Best method to determine position at night to check for anchor drag?

[DangerousPirate]

Going on a trip soon and the plan is to anchor overnight, which is going to be a first for me. I know the theory about scope and plan to lay out at least 4:1 and anchor in the lee, I also have a bit of anchoring experience from lunch breaks before, but the first night out, and solo on top of that, at anchor is a little scary.

So I will use some app for gps locating me and give an alarm if I go out of my swing radius, but just in case my phone dies overnight, the app doesn't work properly or something else - how do I know if the anchor holds at night? I think taking bearings is going to be very challenging in the dark (which I normally do in the daytime).

 

[KompetentKrew]

Do you have a chart plotter? I leave mine on overnight, create a new track when dropping the anchor, and you'll soon see "scribbles" as the boat reaches the end of its scope.

In the image below the wind (or tide) has come from three directions since the anchor was dropped; the wind is presently from the north, and the anchor has tripped and reset, hence the second banana shape behind the first ring.

 

[AntarcticPilot]

Many chart plotters have an anchor alarm function; it might be worth checking the manual for your plotter. Alternatively, there are phone apps. I don't use either, as I find that they tend to give false alarms when the wind or tide changes.

 

[Neeves]

Chart plotter alarms tend too be unobtrusive (maybe good when you are helm) but as some sleep in the forepeak and the Chartplotter is at helm (lots of threads on this ) - consider wiring in a pixel electric alarm - that will wake you

Better to haver a reliable anchor......

Jonathan

 

[Crinan12]

I've started anchoring fairly recently and was nervous about sleeping

The app 'anchor' has given me a lot of confidence. I find it very good/accurate and always set it when i anchor.

It's easy to use but you can download it and mess about with it at home so you know how it works before you use it on the boat.

 

[RJJ]

Amid all the talk of alarms....and in addition.

Check weather forecast. Try to understand what holding is like. Know if the tide will turn and how vigorously.

Upon arrival, set the anchor with a bit of extra scope if you can e.g. 5:1 or more. Once she has settled, back down gently at first, then at decent revs to dig in. Then if needed pull back up to 4:1.

Sit in the cockpit with your beer and gaze at the horizon. Feel the movement of the boat. See if you can relax. If so...then you'll be fine. Probably a good idea to rouse yourself at turn of tide.

The anchor alarm is a useful complement to basic seamanship.

 

[Refueler]

Have a normal alarm clock and rise at intervals through the period ... it may make you feel tired by time you lift and go on with your journey - but at least you will be sure of that night. There really is no substitute for 'Prudence'.

Anchor Watch alarms on phones - some are surprisingly good and its not hard to have your phone on a charger through the night ... if Chart Plotter has alarm - set that as well ... at least when you rise at intervals - that will then be heard if not waking you.

 

[Bristolfashion]

We anchor pretty frequently. A depth alarm on your instruments can be useful depending upon the particular anchorage.

We like to get in relatively early so we can observe the boat movement and GPS track to be sure we've set.

We find "Anchopro" good on our Android phone.

We try to anchor so that any slip is towards safety - not always possible however. As others have said, careful choice of anchorage is half the battle.

The selection of what type/size of anchor, rode and tackle is completely unimportant, any old combination will do! (Only kidding, just trying to wind up Neeves!)

 

[GHA]

but just in case my phone dies overnight, the app doesn't work properly or something else - how do I know if the anchor holds at night?

anchor pro et al apps work fine all night every night, lots of cruisers use them every night of the year. Just keep the phone charged. And keep an eye on the weather. ?

 

[Porthandbuoy]

Don’t forget the shallow and deep alarm function on your echo sounder (if you have one).
It’s also a good idea, while it’s still light enough, to take a bearing towards safe water. If you were to drag in the pitch black it helps to know which way deeper water lies.

 

[Stemar]

I use Anchor Lite.

It seems to do the job - it certainly informed me of its displeasure in no uncertain terms when I forgot to stop it leaving my anchorage!

 

[boomerangben]

Try to find out what the seabed is made of at your potential spot is and be aware of what effect this might have on your anchor

 

[awol]

If single-handed use all chain rode and sleep in the fo'c'sle - you'll soon wake up if the anchor drags. - the only reason I know for not using a snubber. Otherwise, as skipper, designate the crew to keep anchor watch if you deem dragging is likely.

 

[Rhylsailer99]

hand held Garmin GPS next to my pillar and 2 alarms set and still managed to wake up once in the middle of the channel in the Menai straits . The alarm did wake me in time to take action though and mutter a few swear words to myself.

 

[Graham_Wright]

We always take turns with anchor watch.

 

[Bilgediver]

Going on a trip soon and the plan is to anchor overnight, which is going to be a first for me. I know the theory about scope and plan to lay out at least 4:1 and anchor in the lee, I also have a bit of anchoring experience from lunch breaks before, but the first night out, and solo on top of that, at anchor is a little scary.

So I will use some app for gps locating me and give an alarm if I go out of my swing radius, but just in case my phone dies overnight, the app doesn't work properly or something else - how do I know if the anchor holds at night? I think taking bearings is going to be very challenging in the dark (which I normally do in the daytime).

I use Navionics on phone or tablet switch tracking on. You soon see if you are swinging within the normal scope pattern or wandering down wind or tide. wWhen running Navionics then turning the screen brightness down helps or plug in to charge. My Hudl 2 usually is delegated to this task.

 

[Bilgediver]

We always take turns with anchor watch.

The crew may have jumped ship or failed to sign on at port of departure.

 

[TSB240]

I think I have lost more sleep by setting a gps anchor alarm. If I do it right my brain seems to compensate by not allowing me any deep sleep!

Anchor dragging is usually a function of wind or tidal changes that cause your anchor to unset and or reset or not as may be the case. It's easier on my brain to set an alarm and be on watch for these predictable or forecast times.

The prudent will anchor such that they drag into deeper water so setting your upper and lower level depth alarms to suit your anchorage is my preffered alarm in most conditions. If I know I will drag into deeper water then the call to action in response to an alarm is not as urgent unless in a crowded anchorage.

I usually leave my VHF on at all times. Recently experienced another boat dragging nearby and was able to warn them via VHF. Judicious use of the squelch control allows you to filter calls to you from only nearby or powerful signals. Alternatively go to bed with a hand held on stand by.

 

[doug748]

Remember to set your anchor alarm from the moment the anchor hits the bottom/digs in, not when the boat has settled back anchored at rest. Else your initial position will be a misleading one and you will get loads of false alarms .

 

[capnsensible]

Transits. Easy peas, no batteries required.