Chesapeake Anchor Holding Power Test

Delfin · Oct 4, 2014

Noelex said:
The advantage of the roll bar is that you dispense with the need for the bulky ballasted tip that is needed in anchors like the fixed convex plow models.

A bulky ballasted tip has to penetrate the substrate for the anchor to get any grip at all. On the other hand the rollbar is at the back of the fluke. Before the rollbar presents any resistance, the fluke has to be almost completely buried.

As the anchor buries more, the rollbar does present some resistance to the anchor diving, but I believe it less of problem than the bulky tip. The ultimate design is to remove both the bulk of the ballasted tip and the rollbar. Anchors like this (such as the Raya, Oceane and Sword) have tended to be slightly erratic (the Boss is a bit new to tell).

One of my reasons for taking photos is to dispel some myths.

Have a look at the photos and you will see plenty of examples of bulky tips especially on the convex plow anchors simply "piling up debris in front".

The Mantus has a thin rollbar so is obviously less likely to pile up debris if it was going to occur, but if you look at the photos I have taken of the other rollbar anchors it does not show this phenomenon. Even if we look at the Bugel which has a very thick roll I see no evidence of the roll bar "piling up debris" and lots of evidence of anchors with bulky ballasted tips doing exactly that.

A fixed convex plow anchor piling substrate in front of it:

The essence of any meaningful "test" purporting to compare two things is that the test applies uniform test conditions to the things being tested. For an example of a meaningful test, please see Fortress' methodology in the Chesapeake. Comparing the anchor set of your oversized Mantus that you select to post with an anchor 1/3 the size is completely meaningless. Add to that the different techniques applied to set the anchor by two different people - one of whom could as easily be a drunk Italian charterer as Robin Knox-Johnson and you have no test, just a very misleading representation of selective information that certainly appears to have a commercial intent. I don't think you are "dispelling myths", although you are creating some of your own. I just don't see a lot of people buying what you're selling on this Noelex.

Art · Oct 4, 2014

Ya know...

When parking any type vehicle, sometimes the "driver" (no matter how good/experienced they may be) needs to pull it out and readjust vehicle to correctly parked position/angle in location chosen. May even need to move-to/find a different location.

Similarly, when setting any type anchor, sometimes the "setter" (no matter how good/experienced they may be) needs to pull it out and readjust anchor to correctly set position/angle in location chosen. May even need to move-to/find a different location.

Brings me to this point: There are one heck of a bunch of well-designed anchors here trying to beat each other over the head regarding some really meaningless frivolities.

Three most prominent needs:

1. Anchor’s Good-Holding Design – There are a bunch to choose from that have been fully discussed in this thread… some better than others in certain bottom conditions… having one or two choices aboard is wise if boater plans to anchor in considerably differing bottom conditions

2. Anchor’s Design Fitting On-Board Storage Position – There are many anchor designs to choose from… get creative as to how/where your desired design “primary anchor” will be stored on your boat

3. MOST IMPORTANT NEED… Correct Anchor Setting Capability – If you think you can simply drop an anchor with its chain/line like a ton of bricks (off bow or stern), providing enough chain/line to establish sufficient scope… and then simply pull away by engine or shut down engine(s) to let wind or current set anchor for you – Well, Think Again! Then carefully read post #604 on page 31

In closing:

There are autos now that can park themselves via computer controlled actions. They NEVER make a mistake and NEVER need to reset vehicle. Until that becomes generally produced throughout auto industry – well – we simply need to be good at parking our own vehicles. Remember, there are many different model/design vehicles you can chose to own/drive; each has different qualities regarding parking characteristics.

So far (to my knowledge) – There is no boat and anchor combination that is (or can be) computer controlled accurately enough so that it can NEVER make mistakes while setting anchors (Anchor setting has plethora of more complicated dynamics than parking a car). SOOOO… learn to me a GOOD Anchor Setter with the design anchor you chose to use! Again, read post #604 on page 31 of this thread That’s the answer – What’s the question??? :facepalm:

Happy Anchor Daze! - Art

Delfin · Oct 4, 2014

ranger42c said:
Ummm... Seems to me part of this debate is "what's a plough?" (plow?)

Rex says the Excel is not a plough, Marin says it is.

Why is it not a plough? Why is it a plow? Explanations? Thoughts?

-Chris

None of them are plows - at least in the agricultural sense - because they are all double sided. CQR apparently thought it good marketing to call their design a "plough" anchor, but it isn't a plow any farmer would recognize. But even if an anchor could be designed that could be set as a single sided plow, anyone who has bogged a four wheel drive tractor because they set the gauge wheel too high and had the plow start digging to China can attest to their holding power.

