First stockless SHHP anchor

My gift to Eric and the forum is a new anchor to discuss

The Posidonia PTW+® Anchor, the first stockless anchor to be rated by Lloyds as super high holding power;

POSIDONIA SRL - Products > Anchors > Yacht anchors > PTW+ Anchors

Italian made, comes in sizes down to 17kg (pretty suspect at that size I bet) but would look pretty damn cool snuggled up against the bow through the hawse pipe of a medium to large sized trawler...

Interesting indeed,
The Ultimus and Kedge (very similar anchors) offered by Manson are HHP not SHHP.
That's true but it says nothing about it's setting abilities. Hard to imagine it having problems though. Stranger things have happened however. The Mansons are cast or forged. The Posidonia is a weldment ... looks strong enough to me but ??
You're right Murray .. a good one to mentally play with. Hang'in it on the bow may present problens. I think these TF guys are too old fashioned, conservative and generally resistant to new things to be tempted w this "Big Boy" anchor. Thanks for posting.

Nice. Sure looks a lot like the ones Greenline uses on their hause mounts.

Here's another Greenline.

Larry,
I don't think either one of those Greenlines have the Posidonia anchor.

The top one has higher aspect ratio flukes and they are not flat.

The second one (Greenline) has higher aspect ratio flukes and the shank doesn't attach as high as the Posidonia.

I'd guess the first Greenline's anchor is a Manson and have no guess for the second.

The 40 degree shank-to-fluke angle is a bit wide. Seems like a compromise between a mud and a sand anchor. In any case, I've contacted them to price it and compare against the AC-14 the we were planning to install.

Even with a weight advantage I would imagine that the 62kg Italian anchor will still price much higher than the 90kg Chinese made one, so it might not offer much of an advantage in our case. An extra 65 lbs on the nose of the boat is not much and there are times when a heavy stockless has advantages, especially when it's just sitting on the bottom with rocks that prevent penetration.

Still, will see what it prices at and hopefully it is competitive.

Hi makobuilders,

I think the important difference between the AC-14 and the PTW+ is not in the fluke angle, but in the PTW+'s extra "meat" past the pivot pin.

Imagine an anchor doing it's work on the bottom...there is always a mound of bottom material that gets piled up in front of an anchor as it sets into the bottom.

The extra metal past the pivot pin of the PTW+ would make for a higher pile, with more material, where the AC-14 might let that material slide over top as it gets pulled. My coffee sipping, navel gazing theoretical analysis of the two suggests that is what pushed the PTW+ into the SHHP classification.

If you do begin a dialogue with the makers...could you ask them what the difference is between the PTW and PTW+? From photo's on their site they appear identical.

MurrayM said:

Hi makobuilders,

If you do begin a dialogue with the makers...could you ask them what the difference is between the PTW and PTW+? From photo's on their site they appear identical.

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Just checked the PDF's for both the PTW and PTW+...the difference appears to be in the greater width (surface area) of the PTW+'s flukes as compared to a similarly weighted PTW.

Yes the surface area seems to be maximized and the flukes are thin and flat .. probably optimized for penetration. And that is significantly dependent on the ability of the anchot's weight to push the flukes down into the seabed.

This type of anchor is basically a bull dozer. Their holding power roughly dependent on the pile of seabed in front of it.

The 40 degree fluke angle is common w this type of anchor .. even 45 degres. My Dreadnought had a fluke angle of over 40 degrees and I atteched blocks w JB Weld to reduce the angle to about 37 degrees. Maybe I'll get a chance to see how it works. The Navy anchor is the most common of this type (except on ships) and I'd like to see one of those in action too.

I like the Posidiona anchor. But I like most anchors.

...and it is a welded design, so presumably one could have it made locally in stainless steel for less than a galvanized one could be shipped?

Speaking of stainless steel PTW+ anchors, Posidonia made a 2,025 Kg PTW+ SS anchor for a 180 metre mega yacht;

POSIDONIA SRL - Products > Anchors > Yacht anchors - World's biggest stainless steel anchor!

MurrayM said:

...and it is a welded design, so presumably one could have it made locally in stainless steel for less than a galvanized one could be shipped?

Click to expand...

Mmmm. I might just check that out. I like this anchor design as a complement to a rollbar style on the pulpit and a Fortress hanging on the rail for either bow or stern throw. I think you may be right about the extra meat past the pivot pin being a critical element in holding.

MurrayM said:

The extra metal past the pivot pin of the PTW+ would make for a higher pile, with more material, where the AC-14 might let that material slide over top as it gets pulled.

Click to expand...

