Anchor Geekdom

wick

Member
330
82
Ontario
So is that a big improvement from the Bruce? The Danforth has a bad habit of getting one oyster shell on each fluke and then refusing to dig in.
The improvement over the Bruce may be partly due to the 5kg weight increase. Weight may also be repositioned. The Bruce would sometimes dig in with only 1 fluke fully covered. Could see it pretty well at our local sand (mostly) bottom anchorage.  Did haul up a 8” round boulder once on the Bruce there on a crowded day when we were farther out. Glacial erratics I think. 

 

Saw Q

Member
109
2
Now for true anchor geeks you need to read this dissertation:

https://core.ac.uk/download/pdf/147126425.pdf

Please note the location for the research also note that the co-authors are giants in anchor research.

This is not opinion its solid research.

Kim takes a number of characteristics of anchors and devises tests to measure the impact of varying these characteristics.  Length of shank, thickness of shank, profile of shank etc etc.

To make it quick for you look at pages 169 and 170 when he looks at the optimum shank location for an unballasted fluke anchor.  Now take that optimum location and apply it to the unballasted fluke anchors available today.

Unballasted fluke anchors would include: Fortress, Danforth, Bruce, Brittany, Mantus M1, Viking, Knox, Bugel etc.  

Now....Rocna is sometime incorrectly considered an unballasted fluke anchor - the reality is that its closest relative is Spade - both are ballasted fluke anchors.  Because Rocna is a poor copy (but much cheaper to make) and does not focus or concentrate the ballast, lead vs steel, Rocna needs a roll bar. 

Much of Kim's research is not original, the optimum location of the shank of an unballasted anchor has been examined by a number of people (including Danforth and Ogg).  The value of the dissertation quoted is that Kim has looked at all the variables you could possibly imagine and collated them into one document.  Any anchor geek will already have this dissertation on file and anyone who wanted to design and market an anchor would have followed the research and incorporated the data into his calculations (especially if you were a budding anchor maker based in Houston (a centre of anchor research and recognised for excellence - internationally).

Its interesting that Bruce took the conclusions to the extreme and the crown of the Bruce is actually behind the back of the fluke.

None of this is new - its all available for free.  Kim also provides references for his work and some of those references merit serious consideration.

Cogitate over the conclusions, then look at crown location of all the unballasted fluke anchors listed (and any I have not listed) and wonder why some might step outside the norm - and importantly what are the implications of steping outside the norm.

Which all comes back to:

DEEP, GOOD.

Have a really great day.

 

Saw Q

Member
109
2
You have a favourite anchor, one you cannot hear a bad word said against it.

I'm providing you with data and illustrations that suggest your confidence might be misplaced.  The data points are not mine but from independent research - so they have no bias either way. You are fully entitled to ignore what the industry says - that is your privilege.  Others may take a different view to you as they may find the links I provide interesting and educational.

I don't think you speak for the silent majority.

So to re-emphasise the point

All, with one exception, unweighted fluke anchors have their crown at the back of the fluke.  Just look at Danforth, Fortress, Knox, Brittany, Bruce, Bugel - then look at your favourite anchor - it has the crown 30% forward from the heel and it is an unballasted fluke anchor.  Your favourite anchor sets at about 16 degrees to the seabed (because the crown is in the wrong place) whereas these other anchors have a seabed/fluke angle of 30 degrees.  Your anchor sets shallow, other anchors set deep

Now recall you have accepted: deep = good

Now go and find an example of your favourite anchor setting at a conventional 30 degrees (in sand) - you will find this impossible and I'll provide you access to hundreds of pictures of your favourite anchor set at 16 degrees.

For further evidence of the downside of shallow setting - check back for the post where I provide an independent series of tests on a Danforth type and how 16 degrees results in half the hold of an anchor at 30 degrees.

Now if this is difficult for you to understand - that is sad, very sad.

But the truth often hurts - stop dreaming ands come back to reality.

Try not to shoot the messenger - others may value the information - unless you are one of the owners of this site you are not high and almighty and are simply making more noise with no technical background to support your clamour.  Everything I post is supported by independent and unbiased conclusions - you are just arguing without any background -

What exactly are you contributing except examples of ignorance and an inability to counter unwelcome data.

But you name is apt - crabs move sideways and hide in the sand.

 

Blue Crab

benthivore
16,506
2,717
Outer Banks
You have a favourite anchor, one you cannot hear a bad word said against it.
I don't. My Rocna was stolen, I'm down to 3 Fortresses* and a bigass Danforth. I almost ordered a Mantus but held up when the Viking started testing well. My mention of the deal was a PSA. 

*I haven't measured the angle of the dangle on the Danforth but the Fortresses have 2 adjustments of the dangle which I take to be a plus tho I wait for your judgement on that.

WTF is going on with this thread? Did someone get past the gate guard into CA that should be elsewhere?
I know ... i know ... I'm leaving. I just can't stand arrogant bullshitters.

 

Saw Q

Member
109
2
I don't. My Rocna was stolen, I'm down to 3 Fortresses* and a bigass Danforth. I almost ordered a Mantus but held up when the Viking started testing well. My mention of the deal was a PSA. 

*I haven't measured the angle of the dangle on the Danforth but the Fortresses have 2 adjustments of the dangle which I take to be a plus tho I wait for your judgement on that.