The purpose of the convex design of some anchors, at least as I understand the mechanics, is to allow the anchor to dive to more compacted conditions, pushing and compacting the soil to the sides. Hoop style, dragon tooth, concave anchors count on their holding by slicing quickly into the sea bed and piling up soil on the top side of the flukes and in front of the hoop. This works fine most of the time in most conditions, which is why people like them. But it is also why they frequently come out lower in holding capacity to well designed diving anchors in comparative tests. Promoters of this type of hook make a great deal of their quick set. But in a practical sense, what earthly difference to a boater does it make if while cutting deeper into the sea bed it is dragged back 10 feet while setting? Zero. Another way to think of this is to ask yourself which hook would you want holding you in a hurricane. An anchor buried 4 inches under the sea bed or one that the harder you pull on it, the deeper it goes to denser and denser substrate? True, there are infrequent conditions where the substrate is solid, and I suppose that is why many people argue that no one anchor design is best for all conditions.

It is also clear that the design of a good diving anchor is a lot trickier than coming up with a decent hoop style since the Delta always seems to be a pretty ho hum performer while the Excel appears to be outstanding. I'd also say that the Super Sarca seems to be a compromise between both designs - a diving anchor with convex flukes with a thin hoop.

Marin · Oct 4, 2014

Peter B said:
Marin, for someone as technically savvy as you are, you have a blind spot re this plough thing. The so-called plow, (I'll use the US spelling hereafter as it's shorter), type anchors are not really plows at all, they just resemble them, so the name sort of stuck.

Peter-- I know exactly how a plough anchor works. It's totally obvious simply by looking at it. Where an agricultural plough is one-sided and pushes dirt off to the side while moving (relatively) easily through the soil carving a furrow for the seed drill, the anchor is upside down and double-sided and by pushing dirt up on both sides, it theoretically forces itself down into the bottom to the point where it resists further forward movement, at which point your boat halts its backwards movement.

Good theory, works fine most of the time. BUT.... when i read about anchor performance from real people using real anchors in real situations (as opposed to tests which are fun comparisons but don't really tell you much that relates to the real world) what anchor do I read about that has the most instances of dragging? Well waddaya know, it's the plough. Most often the CQR, which makes sense as there are vastly more of them in use around the world than the other plough-type designs like the Excel, Delta, etc.

Don't get me wrong. I'm not saying that plough-type anchors are dragging all over the planet all the time. The friend I mentioned in my previous post has been using his good-size CQR for decades with very few problems in the often-challenging bottoms in this part of the world and he's totally satisfied with it. And in bottoms that favor the plough anchor's design theory, hey, great anchor!

I'm simply saying that from all the indications I've got--- mostly reading user comments over the years--- the basic plough concept is more prone to dragging than a design that presents a broad, unbroken, flattish surface at a right angle to the the direction of pull to provide the maximum resistance to movement through the bottom, aka holding power.

Bottom line (pun intended), I don't like plough-type anchors because I feel they add a negative potential to the already-huge list of variables involved in anchoring a boat. To my way of thinking, one less variable is a good thing.

BTW, I don't see why people here are so wrapped around the axle on the notion of an anchor piling up substrate in front of it. Seems to me that any crap an anchor piles up in front of it is that much more stuff resisting the forward movement of the anchor. Personally, I would absolutely love it if our Rocna bulldozed up a mound of bottom muck that was ten feet high and thirty feet long. Jammed into that wall of debris, the little devil wouldn't be going anywhere when the wind came up.

Back in the mid-80s on a film shoot I was directing I was given an opportunity to drive a new Cat D-10. The machine's operator sat in the cab with me and showed me how to operate it. It was being used to level huge piles of excavated dirt at an open-pit coal mine here in Washington. On my first try I dug the blade in a bit too deep and it pushed up a wall of dirt that stopped the machine. This with a 700 hp twin-turbo V-12 diesel. So to my way of thinking, piling up stuff in front is a good way to stop something moving.

PS--I prefer the "proper" spelling of plough, too.

Moonstruck · Oct 4, 2014

I think we are getting really close to everyone being in agreement on anchors. :nonono:

Tom.B · Oct 4, 2014

Moonstruck said:
I think we are getting really close to everyone being in agreement on anchors.

LOL :lol::lol::lol:

I think it's hilarious how everyone wants to give a flying crap about another person's anchor. Why do you care at all if someone else thinks the anchor you use (or are paid to use as the case may be) is better or worse than yours? How does that affect you? ABSOLUTELY ZERO, that how much. You have yours... it works. Good on ya'. There is no liability if someone has a different anchor than you and it fails, and I would bet my extensive fortune

you guys would have zero guilt from it. In fact, you would probably start an "I-told-you-so" thread just to prove how awesomely correct you were from the start.

Y'all really could set the example as a quality boating forum and be the first ever in human history to not argue about anchors. Meh, who am I kidding? :blush:

Jeffrey S · Oct 4, 2014

Tom.B said:
Why do you care at all if someone else thinks the anchor you use (or are paid to use as the case may be) is better or worse than yours? How does that affect you? ABSOLUTELY ZERO, that how much.

