Anchor - Mantus M1 (apologies for the extended opening post - don't read if you have a train to catch).

[thinwater]

The effect of angle is obvious if you have ever used a Fortress at both the 32 degree and 45 degree settings:

32 degrees. Good on firm bottoms, but not overly impressive in very soft mud.
45 degrees. Amazing in very soft mud, but will/may not set in firmer materials.

As you reduce the angle, the trend is that the anchor will set in harder bottoms and not hold as much. This is established fact. And it is on of many compromises that must be made by each manufacturer. What is the best compromise? I now return you to this anchoring thread....

-----

What I have not seen is a large anchoring study conducted since the lastest group of anchors has come out (Mantus M1 and M2, Vulcan, new Lewmar offerings, and some I've missed). I expect we will see some testing in a few years.

The other thing I can tell you about anchor testing is that it is like herding cats. The data are all over the place if you test on several bottom types. And is it about holding capacity, reset behavior, behavior on difficult bottoms, or consistency? All of these, of course. Anchor testing is hard. This is why I have focused on rigging and technique. Then I can be happy with any modern anchor.

 

[lustyd]

All this comparing of equal weight anchors ignores the fact that a large Rocna won’t disassemble for locker storage and so many would potentially carry a much smaller one than a mantus.
which raises a question for me, is there a minimum size of boat required to pull and anchor and make it set?

 

[geem]

All this comparing of equal weight anchors ignores the fact that a large Rocna won’t disassemble for locker storage and so many would potentially carry a much smaller one than a mantus.
which raises a question for me, is there a minimum size of boat required to pull and anchor and make it set?

If you see equal weight Rocna and Mantus anchors next to each other you will see how much bigger the Mantus is. I am not sure why you would want to dismantle a primary anchor to store in a locker rather than on the bow roller. If you are looking at a Rocna as a kedge then you might consider a Spade as they dismantle by removal of a single bolt so they are super quick to assemble. Something that might be preferable if you lose your main anchor and need a second anchor in a hurry

 

[lustyd]

The only time I’ve seen a mantus used was as a hurricane anchor on Sailing Uma. Looked perfect for the job to me and lived in the bottom of their locker flat until needed. Maybe their smaller Rocna would have held in the storm, but they showed a gps track and the strategy seemed to work well while other nearby boats did drag

 

[Skylark]

Simple,

I believe that holding capacity is important.

Delta, Bruce and CQR have about half the hold of most modern anchors, Spade Rocna, Excel, and members here who use the modern anchors would say that the modern anchors are more reliable, more dependable and more predictable. Mantus has roughly half the hold of a similarly sized Rocna, Spade and Excel - yet claims are made that a Mantus is better (without any objective background to define why it is better).

There is a school of thought, to which I subscribe, that hold in itself (or the absence of hold) is not the reason anchors drag - there is some other or 'intermediate' mechanism that results in anchors dragging (yawing and horsing possibly being the prime culprits). The school of though to which I refer considers that high hold results in ability (or anchors with high hold, accidentally, intentionally or fortuitously) have an ability to resist the stresses introduced by yawing and horsing and it is for this reason modern anchors are more reliable.

Consequently high hold appears to have demonstrated reliability - consequently recommending an anchor with low hold (and in the absence of any objective comment on why hold (in a specific case) does not matter) contradicts the school of thought mentioned.

I specifically question the conclusion drawn - that mantus is better than Rocna, as the comment appears to be, very, subjective and the absence of ANY comment on the unique characteristic of Mantus suggest an inability to identify key perameters undermining the conclusion drawn. Additionally the unique characteristic of Mantus, that low fluke/seabed angle has been previous identified, tests have been run and not one single manufacturer, other than Mantus, has adopted is as a standard feature - basically the industry as locked into the 30 degree angle.

If Mantus Anchor, the company, had found a unique advantage derived from their use of a low seabed/fluke angle I would expect them to use it as a marketing feature. However they might want to suppress such an invention (so that they might profit from their design and not haver it copied) but I would expect an independent evaluation of the design by a user to identify this unique characteristic and make a point of underling the advantages. There would be no need to suppress this marvellous design feature.

Jonathan

Thank you, Jonathan for taking the time to respond to my comments.

I remain of the view that anchoring has many variables hence opinions usually contain a lot of subjectivity, supposition and conjecture. Hardly surprising that it results in polarised views.

