How soft is "soft" mud when anchoring?

[Cheechako]

Check what the charts says first. It's very hard to know for sure though. One of the worst conditions is shallow sand over hard clay, hard pan or similar. It seems to be good but is terrible holding. Even your lead line wont tell you that. The chart often will though.

[svinvictus2]

We always back down at 2800 -3000 rpm for a period of time while visually checking the shoreline or other boats to both set the anchor properly and assure we stick.
Using appropriate scope which for us on all chain is never less than three or four to one at the depth were we dropped. Not where we finish letting out. There are frequent times you may drop in 50 ft. of water and once fully let out, 200 or so feet of chain, you're in 30 ft.....always use the depth where you dropped to determine your scope and do not power back until you're at-least 3:1 scope.

[Tbonem17]

What ever is exposed on the banks between the high and low tide lines is usually a good indication in most northern/mangrove rivers in Oz.

The more the mangroves are into the river (actively growing new shoots)the softer it will be. If they are only appear in protected pockets or well back on the bank the harder the bottom will be or the sandier the bottom will be.

Stay away from the really soft stuff for the sake of your boat as that muck sets like concrete when allowed to dry on it.

For laughs on slow fishing days many years ago we used to surf the incoming river tidal waves in the NT in our dingys. Invariably we'd end up very wet standing in muck up to our knees trying to sort boats out. Come to think about it now, that was probably pretty stupid with river names like South and East Alligator yet even the crocks got bogged in that stuff. They could only slide around on it.

Looking at your pic I'd say the bottom in that pic is pretty soft. Like the knee deep stuff.


Edit - I'd stay away from anchoring where that pic was taken because I doubt an anchor would be able to reset itself after pulling out on a tide change. I'd be just a ball of muck hanging on a chain.

[reed1v]

Someone advised to drop anchor and go full reverse throttle. That will either cause the anchor to keep tripping, go sideways, or rip out your fore deck. Imho, that is very stupid advice.

[zeehag]

the anchorage in barra de navidad, a most popular mexico anchorage, is silt over river bed. has rocks, refrigerators, runoff stuff from higher elevations. silt is the topping. we use a good bruce and 130 ft chain. holds well.
the other anchorages here on this coast are combo mud and rock or sand mud rock.
what you see on the shore is predominantly what you will see under you.
the ones who drag in barraś silt mess were those using less than 100 ft chain, or who reversed so hard as to unset their stuff. the best way to anchor in soft mud and silt is set in wind. let the wind blow you back on your anchor set to actually set, not unset it.
my chain and bruce combo works in silt bottomed lagoon to 45 kts winds, then walks slowly back, approx 5 feet per big wind. not bad. .

the lagoon is only 8-10 ft depth.
those using 3:1 or 5:1 or any other alleged regular scope by numbers drags. the least scope for maintaining set is 100 ft in barra. weight of anchor--heavy as hell.
there are some places wherein use of scope measurmement and mandates do no tawork. lay out your chain then figger it out. if silt-- you laid out 50 ft--add 100.

[knockabout]

lime stone is hard to stay put on/mud sand is good/quick sand silt a good anchor drop helps then let the anchor settle if you are there for a while it pays to up anchor and reset every day a cqr will keep pulling in and can be a battle to retrieve

[boatpoker]

I've been using fish finders for years, less expensive than depth sounders and provide a lot of bottom info which you will be able to interpret with experience.
Rock, shale, sand, hard sand mud, weed show up quite well. Not infallible but very valuable.

[RaymondR]

Some of the creeks like the one in your photo have scoured bottoms and are very difficult to get an anchor to set in. One of the tricks I use is to drop the anchor close to the bank then let out a fair bit of chain and attempt a set. Usually works but you need to set the rudder so that the boat hangs away from the bank on a falling tide.

[roygee]

Dear Sir: I have a hummingbird sonar, at about 800. Dollars new, I bought last years Model. Discounted about 250. Dollars. You get dual frequency transmissions and with the supplied video anyone can become proficient in reading it to tell wheither the bottom is Rocky, with drops or cliffs, trashy hard clay ,trees or brushy, and if it is muddy and how deep the mud is or its composition. Very easy to see if its mud over hard pack , in one case I could plainly see the mud was slushy and 18 foot deep. There is absolutely no reason not to have a good quality sonar on board, in my mind it is one of the best tools for providing good anchoring. The price does not include the transducer,which could run around 400, and it does not come with it , as their are different configerations. You can also buy Wifi that includes a 2nd. transducer that will interact with your chart and your primary sonar. This information can be submitted to, in my case, Navonics to establish an updated user base. Lots of fun, if it is.

Originally Posted by troppo

Without putting one's foot in it, how does one know if the bed where the anchor is about to be dropped is soft or hard? And how soft is "soft" mud?

Softness of mud bottom makes a major difference with holding power of anchors and I am very keen to know how others work it out.



Recently I read an article describing holding power of various anchors in extra soft bottom mud. I am not wanting to debate anchors but how to discern the bed make-up. Dipping an anchor toe into muddy waters - MySailing.com.au

Just having come back from a cruise where I was anchored in mud and compliments of a gale force breeze dragged about 50 metres before I released more rode and stopped, I have become more interested in how to recognise what bed is what.