Well, actually...someone else's anchor is about the only thing on their boat that might very well affect me in an anchorage...

Noelex · Oct 4, 2014

Delfin said:
The purpose of the convex design of some anchors, at least as I understand the mechanics, is to allow the anchor to dive to more compacted conditions, pushing and compacting the soil to the sides. Hoop style, dragon tooth, concave anchors count on their holding by slicing quickly into the sea bed and piling up soil on the top side of the flukes and in front of the hoop. .

This description does not bear any reality to how I see anchors behaving underwater.

Here are a couple more photos.

It is the non roll bar anchors that are "piling up soil on the top sides of the fluke".

These are not atypical presentations. It is just the way different anchor designs behave when you actually look rather than believing the spin.

There are exceptions, but your description of the underwater behaviour of anchors is not what is seen in practice.

Noelex · Oct 4, 2014

Delfin said:
Promoters of this type of hook make a great deal of their quick set. But in a practical sense, what earthly difference to a boater does it make if while cutting deeper into the sea bed it is dragged back 10 feet while setting? Zero.

This is fine if you have 10 feet of clear substrate for the anchor to set.
Anchors that take a long distance to set will also move further back as they dig in deeper if the wind picks up.

What if there is an obstruction? Say a clump of heavy weed, a rock, or some rubbish. These are common problems.

An anchor that sets quickly and moves backwards very little as it dives in response to stronger wind is a desirable feature.

Marin · Oct 4, 2014

Tom.B said:
There is no liability if someone has a different anchor than you and it fails,

We watched (from the dock we were tied to) a strong wind wreak havoc among the anchored boats out in the bay. This was in a marine park where some boats were on permanent mooring buoys and others were anchored. For anyone familiar with the San Juan Islands, this was in Fossil Bay at Sucia.

Several anchored boats dragged their anchors and they got caught up in the rodes of other boats or the anchor lines/chains of the permanent mooring buoys.

This was a bit after midnight, and the flashing of lights, sounding of horns, revving of engines, yelling, and the sound of boats grinding and bashing together in the waves was something to hear. It went on for about an hour until the wind began to subside.

I have no idea of the dollar value of the damage done that night. The next morning revealed destroyed handrails, big gashes and scrapes in fiberglass hull sides, crushed caprails, a smashed swimstep and dinghy, a broken pulpit, and this is just the damage I saw and can recall.

So I think Jeff's observation is right on the money. What someone else is using for ground tackle, and how intelligently they use it, is very much of concern to the people in boats around them. At least to those who understand the variables at play in an anchoring situation.

ranger58sb · Oct 4, 2014

Rex said:
Quote from ranger42C

Ummm... Seems to me part of this debate is "what's a plough?" (plow?)

Rex says the Excel is not a plough, Marin says it is.

Why is it not a plough? Why is it a plow? Explanations? Thoughts?

-Chris
__________________
South River, Chesapeake Bay

Quote from Rex:

Chris,
I have been over this so many times, Peter B basically summed it up, watch the environment vid on our web site, you can then judge.

Chris whilst you are there, I notice you are looking for bow roller arrangements, might be something there that will give you an idea.

Regards Rex.
Bay

While somewhat rhetorical, my underlying question was really about why you two differ on whether A or B or whatever is or is not a plough (plow)... when I think you are both looking at the same product, looking at the same videos, looking at the same furrows and burying action (or whatever)...

Without regard to whether A is good/bad/indifferent, it sorta seems to me you guys aren't working with the same definition of plough-hood-ness (plow-it-ivity?)

IOW, I've seen the videos and so forth... but my question really wasn't about any specific anchor, or evaluating whether it's good or better/worse than some other in various substrate... but rather how come two guys can look at the same product and define the rascal in opposite terminology.

Thanks for the tip to roller solutions. I have a pulpit with center slot and imbedded roller... and it never looks to me like I have enough pace on either side of that center slot to add another roller (or bowsprit) system. I'll have to compare measurements to measurements, though. Cheers.

-Chris

CPseudonym · Oct 4, 2014

Moonstruck said:
I think we are getting really close to everyone being in agreement on anchors.

You're correct Don

Everybody is convinced everybody else's anchor, rode, technique is wrong and a terrible danger to society as we know it. Their personal setup will hold the Queen Mary through a hurricane on 2:1 scope whilst the next guys couldn't be trusted to secure a dinghy on a millpond with 10:1 scope.

We should therefor outlaw anchor usage as boat owners are far too irresponsible to take the practice seriously. In exchange we will have strategically located government owned approved docks and mandate all boats secure to them with government supplied 2" diameter steel cables that have been proof tested within the last 12 months.