I know ... i know ... I'm leaving. I just can't stand arrogant bullshitters.
Crab,  I misjudged you - I thought you were defending the indefensible.  You must have more about you than I thought - if you cancelled the idea of buying a Mantus.  Makes a change to cut through the fog and find a man of discernment.

The Fortress and Danforth both address the seabed at around 30 degrees, the Fortress has the option of 45 degrees but this is only really for soupy mud and its the one occasion when a bigger anchor, than on the spread sheet, might be a good idea - and most people out of choice will want to anchor in other locations.  Soupy mud really spoils your day unless you have a really powerful deck wash - and the kids don't like swimming there.  But you know all of this - if you have 3 + 1.  I think the Supermax also offers a variable fluke angle - but it does not get much, any?, of an airing.

Most other anchors address the seabed at 30 degrees, its found to be the optimum, though if you are a real geek and check - it varies between 25 and 35 degrees (no idea why :(   - it does not seem to have anything to do with scope but might be seabed dependent).  If you are a fanatical geek and dive on your anchor looking at the setting angle (that 30 degrees) is a good indication if you are anchor is set well (and not fouled with an oyster shell - when the angle will be lower).  The ballast alters the need for the crown to be at the back of fluke and you will find that ballasted anchors have the crown around 1/3 forward from the back, of the fluke (Spade, Rocna, Excel - I don't see Vulcans nor Epsilons so cannot comment).  Measuring the fluke angle of a ballasted anchor is an act of faith - you need to make a judgement.

 

kent_island_sailor

Super Anarchist
27,673
5,521
Kent Island!
I don't. My Rocna was stolen, I'm down to 3 Fortresses* and a bigass Danforth. I almost ordered a Mantus but held up when the Viking started testing well. My mention of the deal was a PSA. 

*I haven't measured the angle of the dangle on the Danforth but the Fortresses have 2 adjustments of the dangle which I take to be a plus tho I wait for your judgement on that.

I know ... i know ... I'm leaving. I just can't stand arrogant bullshitters.
I have a hard time trusting my Fortress. I love using it as a second anchor, and prior to getting the Bruce I never wanted to sit to just one anchor if I was going to go ashore, but what makes it great for running out in the dinghy also fights against it. The large fluke area and light weight can cause it to come right up to the surface if it pops loose :eek:

I am hoping the Bruce will do the trick for me for one anchor.

BTW - The WORST anchor I ever dealt with was a huge CQR on heavy chain in the BVIs. It tended to slide around on the bottom on its side while tricking you into thinking it was set because it was so heavy. What we ended up doing is dropping it and drifting back, then I would be overboard with a scuba tank and a tennis ball. When I was on the bottom holding the anchor point-down I would let the tennis ball go and when the crew saw the ball pop up they would back down. It was quite interesting to see and feel the anchor dig in, and also quite annoying to have to do so.

Another BTW - Do NOT confuse the Bruce and the Claw. The cheap knockoff is not as good, apparently the design is quite critical, close doesn't cut it.

 
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kent_island_sailor

Super Anarchist
27,673
5,521
Kent Island!
Seaplane anchor:

https://baltimore.craigslist.org/avo/d/stevensville-northill-sea-plane-anchor/7409952852.html

This actually looks like it would work pretty well as far as setting, the fluke area looks small though.

00n0n_jS51BYc7U9Cz_05r07g_600x450.jpg


 

Max Rockatansky

DILLIGAF?
4,031
1,099
The guy who did this to me was laying, and had been all day, to a Bruce. GOM mud. My Manson, quick-set before the storm that precipitated all this, held.

AFAIC, Bruce may be good in rock I guess, but the fluke area is too small for any serious holding. If I see someone setting one and I think I’ll be to lee, I don’t stick around to get nailed again. The Bruce design was for multiple-anchor stationery oil rigs, not for single-anchor pleasure craft.

2810E986-5280-47E4-98BE-F54FC18CC2DE.jpeg

 
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TwoLegged

Super Anarchist
5,891
2,254
Nikki and Jason of "Gone with the Wynns" have got a new Lewmar Epsilon anchor:  https://www.lewmar.com/node/20407

Video at https://www.youtube.com/watch?v=L4SsKipeG08&t=246s -- the anchor segment starts at 4m06s

They have got a stainless one, which to me seems dumb since they are dumping a 6yo stainless Mantus for fear of crevice corrosion.  They have been told that stainless anchors should be discarded after 5 years, so they are breaking down the Mantus to keep it as a backup.  But why not get the new anchor in galvanised steel, so that it has a longer life?

Has Steve tested an Epsilon?

 

kinardly

Super Anarchist
One of the anchors I was most interested in when fitting out my new to me boat was the Kobra, based on reports from Europe and Practical Sailor, but I wasn't able to get one in the US. They are distributed by Plastimo but not here, apparently. I guess that hasn't changed.

My Rocna is a second choice.

 

Saw Q

Member
109
2
With best wishes to you all for an uneventful Festive Season, stay Covid safe, take care and like all anchoring:

Be vigilant.

 

Saw Q

Member
109
2
Its the depths of winter, for most of us, and anchor fanatics don't have much to discuss so this might make a refreshing change.

https://xyzairanchor.com

I have to admire someone with the persistence to persevere with an idea and take it to the market

Discuss

 

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