposed to those who simply copy anything and attribute the ideas to themselves. I admit taking pleasure from the fact people like what I do, show some respect by asking me if they can use my idea, and I derive immense satisfaction from seeing the result of my articles benefitting others.

As to the proportions.

I made a lot of prototypes, all of which worked and the design you 'see' is the best (I thought). I made some very short ones (as some people have little space between windlass and bow roller), I made them to take Omega links - I have many retired examples

If the arm that throws, or self rights, the anchor is too long the anchor is tossed excessively. If the windlass is quick the excessive throw tosses the anchor such that it can hit something, stem or furler, potentially causing damage. I made the arm shorter to reduce the gyration.

I've tested what I've made to destruction and I know it is over engineered. I have had copies made in China (my wife and I ran a business selling into China) in duplex stainless, which is also overkill in terms of strength, but stainless removes the need for galvanising.

The Viking rendition takes all of the work described in the Yaffa article and added to it with more recent progress I have made. I'm not into manufacture nor marketing and simply take pleasure in seeing notice taken of what I do.

I took note of your 'bent link', the Oscalutti version, the idea that someone in America had a similar idea (or I think it is similar) and the fact that a CQR/Delta self rights. There are few novel ideas in the field of anchoring, CQR, Bruce, Spade, the Delta shank and then its largely been incremental.

So that's where we are now.

Jonathan

 

[oldmanofthehills]

You might want to check that capitalized first letter in 'grammar'.

The problem IS dealt with, the lateral forces ARE dealt with.

I am not convinced that there is any grammar error, maybe just slightly clunky writing to helpfully elucidate a situation. Forum is not a writing contest, and if it was grammar sits low on the creativity scale.

 

[NormanS]

Interesting you should comment now - the article on the Boomerang was published a good few years ago and I've linked it frequently - anyone could read that article and make their own - there are no secrets, the article only needs a simply google search. Its 'open source'.

Actually Norman I noted your 'Bent Link' but effectively copied the Oscalutti version (which has adorned many yachts in the Med for decades)., and is similar to yours but the bend is about 1/3 along the length. The Oscalutti version is made in Qingdao by a company specialising in stainless for the leisure marine industry (I know the owner, or manager there quite well). I did not like the idea , or yours or that of Oscalutti, of using rod, see below.

If you look at an anchor shank - it is simply a Boomerang, or a 'Bent Link' with a fluke. All the Boomerang does is the same as the shank - it turns the anchor right way up - but does so before anchor actually arrives at the bow roller. I think the bent shank concept goes back to the CQR, or maybe Bruce and significantly optimised by Gordon Lyall at Simpson Lawrence with the Delta (and copied by everyone ever since)..

The Oscalutti version also has a swivel in it, which makes no sense at all. It also has a fork at one end and people place the fork over the shank (and the fork bends).

I believe there is a much older version in America called a Banana 'something' which I have never actually seen but it has been described to me.

I like the simplicity of your link but I wanted to 'make' something that anyone could make on their kitchen table. So wanted something that could be made using a drill and angle grinder. Bending 1" rod (see below) and welding were both rejected. Welding was rejected as though many can weld I'm not sure they can weld to a sufficient quality to secure the third largest investment they make, after choice of wife and purchase of home.

My design demanded cutting from a high tensile steel plate, Bisplate 80, drilling with a decent drill and then a bit of filing. I admit you need to find a sympathetic galvaniser (based on stories from the UK, sympathetic galvanisers are more common here). One reason for use of plate and the disadvantage of using rod is that when a modern anchor buries it drags down chain. The rod has a larger surface area than a bit of high tensile steel plate and rod inhibits the ability of an anchor to set but HT plate actually has a lower resistance to burial than the chain itself (I've measured all of this). So plate actually enhances anchor performance. Additionally as the plate buries with the plate vertically it acts in a minor way to reduce the impact of veering, a sort of vertical fluke, (again Ive measured it). So I would not want to be critical - but plate is a better medium than rod.