Anchor ownership will still be permitted to maintain the nautical look of the boat they must however be securely welded in place so as to not fall overboard. 6 feet of ceremonial chain will be permitted to complete the look of perceived functionality but must be securely bolted inside the anchor locker so as to be completely unusable for any clandestine anchoring. A recognized international authority will be charged with affixing official lead seals on anchors, if the seal is broken the boat is subject to forfeiture laws.

Nomad Willy · Oct 4, 2014

Marin re the Fossil Bay incident I'm think'in we should'nt have left Alaska.

Ranger42c,
I don't give a rat about plows and farmers but I do think there's a lot to what Carl's say'in re some anchors not penetrating much, some going much deeper and some acting more like bulldozers than anchors. Of course that's dependent a lot on the seabed. I had a Claw buried so deep I had an awful time getting it up. Must have been a very unusual bottom.

To get very deep the shank and part of the rode must be pulled below the seabed and that demands a lot of any fluke. Many anchors have flukes designed to minimize the tendency of the fluke to rise as the anchor moves fwd. Claws for example have a vertical part at the rear that just makes some drag and does not push the fluke up as it goes. So until the Claw gets quite deep the shank dosn't push up while moving fwd. The Danforth's geometry makes the upward force of the shank a given and can't be avoided. So the rest of the anchor must be very efficient to make up for the lifting shank. The Danforth also has the stocks to drag along not terribly unlike the roll bar. Added drag adding slightly to holding power but not efficient to that end.

A concave fluke is better at resistance but has more surface and is heavier as a result BUT ... It's stronger so can be made of lighter and thinner steel. The plow types have a lot more surface area requiring more material and hence are heavier for a given size so that coupled w the weight penalty kinda limits their max performance. But their shape gives a lot of strength so perhaps the trade off is beneficial.

The Holy Grail is of course eliminating all those inefficiencies. And of course nobodies going to do it so anchor designers are probably looking for solutions that have positive side effects. For example the Claw could have a straight shank like a Bugel. It would have less material in non-shank structure that would make it more efficient but it's shank would want to rise up during the critical and important stage of anchoring ... that being half set. And of course that's where the Claw shines.

Re the far from the ideal slightly concave optimum fluke shape the plow types (most) rely on deflectors on the back of the flukes to push material up and out. Not terribly efficient but since there's no roll bar to inhibit penetration the plows probably tend to penetrate deeper. One would think penetrating deep would be a must for HHP but many .. no most anchors don't penetrate much.

But looking at the tests lately it seems the Roll bar types have the edge. Haven't seen the Excel tested but no anchor that looks like it has recorded really high performance holding power wise and most (at least) are shy at short scope. I continue to think the SUPER SARCA is probably the best all around anchor available .. after all things are considered.

As in Marin's post above anchor dragging causing really big troubles is IMO very rare ... at least rare. Most all of us probably don't drag an anchor in 5 to 10 years. Members posts are 99% about setting as most never even reach the limits of low performance anchors. P Smith would like you to believe your'e about to die but most do just fine w the old anchor that came w the boat.

Delfin · Oct 4, 2014

Noelex said:
This description does not bear any reality to how I see anchors behaving underwater.

Here are a couple more photos.

It is the non roll bar anchors that are "piling up soil on the top sides of the fluke".

These are not atypical presentations. It is just the way different anchor designs behave when you actually look rather than believing the spin.

There are exceptions, but your description of the underwater behaviour of anchors is not what is seen in practice.

Yes, they are atypical presentations because light sand bottoms are hardly representative of the 'real world' of conditions. In light sand, no, the hoop will not pill up debris. Move to most other types of bottoms, and yes, they will.

Marin · Oct 4, 2014

Delfin said:
In light sand, no, the hoop will not pill up debris. Move to most other types of bottoms, and yes, they will.

I still don't see why this is considered a problem. An anchor piling up stuff in front of it is simply piling up more resistance to moving forward.

With regards to the rollbar hoop filling up with mud, while we have never done any underwater photography of our anchor set in the bottom, most of the bottoms we anchor in are, in fact, mud. Usually relatively firm mud.

And while there is no question that the anchor fluke itself brings up a dumptruck load of mud with it every time, there has never been any mud packed in or even partially packed in the rollbar opening. The hollow rollbar tube itself will be packed with mud all the way around as I stated in some earlier post, and I have to blast it out with a hose when we get home. But the rollbar hoop has yet to pick up a big rock or a chunk of wood or pack its opening with heavy mud.

And in the many user reports and comments I've read over the years prior to and after our acquiring our anchor, I don't recall any of them complaining about the rollbar opening getting packed up with stuff or doing much of anything to prevent the anchor from setting and holding. Which, of course, is all an anchor is supposed to do in the end.

And in my view, as long as it does those two things, set and hold, the "how," while interesting and perhaps fun to talk about, is sort of irrelevant.

