Chesapeake Anchor Holding Power Test

Djbangi said:

psneeld,

The trouble is I cannot find much info on how anchors work in mud- lots, if not endless stuff, on anchors in harder bottoms - but mud (and weed) appears to be something that has been ignored - though Chris (ranger 42c) seems to suggest its not very nice to work with. So maybe anchor makers do not like to get their hands dirty - or maybe their products do not work. So, personally, I find it refreshing that Fortress have bit the bullet (chartered the wash down hoses) and might be filling a gap in our knowledge base. I hope I can see through any hype and from the content I read on this forum - I think most will also point out sensibly and with reason anything that smacks of 'spin'.

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The word mud doesn't really mean much...some apply the term to a variety of seabeds that go from a consistency of thick soup to something resembling modeling clay.

There are many more scientific descriptors of bottom material and the real problem is often in an anchorage you can have several types and even different layers.

For me...I know most anchors don't hold great in deep soupy mud...so if I think that's what the majority of the bottom is like I either leave or have a hunch the conditions really won't be tested to its fullest.

Either way I'm not basing my anchor on how it holds in mud and more than basing how well it does in sand.

I'm basing my anchor on 2 things..If I have to drop it in an emergency shutdown situation...it has to set and hold quickly in reasonable situations...in mud, weed, sand, oysters etc...etc...I may not have the luxury of pulling it up and clearing the oysters or clam shells or weed from it.

The second is that it need to work OK in a variety of seabeds. I don't base it on ultimate holding power (storm anchor) if I need storm holding power...I'll set a "storm anchor" or work something else out.

Being the best at ONE thing in your life, as a person or anchor by no means makes you top dog.

My experiences in the upper CB is its mostly topsoil runoff. Fine and soft that is compacted further down you go. In the Bohemia River at the top of the bay, you churn up the bottom most of the way to the channel. On a weekend, the BR turns to light brown cloud of silty water. Fill a bucket of water and soon a layer of fine silt will settle out on the bottom of the bucket. The Baltimore Inner Harbor bottom is stiff, sticky muck filled with debris. Trash bags, branches, leaves, and whatever sinks to the bottom from storm drain runoff will be stuck in the anchor flukes when you pull it up. FWIW, my Danforth 12H, 6 ft chain, and 3/8" nylon rode never dragged or failed to set in it.

Djbangi said:

psneeld,

The trouble is I cannot find much info on how anchors work in mud- lots, if not endless stuff, on anchors in harder bottoms - but mud (and weed) appears to be something that has been ignored - though Chris (ranger 42c) seems to suggest its not very nice to work with. So maybe anchor makers do not like to get their hands dirty - or maybe their products do not work. So, personally, I find it refreshing that Fortress have bit the bullet (chartered the wash down hoses) and might be filling a gap in our knowledge base. I hope I can see through any hype and from the content I read on this forum - I think most will also point out sensibly and with reason anything that smacks of 'spin'.

Click to expand...

In that case, I can suggest you have a look at the Super Max anchors, too. Lots of hype (aka "spin") on their site, but if you Google reviews by Cap'n Wil Andrews you might still be able to find some of his -- I think independent, generally consistent, but not strictly scientific -- testing of anchors suitable to soft and/or soupy mud.

FWIW, I said out FX-37 works great but we don't keep it mounted all the time... because we keep an adjustable Super Max on the pulpit. It seems to work equally great in the mud around here, but mostly it rides better in our pulpit/roller design. Can't say much about from personal experience about how it might work in other types of holding ground.

-Chris

The comments about "mud" being way too general a term are spot on. The Chesapeake is a huge and varied body of water. For those who haven't been there, a cursory look at the charts for the Chessie will show all sorts of bottoms: hardness, stickiness, composition, etc. We've cruised and anchored out there, the entire length and both shores, using a Delta and on one trip down, a Danforth (which later became the always ready to deploy backup). Both did fine, just be patient and get get a good set.

The tests in this thread, including some of the later comments by Fortress themselves, point up a problem with anchor tests and with many boater's approach to anchoring. They judge anchors based on the the exact same technique and ground tackle for deploying them, and how quickly they make an initial set, and then "hold" from that initial set. One thing I have learned after a whole bunch of anchoring (anchoring is why we go cruising), is that it is at least 80% technique and about half of that technique is patience. I think I can safely say at this point we have anchored in every kind of bottom and condition. Any problem I have had anchoring was always due to my taking some sort of short cut in the process. Have an emergency and no time? Throw out another one!