Best wishes.

 

[Neeves]

All this comparing of equal weight anchors ignores the fact that a large Rocna won’t disassemble for locker storage and so many would potentially carry a much smaller one than a mantus.
which raises a question for me, is there a minimum size of boat required to pull and anchor and make it set?

All, most?, anchor makers offer spreadsheets of anchor, their anchors, defined by weight and vessels for which they are recommended with the vessels defined by length and sometimes weight.

Many people will choose their anchor by these simple spreadsheets though there is a constant recommendation to buy bigger, than the anchor maker recommends.

The spread sheets do tend to be very simplistic as a 30' yacht might or might not have dodgers, bikinis (auto correct biminis), furling headsails or hanked on etc and all of these variables do impact the windage of the yacht.

In terms of setting the anchor small yachts tend to have smaller engines and bigger yachts bigger engines and a common practice will be to power set the anchor viz deploy the anchor, deploy scope sufficient for the anticipated condition and then ensure the anchor is securely bedded in by applying the engines in reverse. The big yacht with the big anchor usually has a big engine etc. This is all, even more, simplistic. But a typical yacht engine will allow the owner with full revs to set an anchor roughly equivalent to a 30 knot wind - the engine is unlikely to be powerful enough to simulate a stronger wind - the engines are meant to be auxiliary.

So as long as you have a typical yacht with a typical inboard motor you can set the anchor recommended for your yacht to the same depth as would occur if the yacht is subject to 30 knots of wind. Beyond 30 knots a modern anchor will commonly set more deeply, though most people will try to choose an anchorage within which they have shleter and are not exposed to winds over 30 knots - there are exceptions, but as you asked the question I don't think they will concern you, yet.

If you have a MoBo this does not apply in the same way as outboards don't follow the 'rules' I suggest.

If you oversize your anchor then you will not set it so deeply as would be possible if you had chosen the anchor of the right size. A shallow set anchor will not be so secure as shear strength of the seabed increases with the square of depth and if the anchor is side loaded by a sudden gust - it might 'pop out'. If you are in an anchorage and feel you cannot leave, because the weather has deteriorated you can deploy your second anchor - in a 'V' this will give you increased security as your yacht will not veer so much. This alone is a good reason to carry 2 anchors (and enough rope to devise a spare rode).

Your post suggests you might not have a bow roller on which to store your anchor ands that the anchor you think you should carry is too heavy to manhandle. I might suggest then that you consider an alloy anchor, Fortress or Spade (and I think there is still an FOB Lite (about which I know nothing). As Geem says a Spade only needs one bolt (which is not load bearing). But a Fortress even assembled can store flat(ish). If weight is the issue look at the Viking where weight is saved by use of High Tensile steels in the fluke. You could also look at the Lewmar LFX (I've not seen one in the flesh, or metal, but they seem to be like a Fortress - but maybe easier to assemble).

If you carry your anchor un-assembled - one day you will surely regret it - they take long to assemble long enough you might be on the rocks!

I am sure an oversize Mantus will do the job and would certainly be superior to a small 'old fashioned' design (which might drag). We have a 38' cat 7t and use only alloy anchors weighting at 8kg (they would be 15kg if steel) and we carry a FX37 for squishy mud (it is a monster). If a genuine storm forced wind event was forecast we are wimps and would scurry to the most sheltered location within striking distance and would have no hesitation in deploying our FX 37 and one of out other alloy anchors together in a 'V'. Why carry them - if you do not use them. Storms are well forecast and being a cat we can usually snuggle up to shelter. We would have made a mistake if the wind in our anchorage was of a concern. A Mantus to compete with a FX 37 would be very heavy, at least 20kg, and certainly too heavy to deploy from a dinghy.

Jonathan

 

[lustyd]

My point is that you're ignoring the existence of other use-cases outside of primary and kedge anchors. I do have a bow roller, and did on my smaller boat too, both of which were home to Delta anchors which serve the job of primary anchor very well and I see no reason to change that. While technically there may be better anchors there comes a point where good enough is good enough and the extra cost isn't justified. I've never needed a kedge anchor, and see no reason I ever will. That doesn't preclude the possibility of carrying another anchor for other times when exceptional holding is needed, as in the Uma example I mentioned. A friend of mine also carries an anchor several sizes too large for his boat too for those times when you're remote and the wind becomes exceptional. I don't want a 45KG anchor on the front of my boat all day every day, but I can certainly see some times when I'd be glad of a flat packed one in the bottom of a locker! The difference, as I said, is that a Rocna at the bottom of a locker of the same size as the Mantus would very quickly end up in the garage ashore, completely useless in an emergency because the Rocna is inconvenient to store aboard.