Which is why, for example, if a person uses a Bruce anchor--- an anchor I absolutely despise based on our experience with it--- and that anchor has been setting and holding just fine for that person, there is no way I can say that person is using the "wrong" anchor. If it's setting and holding reliably for that person, end of story. No matter how it works, no matter what the anchor tests say, and no matter what theories I might cook up to prove that it's a crap anchor.

So this "the rollbar does this" discussion is tending to sound like a bunch of very plausible theories in search of reality.

I appreciate seeing Noelex's photos because while Carl is absolutely correct in that they illustrate anchor behavior in just one type of bottom, it's good to see firsthand how the anchors behave in that particular bottom. Which, interestingly enough, happens to be very similar to the bottom of one of the bays in the San Juans we like to anchor in from time to time, judging by what our anchor brings up after we break it free with the boat. Now I know why we have to break it free with the boat.

Delfin · Oct 4, 2014

Marin said:
I still don't see why this is considered a problem. An anchor piling up stuff in front of it is simply piling up more resistance to moving forward.

I agree Marin. It is an advantage, until it isn't. And the 'isn't' category won't be encountered until you need something more than the combined holding force of 4 inches of bury and the vertical hoop providing resistance. If you buy an anchor as an insurance policy against extreme conditions, then the hoop isn't your best choice because its ultimate holding will not be as great as a burying anchor. For proof, look at the Fortress. It is the supreme diving anchor and consistently delivers holding that swamps the competitors. If you don't encounter those conditions, then the hoop anchor will be great.

Peter B · Oct 4, 2014

ranger42c said:
………...Thanks for the tip to roller solutions. I have a pulpit with center slot and imbedded roller... and it never looks to me like I have enough pace on either side of that center slot to add another roller (or bowsprit) system. I'll have to compare measurements to measurements, though. Cheers.
-Chris

Chris, would it be possible for you to beaf up the pulpit either side of the central manufacturers slot…(thinking stout timber lengths, screwed and epoxied in underneath), then mount an auxiliary free-standing roller to one side - maybe both sides - then you could have two other options open to you. I guess it would depend on the overall width of the pulpit platform at the outer end. If you added a sort of bridle loop over the top of each roller, that would prevent the anchor skipping off the roller. Just a thought.

Cheers,

Marin · Oct 4, 2014

Delfin said:
For proof, look at the Fortress. It is the supreme diving anchor and consistently delivers holding that swamps the competitors.

Well, the good news is that we did buy a Fortress, even before we bought the Rocna. We bought it just after buying our boat in 1998. Our primary motivation was to have a reliable, user-friendly anchor to use off the stern.

We'd encountered enough situations of the wind holding us one way while the waves came another way (a not-uncommon condition in some of the narrow bays in the islands like Fossil on Sucia, as you probably know) to know that we'd be more comfortable at anchor or on a mooring buoy if we deployed a stern anchor to hold us into the waves.

Even back then we knew about the Fortress' quality, performance, and reputation. Which is why, even though we were after a stern anchor, we sized the one we bought to be the main anchor for the boat, and sized its combination rode accordingly.

The Fortress (FX23) is carried in a transom/swim step mount and its rode is in a milk crate-type box on the aft deck. So we can easily carry everything forward to use off the bow if conditions warrant it. Our horizontal Lofrans Tigres windlass has both a line gypsy and a chain wildcat, so if we did deploy the Fortress from the bow, we can easily pull its rode. (We've had to do this once or twice even using the Fotress as a stern anchor because it dug itself in so well, we had to use the boat to break it out.)

So between it and the Rocna, I guess we've got the best of both worlds.

Nomad Willy · Oct 4, 2014

Who says the Fortress is a deep diving anchor? I'm not convinced it is unless it's very slimy mud and then even a Navy anchor would probably be a diver.

Does anyone care to say what anchor IS a diver? The Bugel or/and Supreme would probably go deep if they didn't have the roll bar ... but they do. My Supreme will be w/o the RB (most of it) but how would I know how deep it went into the seabed?

Carl wrote;
"hoop isn't your best choice because its ultimate holding will not be as great as a burying anchor."
Theoretically I agree but the anchor tests disagree taking the Fortress out of the picture .. but it's there. The shank and the stock are a great hindrance to penetration on Danforth types and so is the roll bar. With the CQR it's the huge hinged shank. The Claw perhaps shows the greatest promise of being a diver. IMO.

But maybe the the difference between a diver and a dozer is only about 2-3" ... depending on sea bottom. A good old Kedge would dive at least 20" in sand before it's stock put a stop to the dive.

I really don't think there is any divers. A deep diving anchor is probably only in our minds.

Peter B · Oct 5, 2014

Marin said:
Well, the good news is that we did buy a Fortress, even before we bought the Rocna. We bought it just after buying our boat in 1998. Our primary motivation was to have a reliable, user-friendly anchor to use off the stern…..so between it and the Rocna, I guess we've got the best of both worlds.