Here in So California the bottom is often mud ranging from soup to thick heavy sticky stuff. I use a 22lb original Bruce with 50ft of 1/4" HT chain and 1/2" three strand nylon rope. Except for the one time I described in my "Embarrassing Anchoring" thread the Bruce has always set on the first drop. I play out the proper scope, tie off to the bow cleat and let it slowly settle in and set for a few minutes. I then apply reverse throttles to hard set and I'm good. I think most anchors will set if allowed time to settle in and soft set before applying reverse throttles.
Jim
1966 Californian.

This is nuts! Someone says the A word and here we are 185 posts later discussing the types of mud. I suggest we classify mud by it's water content. I'll make up some numbers but you science guys can work up the real numbers.
Five gallons per cubic foot will be called "Dirty Water"
Four gallons of water per cubic foot will be "Extra Soupy"
Three gallons per cubic foot will be "Soupy"
Two gallons per cubic foot will be "Mud"
One gallon per cubic foot will be "Dirt"
Less than one gallon per cubic foot will be "Rock"

Now who'll define the types of bottom growth anchors need to deal with?

Why bother with that? "Hard" "Sticky" "Soft" "Ooze" "Stiff" not good enough?

HopCar said:

This is nuts! Someone says the A word and here we are 185 posts later discussing the types of mud. I suggest we classify mud by it's water content. I'll make up some numbers but you science guys can work up the real numbers.
Five gallons per cubic foot will be called "Dirty Water"
Four gallons of water per cubic foot will be "Extra Soupy"
Three gallons per cubic foot will be "Soupy"
Two gallons per cubic foot will be "Mud"
One gallon per cubic foot will be "Dirt"
Less than one gallon per cubic foot will be "Rock"

Now who'll define the types of bottom growth anchors need to deal with?

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You left out "pluff mud," (primarily in the SC low country) which I would define has three parts vacuum cleaner. It will suck your boots off.

Jim I agree re post #185

The whole business of deploying an anchor with a good slow set is grossly under rated. Most set an anchor the way most set the hook in a fish.

It may take some time to get it out too.

But most people like TF members think that holding power is mostly all that matters. Not so. In all the difficulties encountered in anchoring an anchor that does well in all things is much more desirable than the champion types. But anchor tests are easy to perform for one aspect of function and nearly impossible to test for most functions. Quite a few on this forum have done such testing over time in/on many varied waters and bottoms. Sunchaser is such a skipper and he uses an anchor that does poorly in most anchor tests (Claw) and his anchoring experiences are golden. I have used 7 or 8 anchors and never dragged. So I see the notion of needing a new super duper anchor to solve my "problems" as not very monumental.

Analyzing anchors is irresistible fun for me though.

Stuck in the mud we are it seems.

I took soil samples and I am going to have them tested for the "shear strength profile."

Per Bob Taylor: "A typical mud has a strength profile equivalent to about 9-12psf/ft of depth or about 100psf - (0.7psi) at 10 ft. This is what is found in most harbors, deep water Gulf of Mexico, Norwegian Trench, San Francisco bay, South China Sea, etc."

The mud that we pulled up was pretty foul-smelling, which ruined our initial hope that we could market and sell it as a facial product.

It appeared that the oyster shells were packed below this soft nasty stuff, and below the shells was a gritty type of clay.

caltexflanc said:

One thing I have learned after a whole bunch of anchoring (anchoring is why we go cruising), is that it is at least 80% technique and about half of that technique is patience. I think I can safely say at this point we have anchored in every kind of bottom and condition. Any problem I have had anchoring was always due to my taking some sort of short cut in the process. Have an emergency and no time? Throw out another one!

Click to expand...

Very insightful words. Our late company founder, who was also a long time Hatteras owner and he did a circumnavigation in one, said that "When anchoring, time is your friend."

"Why bother with that? "Hard" "Sticky" "Soft" "Ooze" "Stiff" not good enough?"
George those words would be fine, but apparently we need to assign a "Shear Strength Profile" to each of them if we're going to be scientific about this.

Besides which, what's the difference between "Stiff" and "Hard"?
Ok guys, I dare you to do something with that one. Remember this is a family show.