 

[Neeves]

I may have misinterpreted your post and thus apologise.

I think you are describing the possibility of needing a 'hurricane' anchor and you are suggesting that a large Mantus might fit the bill, because you can carry a large version and as its demountable you can store it easily. As long as you appreciate that the hold of the Mantus is no more than a similarly weighted Delta - its a sensible choice but heavy (or really heavy if you have large yacht - and thus difficult to manhandle and deploy (given that you somehow need to get it on to your bow roller.

In your specific situation I would carry either a large Fortress or a Lewmar LFX which being an unballasted fluke anchor offers considerably more hold for its area than a Mantus (if you subscribe to the idea that hold is important). I don't think the LFX is available in the really big sizes - so choice would disappear. The advantage of either of these 2 anchors is they are also light and dismantle into a much smaller pack than the Mantus. For us - we would focus on the, basically, doubling of hold for the given area. Big Fortress are used, on one of the recent Volvo races the whole fleet used them to stem an adverse tide as they passed through Storm Bay on leaving Cape Town and they have been used at Sandy Bay in Auckland Island at 50 deg south on two iterations of the Vendee Globe (and I cannot think of anything more difficult that to anchor an Imoca 60 single handed! beyond the edge of the known world!)

If that 'solution' does not fit I'd look at the Viking better hold than a Mantus (because the crown is near the heel) thus you can have a smaller anchor for the same hold but because its light for its size you get a double benefit. However I am cognisant that it will be considered a risky investment considering few know of it and fewer have used it. It dismantles similarly to a Mantus - except the bolts are not load bearing.

The other options are the aluminium Spade and the aluminium Excel - both of which are an expensive option for 'hope to never need to use' anchor.

Basically the acceptable options are the one you highlight, Mantus, or the Fortress/LFX.

Jonathan

 

[lustyd]

Thanks for clarifying - I think that addresses the topic nicely. I certainly don't have this requirement, I was just highlighting that there are scenarios where the Mantus wins over the Rocna for reasons other than pure holding power, which is less and less important as anchors advance. I'm more than comfortable with a properly sized Delta for my usage as I'm rarely out of the Solent and would probably just stay in the marina if the wind got above 30kt for the night
Personally I wouldn't consider aluminium for this as I don't like how it fails (I've seen Alu fail many times, not on anchors), but I can certainly agree with your reasoning there.

 

[JumbleDuck]

Now - I might be wrong - I’d welcome critical comment and if I am wrong - where am I wrong. I try to be impartial - if I am unwittingly wrong I’m showing bias - there is no intent to troll.

Could you possibly summarise your question in a sentence or two?

 

[Neeves]

Could you possibly summarise your question in a sentence or two?

This is the best I can do, quickly.

If you think I am wrong that a 16 degree fluke/seabed angle is a negative feature, say so. If you think a 16 degree fluke angle makes a Mantus better than a Rocna - please elaborate. Why would someone who has examined his Mantus for over 4 years, recommended it to all and sundry not mention the 16 degree fluke/seabed angle.

Jonathan

 

[noelex]

The conclusion that the fluke to seabed angle of the Mantus is less than the Rocna is not correct. The mistake is in not understanding how anchors work and set underwater. Modern anchors such as Mantus, Rocna, Spade, Ultra etc do not set in the upright position (apart from unusual substrates) they tip on to their side. Indeed this is normally called the “setting position”.

Look at these two photographs of the anchors in setting position.

First the Rocna:

Then the Mantus:

It can be seen that the angle between the fluke and seabed of the Mantus is not less than the Rocna, as has been suggested, it is steeper. The wide wings on the Mantus raise the back of the fluke and create this steeper angle. This also helps give the Mantus is very high tip weight of 50% in comparison to the Rocna at 35%, Delta 28% (the steel Spade is also very good at 47-50% ).