Arguably right up with the best anyway, Marin, and I guess I am asking for trouble here, but as you did not come back about it, I suspect you missed my post no 684 page 35, (i.e. previous page of this thread), so in fairness, to give you right of reply, but also in the hope the post just might be able to relieve you of some of your concerns re the convex fluke, I invite you to have a gander at the post and see whether it does or not. :hide:

Cheers,

Marin · Oct 5, 2014

Peter B said:
I invite you to have a gander at the post and see whether it does or not.

Cheers,

I did. It doesn't.

Djbangi · Oct 5, 2014

manyboats said:
Who says the Fortress is a deep diving anchor? I'm not convinced it is unless it's very slimy mud and then even a Navy anchor would probably be a diver.

Does anyone care to say what anchor IS a diver? The Bugel or/and Supreme would probably go deep if they didn't have the roll bar ... but they do. My Supreme will be w/o the RB (most of it) but how would I know how deep it went into the seabed?

Carl wrote;
"hoop isn't your best choice because its ultimate holding will not be as great as a burying anchor."
Theoretically I agree but the anchor tests disagree taking the Fortress out of the picture .. but it's there. The shank and the stock are a great hindrance to penetration on Danforth types and so is the roll bar. With the CQR it's the huge hinged shank. The Claw perhaps shows the greatest promise of being a diver. IMO.

But maybe the the difference between a diver and a dozer is only about 2-3" ... depending on sea bottom. A good old Kedge would dive at least 20" in sand before it's stock put a stop to the dive.

I really don't think there is any divers. A deep diving anchor is probably only in our minds.

To 'see' and measure a diving anchor you need clear water into which you can either see or dive, safely - so that rules out much of Australia, unless you want to be shark bait. I tie a thin line to 'something' on the fluke with a float. I mark the line and I know how long the line is. As long as I can see the line and I pull it gently 'tight' I can measure how much of the line is under (or inside) the seabed.

Most modern anchors dive. Spade, Supreme, Excel etc (I'm not going to list them all!)

When setting. so after self righting, they lie on their side, toe is touching the seabed as is the shackle (or shank end). As load is applied the toe engages and almost immediately after the shackle end of the shank 'submerges' into the seabed. As load is continually applied the toe and shackle disappear (almost together) and the anchor starts to level out. It now depends on the seabed and load but if the seabed is, say soft sand, and the load sufficient then the whole lot disappears (it dives) until only the top (roughly centre) of the shank is still visible - but it is quite possible for the whole lot to disappear. It is quite possible for the highest part, that's the centre bit of the shank to become quite deep (depends on seabed and load).

Another way to measure is to mark your chain, for say the first 10'. As the shackles end is submerging it needs to pull the chain down at the same time - which is why thin chain can be advantageous (it has less surface area) (and why you cannot compare 2 anchors being tested if one has 5/16th chain and another 1/2 inch chain). But measure how much chain has disappeared and if you know the scope and depth you can do a bit of simple geometry and get an approximation on depth (thin line is better - the 2 together checks for 'errors').

On chain thickness, size. Think also that a swivel can be quite large, quite a large deterrent to diving (think of its diameter compared to the thickness of the shank of your anchor). Consequently an anchor with 1/2 inch chain and a big swivel will not dive as well as the same sized and same brand anchor with 5/16th inch G70 chain and no swivel.

You need to know that chain develops a 'reverse catenary' - so its not a straight line in the seabed (hence the errors). Once your anchor dives and the chain is developing this reverse catenary then scope is less critical as the angle of the reverse catenary at the shackle is the depth controlling factor.

At some point the anchor can no longer drag down the chain and it does not matter how much load you apply - it will not dive deeper (in that seabed). It then swims through the seabed (until it meets something foreign - it will then surface and drag). But if your anchor is larger enough you it will never swim.

There is an interesting question as to how much chain an anchor can drag down (as its the depth controlling factor - everything else being equal). But I have not got my head around it yet.

A Fortress works differently as the shackle end disappears last, but it also dives.

Deltas, CQR and Bruce dive - but they tend to be a bit less efficient and take a bit more time. CQRs as mentioned have difficulty diving as they have that enormous shank (and this is why shanks have become thinner and demanding use of HT steel to keep strength up but thinness minimised).

We commonly find that our anchors, after we have used them at anchor, are simply not visible (Excel, Spade). So our underwater images are pretty boring, just a chain disappearing into the sand!

A smaller anchor with a thinner chain will dive more deeply than a big anchor, with a bigger chain - for the same load. A smaller anchor with the same chain as the bigger anchor will dive more deeply - for the same load. A big anchor will dive more deeply than a smaller one of the same design, with the same chain (which will give it more hold) - but you need more load to get the bigger one to dive more deeply and utilise that potential. If you have a very big anchor (monster) you will never get it to dive sufficiently deep to allow it to reach that 'swim' point (and all you are doing is carrying excess weight). As an example - look at the Fortress tests, size was not critical - the same sized anchors dived differently. Shank angle is critical (it affects the reverse catenary). But in some cases - having a bigger anchor - it would not have helped - and the loads were not that great.

