SPADE Anchor Safety WARNING

[diederik]

Your SPADE anchor may be unsafe.

Mechanical failure of a SPADE Anchor was found
by the Maritime Safety Authority of New Zealand to have directly caused the
loss of the yacht "Deep Blue".

Some simple modifications can make a Spade Anchor safe. Please warn your
fellow mariners who may own such an anchor. Instructions for anchor modification, and the Maritime Safety Authority report, in the URL below.

http://www.geocities.com/spade_anchor_test

The required modifications really are very simple, and critical for safe
boating.

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[kds]

There are other opinions on this event - one posted on this forum. I do wonder what proof there is of whether the bolt did, in fact, "shear". Did they find one end sheared off ? or did they just not find the bolt or nut. In which case - was it securely fastened before being used ? No I don't own a Spade - but experience with nylock nuts would not suggest that they would come loose and the design does not seem to put much stress on the bolt. "Cobbled together" seems a bit harsh - did he think so when he bought it ? I do realise that after the experience of the previous week at sea, they are entitled to be less than open minded. Glad they all survived and share their sadness at loss of boat.
Ken

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[BrendanS]

I have an instictirve dislike of anyone who plasters the same message across many forums.. don't ask me why? but he hasn't answered a reasonable question to the same message on Mobochat

Comes across as someone with a grudge or alterntative agenda

<hr width=100% size=1>Me transmitte sursum, caledoni

 

[webcraft]

I have a Spade anchor, and find this whole incident bizarre.

The bolt does not take any of the anchoring forces when the load is on the anchor - the shank is retained in the fluke by the socket so the whole shank is the lever, with no force on the bolt. Even if there was no nut on the bolt, it is hard to see how it would come out under tension - in fact, the anchor would still stay together under tension (ie when in use) if there was no bolt there. The bolt is no more a structural part of the anchor than the seizing wire used on the shackle on your anchor chain.

The only possibility therefore - and very unlikely in my opinion - is that the bolt came out while the anchor was being deployed or was on the way to the seabed. If this was the case then it should have been immediately obvious to the skipper of Deep Blue that the anchor was not set properly - unless he just threw the anchor overboard and took no other positive action to ensure that the vessel was anchored. If so, then the accident is no-one's fault but his own.

As for the assertion on Deep Blue's website that non-one would trust their rigging to a nyloc - well, for many years I flew microlights. These are highly certified and subject to stringent regulation, and many vital parts are secured using nylocs. The main thing to remember with these nuts is that they should not be used twice. It would be interesting to know if Mr. Meenken had disassembled and reassembled this anchor at any point and, if he had, whether or not he replaced the nyloc with a new one.

I have the deepest sympathy for the crew of Deep Blue, but I think there must be more to this than meets the eye - as is also suggested in the article you can read <font size=1><A target="_blank" HREF=http://www.bluemoment.com>http://www.bluemoment.com</font size=1>

 

[MainlySteam]

I believe that Diederik may be the owner of Deep Blue but stand to be corrected on that.

This loss has come up several times and has been defended by the anchor's designer on these forums. I am not sure that it is therefore fair that another person (seemingly involved with the anchor) stating a contrary view should criticised for claiming the right to state his views as well.

Due to the continuing comments on the role of the anchor I have ordered a copy of the NZ MSA report into the loss (while Diederik infers that the report is available on the Deep Blue site I could not find it).

If anyone has a genuine interest I am prepared to scan it and email it to them - while the other reports I have do not claim any copyright, they being in the public domain, I will just need to clear that point with the MSA first. If a genuine interest just PM me and include your email address (which I will naturally respect the security of) - note that sometimes it takes a few weeks for a report to arrive from MSA.

If the report includes photos, as they often do, then the scanned copy will be a large file.

John

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[MainlySteam]

The main thing to remember with these nuts is that they should not be used twice.

While that is a valid point one assumes that the nut is there so that the anchor can be disassembled, perhaps for stowing, given its bulky shape - why have it otherwise, as if the anchor is meant to be a permanent fabrication then the bolt would be a welded or riveted in pin. To incorporate a part in an anchor which requires replacing each time you use it (use the nut that is) is not great design in my opinion because I suspect a very small percentage of boats with Spade anchors carry spare nyloc nuts for them and few know that single use is correct. Unfortunately, if the anchor is going to be disassembled, then pinning the bolt is not much better in that spilt pins have only limited use as well, but perhaps have the advantage that they are more likely to be found on board.

If failure of the bolt through loss of the nut because of more than one use of it was a factor in the accident (and I don't think anyone knows if the nut was the culprit), then my opinion is that the crew could not be expected to have foreseen that.

John

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[BrendanS]

If Diederik has an involvement in the case, then it would help if he said so, rather than just plastering warnings across all the forums. We are all grown ups here, and can make educated assessments based on facts. If there is an issue with the anchor that needs to be addressed, then fine we can all learn from it, but the original post does not come across that way

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[MainlySteam]

I agree entirely Brendan and I hope I did not infer anything different.

His approach was probably not in the style likely to readily attract the sympathy of this forum's memebers.

