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Old 19-07-2005, 10:04   #31
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You could use a Prusik knot (or Prussik knot, or Triple Sliding Hitch) to secure a second (smaller diameter) rope to the rode.
http://ozultimate.com/canyoning/knots/prusik/
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Old 19-07-2005, 12:37   #32
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Or you could use a rolling hitch.

http://www.42brghtn.mistral.co.uk/knots/42ktroll.html
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Old 20-07-2005, 01:20   #33
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Hey Guys,
This is my first boat with an all chain rode and the information on snubbers is priceless .... but what about a situation where you deploy 2 anchors, such as a Bahamian moor? 2 snubbers?
Bob
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Old 20-07-2005, 02:17   #34
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In my case second anchor is a chain/line rhode so no need for a snubber.

If I had a second all chain I would use a second snubber.
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Old 25-07-2005, 18:57   #35
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I just come by chance to this thread.. and I’m horrified to read some comments and suggestions!..

Please allow me to have different opinions!.

First I should introduce myself: I’m Alain POIRAUD, some of you know who I am: the designer of the SPADE anchor and also a living aboard since more than 13 years now.. and I pretend to have some knowledge and experience on this subject.. :0)

I’m not coming there to say the Spade anchor is the World best… we have never say that.. they are already enough World best..

Let’s look at these different points:
.
"The original Bruce is a good anchor. I wouldn't say the best, but still a good anchor."


Up to my opinion, the Bruce is not “the best” but, like others, it has some advantages:
- it is THE or one of the best setting anchors, and this is due to a very good study done by Peter BRUCE. It is interesting to read the original Patent of this anchor.. pages and pages talking about penetration, angles and so on.. As Alan Wheeler pointed out “This is mainly in angles and shapes of flukes and angle and shapes of the shoe/board.”..

But also as TALBOT states rightly
"Main reason for the popularity of the Bruce is not its holding power, but the easy stowage on the bow."
-

And John D was also right “The Bruce does not seem to do really well overall.” . In ALL tests I have seen, all over the world and without any exception, the Bruce was one of the worse for holding.. and on the opposite to what Alan Wheeler says, “a Bruce will hold and hold well, because of it's shape.”. No, sorry, the Bruce will set well because of it’s shape but doesn’t hold well as it doesn’t have enough surface area..

.“The Genuine Bruce was designed for the North sea oilfields.” This is only a “Pontoon Gossip” Peter Bruce has ALSO designed anchors for oilfields, but they are completely different from the “Bruce” which is used on our sailing boats.

“The Bruce is unrivalled in a soft mud bottom.”. WAOOOOOO.. I have to agree: - the poor holding of the Bruce is unrivalled in a soft mud bottom

“I am really trying to find an all-purpose anchor. “
.
Sorry but it doesn’t exist. When designing an anchor you should compromise between several factors to have an anchor which give satisfactory results in most situations. But this specific product can be exceeded in sand by a product specifically designed for sand or in soft mud by product…
Over several years, “Practical Sailor” have tested anchors in most seabeds and conditions (setting – veering etc..)
No the Spade, has not been the first in all tests.. best in holding in sand; second for setting in sand but only at the sixth position in mud… but as PS said: “The multiple-test approach and the SPADE's consistent showing, make it the first product to make two appearances on Gear-of-the-Year lists."

.“So basically... what I'm getting is that I really need to have a good variety of anchors to work in many types of bottoms that I will encounter.”
Not really, just because you will not know for sure what will be the type of the sea bottom you will anchor in.. IMHO nearly all anchors work quite well in “standard” type of bottoms.. and nearly all have problems setting in weed, and hard bottoms (hard sand, coral.. ) So, take an anchor designed for these “difficult” grounds and it will have all chances to work also in “standard” bottoms. (see "How's" of what makes a good anchor.)

"A heavy anchor is not the only answer,". Right, as lightweight aluminium anchors will have, size for size, the same holding than heavy steel anchors but at half the weight..

“The holding power of an Anchor, is not in it's size”. Again, sorry but up to my opinion, the holding power of an Anchor, is related to it's size (surface area) and to the shape of this surface (concave the best)

Now my turn to explain the "How's" of what makes a good anchor.


A good anchor must first and foremost hold, and ideally increase its holding power as forces incur heavier loads on the vessel. If the load on an anchor exceeds the holding powers of the seafloor in which it is planted, the anchor must slowly drift, conserving its maximal and constant resistance and should ideally never disengage from the seafloor.