The design was copied by the Cruising Yacht Club of Victoria, I think they made around 20 units (and I was involved as I supplied them the drawings as a file) and helped them have the units Armorgalv coated, copied without attribution by Anchor Right and now (who asked permission) by Viking Anchors. Viking Anchors also took note of an article I wrote in Practical Sailor on anchor design An Inquiry into Anchor Angles - Practical Sailor and acknowledged my article(s) - as opposed to those who simply copy anything and attribute the ideas to themselves. I admit taking pleasure from the fact people like what I do, show some respect by asking me if they can use my idea, and I derive immense satisfaction from seeing the result of my articles benefitting others.

As to the proportions.

I made a lot of prototypes, all of which worked and the design you 'see' is the best (I thought). I made some very short ones (as some people have little space between windlass and bow roller), I made them to take Omega links - I have many retired examples

If the arm that throws, or self rights, the anchor is too long the anchor is tossed excessively. If the windlass is quick the excessive throw tosses the anchor such that it can hit something, stem or furler, potentially causing damage. I made the arm shorter to reduce the gyration.

I've tested what I've made to destruction and I know it is over engineered. I have had copies made in China (my wife and I ran a business selling into China) in duplex stainless, which is also overkill in terms of strength, but stainless removes the need for galvanising.

The Viking rendition takes all of the work described in the Yaffa article and added to it with more recent progress I have made. I'm not into manufacture nor marketing and simply take pleasure in seeing notice taken of what I do.

I took note of your 'bent link', the Oscalutti version, the idea that someone in America had a similar idea (or I think it is similar) and the fact that a CQR/Delta self rights. There are few novel ideas in the field of anchoring, CQR, Bruce, Spade, the Delta shank and then its largely been incremental.

So that's where we are now.

Jonathan

As a matter of interest, how thick is your plate for your 6mm chain? And what thickness of plate would you specify for 10mm chain. As I'm sure you're aware, my chain is 10mm, and my bent link is half inch steel (from a standard bolt). I cannot see how my half inch round bar will find it any more difficult to bury itself into the mud than the chain, but not seeing the significance, I haven't carried out any experiments. Maybe you have, and can enlighten us?
My own feeling is that once the anchor has buried, all chain, shackles, links, etc, in contact with the mud, only add to the resistance to movement of the boat, which is what we are striving to achieve.

 

[oldmanofthehills]

Interesting you should comment now - the article on the Boomerang was published a good few years ago and I've linked it frequently - anyone could read that article and make their own - there are no secrets, the article only needs a simply google search. Its 'open source'.

Actually Norman I noted your 'Bent Link' but effectively copied the Oscalutti version (which has adorned many yachts in the Med for decades)., and is similar to yours but the bend is about 1/3 along the length. The Oscalutti version is made in Qingdao by a company specialising in stainless for the leisure marine industry (I know the owner, or manager there quite well). I did not like the idea , or yours or that of Oscalutti, of using rod, see below.

If you look at an anchor shank - it is simply a Boomerang, or a 'Bent Link' with a fluke. All the Boomerang does is the same as the shank - it turns the anchor right way up - but does so before anchor actually arrives at the bow roller. I think the bent shank concept goes back to the CQR, or maybe Bruce and significantly optimised by Gordon Lyall at Simpson Lawrence with the Delta (and copied by everyone ever since)..

The Oscalutti version also has a swivel in it, which makes no sense at all. It also has a fork at one end and people place the fork over the shank (and the fork bends).

I believe there is a much older version in America called a Banana 'something' which I have never actually seen but it has been described to me.

I like the simplicity of your link but I wanted to 'make' something that anyone could make on their kitchen table. So wanted something that could be made using a drill and angle grinder. Bending 1" rod (see below) and welding were both rejected. Welding was rejected as though many can weld I'm not sure they can weld to a sufficient quality to secure the third largest investment they make, after choice of wife and purchase of home.

