Industry NB:- We want a better anchor alarm not a better anchor!

[Robin]

[ QUOTE ]
Well, if you choose to sleep at anchor in the belief that a change in the boat's motion will wake you then I wish you the best of British luck. I can only reiterate that is isn't always like that and you will often find that you only know you are dragging by looking out of the window, hearing someone call, or a crunch. I kid you not. I am perfectly prepared to believe that if anchored in a situation where there is noticeable local sea or swell, your bow might fall away enough, changing the motion, giving you warning, but it is very doubtful, and would be very unreliable.


[/ QUOTE ]

Well I'm with js48 as far as the motion of dragging is concerned. Indeed the first clue that a boat is dragging is that it lies across the wind, it may momentarily straighten up into the wind (maybe the anchor almost bites) but then off goes the bow again. I have watched hundreds of boats do this over the years. The action is very similar when you first drop the anchor, the bows pay off and the boat drops back untill the chain goes taut and the boat straightens up, that is the time to allow the anchor to 'set' and then gently at first dig it in with the engine or backed mainsail.

As far as the motion on board is concerned, there is a 'rythym' of the bows paying off in the gusts, then being brought up at the end of the swing before straightening and maybe swinging the other way, stopping and straightening again. The noise or abruptness of this motion depends on the rode (is it chain, warp, or chain plus a snubber) and the wind strength especially in the gusts. If there is a swell, with or without wind the effect is similar but the rythym is different but still regular.

We use all chain and a nylon snubber line with a rubber mooring compensator in it, we sleep in the forecabin and can sense the regular rythym of the swing and it's being absorbed (damped), albeit noiselessly, by the snubber. Any change in that rythym wakes me enough to monitor it for a few seconds before going back to sleep or getting up to check - but that is VERY rare because we haven't dragged at anchor for many many years now.

Perhaps some of us are lucky to have a 6th sense but I have never felt any need for an anchor alarm and would rather save the amps for the ice.

 

[Pye_End]

I am afraid I have to agree with Lemain from my personal experiences.

I suspect you get both situation though.

Also look at the other side of the coin - how many times do you get up in the night because the motion has changed, only to find all is well. Average 3 or 4 times for me maybe?

 

[Anonymous]

[ QUOTE ]
I am afraid I have to agree with Lemain from my personal experiences.

[/ QUOTE ] I'm sorry you're afraid but your consolation is that you're correct! /forums/images/graemlins/smile.gif

 

[oceanfroggie]

I've used a handheld Garmin GPS76 as our anchor alarm for years. Plugged into 12v beside my berth and placed by the window. Allowed us to sleep easy. Only once it did it wake us up, and that was because I set the radius too narrow, and the wind did a 180 during the night swinging her out of the safety circle. Inexpensive and effective. Also doubles as the grab bag GPS.

 

[Anonymous]

I've been wondering about that...when I set the plotter/GPS as anchor alarm we get false alarms and I have to get up to reset it. If I had one by my bed I might be able to, in effect, snooze it. It doesn't really solve the problem in crowded and small anchorages as you have to set the radius so low, but it is one of the most useful suggestions so far.

 

[Anonymous]

I've waited until now before posting details of the West Marine anchor alarm - obsolete - project details of which were first mentioned in this forum a year or so ago. Have a look at:- West Marine Anchor Alarm Project

Does anyone have any first hand knowledge of this product?

 

[oceanfroggie]

Yes if crowded though, and the wind is ok chuck out a 2nd anchor astern so she won't swing much.

 

[Anonymous]

[ QUOTE ]
Yes if crowded though, and the wind is ok chuck out a 2nd anchor astern so she won't swing much.

[/ QUOTE ]

You won't be Mr Popular if you put out a second anchor in a crowded anchorage /forums/images/graemlins/crazy.gif

 

[VicMallows]

Well, it seems it would certainly wake you up every turn-of-the-tide anywhere I know in Chi Hbr or the Solent!

Vic

 

[Anonymous]

And wind change, of course. But it depends what scope you have out and what radius you choose for the GPS alarm. Problem is that to get a worthwhile alarm radius you will get loads of alarms. What we really want is something to tell us that the anchor itself has moved by more than a preset distance.

How about this.......