Ok I see what you are saying now. Simply put, the fluke area is huge and the end plate at the back acts like a giant bulldozer blade, as manyboats puts it. The end plate of the AC-14 is actually streamlined and would offer little resistance when pulled. The AC does look cooler however! Would really like to see how this new anchor measures in a holding power test against other name brands.

See my high-tech side by side comparison photo below :lol:

My knuckle dragging, slope foreheaded, unibrowed understanding of such things is that a High Holding Power (HHP) anchor means you can get away with an anchor weighing 25% less than 'normal', and a Super High Holding Power (SHHP) anchor means one weighing 50% less than 'normal' will do. Normal in this case would be something like a navy anchor, I presume.

**SWEEPING GENERALIZATION ALERT**

So, if one gets the next size up from what is recommended for their vessel and the worst case winds they expect, a SHHP anchor should still be pretty light weight in the scheme of things.

MurrayM said:

My knuckle dragging, slope foreheaded, unibrowed understanding of such things is that a High Holding Power (HHP) anchor means you can get away with an anchor weighing 25% less than 'normal', and a Super High Holding Power (SHHP) anchor means one weighing 50% less than 'normal' will do. Normal in this case would be something like a navy anchor, I presume.

**SWEEPING GENERALIZATION ALERT**

So, if one gets the next size up from what is recommended for their vessel and the worst case winds they expect, a SHHP anchor should still be pretty light weight in the scheme of things.

Click to expand...

For my vessel the ABS Equipment Number (EN) calculates to 52, so a stockless Navy anchor of 120 kg is specified. For the AC-14 this can be reduced to 90 kg and for this new anchor, to 60 kg.

However in my knuckle-dragging logic this new anchor is achieving such high holding power because it is starting to resemble a Danforth, and Danforths in my experience are handicapped by poor performance during pull direction changes (wind shifts).

While the anchors shown might be pretty as stored and very practical, many anchors can be pulled up to store in a large hawse hole .

In our 90/90 a variety , 35H Danforth , 35 CQR or Bruce will come up for quiet motionless storage , and still leave the mud and gunk outboard to fall away whenever.

Even carried our 60H Danforth hurricane anchor once , but it looked like hell.

makobuilders said:

However in my knuckle-dragging logic this new anchor is achieving such high holding power because it is starting to resemble a Danforth, and Danforths in my experience are handicapped by poor performance during pull direction changes (wind shifts).

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Good point. It's easy to imagine a Rocna, Sarca Excel or Mantus pivoting while still submerged in the seabed under a wind or current shift, but hard to imagine the goings on of a PTW+ under similar circumstances.

In a worst case scenario where strong winds do a 180 degree shift (not uncommon around here in the winter when NE cold outflow winds from the continent stop and a SW storm from the ocean rolls in) I can imagine the anchor levering sideways out of its hole...would it set again right away, or would it "take a while" to sort itself out?

Hmmmm...

Re the Danforth connection I observe that the taper or angled cut of the fluke is on the inboard side of the fluke on these heavy hachors and on the outboard side on almost all Danforth types.

I suspect that the outboard splayed flukes (like the big anchors have) applies the fluke pressure over a wider area of the bottom resulting in higher HP per area of fluke.

The Navy anchor has straight flukes as does my Dreadnought. The forfjord has flukes splayed out (out from the shank line) and I'm quite sure I read that this helps the Forfjord veer or rotate w changing pull from wind and current. The change in pull direction may just cause one fluke to penetrate deeper and the other to come up out of the bottom. Eventially (if the rotating continues) the flukes will flip over and re-set. Perhaps this is part of the way the big anchors work as well. It may be considered an advantage for both the Forfjord and the big anchors in that they (with the above scenario) will keep one fluke burried while veering. The Danforth would break out completely and re-set as in an original deployment.

This may be connected to the fact that almost all Danforth types are w the stock whereas the big anchors are usually called stockless. And they are. And that is probably related to their ability to flop over keeping one fluke burried.

MurrayM said:

I can imagine the anchor levering sideways out of its hole...would it set again right away, or would it "take a while" to sort itself out?

Click to expand...

There are an awful lot of variables in that equation. Type of seabed, amount of surge being transmitted to the anchor, degree of veer, risk of the anchor picking up a rock or other piece of debris, I'm sure you're aware of all of the reasons an anchor might not reset.

The only counters to the risk I can think of are deploy more than one anchor, which can be a hassle, or maintain an anchor watch/reliable alarm so one can take immediate action should the boat veer and the anchor not re-set if it's pulled out.

Marin do you consider one fluke burried all the time "unset"?

As far as I know the best anchor for veering is the Spade. May have something to do w it's extremely low CG. Just from reading many anchor tests but most of the modern anchors veer quite well or are almost bulletproof.