Because where I anchor has high tidal flow, I just assumed the bed was rather hard mud and/or sand. Banks are hard mud covered with mangroves. I assumed soft mud would wash away. But then, if I tried to stand on the banks, I would sink so maybe the banks are not hard mud after all. Perhaps semi-hard or even semi-soft.

Are fish finders with the red line thing indicating the sea floor any use for checking bed consistency before anchoring?

So, how do people check quality of mud beds for anchoring?

[AD28]

Lead line. There is a hollow in the weight - fill that with tallow then drop the lead, thus sampling the bottom.

[ranger58sb]

Originally Posted by wrwakefield

While this isn't a discussion about anchor selection, I want to mention our main bower only because it factors in to our approach for different bottom types. Our boat came with an 80lb adjustable SuperMAX anchor. It has a 3 position adjustable shank readily accommodating hard to very soft substrates. Opened to its widest angle of attack for a very soft [ooze] bottom, it sets quickly and deeply, and is a demon to retrieve. [There are more details on our Ground Tackle Inventory page if you are interested.]

80 pounds! Woof!! That's 30-lbs heavier than our adjustable SuperMAX 17...

Probably heavy enough to anchor the USS Enterprise!

-Chris

[wrwakefield]

Originally Posted by ranger42c

80 pounds! Woof!! That's 30-lbs heavier than our adjustable SuperMAX 17...

Probably heavy enough to anchor the USS Enterprise!

-Chris

Your reaction must mean we are approaching the right sized anchor, Chris.

Our cruising weight is 44k lbs, and the 80# model 20 anchor has a working load of 5k lbs- so it feels about right [especially since the next size up- the #22 weighs in at 112lbs with a working load of 10k lbs- which we might consider if we upgrade to G70 chain- from 5/16" G43- in the future...]

How long have you been using your SuperMAX, and what have your experiences been? [In mud and ooze in keeping with this thread topic...]

Cheers!

Bill

[ranger58sb]

Originally Posted by wrwakefield

Your reaction must mean we are approaching the right sized anchor, Chris.

Our cruising weight is 44k lbs, and the 80# model 20 anchor has a working load of 5k lbs- so it feels about right [especially since the next size up- the #22 weighs in at 112lbs with a working load of 10k lbs- which we might consider if we upgrade to G70 chain- from 5/16" G43- in the future...]

How long have you been using your SuperMAX, and what have your experiences been? [In mud and ooze in keeping with this thread topic...]

Yep, you sound right-sized to me!

We looked at the 20 but it wouldn't fit our pulpit well... and even more to the point, I don't want to have to lift that kind of weight if our windlass craps out.

We started with a 16 on our previous boat in early 2002 when we came back to the Chesapeake from the Miami area. Got our current boat in 2005, but used a lighter weight Fortress (FX-37) here in the mud until we could get an electric windlass installed to handle the additional weight of the MAX... so we moved the 16 to this boat in probably 2007. Just last year, we happened into a good deal from a nearby Trawler Forum subscriber, and moved up to the 17.

FWIW, the 16 worked great, even though under the manufacturer's recommendation for our current boat weight. OTOH, bigger (and heavier, within reason) always rings my chimes... and we have a windage issue sailors wouldn't have (can't reef my flybridge)... and the 17 fits reasonably well. Doesn't self-launch (I have to encourage it off the roller), and it won't auto-dock (I have to lift it that last 3 feet or so), no difference from the 16 in that respect.

Bottom line: so far, they always seem to hold as if we're nailed to the bottom!

-Chris

[wrwakefield]

Originally Posted by ranger42c

Yep, you sound right-sized to me!

We looked at the 20 but it wouldn't fit our pulpit well... and even more to the point, I don't want to have to lift that kind of weight if our windlass craps out.

We started with a 16 on our previous boat in early 2002 when we came back to the Chesapeake from the Miami area. Got our current boat in 2005, but used a lighter weight Fortress (FX-37) here in the mud until we could get an electric windlass installed to handle the additional weight of the MAX... so we moved the 16 to this boat in probably 2007. Just last year, we happened into a good deal from a nearby Trawler Forum subscriber, and moved up to the 17.

FWIW, the 16 worked great, even though under the manufacturer's recommendation for our current boat weight. OTOH, bigger (and heavier, within reason) always rings my chimes... and we have a windage issue sailors wouldn't have (can't reef my flybridge)... and the 17 fits reasonably well. Doesn't self-launch (I have to encourage it off the roller), and it won't auto-dock (I have to lift it that last 3 feet or so), no difference from the 16 in that respect.

Bottom line: so far, they always seem to hold as if we're nailed to the bottom!

-Chris

Thank you for the info, Chris.

Fitting anchors to our bow rollers can be a challenge. We have to cajole ours into launching and manually dock it too.

RE: Retrieving without a windlass, we would have to use one of our manual winches if the manual retrieval on our electric windlass failed for some reason. We typically anchor in 50-80 ft of water, so the dead pull exceeds 160 lbs [not including the basketball sized wad of mud the anchor usually brings home...]- more than I can sustain manually these days...

RE: Holding power- that has been our experience as well- once with repeating short burst 90 knot williwaw gusts through an otherwise benign anchorage. [And people ask why we always anchor as if it is going to blow 60...]

Best wishes and safe anchoring.

Cheers!

Bill

[AD28]

Just saw this at The Boat Galley.

The 'Technique' section is spot on IMO and has worked for me in some serious (50-60kt) blows and reversals

Anchor As If It’ll Blow 50