Helical anchors

[ianybw]

Has anybody tried using a helical anchor for a permanent non-drying mooring? The seabed is a mixture of sharp sand, small rocks and silt.

Are they easy to screw in? Do they last? Do they even work? I heard reports of somebody managing to fix one at a depth of 20ft using a plastic drainpipe and a jack handle. Maybe they are an urban myth and a load of scrap but the idea seems better than hauling tonnes of concrete over the beach.

No need to go into details about the anchor chain offcuts from the Bismark your Uncle Mortimer stole from the naval dockyards I am more interested in whether the anchor is any better than a large lump of concrete.

Thanks in advance.

 

[cliff]

Oh God, are you brave or what - using the "A" word /forums/images/graemlins/grin.gif Now we will have a series of posts from the self appointed "ex-purts" trying to promote their ideas of what is the correct aaaa - nearly did it myself - phew! /forums/images/graemlins/grin.gif

In answer to your question, helical / screw an, an, anc... No I will resist. are extremely secure if sunk deep enough. Google for ground anch... oops nearly did it agaiin..... and you will find several informative sites.
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Artificial Intelligence is no match for Natural Stupidity

 

[William_H]

Well I have heard of them promoted here in Oz. But in that case fitted from a barge with a purpose built driving machine. They were particularly promoted as a design to get the mooring chain off the seabed to avoid damage to sea grass.

I think however that the geometry of the mooring style is all wrong. If I have a post or peg in the ground that I want to remove I force it sideways back and forth until it releases. Exactly the same kind of loads that your boat will exert. Now obviously a helical may be better and much deeper stronger. The side forces are simply over come by brute strength.

By comparison using anchors (I am not scared Cliff) the forces work to bury the anchor deeper. So while i am not so keen on concrete blocks I do think anchors are the easiest DIY mooring. regards olewill

 

[mandlmaunder]

If you mean sandscrews(which I think are the same) the simple answer is YES they work.
Depth of water is not the issue , its how long the screw is and how deep you can get it to bury .The less sticking out the better the hold and less chance of bending or pulling free.
We use two in line , both 6ft long to hold our 36 ft cat.
works very well.

 

[Twister_Ken]

Having only one tree in the garden, we use a ground screw (and an A frame) to hold up the other end of the hammock. Works well under the steady strain of my sylph like, but not sure it would like irregular loading.

 

[michael_w]

They're regularly used in the USA. The one my friends have got, is pretty big at 12' deep. Good for 60' of boat.

 

[ccscott49]

They are excellent on dry land, we used them in the army for ground anchors, for pulling tanks out of bogs, so very strong, I guess they would work in the seabed just as effectively.

 

[Blueboatman]

Sandscrews are the bees knees for diy hurricane moorings,and have proved themselves again and again.
BUT,that success includes consideration of location and installation and you would also want some sort of shock absorbing twixt screw and stemhead I would think, eg a very heavy catenary of chain or some old 3 inch ferry mooring rope with an eye in the end to go over your enormous foredeck cleat/post/winch....

 

[ianybw]

Thanks for the comments. Well I am off to make a couple of 6 footers and give them a try. How hard can it be.........

 

[Tidewaiter2]

[ QUOTE ]
Thanks for the comments. Well I am off to make a couple of 6 footers and give them a try. How hard can it be......... [/quote"

As the Bad little Girl said; "it's got to be hard to be Good" /forums/images/graemlins/grin.gif