I have no idea how well "stockless" anchors handle veering or reversals but I would guess quite well. The only stockless anchor I have is the Dreadnought and having used it only once all I can say is that it set instantly. But as far as I'm concerned keeping one fluke burried is not becoming un-set.

"Danforths in my experience are handicapped by poor performance during pull direction changes (wind shifts)."

Operator problem.

Mr Ogg inventor of the Danforth in his book always suggests 2 or more anchors to solve this problem.

A 12 H stern anchor , hand set ,will solve the "problem" in under 2 min of effort.

A design feature of the Posidonia anchor almost unique is the high or fwd attach point of the shank .. to the anchor. Almost all Danforths have flukes attached at the crown or nearly so. The Posidonia, Manson Ultimus (and probably others) have flukes attached much higher .. much closer to the center of the fluke area. Anchors w the shank attached to the crown like Danforths have high bending forces and probably need a very shallow throat angle to keep the flukes down and in the seabed. Can you imagine a mushroom anchor w the shank attached to the rim (outer edge) of the fluke? Would break right off if it ever set. And of course a Danforth w a 90 degree throat angle would just jack itself up and tip over.

However the ideal attach point (of the fluke) is near the center of the fluke area. Danforth anchors have light flukes and would be next to impossible to set if the shank attach point tended to lift the flukes even slightly. So their shanks are attached where 100% of the fluke weight is felt (in varying degrees) on the fluke tips.

The big stockless anchors have a crown shape that raises the back of the anchor up and and transfers downforce to the fluke tips. In addition the much greater weight puts a lot of pressure on the fluke tips. So much so (on both counts) that the attach point of the shank can be raised bringing it much closer to the center of the fluke area. The larger fluke area of the Posidonia anchor helps a lot but the shank attach point probably is the main reason the anchor is rated for SHHP status.


Re the Danforth veering an anchor test by Practical Sailor magazine (Jan 15 2001) addressed that issue directly.
West performance Rolled up 45 degrees, pivoted on one fluke
flattened. Reset in 2'
Fortress F-X 16 Swiveled very flat, crown moved very
little.
Danforth Deepset ll Did not break out flukes. Stayed buried.

Seemed the Danforth types did very well veering.

Eric-- I consider an anchor to be unset when it's not holding the boat anymore.

That's a good one Marin.

But w no wind or current your chain holds the boat w the anchor just lay'in on the bottom.

How would you like to have one of those Posidiona stockless anchors on your bow? An extra 100lbs but think of all the attention you'd get.
Seriously I wonder if these "stockless" anchors will evolve to be suitable for toy boats? It would suffer like the Bruce. Not very compatible w bow pulpits. But your faforite anchor did fairly well w that limitation. Merry Hollidays!

manyboats said:

But w no wind or current your chain holds the boat w the anchor just lay'in on the bottom.

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With no wind or current we don't need an anchor.

How would you like to have one of those Posidiona stockless anchors on your bow? !

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We've already got the world's best all-around anchor design on our pulpit. So why would we want to swap that out for something less?

It's old now Marin.
Gotta get something new.

Seriously though I have plenty of good anchors (at least the haven't dragged yet). But the potential for these "stockless anchors" to replace the anchors we now use is at least very interesting. It would be nice to know what the good and bad features of all anchors .. modern or old .. Would be. Not just a contest of the latest fad anchors. Gotta get a haircut .....

manyboats said:

Almost all Danforths have flukes attached at the crown or nearly so. The Posidonia, Manson Ultimus (and probably others) have flukes attached much higher .. much closer to the center of the fluke area.

Click to expand...

Bingo.

This makes sense, and reminded me of a snow fluke; an emergency anchor point used in mountaineering. There are two attachment points on a snow fluke which align the direction of pull to near centre, exactly what you were talking about.

https://en.wikipedia.org/wiki/Snow_protection

The crown shape of the Posidonia would have two benefits then, because of the increased amount of material piled up and the direction of pull coming from lower down in that pile.

That big square shank probably impedes penetration. I'll bet a shank cross section like a Fortress would help.

Murray I wonder what advantage those holes are in the snow fluke?
We should ask Rex.

manyboats said:

It's old now Marin.
Gotta get something new.

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Eric-- The only time I replace something old with something new is when the new something is a better design or works better than the old something. Which is the case 99.99999 percent of the time.

But in the case of anchors Pete Smith got it right the first time around; nothing since has a better design or works better on an all-around basis. So if it ain't broke, why fix it, right.

Just funn'in ya Marin,
I think I've come up w something better than the roll bar on my Supreme. I'll post some pics later. The boss and the Vulcan gave me the idea. I welded back something I cut off my XYZ .. decided it needed the ballast. Looks like we've got 10 days coming up w no rain.