Fortress Anchors said:

I took soil samples and I am going to have them tested for the "shear strength profile."

Per Bob Taylor: "A typical mud has a strength profile equivalent to about 9-12psf/ft of depth or about 100psf - (0.7psi) at 10 ft. This is what is found in most harbors, deep water Gulf of Mexico, Norwegian Trench, San Francisco bay, South China Sea, etc."

The mud that we pulled up was pretty foul-smelling, which ruined our initial hope that we could market and sell it as a facial product.

It appeared that the oyster shells were packed below this soft nasty stuff, and below the shells was a gritty type of clay.

Click to expand...

Our experience anchoring around the Chesapeake Bay is that the bottom is almost always heavy grey clay like mud that has the consistency of modeling clay. More times than not our Delta comes up with 10 lbs (guesstamit) of the grey stuff and a few oyster shell embedded in the clay. I have an 80 psi wash down pump and it is still a chore to clean thing so the crap doesn't end up in the chain locker.

I had an unpleasant anchoring experience in Calder Bay Alaska on the north end of POW island. Lots of room so I could have been at 10-1 scope. A first for me probably.

It was supposed to blow 40+ but it probably didn't quite do that. Don't know why but I used my 13lb Danforth. In the second pic you can see an angel's breath of sea foam in the water not long after I set the Dan. The whole bay was about 20' deep and there were lots of Sea Otters about. Ten or 15 in one group.

Since the 40 knots was predicted I set the Dan hard on long scope the night before. It was a pleasant morning as I hauled in the rode. Dry pass was next for me and I was looking fwd to the pass. Pulling up my anchor in the very light morning breeze was a typical nice boating moment. But soon I got the rode vertical and the Dan was sorta stuck. This was before my capstan so I got it as tight as I could pulling on the rode and made it fast to the dedicated anchor cleat. Backed down a tad and stop. Nudged fwd a tad and stopped. Then it came loose and I was once more ramping up my nice day underway to Craig. It was hard work as it seemed too heavy. Then I saw it .. later rather than sooner as it (the Dan) was a huge lump of black mud w flecks of white shell. It was sticky. It was very stinky. Used a broom for the next 20+ minutes dipping in the water and scrubbing off the black mud. Finally got the chain and anchor clean enough to come aboard. For months I was smelling that black crap just like I was leaning over the side cleaning it off again.

I suspect the mud was largely rotten and rotting clam/oyster shells deposited there by all the Sea Otters over thousands of years. The bay was probably shallow because of all the shells. A good sized bay 20' deep is not common in Alaska.

Fortress Anchors said:

Here's a real world experience that will back up this theory:

During 1996-2006, North Carolina was hit by 11 hurricanes and several tropical storms. Jet Matthews, owner of Matthews Point Marina (as I recall it has 120 slips) in Havelock became very experienced in preparing boats under his care for the approaching storms.

He became a very strong advocate for using wire rope on the anchors, as he found that it had a knife like effect and it would allow the anchors to bury far deeper into the nearby soft mud bottoms.

Brian

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Brian, are you going to post a table version of the testing, or is your potted verbal summary all we are going to get..?

caltexflanc said:

Why bother with that? "Hard" "Sticky" "Soft" "Ooze" "Stiff" not good enough?

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Not to forget that sticky, oily looking, black, what I call 'weapons grade mud', which we have in places in our Moreton Bay here in Queensland. I'm sure you have it in the US as well. Yes you do. Here's where Eric describes encountering some...

" ....later rather than sooner as it (the Dan) came up, on it was a huge lump of black mud w flecks of white shell. It was sticky. It was very stinky. Used a broom for the next 20+ minutes dipping in the water and scrubbing off the black mud. Finally got the chain and anchor clean enough to come aboard..."

Peter B said:

Brian, are you going to post a table version of the testing, or is your potted verbal summary all we are going to get..?

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Peter, yes. We conducted 60+ test results, and we hope to publish a data set for each anchor which plots out their 5 pulls on a single graph.

Additionally, for the sake of comparison we will have a chart from when we pulled the chain only with no anchor attached, and one from when we pulled a 45 lb cement mushroom type anchor.

Given their limited space, I am sure that the magazines will want something far more condensed, possibly in a single chart or two, and we are discussing how we can provide that data as well.

In the near future, we hope to also release videos from each of the 4 days, and the last day is being edited right now by our videographer who filmed the entire event.