My design demanded cutting from a high tensile steel plate, Bisplate 80, drilling with a decent drill and then a bit of filing. I admit you need to find a sympathetic galvaniser (based on stories from the UK, sympathetic galvanisers are more common here). One reason for use of plate and the disadvantage of using rod is that when a modern anchor buries it drags down chain. The rod has a larger surface area than a bit of high tensile steel plate and rod inhibits the ability of an anchor to set but HT plate actually has a lower resistance to burial than the chain itself (I've measured all of this). So plate actually enhances anchor performance. Additionally as the plate buries with the plate vertically it acts in a minor way to reduce the impact of veering, a sort of vertical fluke, (again Ive measured it). So I would not want to be critical - but plate is a better medium than rod.

If you think all of this is rubbish - consider that everyone now introducing a new anchor always, without exception, uses a thin shank. Why - because a fat shank reduces anchor performance. Look at an oil rig anchor, they have rejected the shank used by Bruce and now fabricate their shanks (including the modern rendition of the Bruce) - engineering strength but minimising any thing that inhibits burial.

The design was copied, in consultation with me, by the Cruising Yacht Club of Victoria, I think they made around 20 units (and I was involved as I supplied them the drawings as a file) and helped them have the units Armorgalv coated, copied without attribution by Anchor Right and now (who asked permission) by Viking Anchors. Viking Anchors also took note of an article I wrote in Practical Sailor on anchor design An Inquiry into Anchor Angles - Practical Sailor and acknowledged my article(s) - as opposed to those who simply copy anything and attribute the ideas to themselves. I admit taking pleasure from the fact people like what I do, show some respect by asking me if they can use my idea, and I derive immense satisfaction from seeing the result of my articles benefitting others.

As to the proportions.

I made a lot of prototypes, all of which worked and the design you 'see' is the best (I thought). I made some very short ones (as some people have little space between windlass and bow roller), I made them to take Omega links - I have many retired examples

If the arm that throws, or self rights, the anchor is too long the anchor is tossed excessively. If the windlass is quick the excessive throw tosses the anchor such that it can hit something, stem or furler, potentially causing damage. I made the arm shorter to reduce the gyration.

I've tested what I've made to destruction and I know it is over engineered. I have had copies made in China (my wife and I ran a business selling into China) in duplex stainless, which is also overkill in terms of strength, but stainless removes the need for galvanising.

The Viking rendition takes all of the work described in the Yaffa article and added to it with more recent progress I have made. I'm not into manufacture nor marketing and simply take pleasure in seeing notice taken of what I do.

I took note of your 'bent link', the Oscalutti version, the idea that someone in America had a similar idea (or I think it is similar) and the fact that a CQR/Delta self rights. There are few novel ideas in the field of anchoring, CQR, Bruce, Spade, the Delta shank and then its largely been incremental.

So that's where we are now.

Jonathan

Back to the thread. I was interested in the boomerang as my anchor jams worse on our new boat.. Not having metal construction facilities I though about purchasing something, however the idea of a non readily examinable weak point as in Oscalutti made me simply wonder if the commercial people actually knew what they were doing.

I will investigate the Viking product

 

[thinwater]

I'm assuming 74knts would be a gust, not wind strength? If it's gusting 74, you could expect wind speeds around 50knts +.

42knts is from the ABYC table & is the suggested point for coastal or ocean cruisers whereas long-distance cruisers should consider up to 60knts. I guess it's all about how much shelter is around & the ability to run to safe harbour. We've certainly anchored when general wind speeds were higher, but the actual speeds at our sheltered anchorage were more acceptable. As a UK coastal cruiser, I'd never expect to anchor in a position & with a forecast that led to a sustained wind speed of 60knts plus gusts (or, to be honest, 40knts +)

To be really sure of security in a plus 60knt wind I'd need to look at 1" rope and 12mm chain - huge on a 8.5m boat. I think at that point, something else would break! In open seas the max probable wave height is 16m!