There is still much to learn.

Happy to clarify anything.

Jonathan

Marin · Oct 5, 2014

Djbangi said:
To 'see' and measure a diving anchor you need clear water into which you can either see or dive, safely - so that rules out much of Australia, unless you want to be shark bait. I tie a thin line to 'something' on the fluke with a float. I mark the line and I know how long the line is. As long as I can see the line and I pull it gently 'tight' I can measure how much of the line is under (or inside) the seabed.

Most of us have seen the GoPro video that went viral awhile back in which a GoPro in a home-made waterproof case was towed behind a fishing boat off Southern California. The intent was to see tuna coming up to the lures, but what they got was a bunch of Pacific White-sided dolphins coming up to inspect the camera.

So what if you did the same sort of thing to see how an anchor behaved on the bottom? The GoPro in its waterproof housing could be attached to the anchor chain several feet in front of the anchor. The underwater housing could be given very slight buoyancy so it floated a bit above the chain but not pull so much that it affected the behavior of the anchor or the rode.

We use GoPros in our work at Boeing so are very familiar with its characteristics. With its extremely wide lens it would capture the anchor in the shot even if the housing was a bit off in its alignment.

GoPros are very cheap in the overall scheme of things, and creating a Plexiglas waterproof housing that would be good for depths of 20 feet or so would be pretty simple. There may even be underwater cases for GoPros on the market already. You'd want to conduct the anchor settings where a fair amount of light reaches the bottom, so that might rule out the Pacific Northwest. But Florida, Southern California, etc. could work well.

This could be a way of recording real-life anchoring situations on a very reasonable budget.

Noelex · Oct 5, 2014

Delfin said:
Yes, they are atypical presentations because light sand bottoms are hardly representative of the 'real world' of conditions. In light sand, no, the hoop will not pill up debris. Move to most other types of bottoms, and yes, they will.

Thanks, its nice to get some agreement that roll bars do not pile up sand at least.

I will able to get more photos in different substrates as my location and the season changes.

The other side of the coin there are plenty of anchors that will pile up substrate in sand. Many anchors cannot penetrate if there is a firmer layer of substrate under the soft sand.

Their primary holding method is to scrape along the softer sand on the top layer until enough of it piles up in front of the anchor.

This actually works quite well at low to moderate wind speeds and these anchors can be very reliable in these conditions. In high winds the anchor must dive down below this soft surface sand to provide enough grip. Anchors that just pile up sand are not very reliable then.

There are anchor designs that consistently do this sort of set in any substrate with a hard layer. This is Delta that took about 5m (15 feet) to this point.

It is actually a better set from the Delta than I normally see with most of the fluke and shank covered, but nearly all of this burying is a piling up of sand rather than fluke diving down.

You do have to be a bit careful with this sort of set if you are looking at your anchor from the surface. It can look very good with the anchor buried by the substrate, but not much of the anchor has penetrated below the surface of general seabed.

Note this is an extreme example. The camera angle has also tended to exaggerate things slightly, but it was an exceptionally large mound of piled up substrate.

Djbangi · Oct 5, 2014

Marin,

Great minds.

We have friends who are pioneering commercial fishing on seamounts in the Tasman at 400m - 600m using hydraulic reels and long lines. They are pushing the limits here and 'Fishery habitat protection bureaucrats' have subcontracted to them to define what is down there. They have been using GoPros in special cases (and lights).

In the grand scheme of things this seems to 'answer' what you are suggesting (and saves getting eaten by a shark for the sake of anchor science).

Its on the agenda.

But you can see something similar if you watch anchors in shallow water but correlating what happens in shallow water is the same as 10m needs to be completed - to identify any differences (if any).

My wife and I have just made 3 short videos, not yet edited, on anchoring for some lectures I give. Its incredibly time consuming.

One needs patience.

Jonathan

Tom.B · Oct 5, 2014

Jeffrey S said:
Well, actually...someone else's anchor is about the only thing on their boat that might very well affect me in an anchorage...

That may well be one way to spin it, Jeff. But how does arguing about it here do any of us any good? In case people haven't noticed, nobody's opinion here seems to be changing anyone's mind. So why do some continue to insult, belittle, and treat one another like your opinion (not you specifically, Jeff) is the only correct one? How often we any of us be in an anchorage full of TF members when a squall blows up hard enough that tests the outer limits of everyone's ground tackle? I'm going out on a limb here and say zero to that.

(Edited to not specifically call out one person)

Delfin · Oct 5, 2014

manyboats said:
Who says the Fortress is a deep diving anchor? I'm not convinced it is unless it's very slimy mud and then even a Navy anchor would probably be a diver.

