Mantus Anchor "Resetting"

[model 10]

Originally Posted by Kenomac

One word: Gravity. I'm a believer in gravity... Bigger is better. Our boat weighs 25 tons, nobody is going to convince me that smaller (lighter) is a better choice... I took physics.

If I had some dinky, undersized anchor plugged up with mud, right up to its eyesore roll bar, there's no way the thing is going to dig back in. It would be like trying to dig in a small ball of mud. The Ultra doesn't have a roll bar plus the weighted tip curves downward to grab. Without the roll bar, it's able to shed the mudball over the fluke unlike the roll bar types. However, clogged with weed or grass, none of the designs will reset without first removing the debris. But again, without the roll bar, the Spade and ultra have a better chance of digging and turning like the photos of the Mantus in sand.

I get all that, we have a 53lb anchor on an 18,500 lb boat.. However, you said a heavier anchor digs in better. I think a smaller anchor would dig in just as well but just not hold as well. Not sure if that would be true of a plow type anchor but with the large surface area of something like a Rocna, perhaps.

[Andrew Troup]

Originally Posted by Guy

I'm a little confused why a larger anchor would sink/dig in better than a smaller one. A larger anchor is bigger and has more surface area. It seems like they would dig in about the same per pound. The surface area would only come into play if it was going to drag.
....

I don't know how important it is in practice, but in theory:

An anchor scaled (maintaining all the proportions) to be twice as long will have four times the fluke area but eight times the volume, and hence weight.

IOW the weight of an anchor goes up more steeply than the area.

And if you think that big anchors are necessarily different in proportions to small ones, not all anchor manufacturers would agree

[JonJo]

Originally Posted by Andrew Troup

With regard to the 'good holding' bottoms most anchors are optimised for, I sometimes wonder if we are at or near some dotted line of 'diminishing returns' in our search for raw holding power.

Not a very good analogy, I know, but we don't see that many supersonic passenger planes these days.

Pursuing narrow 'measures of merit' does not lead inexorably to nirvana.

If we had taken this attitude 15 years ago we would not have the Rocna, Ultra, Excel, Mantus, Supreme nor Boss to discuss. The choice would be CQR, Fortress, Delta, Bruce, SARCA and Spade. Some developments do not quite work, like the hydro-bubble and XYZ but that does not mean anyone should be discouraged from trying. And if we had taken this attitude 5 years ago we would not be discussing either the Mantus nor Boss. I think we are richer for not accepting that improvements cannot be made.

One reason for the demise of supersonic passenger planes was the change in the cost of fuel, one reason for the development of many new anchors has been the more cheaply available and workable HT steel.

Jonathan

[Andrew Troup]

I wrote above that according to mythology <<the makers of CQR did some tests when the success of the one-piece Bruce design started to really carve into their podium position, with the result that they came up with the one-piece Delta, which (in all their own tests) held better in practice.>>

I checked my copy of the Delta patent, and the diagram attached seems to substantiate the myth, although it's interesting (but no surprise) that they found their own CQR to provide much better holding force than the Bruce.

It's intriguing that anchor manufacturers' own tests always seem to have this 'feature'.


On the basis of these results, you'd have to wonder why they would ever have thought it would be a good idea to adopt the fixed shank of the Bruce !

[JonJo]

I spoke with Gordon Lyall who was TD at Simpson Lawrence and led the team that developed the Delta. The Delta was not actually a major priority for them and took 6 years to put together. The most lasting concept is the self righting and self launching shank - which is common on so many anchors today.

He used to give talks on the Delta locally and used a Delta and Bruce as part of his props. The party trick was to see who could catch a tennis ball in the fluke (for tennis ball read ball of mud) - no-one ever caught a tennis ball in a Delta.

Its the same debate today - nothing has changed.

Jonathan

[Coops]

Originally Posted by JonJo

If we had taken this attitude 15 years ago we would not have the Rocna, Ultra, Excel, Mantus, Supreme nor Boss to discuss. The choice would be CQR, Fortress, Delta, Bruce, SARCA and Spade. Some developments do not quite work, like the hydro-bubble and XYZ but that does not mean anyone should be discouraged from trying. And if we had taken this attitude 5 years ago we would not be discussing either the Mantus nor Boss. I think we are richer for not accepting that improvements cannot be made.

One reason for the demise of supersonic passenger planes was the change in the cost of fuel, one reason for the development of many new anchors has been the more cheaply available and workable HT steel.

Jonathan

Actually that last statement is not really viable. The fact that one of the Concordes crashed in France had most to do with it. Richard Branson is planning on bringing supersonic passenger travel to the table again as are a couple of others apparently.

Coops.

[a64pilot]

Originally Posted by Coops

Actually that last statement is not really viable. The fact that one of the Concordes crashed in France had most to do with it. Richard Branson is planning on bringing supersonic passenger travel to the table again as are a couple of others apparently.

