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Old 03-07-2013, 06:20   #1
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Anchor Shank Length

HWMO wants to cut the shanks of our anchors a little shorter so they fit on the bow better.

What repercussions is this likely to have? I'm against the move, but don't know why. Yet.
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Old 03-07-2013, 06:52   #2
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Re: Anchor Shank Length

This guy had the same idea, but I think he went a bit too far.

What model anchor is it?

There is theory that anything you do to a CQR can only improve it (only joking CQR fans)

I would not do it.
Anchor weight distribution and balance is reasonably critical. The manufacturers would love to make shorter shanks because they could then make the blade area bigger for the same weight.

They try to keep the shanks as short as possible.

You will also experience more problems breaking the anchor out.
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Old 03-07-2013, 06:57   #3
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Re: Anchor Shank Length

It's a sand anchor, like the Fortress, but a local variety. TBF, he already did it to one, and it doesn't actually ever seem to dig in. But then again, he just tosses it over the front and doesn't do any of the engine dance that other folk seem to. It's so bloody heavy, that with the ten mil chain, we've only had it drag once in very heavy winds. That's once too many for my liking.

Now what I need is hard evidence to convince him that we need to get another anchor, and not screw around with it next time....
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Old 03-07-2013, 07:07   #4
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Re: Anchor Shank Length

My gut feeling is that shortening the shank will have less impact on a Danforth than other designs.
Hopefully the many anchor manufacturers will be along shortly and they will have a better idea.

Sounds like a good excuse to get a new anchor to me.
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Old 07-07-2013, 08:26   #5
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Re: Anchor Shank Length

Clearly wifey has no faith!!!!

It is a spade Anchor.

Theoretically spade digs in when under tension which will be the angle of the shank or chain which ever is shallower. Hence theoretically it will improve holding as shorter shank offers less resistance to soft ground so should dig in deeper and at a steeper angle - both increasing holding power!

With any fixed (not moving parts) the above obviously would not apply!


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Old 07-07-2013, 08:45   #6
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Re: Anchor Shank Length

The Spade shank is hollow (other than the very small models). It will require some work to make the chain attachment point satisfactory when it has been shortened.
I would still be concerned about the modifications altering the balance. The Spade is probably the most high tech anchor (along with the Ultra) produced at the moment and the effects of this sort of change are difficult to predict.

We don't want to see SS on the rocks we need her here at CF.
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Old 07-07-2013, 09:28   #7
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Re: Anchor Shank Length

It's not a Spade then, cos this shank isn't hollow.

Where are all the other anchor guys? I need some feedback - this is NOT a trick question to catch 'em out!!
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Old 07-07-2013, 09:41   #8
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Re: Anchor Shank Length

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Originally Posted by SaucySailoress View Post
It's not a Spade then, cos this shank isn't hollow.

Where are all the other anchor guys? I need some feedback - this is NOT a trick question to catch 'em out!!
Just spit balling here, but if shortening the shank had no adverse impact on performance, why would not all manufacturers already do it? Improved fit on the bow, less steel to buy, less steel to ship, more weight in the tip. The fact that they don't might be a sign of something. Or other.

Just saying.
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Old 07-07-2013, 09:45   #9
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Re: Anchor Shank Length

I have seen Spade anchors with solid shanks. I think it was only the smaller models, but perhaps, rather than the small models it was the early models?

Someone will know and clarify.

This is a photo of a Spade anchor, not much else has a similar appearance.

The anchor manufacturers will have tried models with shorter/longer shanks and I am sure they could make more informed comments. Brian, Greg, Rex and Ternmarine where are you....
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Old 08-07-2013, 01:15   #10
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Re: Anchor Shank Length

I would not recommend cutting the shank and shortening it.

Design calculations, while not rocket science, definitely come from another planet.

There is a fine balance between being too short and too long and upsetting the balance of the anchor and affecting the setting and digging ability of the blade.

This is where many of the cheap knock offs come unstuck and don't work because the manufacturer does not understand how critical the relationship is between the length of the shank, the angle of the blade, the weight distribution and balance of the overall design.

Either get a shape that does fit with a shorter shank or extend your bow roller out further so that it does fit with enough clearance is my recommendation.
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Old 08-07-2013, 04:23   #11
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Re: Anchor Shank Length

I'm with Noelex,

If it was meant to have shorter shank it would have one. But as its a copy I'd go with Tern - it might not be a good copy - but referring back to Noelex, the last thing they would do is use more metal if they could get away with less.

Why on earth are you using copy anchors in the first place - they seldom work You might find buying a brand name, original (of a smaller size) would work better than the copies and have a shorter shank.

Just a thought

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Old 15-07-2013, 12:58   #12
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Re: Anchor Shank Length

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Originally Posted by Delfin View Post
Just spit balling here, but if shortening the shank had no adverse impact on performance, why would not all manufacturers already do it? Improved fit on the bow, less steel to buy, less steel to ship, more weight in the tip. The fact that they don't might be a sign of something. Or other.

Just saying.
That's EXACTLY what I'm trying to find out.

It's not a Spade. We do have a Spade, but that's not the one he's shortened the shanks on. The ones he has shortened are most definitely like the Fortress anchor: Fortress Anchors – The World's Best Anchors!

I'll take a photo and post it tomorrow - it's dark here now.

Why buy copies? Cos we live in the Middle East, there are no local suppliers in Kuwait where we bought them, so we buy what's on the local market. We very rarely buy a brand name item and pay brand name prices plus exorbitant shipping when we can buy a similar item locally that probably came from the same factory in Taiwan and has simply bypassed the branding prices!
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Old 15-07-2013, 13:27   #13
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Re: Anchor Shank Length

Shank length gives leverage when lifting to break out. Shorter shank would be harder to break out. I would think cutting 10% off would be no problem.
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Old 15-07-2013, 13:38   #14
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Re: Anchor Shank Length

Sorry just assumed it was a spade anchor - have learned that spade anchors could even be ploughs! So majority from internet search it is a FLUKE ANCHOR



So assuming ground conditions are sandy / muddy anchor should land flat.

as tension comes on the end of the shank, provided it is not too short for leverage, the spades will start to dig in.

Assuming there is sufficient "holding power" in the ground it will continue to dig in until either the shank is pulled more vertically or the drag is greater than the holding power.

All that the shank length does is determine the angle of the "dig, the shorter it is the steeper the angle of dig as there is less leverage between the flukes and the chain. Too sort however then you are creating a reverse "vertical" situation where you are at risk of pulling it out or it not even digging in at all - at a guess shortening the shank considerably less than the ends of the flukes - which would be rather stupid as the probabilities increase that chain would then get tangled in the anchor!
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Old 15-07-2013, 13:41   #15
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Re: Anchor Shank Length

I bet that in the long term your peace of mind will be a LOT better if you modify your bow roller than if you modify your anchor.

I give peace of mind a lot of credit when doing things.
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