In truth, ABYC H-40 tables 1 does not actually relate to a specific wind strength in harbor or even an open rodestead. It is the maximum tension that is likely in an exposed location, with relatively show water, with very steep waves, and no snubber. A WORST case scenario that will likely never happen in your sailing career. The force is about 3-5 times higher than the boat would see in the protected waters of a cove or in deep water. For example, the OP will probably never see more than 200 kg at 42 knots and his working load at 70 knots sustained is probably about 550 kg. If you would like to confirm this, buy cheap load cell, take readings on a breezy day, and extrapolate F~V^2. I've taken lots of readings, as has Neeves. You can also consider the common sence, that the OP can probably haul his rode by hand up to 25 knots. If that is 80 pounds, then 42 knots would be 80 x (42^2/25^2)=225 pounds at 42 knots (could be 200 kg in some waves and gusts). But measure it!

This is why the ABYC, over many decades of application, has settled on these requirements, and why in more resent versions of H-40 they removed the wind speed and say only "storm" or "permanent mooring." Well-maintained chains don't break, but anchors do drag. Fantastic forces only occur on smaller boats if they are caught in waves, in shallow water, and the chain snaps tight. The wind alone won't do it.

 

[thinwater]

"...problem with lateral forces IS dealt with by having ...." Nothing personal, Bristolfashion, but I despair at the abysmal standard to which English Grammar has descended. They don't seem to teach it properly any more.
I constantly see and hear plural verbs thrown mistakenly into main clauses whenever a plural appears in a subordinate clause.
( Apologies for thread drift)

According to OED, Bristol fashion is two words.

 

[Neeves]

As a matter of interest, how thick is your plate for your 6mm chain? And what thickness of plate would you specify for 10mm chain. As I'm sure you're aware, my chain is 10mm, and my bent link is half inch steel (from a standard bolt). I cannot see how my half inch round bar will find it any more difficult to bury itself into the mud than the chain, but not seeing the significance, I haven't carried out any experiments. Maybe you have, and can enlighten us?
My own feeling is that once the anchor has buried, all chain, shackles, links, etc, in contact with the mud, only add to the resistance to movement of the boat, which is what we are striving to achieve.

Theoretically the plates should be the same thickness as the chain. The holes in the ends need to accept the appropriate shackles and the most easily available strong shackles, Grade B, start at a 3/8th" size. So the holes need to accept the eye of a 3/8th" shackle. The steel round the hole should be a minimum of chain thinkness. So the minimum thickness of the steel, a 800 MPa steel, is a square section and a square section is bigger than the round of the wire used to make the chain and both are a 800 MPa steel. So the Boomerang is stronger than the chain. Because I use 6mm HT chain I have made my own Boomerang that accepts a 6mm Omega link (fr the same strength as the chain, actually stronger as they are G100).

The reality is that the steel round the shackle holes are bigger than the minimum - so there is a safety margin. The Boomerang is only ever in tension, the tension in the rode, and I have never had a situation, nor can conceive of one where the Boomerang would be side loaded. Most Boomerang are thus much stronger than the chain as most people will be using a G30 or G40 chain. The Boomerang can be made from 316 stainless and it will have the same tensile strength as the chain - asx long as the sizes and proportions are maintained.

When the anchor buries, a modern anchor, the shackle end of the shank and the anchor fluke toe bury together. The shackle end of the shank continues to bury as the anchor fluke buries but does tend to bury at a reduced rate (compared to the toe) as the anchor goes more deeply. The buried chain develops a reverse catenary and the shackle angle (which dictates the angle of tension), slowly lifts. It is possible to measure the length of buried chain - the length of buried chain is always longer with a correctly sized boomerang compared to a chain with no boomerang. If you have a swivel, instead of a Boomerang, the buried chain is even less. Buried chain resists veering and from subjective tests reduces the movement of the anchor, twitching, from movement of the yacht at anchor. A twitching anchor, noting the an all chain rode is a perfect conductor of movement of the yacht will reduce the shear strength of the seabed in immediate proximity to the anchor. A snubber (because textile is a less effective transmitter of movement) or chain on the seabed (and buried chain) all reduce twitching.