Coops.

Coops, it is actually pretty correct, even military aircraft only run supersonic only when necessary due to the enormous increase in fuel consumption required to do so, I believe it wasn't until the F-22 until "supercruise" was even possible.
Supersonic transport of the masses will never happen in our lifetimes, you will soon see supersonic "business jets" though I bet.

The 747 was not designed to be a people carrier, it was meant to carry cargo, who would fly subsonically once the SST entered service?

Boeing 2707 - Wikipedia, the free encyclopedia

Environmental concerns pretty much killed the SST. fuel costs were the coffin nail, but unless the general public an afford to pay a min. of 400% more for airplane tickets, it just ain't gonna happen.

What did a ticket on the Concorde cost?

[Blue Crab]

Originally Posted by Andrew Troup

... Pursuing narrow 'measures of merit' does not lead inexorably to nirvana.

I made this same point to the Buddha one day and his reply was: "True Grasshopper-san, as nirvana would require no anchor whatsoever."

Following accepted practice, I then killed the Buddha.

[Andrew Troup]

Originally Posted by Blue Crab

I made this same point to the Buddha one day and his reply was: "True Grasshopper-san, as nirvana would require no anchor whatsoever."

Following accepted practice, I then killed the Buddha.

Yeah, well nobody likes a s-a ! (specially not them Talley- Bahn fellas!)

Coming back to the topic, or, as a Frenchman might say "returning to our muttons":

I had another thought the problem of those anchors which might need a bit of encouragement to remain set, while simply shuffling about.

A key to that is avoiding (to the extent possible) uplift of the shank. That's particularly hard to avoid in shallow anchorages, where catenary due to chain weight is little help.

When I was doing my field testing of a Bruce anchor decades ago (using a small one, 10kg, IIRC) to see how it handled 180deg windshifts, I found that it was rather sensitive to the weight of chain in shallow water, but the length of heavy chain could be quite short. (Incidentally, that also seems to be the remedy for the widely rumoured deficient holding, in the more general case, for Bruce anchors in small sizes)

Ever since then it has seemed to me that reversal situation is one where a heavy chain fore-runner (a short section of very heavy chain between bow-roller and windlass, if fitted) can be a big help to an anchor. A heavy section of chain in this location is much more inclined to describe a "U-turn" on the bottom, bringing the anchor with it, as opposed to delivering a straight, lifting pull at 180 degrees, like a bottle-opener.

But there's another way of achieving a similar, arguably better effect, in cases where you're vulnerable to a windshift or current reversal:

I've taken to the notion of carrying a few three-link sections of seriously large stud-link chain (in my case, 30mm; each link nearly the size of my open hand).

It gets regularly condemned; I get if for free from a local outfit which services the fishing fleet. If you expected to use it frequently you could regalvanise the short shots. If you've a heavy chain rode, paint should be fine.

The size should be chosen in consideration of the layout of your bow roller: It may NOT have to be able to pass between the sideplates ... but depending on design, it might.

I have an endless webbing sling permanently cow-hitched to one end of the short shot, using a sling long enough to then be cow-hitched to the chain near the shank of the anchor, before lowering the anchor.

A soft shackle of relatively light line can be used at the far end of the shot, or just a quick lashing, so that the entire 'ballast shot' is lifted off the bottom if the chain tries to lift.

If your bow roller is problematic, you can delay securing the 'second end' until the shot is outboard of the bow, and in this case a lashing line is preferable to a soft shackle, if your 'shot' is heavy.

On the way in, be prepared with a serrated sharp knive (as fitted to a Leatherman) to cut the lashing as it approaches the bow roller. You can then blip the shot up to the roller, then flip the bulk of it over to lie on top of the cheek plates, so it won't jam.

If conditions are torrid, you'll probably want to slice through the endless sling as well, once the shot is on the foredeck.

If major challenges are expected, there's nothing to stop you fitting more than one shot. As well as the gravity assist, the added friction with the bottom when the wind veers or backs has to be beneficial in providing a sort of 'horizontal catenary cushioning', reducing the chances of snatching the anchor from the soil.

[Coops]

Originally Posted by a64pilot

Coops, it is actually pretty correct, even military aircraft only run supersonic only when necessary due to the enormous increase in fuel consumption required to do so, I believe it wasn't until the F-22 until "supercruise" was even possible.
Supersonic transport of the masses will never happen in our lifetimes, you will soon see supersonic "business jets" though I bet.

The 747 was not designed to be a people carrier, it was meant to carry cargo, who would fly subsonically once the SST entered service?

Boeing 2707 - Wikipedia, the free encyclopedia

Environmental concerns pretty much killed the SST. fuel costs were the coffin nail, but unless the general public an afford to pay a min. of 400% more for airplane tickets, it just ain't gonna happen.