Commercial and oil rig anchors such as the Stockless, Stevshark etc, as well as fluke anchors such as the Danforth and Fortress all set in flat orientation. They do not tip on their side. The papers referenced discussing suitable fluke angles are for this type of anchor. Using the simple formula, anchors such as the stockess and the Fortress have significantly higher fluke angles than the Rocna. It is not that either the Rocna or the Fortress are wrong, rather the se anchors do not set in same way. So the Rocna needs a flatter fluke angle than the Fortress or stockless to work correctly. As the Rocna tips on side to set, the fluke to seabed angle is higher than the fluke shank angle, this does not apply in the same way to the Fortress. No one would suggest the stockless anchor has a higher holding power than the Rocna although the Rocna has a shallower fluke angle.

So the Mantus starts setting with a steeper fluke angle than the Rocna. As the fluke penetrates deeper (for most substrates), the material becomes significaly more compacted and firm. Unfortunately you cannot use a steep fluke angle angle on a firm substrate. If the fluke angle is too large the anchor becomes unstable and will break out. Exactly what you do not want, particularly as at this stage the anchor is already buried. Ensuring the anchor is stable when set and will not break out with changes in the direction of pull is one of the cornerstones of good yacht anchor design.

So for both the Mantus and the Rocna the fluke seabed angle starts out steeper and becomes flatter as the anchor digs in deeper. This is exactly what is wanted and is part of the reason these models work well.

It is not accurate to say the Rocna has a steeper fluke seabed angle compared to the Mantus. It is true to say the Rocna starts out a bit shallower and ends up a bit steeper although the difference is not great. If you place the two anchors side by side flat on the ground they sit almost at the same angle, but the Mantus roll bar is wider and its fluke is a little longer.

How does this work in practice? The Rocna is an excellent and very capable anchor, but as I have indicated, I have used an identically sized Rocna and Mantus extensivly with over 1500 night at anchor using each model in the same cruising area. On many of these occasions I have dived to observe the performance, as well as sustained some significant weather events with both models. In my view the Rocna is excellent, but the Mantus M1 is slightly better.

I received the Mantus initially at no charge to test, but I insisted (even though this not required) on paying normal retail price for the anchor at the conclusion of the test to maintain my absolute independence from any anchor manufacturer.

Finally a word of caution. The Rocna and Mantus M1 are very similar designs. They work in the same way. The above comments highlight some of the minor differences, but they both excellent anchors and the differences are small. Also be aware the slightly better (in my view) performance of the Mantus M1 comes at a cost. The Mantus is significantly wider, the fluke is longer and more tapered and the shank is longer. This makes the Mantus M1 more difficult to fit on some boats.

If you have lasted this long you have:
a) Certainly now missed your train
b) Must be a true anchorholic

 

[Neeves]

Thanks for clarifying - I think that addresses the topic nicely. I certainly don't have this requirement, I was just highlighting that there are scenarios where the Mantus wins over the Rocna for reasons other than pure holding power, which is less and less important as anchors advance. I'm more than comfortable with a properly sized Delta for my usage as I'm rarely out of the Solent and would probably just stay in the marina if the wind got above 30kt for the night
Personally I wouldn't consider aluminium for this as I don't like how it fails (I've seen Alu fail many times, not on anchors), but I can certainly agree with your reasoning there.

You can bend any anchor if you try hard enough.

I did just that:

Anchor Tests: Bending More Shanks - Practical Sailor

I bent the shank of the Fortress, replace under their no questions asked policy. The flukes did not bend.

I bent the shank of a steel Spade, I have seen other Spade anchors with the shank destroyed.

Mantus shanks bent, not be me, they were warned the shanks should not be based on mild steel - they learnt and replaced with a 800 MPa steel. I have seen Mantus with a cracked toe, where the weld is located in the toe and seen the front half of a Mantus slightly bent.

If you has asked me I would have said the toe of a Rocna was bullet proof - a British yacht in Honfluer had bent the toe over the 'area' of the ballast.

I totally destroyed an aluminium Excel, they re-engineered the fluke and a replaced the shank with the 7075 alloy of aluminium. We are still using the model with which the damaged anchor was replaced.

I bent the shank of a SARCA the shank of these models was replaced with a 800 MPa steel.

Jonathan

 

[Neeves]

The conclusion that the fluke to seabed angle of the Mantus is less than the Rocna is not correct. The mistake is in not understanding how anchors work and set underwater. Modern anchors such as Mantus, Rocna, Spade, Ultra etc do not set in the upright position (apart from unusual substrates) they tip on to their side. Indeed this is normally called the “setting position”.