Brian

Peter B said:

Brian, are you going to post a table version of the testing, or is your potted verbal summary all we are going to get..?

Click to expand...

Peter,
I was holding back determined not to be the one to ask Brian that question and I succeeded thanks to you.

I'm not interested in pulling only chain but I've always been curious how much those crude mushroom anchors resist a pull.

Mushroom anchors are what the lightships used,and they had to ride out everything the weather threw at them. Of course, theirs were a wee bit larger then the little toy anchors the recreational boat crowd uses.

Here's a mushroom anchor on a lightship.

That was the lightship we sailed around on the annual "Lightship Race" in the sixties. However, in relation to the small boats we use, that mushroom is small.

My understanding of how a mushroom anchor works is that, assuming it is large and heavy enough for the job, it continues to bury itself into the bottom as it "works" from the pulling of the vessel attached to it. So the more it gets pulled and jerked on, the deeper it digs itself. I would imagine that when a lightship like the one in Al's photos had to come in for servicing, it was a hell of job getting the anchor out of the bottom.

They probably just took their time, oozing through the mud.

Marin wrote;
"So the more it gets pulled and jerked on, the deeper it digs itself."

As far as I know every anchor acts in that way. Probably the best way to set ... a long line of little jerks.

Mushrooms are considered permanent anchors because they dig in further no matter which way the pull as opposed to the anchors most people lie to for a temporary time.

Anchor - Wikipedia, the free encyclopedia

Mushroom anchor[edit]


Mushroom anchor on the lightship Portsmouth in Virginia.


The mushroom anchor is suitable where the seabed is composed of silt or fine sand. It was invented by Robert Stevenson, for use by an 82-ton converted fishing boat, Pharos, which was used as a lightvessel between 1807 and 1810 near to Bell Rock whilst the lighthouse was being constructed. It was equipped with a 1.5-ton example.
It is shaped like an inverted mushroom, the head becoming buried in the silt. A counterweight is often provided at the other end of the shank to lay it down before it becomes buried.
A mushroom anchor will normally sink in the silt to the point where it has displaced its own weight in bottom material, thus greatly increasing its holding power. These anchors are only suitable for a silt or mud bottom, since they rely upon suction and cohesion of the bottom material, which rocky or coarse sand bottoms lack. The holding power of this anchor is at best about twice its weight until it becomes buried, when it can be as much as ten times its weight.[17] They are available in sizes from about 10 lb up to several tons.

Then there's taffy mud, like the mud along Turnagain Arm along the Seward Highway - that mud eats tourists once in a while. They don't respect the mud (despite the warnings) and then the tide comes in...

I put myself through college working for my dad's commercial diving company. No glamorous deep sea work, no, lots of shipping terminal, piling, power plant, and dam jobs - and mud, mountains of mud. We'd use 6" trash pumps to pump mud out of cooling water intake canals, cooling towers, buried cables, clearing underwater valves and machinery and trash racks. Did that for about five years. Felt like I pumped enough mud the fill the Grand Canyon. We had a lexicon for mud. Baby s--- mud (we liked that, easy to pump). Stick-mud was the worst, mud with sticks in it. Jammed the pumps if the sticks were big enough, if you let them get sucked into the intake. Yes, mud is fascinating stuff. Once in a while too we'd strike a vein of mud that would smell so bad you'd almost throw up in the helmet - I always wondered if those spots were from things like dead cattle or large animals that sank to the bottom and decayed into mud themselves after a few dozen years. Ah yes, mud. Mud paid for a good portion of my college degree. Where would I be now without mud.

kthoennes said:

Then there's taffy mud, like the mud along Turnagain Arm along the Seward Highway - that mud eats tourists once in a while. They don't respect the mud (despite the warnings) and then the tide comes in...

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I've seen that mud, and last time I was in Alaska a tourist did indeed get stuck in it (but they got him out). Oh well. Helps the gene pool to lose people like that.

Brian,
When will the test results be posted.

Thanks

READY2GO said:

Brian,
When will the test results be posted.

Thanks

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I think we will post the charts this week and possibly the videos from all 4 days on YouTube.

Regards,
Brian

You Tube .... kinky stuff then eh Brian?

I was wondering too but didn't want to be the first one to ask.

Thanks READYTOGO.
You were ready eh?