Regards

John

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[AlexL]

nylocks should indeed not be used twice - however if you did use one twice in that sort of application where the bolt takes no load and there is no vibration (which is what causes nuts to come undone) then it would almost definately not fail. I think there is an alternative agenda here - aparently the yacht was not insured so its useful to have someone to sue and apparently the bits were never found, so it has been assumed that it came undone - I seriously hope that the report was not written by an engineer, as no even remotely competent engineer could conclude that the nut could come undone with no load and no vibration.
And as has been said here, Nylocks hold pretty much everything airbourne together from microlights to 747's

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[MainlySteam]

I see that the MSA report is on the site Diederik mentions - it did not appear for some reason on the menu list when I looked earlier today (maybe I was temporarily blind /forums/images/icons/shocked.gif).

John

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[cpedw]

The MSA report is at
http://www.geocities.com/spade_anchor_test/MSAReport.pdf

Derek

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[MainlySteam]

Nylocks hold pretty much everything airbourne together from microlights to 747's

Which may be very well be true, but I doubt whether there is a yacht in existance that is inspected and maintained to the same level as a Boeing 747. As far as I know Boeing 747's do not get treated to the disrespect of being periodically chucked over the side in 20m of water on the end of a chain and buried in sand, mud and rocks - the average anchor is lucky if it gets anything other than a cursory glance and it should be designed for that low level of care. The comparison is spurious.

I have a situation on my boat where a nyloc nut (around 14 - 16mm, being on the belt tensioning stay bar of our services alternator) comes loose - another lock nut against it is required. So they are not infallible.

John

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[snowleopard]

a grudge or alterntative agenda

it seems that we often see a 'new user' with an axe to grind and they almost always post on every forum so presumably they are going to other sites and doing the same.

if one of the regulars on this site posted something like that we'd assume it was a friendly warning but in cases like this it seems a fair bet that it's someone trying to put a company out of business or similar intentions.

so come on diederik, who are you and why are you so keen to tell us spades are no good?

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[AlexL]

"I have a situation on my boat where a nyloc nut (around 14 - 16mm, being on the belt tensioning stay bar of our services alternator) comes loose - another lock nut against it is required. So they are not infallible."

You are quite correct, but in that use it is subject to vibration and heat - neither of which applies to an anchor


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[MainlySteam]

So I can be assured that the wings will not fall of the next 747 I fly in 'cos the nyloc nuts holding them on are only exposed to cold and no vibration.

I also have to say that I had not noticed much heat and vibration with our alternator's installation before, but now that you have inspected it on board (I guess you knew that one of our marina inhabitants has a set of keys, but I haven't worked out how you got the 747 to get you from your place to mine in a couple of hours to get them) and drawn it to my attention I will ensure that it is cooled and the vibration damped so that I can rely on the nyloc nut again /forums/images/icons/smile.gif.

Regards

John

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[AlexL]

I was just making the point that some environments are alot harsher for hardware than others - thermal expansion and contraction being one, and vibration the other. Its pretty difficult for a bolt to come undone without one or the other.

To get back to the orignal thread I cannot see any circumstance where a nyloc nut (or any nut) holding two parts of an anchor together in that configuration can possibly "come undone" unless it was never done up to start with.

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[webcraft]

Nyloc red herring

I think all this harping on about nylocs is a bit of a red herring. In twenty odd years involvement in microlighting - huge vibration from indifferentlyy mounted two-stroke engines on lightweight airframes - I've never heard of nyloc failure causing disaster - and many cheapskates DO re-use them.

I don't believe many people disassemble their Spades anyway - they are an expensive investment, and so most people will use use them as their main anchor. If you want a spare stow-flat anchor most people get a Fortress or something similar.

The scenario I postulated as being the only credible one if there is any truth in Deep Blue's story is that:

the nut must have come off
AND
the bolt then slid out
AND
the shank somehow disengaged from the socket
all WHILE
the anchor was on the way down to the seabed,
AND
that the skipper of Deep Blue then did nothing to check that the anchor had set (i.e. reversed under power or waited for the yacht to fall back and then watched for drift / taken bearings etc).

If he did not check that the anchor was set then he is primarily to blame for the disaster even assuming the shank had parted from the fluke on the way down. If this was not the case then we would all be chucking the hook over the side and going straight to the pub without checking it was set, secure in the knowledge that we could sue the anchor maker if the boat dragged.

In the unlikely (if not impossible) event that the nut / bolt failed while the anchor was set this would not result in the shank coming out. Anyone who has had a good look at a Spade would see this.

Anyone is entitled to express an opinion on these fora, but this post is obviously designed either to damage the company in question or to put pressure on them to pay some sort of compensation. You can't blame the guy . . . but you can wonder if he is being strictly honest here.

Has this post had the effect desired by the poster? Anyone else got a Spade and is worried about it after this? Anyone been put off buying a Spade as a result?

- Nick


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[Niord]

I have a Spade anchor One of the first imported into the UK,it came direct from Tunisia. I have been using it regularly for 4 years without any problems.
I have never disassembled it and when I first assembled it I thought that the bolt was a bit over the top. The shank is threaded onto the blade and fits into a tapered recess in the blade. I cannot see how the blade can be pulled off the shank unless the blade splits in two or the end of the shank breaks off. The bolt and nyloc merely stops the blade from moving up the shank towards the chain.
I read the MSA report and sincerely hope that a fuller investigation and more detaild report is produced if I ever am in a similar situation. Lets see a photo of the recovered bits.
As an asside IMHO he did not have enough scope for an all chain rode let alone a mere 10 m of chain the rope.

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[Niord]

PS to my last post I have NO connection to Spade except as a satisfied customer

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[bruce]

looked at my spade last week, no nylock nut on it either.

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