Attached to the anchor is an apparatus that fires a passive transponder into the sea bed. A transmitter/receiver mounted on the anchor interrogates the transponder regularly and stays in contact via sonar with the boat. If the link between the anchor and the transponder fails you raise an alarm. The technology is very cheap - tags from the retail article protection industry. But, should we litter the sea bed with this trash? Or can we make it soluble in sea water after several months? Or can we recover the transponder? Anyway, something like that could work.

 

[Robin]

[ QUOTE ]
Also look at the other side of the coin - how many times do you get up in the night because the motion has changed, only to find all is well. Average 3 or 4 times for me maybe?

[/ QUOTE ]

Read what I said again please because I said that I wake up for just long enough to monitor the 'rythym' and only get up IF I'm concerned which is so rare I cannot remember when I last had to! Lots of other clues to the senses, like the stars seen through the hatch, or the light patterns or ...


Do you get up 3 or 4 times per night because you think you are dragging or because you ARE dragging? Either way you must be a nervous wreck for which the only cure is a marina berth!

IMO if you are going to anchor and enjoy it then you need confidence in your anchor and your anchoring technique. When we drop anchor it is with an anchor I trust, on all chain and enough of it, with a snubber to take out snatch loads and with the anchor set and holding gradually increasing to full reverse power from the engine. That plus the fact that we will have probably been there without dragging for some hours at least before going to bed means I do not expect to drag unless something significant changes in the way of wind or waves. The longer the stay the more confident you can be that all will remain well surely? A lot of folks seem under the impression that they can cause an anchor to drag just because it has got dark and they have gone to sleep!

 

[oceanfroggie]

As I said before the little GPS76 in the window beside the bed with the alarm radius set to twice the scope plus 10% has worked fine for years. Keep it simple.

Btw, I never wake up or get up to check - I get a good nights sleep (ok if there is a gale we'll watch, but we tend not to anchor in bad conditions). Agree with Robin's points 100%

 

[Ships_Cat]

A lot of folks seem under the impression that they can cause an anchor to drag just because it has got dark and they have gone to sleep!

You know anchors are nocturnal and "come out" at night like false teeth /forums/images/graemlins/smile.gif.

I go along with what you say, if the anchor is set then it is hardly likely to unset itself unless there is a significant change of circumstances. We mainly anchor in low tidal areas so most occasions is only wind changes that affect us and usually wake up (but rarely feel the need to get up) if more than a gentle change but we have never dragged.

We do always rely on the GPS anchor watch usually set 10 -20m greater than our scope and don't get annoying alarms - if we do is 'cos not set it over the drop point or lose satellites if tucked in close to hills. But we normally anchor in deepish water so takes one hell of a blow to get us out to even close to our swing radius.

I suspect if boats are so close that the GPS anchor watch is not sufficient (ie if they swinging out of concert due to lack of tide, no wind or swirling gusts) then the only solutions are to keep a watch all night or as I do tell them to piss off when they arrive (and seeing they mostly seem to be Brit's on charter yachts who don't seem to realise that one generally swings 50 - 60m or so radius in 20 m of water they do /forums/images/graemlins/smile.gif).

John

 

[Robin]

[ QUOTE ]
You know anchors are nocturnal and "come out" at night like false teeth .


[/ QUOTE ]

And next door's randy cat too! /forums/images/graemlins/smile.gif One of these days I'll be on target with the bowl of water.

Robin

 

[Ships_Cat]

/forums/images/graemlins/smile.gif

Pouring with rain here so the bowl of water could be wasted, also good anchor alarm testing weather -

Forecast
*STORM WARNING IN FORCE*
Southerly 60 knots easing to 45 knots tonight

Must be spring /forums/images/graemlins/frown.gif

Can't post a picture from the harbour entrance webcam, its seems to have dragged its anchor and disappeared.

John

 

[GMac]

And it's wet up north as well John, very wet.

I'm going to agree with Robin. Once you're tuned in to your boat small changes are easily picked up. I've never had an anchor drag without some form of warning usually the rode snatching. Never just drifted away quietly and finding it a bit hard to imagine how you could if you have set the anchor well. I'm sure there is a way but it does just not come to mind easily. NB: talking about boating people here not the cheque book newbies i.e. use 10mts of rode in 8mts of water at low tide with a 3mt range, seen that done more than once.

