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

[RupertW]

So I started off with anchor watches many decades ago, then moved quickly to alcohol instead. Transits followed and I still do those but those will just confirm whether you have moved when you are already awake and up in the cockpit. After that I used shallow and deep depth sounder alarms which are great, would wake me up with plenty of time in most situations but are limited where there is a very shallow slope bounded by rocks.

So now I use the Anchor! app on my phone which sits charging beside me when I sleep - it allows you to set a margin preferably longer than the chain you have out and allows you to re-centre where the anchor probably is. It works well although typically only goes off when we up anchor and motor.

Of course the real trick is anchoring technique including digging in hard in reverse (building up revs very slowly) to test the seabed. Chances are if full reverse can’t shift it then you can sleep much better, even with turning tides or changing winds.

 

[Bristolfashion]

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 .

AnchorPro (and probably others) allows you to specify distance & bearing to the anchor, which is a handy feature.

 

[Bristolfashion]

I've just remembered that AnchorPro (and again, probably others) has low battery and lost GPS fix alarms. It can also send an alert to a mobile via SMS if that's your thing i.e you're in the pub!

 

[steve yates]

Set your alarm for turn of the tide and get up and check, when happy, go back to sleep

 

[Alex_Blackwood]

So I started off with anchor watches many decades ago, then moved quickly to alcohol instead. Transits followed and I still do those but those will just confirm whether you have moved when you are already awake and up in the cockpit. After that I used shallow and deep depth sounder alarms which are great, would wake me up with plenty of time in most situations but are limited where there is a very shallow slope bounded by rocks.

So now I use the Anchor! app on my phone which sits charging beside me when I sleep - it allows you to set a margin preferably longer than the chain you have out and allows you to re-centre where the anchor probably is. It works well although typically only goes off when we up anchor and motor.

Of course the real trick is anchoring technique including digging in hard in reverse (building up revs very slowly) to test the seabed. Chances are if full reverse can’t shift it then you can sleep much better, even with turning tides or changing winds.

Just being awkward and pedantic but I thought the maritime terminology was Astern . Road vehicles go in Reverse.

 

[DangerousPirate]

Cheers for all the support of anchor alarm apps. And I think the tracking option is a really good idea so see quickly if something has changed and if I need to take action.

The issue is that the winds will be at 20kts around even at night, and I am not sure how much shelter I will get in my planned anchorages (all in the lee of land). Here in scotland it's all quiet easy with the tides, they're are not very strong at all and don't worry me. I would postpone the trip even more for calmer conditions, but it doesn't seem to quiet down, and I am watching since over a week and don't fancy paying any more.

So I will implement these ideas, and if I chicken out I can always go to nearby marinas for the night.

 

[Bilgediver]

Transits. Easy peas, no batteries required.

In a wet and windy Typhoon no transits. Also applies to a dreich night in Scotland

 

[Bilgediver]

Cheers for all the support of anchor alarm apps. And I think the tracking option is a really good idea so see quickly if something has changed and if I need to take action.

The issue is that the winds will be at 20kts around even at night, and I am not sure how much shelter I will get in my planned anchorages (all in the lee of land). Here in scotland it's all quiet easy with the tides, they're are not very strong at all and don't worry me. I would postpone the trip even more for calmer conditions, but it doesn't seem to quiet down, and I am watching since over a week and don't fancy paying any more.

So I will implement these ideas, and if I chicken out I can always go to nearby marinas for the night.

Do not forget that the first indication of dragging can be the audio alarm from the anchor chain it self It can be amazingly loud.

 

[DangerousPirate]

Do not forget that the first indication of dragging can be the audio alarm from the anchor chain it self It can be amazingly loud.

So better sleep forward then? Cause that will be right above my head.

 

[Bilgediver]

So better sleep forward then? Cause that will be right above my head.

The sound even reaches the aft cabin on a friends Westerly Tempest.