I can assure you that if you take a 1" rod, call it 25mm, and a piece of 10mm plate, both the same length, you will find it significantly easier to force the 10mm plate into wet sand that you will a 25mm rod (you are trying to force both into the seabed with the items horizontal). The fact your rod is round and the plate square ended will make no difference the 10mm plate will be easier to bury. Just imagine a garden spade with a 1" round rod welded to the end and a spade made from 10mm plate.

I spent a lot of time (I really need to get a life!) setting anchors in the intertidal zone, letting the tide recede and then digging the anchor and buried rode out. Basically I dug big holes exposing the anchor and rode being careful not to disturb the anchor, shackle and chain (plus where relevant Boomerang and swivel). I did this a number of times with different rode configurations but in the same place, or adjacent bit of seabed, and same anchor - all at a similar tension. I can actually do this fairly easily as we can deploy from our cat, wait till the tide goes out (and the cat high and dry). Do some digging, take some pictures, make som e measurements )check anodes, clean hull etc etc (go for a walk along the beach) - wait for the tide to return and float off.

Using a big shackle, big chain, swivel (worse a big swivel) all reduce the amount of chain buried and the less chain buried the less well set the anchor (as its the anchor that is 'pulling' all this stuff down).

Moving down in chain size is the most significant improvement - everything else is of lesser importance - but its cumulative, so a big shackle and a swivel is noticeable. The Boomerang because it 'sits' in the seabed vertically, and its area is quite large vertically, offers the best resistance to veering (if buried). If its not buried it simply lies flat on the seabed and does no more than chain lying on the seabed.

Moving on slightly. I like the Viking anchor because it is made from high tensile steel and use has been made of thin steel. In the same way that a Boomerang buries more readily than chain, because the Boomerang offers less resistance to burial, the Viking anchor buries more deeply than an anchor of the same area. This is no different in performance to Fortress, which is also made from thin plate. If you look at the toe of a Rocna the plate used is really beefy (because it is ballast). The toe of the Viking is very malnourished. The Viking anchor thus pulls the chain, and any attached Boomerang, more deeply into the seabed enhancing the side benefit of reducing the impact of veering. Equally the Boomerang enhances the performance of the anchor as it reduces the resistance of the rode to burial. It seems like a win win.

I'd like to say this is all well thought out in advance - its not, its simple luck - or maybe some form of subconscious thought. The increase in veering resistance was not identified by me at all, it was noted by another investigator (on another continent) to whom I sent a sample. The redused resistance to burial I found when looking at shackle angle of the buried shackle (again pointed out to me by one of the 'Giants' in anchor research in the US (Robert Taylor - check his credentials through google). NormanS gave me the confidence to investigate Boomerang design but the Oscalutti predates my knowledge of Norman's version. I only used plate because Bisalloy gave me a piece of plate, about 1m square, for this 'sort' of work (I helped them with some work on yacht keels - for which Bis 80 is used).

There is a lot of serendipity in all of this - but that's what life is about.

If you check Robert Taylor's work - he has done work on shackle angle and the impact of reduction in shear strength of the seabed, amongst much else.

Finally - attaching a Boomerang is dead easy - you just need to follow very simple instructions - but if you don't attach it correctly it will not sit vertically in the seabed and it will not self right the anchor - it will in fact make everything much worse. Normally people will attach correctly - but if you then cut of a few links because they corrode (a very common phenomena) it is very easy to finish up with the Boomerang, or anchor - misaligned - and then it will NOT work.

If you don't have enough room for a Boomerang and the links recommended in between - have a word with Viking - they might make a batch of shorter ones and you can reduce the number of links between anchor and Boomerang - in this case the anchor will self right more quickly. I have a really short Boomerang, I've tried it, it works, it simply gyrates the anchor a bit more repidly.

If anyone wants to make their own Boomerang the intructions are in the article - if you need 'help' send me a PM. You need an angle grinder (with those thin slitting blades), a decent bench drill, files and some patience.