In order to hold, an anchor must first deeply penetrate and set in the various types of seafloors

To ensure a speedy setting in virtually all types of seafloors, there are a certain number of physical characteristics to respect:

Regardless of the tool, depending on the substance, two parameters ensure good setting:
- The proper setting angle and
- The highest amount of pressure possible.

The optimal setting angle adapted for anchoring is the “wood chisel.”


Spatula Angle:

Plow anchors, once resting on a hard surface, assume a “spatula” angle with respect to the seafloor. Once the tip encounters a softer spot, it embeds by measure of its own weight to its upper apex, thereby assuming the “chisel” angle, which allows the anchor to completely embed. As previously mentioned, on a compact or weedy seafloor, the plow remains in its “spatula” angle, without setting.

Scraper Angle:
Anchors such as the old FOBs, with a bulky hind portion, tend to do a “handstand,” alighting on their flukes. At this point the flukes meet the seafloor almost perpendicularly, raking the surface without setting.


Chisel Angle:
Three principle examples of this are the Bruce anchor, the German “Bügel” anchor and the SPADE. All three approach the seafloor at an angle superior to 90 °, up to 120 °. These anchors have the reputation for rapidly setting in a majority of seafloors.

Razor Blade Angle:

This angle, superior to 150°, is typical of plate or articulating anchors (Danforth – Fortress). They necessitate contact with a sand ripple or soft area for their fluketips to pierce the seafloor surface; they then assume the chisel angle and set. On compact or weedy seafloors, these anchors shave the bottom without taking hold.

Setting Pressure:

Pressure is defined as force divided by surface area. Here, we have two variables: force (daN) and surface area (mm²). The force must be as high as possible and the surface as small as possible to maximize the pressure. A number of anchors have sharpened setting edges, as do the Fortress, the Bügel or the Spade.

The distribution of weight in the fluke tip makes sense in anchor design as it facilitates setting. We can see a great disparity amongst fluke ballasting in various anchors: The fluketips of flat anchors and the CQR comprise between 12 and 16 % of the total weight of the anchor, while the ballasted tip of the Delta contains 28% of its total weight. The best distribution of weight is the SPADE anchor, with 47% of its total weight in its point.

We can see that an anchor will tend to set more easily in the seafloor when it launches with the appropriate penetration angle coupled with the maximum pressure on its fluke tip.

Anchor Holding:

Anchor holding depends on three parameters: its surface area, the form of this surface and the anchor’s auto-stabilizing capacity, meaning its ability to stay completely embedded.

In general, plate anchors without a stabilizing stock (Britany – FOB) offer only a weak holding capacity. As soon as force upon the anchor increases, these anchors quickly rotate and disengage one fluke at a time.


Anchors with a stabilizing stock (Danforth – Fortress) are more stable since their stock prevents rotation, therefore hindering (but not preventing) the anchor from dislodging. However, once their holding capacity is exceeded, they rotate and disengage without any chance to set again.

Once set, auto-stablizing anchors (Bügel, Delta, Kobra, SPADE, and Oceane) remain fully embedded in the seafloor, their holding power limited only by the seafloor in which they are implanted. Under high load, these anchors will slowly begin to drag when they reach their maximum holding capacity without disengaging.

The larger the surface area embedded in the seafloor, the better the hold. Should the weight of an aluminium Fortress and a steel Danforth be equal, the surface area of the Fortress would be three times as large, offering the higher holding capacity.

The form of the anchor surface is also important in determining holding power. The concave shape has by far the strongest holding coefficient, followed by the flat and the convex shapes.

They are many other factors, but setting ability and holding are the most important ones.


Now, lets talk about other mooring related subjects.. where I don’t have ANY commercial interest..

Before giving my own opinion on these subjects, I will be pleased to invite those of you who want to know these points more deeply, to have a look at the very well documented Web page “Tuning an anchor rode” http://alain.fraysse.free.fr/sail/rode/rode_b.htm

"The chain plays just as important a role.".
For me the chain is the part that connects the boat to the anchor, and that’s all… OOPS sorry!.. this is also the best means to avoid shaffing of the anchor rode on the seabed..

. “The heavier chain will help to make the anchor dig in,” NO, take any anchor with a wrong penetration angle and a bad weight distribution in hard sand. You can take any chain size you want. Your anchor will NEVER penetrate.

