Dragging anchor

[doug748]

I often set my Bruce on a very short scope for lunch stops, in order to save on pulling up the chain. Against the odds it normally sets well and holds.
At the weekend I anchored off a local river mouth and let out the depth plus a small amount of chain. It held at first and then slowly dragged, about 200yards, throughout the afternoon. No surprise there as the tide was rising... but it did drag in silence, with no noise at all to indicate what was happening.
Reflecting on this, I conclude that the noise of an anchor drag is mainly the chain being dragged across the seabed and not the anchor at all. We are all familiar with this noise as the chain is dragged at the turn of tide.
I am not sure where all this takes us but I felt I had to share it!

 

[craigsmith]

An anchor does make some small noise when dragging, something like a spade moving in soil - no surprises - but it's nothing that will be broadcast to the boat, unless it's grinding or bouncing around on rock.

Chain rumble however is usually quite obvious, as the links create noise against each other as well as the seabed.

A snubber will eliminate most noise from chain rumble, and slow dragging will be silent, so noise can't be relied upon as an alarm.

 

[Bosunof]

Can you set an alarm on GPS for any movement?

 

[KINGFISHER 9]

Bruce? ... you don't want to use a Bruce ... you're using the wrong anchor!

Now, have you tried a .............?

/forums/images/graemlins/grin.gif

 

[Scotty_Tradewind]

what snubber would you fit and how?
Any photos?

 

[LadyInBed]

depth plus a small amount of chain.
So not much chain (if any) on the ground to make a noise!

 

[craigsmith]

[ QUOTE ]
what snubber would you fit and how?
Any photos?

[/ QUOTE ]
Just a short length of nylon and the chain slackened will eliminate most chain rumble. It needn't be the length usually required of a snubber for shock absorption, if that quality is not desired.

Try here re snubbers:
www.rocna.com/kb/Snubbers

 

[AncoraLatina]

[ QUOTE ]

<span style="color:blue"> I anchored off a local river mouth and let out the depth plus a small amount of chain. It held at first and then slowly dragged, about 200yards, throughout the afternoon. No surprise there as the tide was rising... but it did drag in silence, with no noise at all to indicate what was happening. </span>


[/ QUOTE ]

Hi Doug,

I don’t know the specific conditions of your local river mouth, but one anchor which drag in MUD ( soft ?) doesn’t make any noise !..

João

 

[wotayottie]

you were "drudging", a handy old fashioned technique for progressing up a flowing river, without engine and with little / no wind. it keeps steerage by keeping a flow of water over your rudder. so you see you were exercising inate sailing skills. it wasnt a cock up after all! /forums/images/graemlins/grin.gif

 

[Stemar]

[ QUOTE ]
what snubber would you fit and how?
Any photos?

[/ QUOTE ]Sorry, no photos - the boat's a long way off.

I made up a length (about 6 ft of 10mm for my 24 footer) of nylon rope with an eye splice at each end of a size to fit comfortably over my samson post. On one end are two hooks, one of a size for the anchor chain, the other for the mooring chain. In the middle is a rubber mooring shock absorber and a bit of hosepipe to protect the rope where it passes over the bow roller

The chain comes on board through one of the bow fairleads and is made off in the usual way. I hook the snubber far enough down the chain that the strain is taken by the snubber and lead it over the bow roller to the samson post.

Result: a peaceful sejour with no graunching from the bow roller to disturb my repose and no snatching in a chop. If the snubber were to fail, the chain would take over via the fairlead, which isn't ideal, but is fine until I can sort things out.

Pace a recent thread about GPS anchor watches, I set mine at night 'cos I expect the snubber's pretty good at silencing dragging noises!

 

[Scotty_Tradewind]

You can on most plotters.
My 4 yr old Standard Horizon CP175 sets an anchor alarm to 0.01 miles or more