Jonathan

 

[NormanS]

I think you may have misunderstood me. As I said, my bent link is made out of half inch (0.5") round bar. I would imagine, although I have no proof, that half inch round bar will have less resistance to cutting into the mud, than my 10mm chain. Quite why you quote 1" round, escapes me. My bow roller, for chain, is shaped with a 16mm slot for the chain to sit in. Part of the reason for using round material for the bent link, is that it can rotate much easier on the roller than something made out of plate, which might jam in the slot. My reason for responding in #25, was simply to ask why your boomerang, which does precisely the same job as my bent link, has a long leg and a short leg. I don't think you have explained that, (although you write so much, that I may have skipped over any explanation). ? If so, please accept my apologies.

 

[Neeves]

Sorry Norman, I don't know why I quote 1" either!



I'll try to make this specially short for you

Great minds think alike - I did wonder about slotted bow rollers and considered welding a bit of rod along the backbone, to ease rotation. I then dismissed it as an extra step and as no-one has commented that its an issue - I've left it.

When a bent link/Boomerang arrives at the bow roller such that the anchor is inverted then the Boomerang is also inverted. Our windlass, in common with other modern windlass, retrieves quickly, about (or almost exactly) 0.5m per second. Consequently the longer the arm of the boomerang stays on the bow roller the better to allow the boomerang to invert the anchor - you really want the Boomerang to rotate the anchor when the long of the arm or the horizontal part is still on the bow roller (and before the bent part gets to the bow roller). So very simply having more of the long part of the Boomerang on the bow roller the better - hence the difference in length.

I don't know we have optimised the ratios of the 2 lengths - except you need it to be bent, you need room for a shackle in both parts. I think its 'about right' but would take on board any comments. I have made a very short Boomerang, about 75mm total length - the anchor is still being rotated when its coming over and onto the bow roller.

We actually made a video of how the Boomerang works but the windlass was so quick you actually could not see what happened (the Boomerang is only 200mm long (or so) so it turns the anchor the right way round so quickly, fractions of a second - blink and you miss it. Manual retrieval was the answer.

I hope your attention span lasted long enough and that my explanation does not require, even, more detail

Apologies again for making mention of 1"

It would help if we had agreed terms for the 2 portions of the Boomerang..........

Jonathan

Mulling all of this over - you make me consider that if one has a slotted bow roller and down size the chain - you might need a new roller.

But if you, Norman, have a slotted bow roller then unless the chain 'jumps' out of the slot then you should have no need for a Bent Link (our bow roller is not slotted) - unless your chain is twisted anyway (a common issue).

J

 

[noelex]

The depth of bury and hence the holding power of the anchor is reduced by any extra resistance on the anchor to chain connection.

The Boomerang introduces an extra shackle and a wide, flat plate, and these elements have the potential to significantly reduce the anchor’s holding ability. I have observed a lot of anchors underwater and the contention that the flat plate remains constantly vertical seems unlikely. Even if it only occasionally sits other than absolutely vertical, this loss in holding power is a concern. The manufacturer’s website has a photograph of the Boomarang sitting in the horizontal position.

Personally I would not use a Boomarang or even the more common, streamlined round anchor straightener on my anchor, at least for overnight anchoring.

 

[boomerangben]

If you are content with the concept and practicality of a mixed rode, just how much chain do you need? To my mind you need sufficient chain to keep the rope segment out of the seabed. 15 to 20m would cover most tidal ranges so weight vs a mm or two in size is largely irrelevant and cost will be a lesser factor.

 

[Solent sailer]

Have a look at the ultra flip swivel from Jimmy green great load rating and actually does what its supposed to and brings the anchor up the correct way round!

 

[NormanS]

Sorry Norman, I don't know why I quote 1" either!



I'll try to make this specially short for you

Great minds think alike - I did wonder about slotted bow rollers and considered welding a bit of rod along the backbone, to ease rotation. I then dismissed it as an extra step and as no-one has commented that its an issue - I've left it.

When a bent link/Boomerang arrives at the bow roller such that the anchor is inverted then the Boomerang is also inverted. Our windlass, in common with other modern windlass, retrieves quickly, about (or almost exactly) 0.5m per second. Consequently the longer the arm of the boomerang stays on the bow roller the better to allow the boomerang to invert the anchor - you really want the Boomerang to rotate the anchor when the long of the arm or the horizontal part is still on the bow roller (and before the bent part gets to the bow roller). So very simply having more of the long part of the Boomerang on the bow roller the better - hence the difference in length.