“The chain will also play a bigger part in damping any oscillation on the anchor rode. to act as a shock absorber” .
YES True.. with only light winds when nobody cares about the anchor holding.. but as soon as the wind build up (25 to 30 knots) and when you really need damping, your chain is nearly bar tight and doesn’t procure anymore damping effect.. that’s why you should always use some nylon rode or at least a snubber.

."The chain also acts as a means of keep the attitude correct, "
No, if the anchor alone is not able to keep the correct attitude, then the chain will not make it a good anchor

."Chain is more important to the holding power than the anchor is,"

If you believe this point.. it is time for you to think about changing your anchor.. :0)
The increase of holding given by the chain itself, compared to the holding of the anchor is just negligible.. It is the anchor which give the holding and not the chain..

Peaceful anchoring to all..

Alain
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Old 25-07-2005, 20:37   #36
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Thanks Alain, that was very imformative.
If I have no objections from others here, I would like to ask you if you would share with us on how you came to the design idea's you used with your own anchor. And, what were you trying to achieve and did the idea's work as you would have liked or not.
Thanks and regards,
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Old 26-07-2005, 20:44   #37
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The Spade--a user testimonal

Alain thank for the great anchor write up and a great anchor. We use the Spade as our primary and it has yet to let us down. It has set fast and hard in every bottom from the Cheasapeake bay to Venezuela.

We are seeing more and more cruisers with one hanging on the bow as a primary. The fact that people who are out on the hook day after day are switching from the traditional loved brands to the Spade says a lot for a relatively new anchor.
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Old 26-07-2005, 21:11   #38
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Hmm, tried the SPADE once on a friends boat.
It dug in the first time and held with no dragging in a muddy bay.
Also backed down on the anchor @ nearly full astern power, it never budged.

Pretty impressed there.
What scares me is the 2 piece design with a bolt and a nut holding the 2 pieces together...Some cruising magazine had a blurb on a guy who lost his boat cause the bolt, or the nut on a SPADE corroded and let go...I am sure there is another side to that story..?
Any other reports on the 2 pieces separating?


On my boat I shoot for a "one-piece" over-kill:

A 55 lbs DELTA on a 33 CSY sailboat.
That is my lunch-hook, my working anchor and my storm anchor.
All wrapped into one big plow..

Have 215 feet 5/16 HT (G4) chain spliced onto 250 feet 3/4" three strand nylon.

I sleep really well at night when the wind picks up...And it does anytime a thunderstorm pipes up in Florida or the Bahamas, 45 knots of wind and boats left and right dragging and cursing and praying...I just roll over in bed, (bunk) and keep snoring.,..
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Old 26-07-2005, 21:58   #39
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FWIW: There’s earlier discussions of this issue at: http://cruisersforum.com/showthread....ighlight=spade
and again at:
http://cruisersforum.com/showthread....ighlight=spade
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Old 26-07-2005, 23:44   #40
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Fortress bolt together

As Gord put up above this anchor has a lot of previous discussion.

Anchor maintenance is important. I inspect the ground tackle everytime it goes up and down.

I have never heard anyone worry about the Fortress anchors. Many of theres are bolt together for easy storage.

Sorry about the rambling. Have been holed up in the boat for the last few days because of rain.
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Old 27-07-2005, 10:29   #41
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Like the current Spade, the Fortress uses “Nylok” self-locking nuts.
It should be remebered that ‘Nylok’s’ are on-time use nuts, and must be replaced, not re-used, after removal (never installed twice). Add these to your spares 'insurance' inventory (have them and you'll never use them).
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Old 27-07-2005, 20:22   #42
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Just to dredge up the issue of two piece anchors. There is nothing wrong with two piece. As long as you check the bolt and replace when needed. But think of it this way. You have hundreds if not thousands of "links" in the anchor system. The chain and the shackles and even more importantly the rope rode to chain connection for those that use rope, are all waay more prone to failure than that one bolt. So being afraid of the bolt failing is focusing your fear on the wrong item. Plus the bolt itself, doesn't take the load. It just holds the two pieces together till the anchor reaches the bottom.
Also, one failure occured(the boat going aground in ruff conditions in NZ). It has also been disccused in great lengths in many articles, the many mistakes made by the skipper in that story. I won't dredge that up again.
But from another angle, how many failures in anchoring have there been around the world, in regards to some other component including anchor not holding, being the cause of a disaster. Yet one bolt failure becomes a major issue for some reason. I scratch my head at that one.
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Old 28-07-2005, 01:41   #43
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The story of the birth of the Spade anchor...