Look at these two photographs of the anchors in setting position.

First the Rocna:

Then the Mantus:

It can be seen that the angle between the fluke and seabed of the Mantus is not less than the Rocna, as has been suggested, it is steeper. The wide wings on the Mantus raise the back of the fluke and create this steeper angle. This also helps give the Mantus is very high tip weight of 50% in comparison to the Rocna at 35%, Delta 28% (the steel Spade is also very good at 47-50% ).

Commercial and oil rig anchors such as the Stockless, Stevshark etc, as well as fluke anchors such as the Danforth and Fortress all set in flat orientation. They do not tip on their side. The papers referenced discussing suitable fluke angles are for this type of anchor. Using the simple formula, anchors such as the Fortress have significantly higher fluke angles than the Rocna. It is not that either the Rocna or the Fortress are wrong, rather these anchors do not set in same way. So the Rocna needs a flatter fluke angle than the Fortress to work correctly. As the Rocna tips on side to set, the fluke to seabed angle is higher than the fluke shank angle, this does not apply in the same way to the Fortress.

So the Mantus starts setting with a steeper fluke angle than the Rocna. As the fluke penetrates deeper (for most substrates), the material becomes significaly more compacted and firm. Unfortunately you cannot use a steep fluke angle angle on a firm substrate. If the fluke angle is too large the anchor becomes unstable and will break out. Exactly what you do not want, particularly as at this stage the anchor is already buried. Ensuring the anchor is stable when set and will not break out with changes in the direction of pull is one of the cornerstones of good yacht anchor design.

So for both the Mantus and the Rocna the fluke seabed angle starts out steeper and becomes flatter as the anchor digs in deeper. This is exactly what is wanted and is part of the reason these models work well.

It is not accurate to say the Rocna has a steeper fluke seabed angle compared to the Mantus. It is true to say the Rocna starts out a bit shallower and ends up a bit steeper although the difference is not great. If you place the two anchors side by side flat on the ground they sit almost at the same angle, but the Mantus roll bar is wider and its fluke is a little longer.

How does this work in practice? The Rocna is an excellent and very capable anchor, but as I have indicated, I have used an identically sized Rocna and Mantus extensivly with over 1500 night at anchor using each model in the same cruising area. On many of these occasions I have dived to observe the performance, as well as sustained some significant weather events with both models. In my view the Rocna is excellent, but the Mantus M1 is slightly better.

I received the Mantus initially at no charge to test, but I insisted (even though this not required) on paying normal retail price for the anchor at the conclusion of the test to maintain my absolute independence from any anchor manufacturer.

Finally a word of caution. The Rocna and Mantus M1 are very similar designs. They work in the same way. The above comments highlight some of the minor differences, but they both excellent anchors and the differences are small. Also be aware the slightly better (in my view) performance of the Mantus M1 comes at a cost. The Mantus is significantly wider, the fluke is longer and more tapered and the shank is longer. This makes the Mantus M1 more difficult to fit on some boats.

If you have lasted this long you have:
a) Certainly now missed your train
b) Must be a true anchorholic

I'd suggest you are obfuscating - or .....?

Please explain why every image in your thread shows the 'long' of the shank of the Mantus horizontal which clearly is as result of the fluke being at 16 degrees. Please also show a Rocna with its fluke buried and the anchor sy of the symmetrical - then compare the two - how they engage with the seabed does not reflect how they are orientated when they 'lock up'.

Jonathan

 

[vas]

I really feel I should look for help, medical help I mean, maybe after all I'm an anchorholic as I keep on coming back for more anchor fights...
OK, I'm not a native EN speaker, although I believe I'm reasonably good after 40odd years at it.
Could someone explain preferably with a comparison of proper side elevation drawings where are these elusive differences in these 16 vs 30or whatever degrees?
How do you measure them? anchors look rather similar...
I'm very confused!

V

Disclaimer:
I also do own a lunch hook sized Mantus (following noelex thread on CF in spite Neeves ditching them...) 20kg for a f/b 43ft 11t mobo (couldn't afford anything bigger!).
Happy at up to 35kn tested on a few occasions chain held by winch alone as well but always with a stern rope to the rocks behind...

 

[stephen_h]

I really feel I should look for help, medical help I mean, maybe after all I'm an anchorholic as I keep on coming back for more anchor fights...
OK, I'm not a native EN speaker, although I believe I'm reasonably good after 40odd years at it.
Could someone explain preferably with a comparison of proper side elevation drawings where are these elusive differences in these 16 vs 30or whatever degrees?
How do you measure them? anchors look rather similar...
I'm very confused!

