Rusty Spade anchor

Some made the point about potential explosion. This occasionally happens. It's more common where there's a little moisture involved as the expansion is so dramatically increased. (heat air and it expands a bit. Boil water and you have a pressure vessel, at least huge pressure. Imagine the pressure in a steam train - that's maybe 150C, but in zinc its 450C, so the pressure usually exceeds the ability of the hollow item to contain that pressure. So it blows apart, but does that while partly submerged in zinc. I've seen 11 tonnes of zinc erupt onto the floor from a piece of 20mm diameter pipe about 300mm long. (closed both ends)
I doubt a galvanizer would risk taking an anchor that's said to have a hollow shank without both a vent and a drain hole. (Our company would not).

On another tack, I anchored today using my new Knox. Was in 3m water, only put out 10m of chain in the water, and could not budge it no matter how hard we tried. Full astern and going nowhere (30hp, 3000 rpm)
I was very impressed. I'd have dragged a CQR about 50m like that! (and have done).
Now that's only a sample of one, I'll do more tests, but its an encouraging start.
 
Thanks Geoff for your insights. It is great to have someone experienced with galvanising who is prepared to answer questions in such detail.

I am hard on anchoring gear and have found chain and anchors can need re-galvanising in as short as 3-4 years, so it is an important issue for me.

It would also be great to hear more reports about the Knox. I have not seen one yet, but it looks like a promising design.
 
Looks like it may be even better than my Bruce for dredging up boulders and catching kelp roots That's one reason I went for the Spade along with it's compact size to pass through the bow roller and be easily man handled aboard without fouling the pulpit rails and furling gear.
 
KAM said:
Looks like it may be even better than my Bruce for dredging up boulders and catching kelp roots That's one reason I went for the Spade along with it's compact size to pass through the bow roller and be easily man handled aboard without fouling the pulpit rails and furling gear.
Click to expand...

Its a pity you do not have access, or cheap access, to an Excel. As Ponope surmised its one of the best on the table. Mind you he got one, maybe you should contact Anchor Right.

Jonathan
 
I forgot to mention that I purposely chose my test location (for the Knox) to be sand / mud. The area is known to be flat and weed and rock free.
There was a wind of about F4 adding to the pull in the initial direction. Movement was monitored by two landmarks against distant background, and also proximity to a nearby piled marker.
Anchor came up fairly clean, just a little sand/mud to wash off by "jiggling" the chain when anchor at surface.
 
When I was at BE Wedge collecting re-galvanised chain they showed me a Manson copy of a CQR that had lead cast into the enclosed tip triangle. They had asked the owner whether there was lead in there, to which he insisted there was not. When they loaded it into the zinc bath it exploded, fortunately without injuring anyone but they were less than pleased.
 
It will be the moisture in there with the lead that exploded. Can't see any good reason for the lead itself to explode.
If lead was added, there must have been a hole to get it in. And that hole would let some water in too, perhaps into the shrinkage cavities caused when the lead solidified. (shrinks in volume as it solidifies).
 
Neeves said:
The hollow shank is an issue - I think when galvanised originally the shank has an air hole at the shackle end, to allow the air out when it is dipped - you obviously need to get the inside of the shank galvanised as well as (if not better) than the outside - because you cannot see the inside and you do not want it corroding from the inside out.

Having a careful look in the shackle hole there is an air hole , along the shank axis, so the only problem would be if the hollow section is crudded up . Phil
Click to expand...
 
If its crudded up it needs cleaned. Any crud will hold salt water and accelerate corrosion. It will also affect balance.

If you anchor in mud a lot I might suggest some form of plug at the open end of the shank. We have not found it necessary.

Jonathan
 
RAP77 said:
View attachment 56818
I don't understand this talk about 'hollow' shank on a spade anchor.
I have a Spade 100 and the shank is most certainly not hollow, it is either cast or forged most probably cast see pic
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Well, like others that shank looks like no Spade I've ever seen, although the blade certainly looks fairly spade-like. Mine, and every other one I've ever seen, has the hollow trapezoidal shank Vyv mentions.
 
Most Spade anchors have the fabricated hollow triangular shaped shank. However some of the earlier smaller Spade anchors had a solid "I" beam shank a little like the new Rocna Vulcan.

It is little hard to tell from the the photo if this is genuine Spade (and this is April 1:)) but not all Spades have a hollow, fabricated shank.
 
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noelex said:
Most Spade anchors have the fabricated hollow triangular shaped shank. However some of the earlier smaller Spade anchors had a solid "I" beam shank a little like the new Rocna Vulcan.

It is little hard to tell from the the photo if this is genuine Spade (and this is April 1:)) but not all Spades have a hollow, fabricated shank.
Click to expand...

But he does say it is a 100 model, not one of the smaller ones.
 
vyv_cox said:
But he does say it is a 100 model, not one of the smaller ones.
Click to expand...

With Spades current steel anchors only the smaller S40 and S60 do not have the hollow fabricated shank, but I have a feeling that with some of the early models this was true of some of the larger sizes

Manufacturers often alter anchor models without any announcement . Sometimes the changes are to try to improve performance other times it is just a means of cost reduction. Small differences tend not to have any practical effects, but it would still be nice to know especially when it is a change that not visible such as the amount of ballast or the quality of the steel used.
 
noelex said:
With Spades current steel anchors only the smaller S40 and S60 do not have the hollow fabricated shank, but I have a feeling that with some of the early models this was true of some of the larger sizes

Manufacturers often alter anchor models without any announcement . Sometimes the changes are to try to improve performance other times it is just a means of cost reduction. Small differences tend not to have any practical effects, but it would still be nice to know especially when it is a change that not visible such as the amount of ballast or the quality of the steel used.
Click to expand...

Dreams are free :)

Small changes can have a dramatic effect. I remain interested in Fortress Chesapeake soft mud test where the Ultra and Spade performed so differently as did the Rocna and Supreme (and less surprising the Danforth and Fortress). Ostensibly similar designs but with factorially difference in performance. Similarly the Excel, ostensibly and said by some to be like a Delta, but shown by Panope in his videos as being 'one of the best on the table'. Looks are deceptive as are small differences and can lead to some making child like comment.

Jonathan
 
Small differences yes. I am sure a genuine Bruce would have done much better than the claw. Testing in one medium is good for comparing performance in that medium but no measure of a good anchor. Despite the issues discussed above the spade has worked well in some difficult situations with boulders and kelp which were sometimes a problem for my trusty old Bruce. I am sure that some of the designs in the test would fare very badly in difficult anchoring situations.
 
Totally agree.

Most anchors work well in sand (basically that's were most anchor tests are conducted) - its in the 'peripheral' seabeds, where anchors are seldom tested, that differences arise. It is useful to know which anchors work well in thin mud (and which do not) and which anchors perform better in seabeds with lots of stones and pebbles etc.

Spade is one of the standout performers, we would not leave home without one.

Jonathan
 
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