" Alan Wheeler : - If I have no objections from others here, I would like to ask you if you would share with us on how you came to the design idea's you used with your own anchor."

Hi Alan,

Hummm.. a long story..

I could start telling you: “ After many years of intensive studies done by powerful computers and a large team of engineers.. “

First, I have a background of biomedical engineer, specialised in Heart valves prosthesis and artificial heart.. nothing in relation with anchors, except biodynamic and the need of a 100% safe product..

And also a sailor since ***teen. One day I decided to start building my own sailing boat from scratch and after 10 years of hard work, during week-ends and vacation.. I finally launch her in a river near Paris ( see: www.hylas.ws )

From there, I went down through rivers and canals to the Med and I started to sail full time.

I had a good background in sailing, and mostly racing at the French national level.. but I had very few experience of anchoring.

Following the usual advices, I took two different anchors, to be adapted to different grounds : a CQR and a Britany anchor (similar to the Danforth without the struts).

The bottom of the Med is one of the most difficult one for anchoring.. hard packed sand covered by weed.. and I started learning the anchoring technique on the hard side.. My CQR didn’t dig in and hold, most of the time.. my Britany was corkscrewing and breaking free. I tried different techniques such as “tandem set” without no more luck. And that’s why I started to look at other anchors..

At that time, it seemed to me that the Delta anchor would be a good choice.. but no Delta was available either in Greece or in Turkey where I was sailing.. But in Turkey, they are plenty of metal workers and they can do all what you want, at very low cost.. I had a very precise drawing of the Delta and I decided to try to find out the right dimensions and to make a copy, at least until I could buy a genuine one..

And I started working on my chart table, with some cardboard and a chisel, trying to find out the right proportion of the Delta.. when I suddenly realised that the Delta design was wrong and that the design should be exactly the opposite..

Using the theories of the metal cutting tools , I stated that the penetration angle of the anchor tip shouldn’t be like a spatula, but like a wood chisel, and that the maximum pressure should be distributed at the tip level.. Therefore I designed the anchor in order to have about HALF the anchor total weight distributed on the tip..

Then, using the aero-dynamical coefficients of various shapes, it was obvious for me that the blade should be concave (the highest coefficient) .. The “Spade” was born..

After testing some cardboard prototypes in dry sand, I had one steel prototype made by a small metal workshop.. (Bodrum – Turkey – 10 / 15 / 1994) and I started sailing again, anchoring with my “new – no name” anchor..

The difference was huge.. the “new anchor” setting at the first attempt and holding like hell..

At the beginning, I was not looking to make a business, but only a good anchor for myself.. but when I realised the improvement over the existing anchors, I spent the following winter in Tunisia and I took the Patents..
At the same time, I worked in relation with the Engineer School of Monastir (ENIM) to organise more “professional” tests and comparisons with existing anchors..

Then I tried to sell the patents, but despite sending proposals to a large number of nautical manufacturers; I didn’t receive any single answer.. and that’s why I finally created the “ Société de Production d’ Accastillage et Divers Equipements” (S.P.A.D.E.)

And that was only the starting point of a long, exciting and successful adventure..
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Old 28-07-2005, 04:13   #44
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Quote:
The difference was huge.. the “new anchor” setting at the first attempt and holding like hell..
Hmm, all good and nifty, but what about that little pesky bolt and that little nut that could come loose and separate all the hell-holding from the boat...?

Did ya ever consider welding the pieces together?

Maybe rubber-dinghy sailors care about taking their anchors apart to store 'em with the rolled up dinghy for minimum space in the garage, but normal boaters leave their anchors up on the bow, or in the water, year around.

No need for taking the anchor apart...?

Cheaper production?

Cheaper transportaion and shipping?

(Scratching my nogging here...Why introduce a weak link in a strong anchor..?)
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Old 28-07-2005, 12:35   #45
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Year and half on the anchor

We have been using the Spade in the Caribe for a year and a half now in every bottom. We have not had the nut loosen at all. It is checked everytime the anchor is raised or deployed.

Many cruisers use the bolt together fortress because it stores. 99% of the time there is only a need for 1 or 2 anchors. But is times of bad weather or huricanes it is good to be able to pull up and deploy additional ground tackle.

We spent Ivan in the Curacao. Some of the cruiser in Spanish Waters had 3 & 4 anchors out. Not all are carried on the bow roller, but brought up from below, assembled, and deployed.

2 verisons would be nice, but probably increase the cost.
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