 

[RunAgroundHard]

You appear to have all the i’s dotted and t’s crossed if what you say in your OP is an honest appraisal of your skills.

If your electronics fail and it’s so black that you can’t see anything, then make a rational analysis of wind strength, current direction and quality of the bottom. Then look at your anchor chain. If it’s more or less straight up and down, not dragging, if it’s at a high angle and is jumping, snatching, maybe with associated jerks and snubs which you can feel through the chain, then you might want to get the lead line out and check what is happening to the depth. One other thing, the aspect of your boat to the wind. When I have dragged, my bow shears off down wind faster than my stern, which catches up with the bow, and then repeats.

Honestly, with what you say, you are covered, enjoy the experience. A word of caution as you are single handing, use your harness to go forward and don’t rush, trip and knock your head on any number of hard bits; that should be your concern more than dragging.

All the best.

 

[ctva]

In a wet and windy Typhoon no transits. Also applies to a dreich night in Scotland

But the sheep come down to the shore when it's dreich, so just use them as a transit. Never failed me yet...

 

[Bilgediver]

But the sheep come down to the shore when it's dreich, so just use them as a transit. Never failed me yet...

Just wish they would stand still. Can be confusing and give the wrong signals

 

[DangerousPirate]

Just wish they would stand still. Can be confusing and give the wrong signals

How do scottish shepherds know how many sheep they have in their flock? They count the feet and divide by 4.

 

[Bilgediver]

How do scottish shepherds know how many sheep they have in their flock? They count the feet and divide by 4.

Heads are in the low clouds! If I can count the legs then too close to shore.

 

[DangerousPirate]

You appear to have all the i’s dotted and t’s crossed if what you say in your OP is an honest appraisal of your skills.

If your electronics fail and it’s so black that you can’t see anything, then make a rational analysis of wind strength, current direction and quality of the bottom. Then look at your anchor chain. If it’s more or less straight up and down, not dragging, if it’s at a high angle and is jumping, snatching, maybe with associated jerks and snubs which you can feel through the chain, then you might want to get the lead line out and check what is happening to the depth. One other thing, the aspect of your boat to the wind. When I have dragged, my bow shears off down wind faster than my stern, which catches up with the bow, and then repeats.

Honestly, with what you say, you are covered, enjoy the experience. A word of caution as you are single handing, use your harness to go forward and don’t rush, trip and knock your head on any number of hard bits; that should be your concern more than dragging.

All the best.

The only thing I haven't mentioned is that I have not anchored this boat in particular before, only for 10 minutes once, and then it was flat calm anyway. It is fairly new to me.
I am limited by my chain and warp length, I got only 6m of chain and 40 meters of rope and the anchor is a bruce, which I don't have experience with. It's safe to say I am unprepared in that regard but I do my best with it. Baptism of Fire.

 

[awol]

The only thing I haven't mentioned is that I have not anchored this boat in particular before, only for 10 minutes once, and then it was flat calm anyway. It is fairly new to me.
I am limited by my chain and warp length, I got only 6m of chain and 40 meters of rope and the anchor is a bruce, which I don't have experience with. It's safe to say I am unprepared in that regard but I do my best with it. Baptism of Fire.

Good lord! You have no chance! Use the search function for "anchor" and next year when you finish reading you will know why.

 

[DangerousPirate]

Good lord! You have no chance! Use the search function for "anchor" and next year when you finish reading you will know why.

Always those dramatic people.... The amounts of times people told me I would be a goner for trying things out without being a master at it or being perfectly equipped. Still made it every time.

 

[Daydream believer]

I did try anchoring about 50 years ago. Knew I had dragged because as the boat grounded, I got tipped out of bed. At the same time the kettle fell on the floor with a frightening crash.
I looked out through the hatch, realised that I was going nowhere, so I crawled over to the opposite berth & went back to sleep ?

 

[jamie N]

Why have an anchor dragging alarm when you can obviate the need for one by deploying a CQR?