If asleep and the rode starts snatching I get up and let more rode out and go back to bed. More than once I've woken thinking "Opps whats happening" only to find it probably was a dream about the neigbour (I think the phrase is Yummy Mummy) or nothing at all. On the odd occasion I've sat up for a while if the weather has gone bad but never dragged without knowing. Maybe being brought up 'old school' by my fussy boating father was a good thing, no magic beep beep boxes for me. Either that or the wife is right "going bloody boating AGAIN are you" /forums/images/graemlins/mad.gif /forums/images/graemlins/mad.gif

Feel the force Luke, just feel the force /forums/images/graemlins/smile.gif

 

[Robin]

It was raining hard all night here too but it didn't stop their cat's antics, it just sheltered under our car!

Forget anchor alarms I need a cat zapper.


Robin

 

[SlowlyButSurely]

"I'm going to agree with Robin. Once you're tuned in to your boat small changes are easily picked up."

Yes, I agree with Robin too.

 

[Pye_End]

[ QUOTE ]
Do you get up 3 or 4 times per night because you think you are dragging or because you ARE dragging? Either way you must be a nervous wreck for which the only cure is a marina berth!

[/ QUOTE ]

Well not quite.

3 instances come to mind. Firsly there is one place with hard sand that I anchor in on an exposed coast. Only do it because it is close to home. Have dragged there on the turn of the tide. The tide changes the motion. I get up and generally satisfy myself that when if 25CQR breaks out it goes back in quick. Unfortunately the tide turns me by 90degrees for an hour and then the final 90 degrees. The anchor has broken out before in light winds so yes I sleep lightly here. Because of the manner in which it drags (ie in a straight line) there is no obvious 'feel' that she is dragging.

Places like Pyefleet - never dragged, but seen other do so particularly at change of tide - again even in light winds. Very often get woken up by a motion change and tend to get up to check that nobody is getting too close. No worries about dragging sleeping here, but the change in motion regularly wakes me.

Anchoring in strong winds - never sleep well because of the noise. With continual noise from chain scraping the floor, and the boat veering around by 30 degrees (therefore creating some of the feelings described by a dragging boat before), tend to get up more anyway. Never dragged in stong winds except on the sandy bottom described above.

If you sleep well through all of the above then you are luckier than me.

 

[Robin]

[ QUOTE ]
3 instances come to mind. Firsly there is one place with hard sand that I anchor in on an exposed coast. Only do it because it is close to home. Have dragged there on the turn of the tide. The tide changes the motion. I get up and generally satisfy myself that when if 25CQR breaks out it goes back in quick. Unfortunately the tide turns me by 90degrees for an hour and then the final 90 degrees. The anchor has broken out before in light winds so yes I sleep lightly here. Because of the manner in which it drags (ie in a straight line) there is no obvious 'feel' that she is dragging.


[/ QUOTE ]

Maybe the key is the combination of hard sand and just a 25lb CQR, is that a genuine CQR BTW or a copy? Unless the tide is exceptionally strong (and I would avoid such a place, especially if there was any chance of wind against tide), I am surprised that a fully dug in genuine CQR with an all chain rode would even break out and reset with the tide change, often the boat will lie to just the weight of the chain. So maybe the 25lb weight isn't enough to get the anchor to start in so it can be really dug in under power? I work on the principle that if I pull it IN with 44hp astern no little tide stream or wind will pull it out easily!

[ QUOTE ]
Anchoring in strong winds - never sleep well because of the noise. With continual noise from chain scraping the floor, and the boat veering around by 30 degrees (therefore creating some of the feelings described by a dragging boat before), tend to get up more anyway. Never dragged in stong winds except on the sandy bottom described above.

[/ QUOTE ]

We use a nylon snubber line with a rubber mooring compensator set in it, attached with a chain hook to the main chain and taken back to a foredeck cleat so that thge main chain hangs in a slack loop below it. With this even if the boat is veering +/- 30 degs there is no snatch which could 'jerk' the anchor out, nor is there any noise of chain on the bottom moving around as the soundpath is blocked by the nylon.

Sleeping at anchor is a matter of having confidence in your anchor, having adequate chain out and having set the anchor initially. As I said if it will take (in our case) 44hp in reverse and we haven't dragged during the day then why would I wake up worrying that it will drag at night?

I don't know the size of your boat, but I might not like to go as low as 25lbs with a CQR and especially not if it was not a genuine one.