Anchors - Bigger is Better ?

[congo]

Noelex wrote:

Here are couple of photos to show the underside of tip of the Delta is convex.
It is not very curved the centre is about 1cm deeper than the outside (for a 20kg anchor).
It is less convex than the Excel and much less than the Spade or Ultra. I believe the Spade and Ultra have a completely different shape from the Excel and Delta to the underside (and topside) of their fluke.

Attached Thumbnails
Rex Wrote:

This photo of the Delta is a genuine Simson and Luarence one, no longer available, the one in the top photo with the very flat base is a unit made in China.

Regards Rex.

[Delfin]

Originally Posted by noelex 77

Here are couple of photos to show the underside of tip of the Delta is convex.
It is not very curved the centre is about 1cm deeper than the outside (for a 20kg anchor).
It is less convex than the Excel and much less than the Spade or Ultra. I believe the Spade and Ultra have a completely different shape from the Excel and Delta to the underside (and topside) of their fluke.

That is not a Delta. Give it up.

[Delfin]

Originally Posted by downunder

Delfin,

The convex undersides on the Excel, Spade and Ultra is demonstrated in these photos. All much more complex than the CQR or Delta.

Cheers

Yep. Which was my initial point. A convex toe imparts greater holding capacity than a flat toe like the lower performing Delta.

[Cotemar]

Delfin,

You really need to put your eye glasses on.

noelex 77 showed you an image of a Delta Lewmar anchor with a Convex bottom toe.

The Delta Lewmar does in fact have a Convex bottom toe.

[Delfin]

Originally Posted by Coops

Now that, is one sweeping statement.

Coops.

Oh yeah, we want to avoid sweeping, unsubstantiated statements of opinion made as if factual at all costs......

Originally Posted by noelex 77

These are exciting times for anchors with the current best anchors Rocna/MS and Spade,

[estarzinger]

Really you guys.... do you just like arguing with each other?

Lewmar publishes CAD drawings of their anchor designs right on their website.

I can't post cad here, but here is a clip from one view converted to jpg . . . you can get the full cad by going to their delta page and clicking on the "CAD Drawings" tab.

[Cotemar]

Originally Posted by noelex 77

These are exciting times for anchors with the current best anchors Rocna/MS and Spade, both having new similar designs with some tweaks from rival manufacturers (in the Mantus/Knox and the Ultra respectively)

I would have added Fortress after Spade in the above statement, since almost every cruiser has one on board as a storm 2nd anchor.

I love the tag line. Fortress is an anchor even a woman can throw.

[Cotemar]

Originally Posted by estarzinger

Really you guys.... do you just like arguing with each other?

Lewmar publishes CAD drawings of their anchor designs right on their website.

I can't post cad here, but here is one view converted to jpg . . . you can get the full cad by going to their delta page and clicking on the "CAD Drawings" tab.

Attachment 71494

That is the Delta Lewmar 3D CAD model that I rotated above to show the Convex bottom toe.

http://www.cruisersforum.com/forums/...ml#post1406781

[Delfin]

Originally Posted by Cotemar

Delfin,

You really need to put your eye glasses on.

noelex 77 showed you an image of a Delta Lewmar anchor with a Convex bottom toe.

The Delta Lewmar does in fact have a Convex bottom toe.

Well, that will come as news to Lewmar as well as the guys on the shop floor who make them, because their CAD drawings show a flat bottomed toe, just as every Delta on my dock has, and just as Noelex's photo shows.

This is what is so amazing about threads like this. People who should know better but apparently know little about a subject post objective horse puckey as fact and repeat it endless numbers of times (sometimes with colorful and emphatic font sizes) in the hope that will make it true. Fascinating.

[Delfin]

Originally Posted by estarzinger

Really you guys.... do you just like arguing with each other?

Lewmar publishes CAD drawings of their anchor designs right on their website.

I can't post cad here, but here is a clip from one view converted to jpg . . . you can get the full cad by going to their delta page and clicking on the "CAD Drawings" tab.

Attachment 71494

Beat me to it. Or, one could walk the dock and actually look at Deltas......naaaah.

[Delfin]

Originally Posted by congo

Noelex wrote:

Here are couple of photos to show the underside of tip of the Delta is convex.
It is not very curved the centre is about 1cm deeper than the outside (for a 20kg anchor).
It is less convex than the Excel and much less than the Spade or Ultra. I believe the Spade and Ultra have a completely different shape from the Excel and Delta to the underside (and topside) of their fluke.

Attached Thumbnails
Rex Wrote:

This photo of the Delta is a genuine Simson and Luarence one, no longer available, the one in the top photo with the very flat base is a unit made in China.

Regards Rex.

Rex, do you know if the original S&L Delta had better performance than the current Lewmar version? I presume Lewmar changed the toe shape in the interest of lowering manufacturing cost, but I wonder what effect it had on performance.

[estarzinger]

Originally Posted by Cotemar

That is the Delta Lewmar 3D CAD model that I rotated above to show the Convex bottom toe.

Yes . . . (and you were certainly technically right)

But does this slight convexity in the delta bottom make any difference vs a flat bottom - none of you actually know. Yet you continue to argue about it. Hey, for a while that's the internet . . . but 96 pages with almost no real content . . .come on.