I don't know we have optimised the ratios of the 2 lengths - except you need it to be bent, you need room for a shackle in both parts. I think its 'about right' but would take on board any comments. I have made a very short Boomerang, about 75mm total length - the anchor is still being rotated when its coming over and onto the bow roller.

We actually made a video of how the Boomerang works but the windlass was so quick you actually could not see what happened (the Boomerang is only 200mm long (or so) so it turns the anchor the right way round so quickly, fractions of a second - blink and you miss it. Manual retrieval was the answer.

I hope your attention span lasted long enough and that my explanation does not require, even, more detail

Apologies again for making mention of 1"

It would help if we had agreed terms for the 2 portions of the Boomerang..........

Jonathan

Mulling all of this over - you make me consider that if one has a slotted bow roller and down size the chain - you might need a new roller.

But if you, Norman, have a slotted bow roller then unless the chain 'jumps' out of the slot then you should have no need for a Bent Link (our bow roller is not slotted) - unless your chain is twisted anyway (a common issue).

J

Hello again Jonathan. When we anchor, (I say we, but I just position the boat, and give a nod to the boss), the initial drop until the anchor hits the bottom, is done by free fall by declutching. So yes, even with the slot in the bow roller, the chain sometimes jumps and develops twists. I've made a new and slightly larger bow roller, which hasn't been tried yet, but I'm pretty sure that it'll behave the same. I accept that as a fact of life. Possibly if I powered the anchor down, the chain would stay rigidly in the slot, but my frugal attitude (OK, read Scots Presbyterianism) wouldn't allow me to use power, when good old gravity does it for free and better.

Anyway, be that as it may, I'm still left wondering why your boomerang needs the sophistication of a long leg and a short leg?

 

[NormanS]

The depth of bury and hence the holding power of the anchor is reduced by any extra resistance on the anchor to chain connection.

The Boomerang introduces an extra shackle and a wide, flat plate, and these elements have the potential to significantly reduce the anchor’s holding ability. I have observed a lot of anchors underwater and the contention that the flat plate remains constantly vertical seems unlikely. Even if it only occasionally sits other than absolutely vertical, this loss in holding power is a concern. The manufacturer’s website has a photograph of the Boomarang sitting in the horizontal position.

Personally I would not use a Boomarang or even the more common, streamlined round anchor straightener on my anchor, at least for overnight anchoring.

As said, my bent link is made out of round bar, so it doesn't matter which way it lies. I've used it without any problem for the last ten years or so. Why wouldn't you use one overnight?

 

[thinwater]

The depth of bury and hence the holding power of the anchor is reduced by any extra resistance on the anchor to chain connection.

The Boomerang introduces an extra shackle and a wide, flat plate, and these elements have the potential to significantly reduce the anchor’s holding ability. I have observed a lot of anchors underwater and the contention that the flat plate remains constantly vertical seems unlikely. Even if it only occasionally sits other than absolutely vertical, this loss in holding power is a concern. The manufacturer’s website has a photograph of the Boomarang sitting in the horizontal position.

Personally I would not use a Boomarang or even the more common, streamlined round anchor straightener on my anchor, at least for overnight anchoring.

I've tested one (the plate sort) both on the beach and dove on ones in the water. No supposition here:

• The bend makes it alighn vertically when pulled down through mud. It cannot ever be otherwise. Try it.
• It has considerably less cross section than chain when vertical. This will offset the shackle drag.
• It better resists side rotation than chain (yawing). And it pushes the chain down while doing this.

Yes, this could use more testing, rather than making guesses one way or the other. My brief tests suggest that the impacts are net positive, but very likely too small to measure either way. What I am 100% certain of is that it does not through the mud sideways for the same reason that it rotates an anchor; that is the function of the bend. A flat plate with no bend could orient itself randomly.