Does anyone care to say what anchor IS a diver? The Bugel or/and Supreme would probably go deep if they didn't have the roll bar ... but they do. My Supreme will be w/o the RB (most of it) but how would I know how deep it went into the seabed?

Carl wrote;
"hoop isn't your best choice because its ultimate holding will not be as great as a burying anchor."
Theoretically I agree but the anchor tests disagree taking the Fortress out of the picture .. but it's there. The shank and the stock are a great hindrance to penetration on Danforth types and so is the roll bar. With the CQR it's the huge hinged shank. The Claw perhaps shows the greatest promise of being a diver. IMO.

But maybe the the difference between a diver and a dozer is only about 2-3" ... depending on sea bottom. A good old Kedge would dive at least 20" in sand before it's stock put a stop to the dive.

I really don't think there is any divers. A deep diving anchor is probably only in our minds.

The Coast Guard has abandoned at least one Fortress I know of they could not retrieve because it had dug in to deeply. If you look at the data from the Fortress test you'll note that the anchors that produced the highest holding brought up different muck from a deeper layer. Finally, a nicely set Excel, Ultra, or Spade is one you can't see anymore. A nicely set Rocna has half the hoop exposed.

Yes, some anchors will keep going deep when you pull on them and some will not. If you used cable instead of chain, they would bury even deeper, which is why some people firmly believe in a length of cable between the chain and the anchor.

Delfin · Oct 5, 2014

Marin said:
Most of us have seen the GoPro video that went viral awhile back in which a GoPro in a home-made waterproof case was towed behind a fishing boat off Southern California. The intent was to see tuna coming up to the lures, but what they got was a bunch of Pacific White-sided dolphins coming up to inspect the camera.

So what if you did the same sort of thing to see how an anchor behaved on the bottom? The GoPro in its waterproof housing could be attached to the anchor chain several feet in front of the anchor. The underwater housing could be given very slight buoyancy so it floated a bit above the chain but not pull so much that it affected the behavior of the anchor or the rode.

We use GoPros in our work at Boeing so are very familiar with its characteristics. With its extremely wide lens it would capture the anchor in the shot even if the housing was a bit off in its alignment.

GoPros are very cheap in the overall scheme of things, and creating a Plexiglas waterproof housing that would be good for depths of 20 feet or so would be pretty simple. There may even be underwater cases for GoPros on the market already. You'd want to conduct the anchor settings where a fair amount of light reaches the bottom, so that might rule out the Pacific Northwest. But Florida, Southern California, etc. could work well.

This could be a way of recording real-life anchoring situations on a very reasonable budget.

I've thought exactly the same thing, Marin. It would allow you to see what you were dropping your hook onto, like the engine block of a De Soto, as well as penetration. The tricky part would be figuring out how to orient it so it was pointed in the right direction, as well as uploading real time information. Pretty expensive bit of gear I should think, but one that some would certainly buy.

Delfin · Oct 5, 2014

Djbangi said:
A big anchor will dive more deeply than a smaller one of the same design, with the same chain (which will give it more hold) - but you need more load to get the bigger one to dive more deeply and utilise that potential. If you have a very big anchor (monster) you will never get it to dive sufficiently deep to allow it to reach that 'swim' point (and all you are doing is carrying excess weight). As an example - look at the Fortress tests, size was not critical - the same sized anchors dived differently. Shank angle is critical (it affects the reverse catenary). But in some cases - having a bigger anchor - it would not have helped - and the loads were not that great.

There is still much to learn.

Happy to clarify anything.

Jonathan

Good post. If I understand you correctly, I would take issue with this last, in that I can't see how a large anchor is ever less efficient than a lighter one. If you look at the ratio of weight to surface area of the Ultra as an example you can see what I mean. A 46# anchor has a "holding surface" of 50 cm2 per pound. My 176# anchor has a holding surface of 32 cm2 per pound. Which is more likely to dive the deepest - the one that has less weight per square cm it needs to bury or the one with more weight per square cm? Clearly the later. If this reasoning is correct, and I can't see how it is not, then the heavier the anchor the deeper it will bury. Your point about requiring more force to get the anchor to bury is of course correct. I think what that means is that as the force on the vessel increases, the more holding power a diving anchor will develop with the heavier developing the most holding. This is the fundamental reason I go on about the only limitation I see in hoop style anchors - if they don't dive, their maximum hold is static so what you get setting it in 20 knots is pretty much what you'll get in 80 unless it drags and hits something solid.

I've always assumed this is why the big Claw I had worked so well, 100% of the time. It was heavy enough relative to its surface area that it always dug in deep, while a lighter Claw would not have done so.

By the way, does this mean you are finally willing to admit you are not a Zulu warrior??? :socool:

Delfin · Oct 5, 2014

Jeffrey S said:
Well, actually...someone else's anchor is about the only thing on their boat that might very well affect me in an anchorage...

Chesapeake Anchor Holding Power Test

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