96 pages mostly arguing about stuff you either have no really relevant science on (like your 'problem bend'), or making (bad) assumptions on (like rex being wrong about the anchor in Maine Sail's video).

I look at the thread because I am interested in anchors and I keep hoping for some intelligent well researched thoughtful discussion. All of you are smart guys, but you have just gotten caught in an endless cycle slugging match where none of you are being careful and checking or (apparently) thinking much about what you say.

------------------------------------------

I think JoJo's original point is interesting. If the 'next gen' anchors are in fact so much better why are recommended sizes not significantly smaller for them and why are people usually upsizing when they get one?

I don't think the mfg's here have really answered this question from their perspective . . . Rex, if your anchor is twice as good as a Supreme, rocna or delta, why do you not recommend a much smaller (half?) one than a supreme, rocna or delta does? Same question for Mantus here?

I have suggested what I think the answer is - real world anchor performance is not only about holding in good bottoms, its also about setting and about holding in less good bottoms. But I am certainly not an anchor expert.

[Delfin]

Originally Posted by JonJo

One facet to come out of this thread is that if anyone knows how the different designs work - they are keeping very quiet.

We have a unique concave anchor, Rocna, with an upturn to the back of the fluke and a roll bar. It was mentioned the upturn was to allow the seabed that was passing through the fluke to be compressed between upturn and roll bar. As far as I am aware none of the other concave anchors have this upturn and roll bar. We have the Supreme with a tight concave fluke, no upturn, and roll bar and the Mantus with a very shallow concave fluke and extremely wide roll bar. It has been suggested that the 'wideness' of the fluke and roll bar of the Mantus is to ensure there is no compression. In each of these anchors the roll bar is a self righting device, though it also serves to compress in the Rocna.

One thing the Rocna, Mantus and Supreme have in common (to a greater or lesser extent) is a 'weighted' toe - that thickened plate.

So 3 anchors all crudely classified as concave, but all apparently working differently. In fact the design characteristics of the Rocna have been completely designed out of the Mantus?

Then we have 2 more concave anchors, Bruce and Boss, no roll bar, no (apparent) compression.

And finally another 2 anchors, Spade and Ultra, with very shallow concave flukes, upturn at the rear but prominent wedged soles and weighted toes.

We have an equal diversity in convex anchors with the SARCA (or if we are to be pedantic Super SARCA) shallow convex, no weighted toe and roll bar.

Finally the Kobra and Excel, convex but with convex sole, with weighted toes.

To provide balance we also have the Fortress a superbly engineered fluke anchor that in the right seabed possibly has the highest holding capacity of any of the above anchors in terms of hold per unit anchor weight.

All of these anchors perform over most seabeds, some are possibly better than others in specific environments but if you had 2 contrasting designs you would probably have a pretty fool prove arsenal.

In addition we have 3 basic materials, gal steel, alloy and stainless - which introduce other variables, smoothness (imparting a better ability to dive?), lightness without compromising strength and then a myriad of choices of steel, mild through to high tensile.

And to add to the variables we have simple plate steel shanks, Rocna, Excel, Mantus, Kobra (some of questionable strength), very thin shanks, Boss and the hollow shanks of the Ultra (it has buoyancy?) and Spade.

But despite the design differences we really do not know how these anchors actually work - and they obviously work completely differently and possibly there are strengths and weaknesses that have not been defined.

But to classify a Spade and Rocna as the 'same' or even the Mantus and Rocna as the same looks overly simplistic.

Jonathan

That's a great overview and summary, Jon.

I still think it is useful to categorize anchors into diving and non-diving. I couldn't care less if an anchor takes 10' to bury itself to a substrate where it will not budge, and would much rather have that than a hoop style that sets immediately but has lower ultimate holding since the hoop inhibits its diving. That said, it does appear, at least based on the re-set tests done by Practical Sailor, that diving anchors like the Spade, Ultra, etc. set certainly as fast or faster than their hoop counterparts, so I don't see much of a trade off between diving and quick set ability.

Then, within those two broad categories you can decide if mild steel shanks are just as good as high tensile shanks, etc.

[Delfin]

Originally Posted by estarzinger

Yes . . .

But does this slight convexity in the delta bottom make any difference vs a flat bottom - none of you actually know. Yet you continue to argue about it. Hey, for a while that's the internet . . . but 96 pages with almost no real content . . .come on.

Someone on a prior thread (might have been you), commented that the Excel was an analog of the Delta. However, the Delta doesn't perform the same as the Excel so even though they look similar there are clearly design differences that matter in ultimate performance. So there isn't any need to argue over whether these differences matter since the question resolves itself in terms of performance. I would like to understand the 'why' of that performance, which is the reason I think the discussion is worthwhile. If not for someone else, then by all means, change the channel.

[Cotemar]

Originally Posted by Delfin

Well, that will come as news to Lewmar as well as the guys on the shop floor who make them, because their CAD drawings show a flat bottomed toe, just as every Delta on my dock has, and just as Noelex's photo shows.

WOW, even the Delta drawing you posted, shows the convex bottom toe.

Let me make it easy on your eyes.

Here is a cross section of the 3D Cad model from the same drawing you posted above.