What did a ticket on the Concorde cost?

Your life on the last flight.

If my post was in error then it all shows then that it depends what you read and where you get your information from as to how accurate and factual any comment is on any subject. Unless you have done it yourself of course.

Coops.

[model 10]

Originally Posted by Coops

Your life on the last flight.

If my post was in error then it all shows then that it depends what you read and where you get your information from as to how accurate and factual any comment is on any subject. Unless you have done it yourself of course.

Coops.

OK, I came up with this myself, the Concord was to small, used to much fuel, needed to much maintenance and it had very limited routing because of the noise.

[JonJo]

Usually when planes crash, they fix the problem - the investment is sufficiently huge that the loss of a few lives is sadly not the determining feature. Fuel costs, pollution, noise and the limited routes caused (I recall primarily) by noise had already ensured the demise of Concorde. It was unsuccessful even before the crash - no interest by other carriers - but maybe they had better crystal balls.

As Andrew suggested, a bit like anchors - when something is not quite right, say like the shank, by the time it is identified there is so much invested that remedial action is taken - you do not abandon the concept.

Also a bit like anchors that pass by the wayside, if they do not have sufficient uptake because they are too expensive or they do work as well as others etc - they fall below the horizon.

Jonathan

[Andrew Troup]

Originally Posted by Guy

OK, I came up with this myself, the Concord was to small, used to much fuel, needed to much maintenance and it had very limited routing because of the noise.

Spoken like a Luddite.

These are trivial, pedestrian concerns.

Man's need for speed is unquenchable !

<insert ironic emoticon - I am paraphrasing
how this prognosis might have been received
when Concorde was the last word in modernity>

[JonJo]

Originally Posted by Andrew Troup

Man's need for speed is unquenchable !

Which is why there has been a focus on fast setting anchors? in the hope they will also become fast selling?

Jonathan

[Stu Jackson]

Andrew, isn't this essentially a kellet or sentinel?

Originally Posted by Andrew Troup

Yeah, well nobody likes a s-a ! (specially not them Talley- Bahn fellas!)

Coming back to the topic, or, as a Frenchman might say "returning to our muttons":

I had another thought the problem of those anchors which might need a bit of encouragement to remain set, while simply shuffling about.

A key to that is avoiding (to the extent possible) uplift of the shank. That's particularly hard to avoid in shallow anchorages, where catenary due to chain weight is little help.

When I was doing my field testing of a Bruce anchor decades ago (using a small one, 10kg, IIRC) to see how it handled 180deg windshifts, I found that it was rather sensitive to the weight of chain in shallow water, but the length of heavy chain could be quite short. (Incidentally, that also seems to be the remedy for the widely rumoured deficient holding, in the more general case, for Bruce anchors in small sizes)

Ever since then it has seemed to me that reversal situation is one where a heavy chain fore-runner (a short section of very heavy chain between bow-roller and windlass, if fitted) can be a big help to an anchor. A heavy section of chain in this location is much more inclined to describe a "U-turn" on the bottom, bringing the anchor with it, as opposed to delivering a straight, lifting pull at 180 degrees, like a bottle-opener.

But there's another way of achieving a similar, arguably better effect, in cases where you're vulnerable to a windshift or current reversal:

I've taken to the notion of carrying a few three-link sections of seriously large stud-link chain (in my case, 30mm; each link nearly the size of my open hand).

It gets regularly condemned; I get if for free from a local outfit which services the fishing fleet. If you expected to use it frequently you could regalvanise the short shots. If you've a heavy chain rode, paint should be fine.

The size should be chosen in consideration of the layout of your bow roller: It may NOT have to be able to pass between the sideplates ... but depending on design, it might.

I have an endless webbing sling permanently cow-hitched to one end of the short shot, using a sling long enough to then be cow-hitched to the chain near the shank of the anchor, before lowering the anchor.

A soft shackle of relatively light line can be used at the far end of the shot, or just a quick lashing, so that the entire 'ballast shot' is lifted off the bottom if the chain tries to lift.

If your bow roller is problematic, you can delay securing the 'second end' until the shot is outboard of the bow, and in this case a lashing line is preferable to a soft shackle, if your 'shot' is heavy.

On the way in, be prepared with a serrated sharp knive (as fitted to a Leatherman) to cut the lashing as it approaches the bow roller. You can then blip the shot up to the roller, then flip the bulk of it over to lie on top of the cheek plates, so it won't jam.

If conditions are torrid, you'll probably want to slice through the endless sling as well, once the shot is on the foredeck.

If major challenges are expected, there's nothing to stop you fitting more than one shot. As well as the gravity assist, the added friction with the bottom when the wind veers or backs has to be beneficial in providing a sort of 'horizontal catenary cushioning', reducing the chances of snatching the anchor from the soil.