V

Disclaimer:
I also do own a lunch hook sized Mantus (following noelex thread on CF in spite Neeves ditching them...) 20kg for a f/b 43ft 11t mobo (couldn't afford anything bigger!).
Happy at up to 35kn tested on a few occasions chain held by winch alone as well but always with a stern rope to the rocks behind...

If you want some further real world information (as well as the excellent Noelex thread on CF) have a look at Panope. He has a Youtube channel and can be found on CF. He does a lot of testing of different anchors and films them setting etc. So far his results match those of Noelex so I would ignore all this angle stuff and look for real world experience and proof!

 

[noelex]

How do you measure them? anchors look rather similar...
I'm very confused!

No , you are not confused, this observation is quite accurate.

The fluke shank angles of the Mantus and Rocna are very similar. When placed side by side they are almost identical.

All new generation anchors set while on their side and this enables them to employ a variable fluke to seabed angle as they dig down into the substrate. The idea is the fluke to seabed angle flattens as the anchor dives. This ensures the initial penetration is steep but flattens, as is should do as the substrate becomes firmer with depth.

Firmer substrates require flatter fluke to seabed angles otherwise the anchor becomes unstable. Even a well set anchor will break out if the fluke to seabed angle is too large. This is clearly shown in many anchor studies. The second reference quoted in the first post states that “A fluke angle greater than the critical angle generates instabilities” and also notes “it may be simply stated that stability is synonymous with safety.”

Modern anchor design philosophy is geared to producing anchors with large fluke areas combined with a concave shape to ensure high resistance. Skid plates (Rocna) and wings (Mantus) help ensure the initial angle attack is large, but as the anchor buries and encounters a firmer substrate the fluke to seabed angle should flatten keeping the anchor stable and at low risk of breaking out. This is especially important in designing a versatile anchor that can cope with wide range of substrates and one that can stay firmly engaged if the direction of pull changes.

An unstable anchor occurs when the fluke to seabed angle is too large for the firmness of the substrate. This is very detrimental and will cause even a well set anchor to break out. Both the Rocna and the Mantus and many other modern anchors such as the Spade accomplish this design criteria well. The differences as noted above are small, but the Mantus starts slightly steeper than the Rocna and and ends a little flatter.

So apologies for another long winded post. Anchor discussions on YBW sadly have a history of evolving into personal attacks. Personally, I think this is very detrimental to the quality of the information and the integrity of the Practical boat owner forum and I normally limit my input to this type of thread.

However, I have been observing anchors underwater for several decades. While everyone is entitled to their opinion it is amazing to me that someone could view my photos of the Mantus and come to the conclusion that the anchor is performing anything other than superbly. To repeatedly express the view that these images show the Mantus performing poorly is simply incorrect and this deserves to be challenged in the strongest way.

I would urge everyone look at the images yourself and draw your own conclusions.

 

[NormanS]

That's an interesting take on fluke angles, and how they start off steeply, and reduce as the shank levels. Just for devilment, might I point out that the exact opposite is the case with Danforth/Fortress types.

 

[vas]

No , you are not confused, this observation is quite accurate.

...snip...

I would urge everyone look at the images yourself and draw your own conclusions.

thanks, although it doesn't really help me in deciphering this dispute (if I'm allowed to call it as such)
I've seen lots of pics (many from your thread in CF), checked prices and thus decided to buy a Mantus (was on offer though).
I'm v.often anchoring after a few hours motoring session midday so once wife or son or whoever jumps in to get the line to the rocks/trees/whatever, on turning the engines off, it's time for a swim (N.Aegean). I v.often, not everytime, have a look (or rather try to have a look) at the set anchor. Cannot be bother with mask/gogles just open eyes in clear waters (often anchor at <10m) so I can easily trace my chain back to someplace that it typically disappears, would need a proper mask, fins and dive to see the rollbar in most cases. TBH, that's enough for me...
FWIW, digging the anchor in is done with both engines in reverse and on idle, enough to have the anchor under the sea bed in our typical sand/mud seabeds.
still intrigued and will try to find line drawings in side elevation and compare the two!

cheers

V.

 

[noelex]

Sorry, duplicate post deleted.