Anchor Alarms?

[Rustic Charm]

Originally Posted by estarzinger

Look . . . I have used both iPhone and iPad navigation 1000nm out at sea. They worked, they very definitely have GPS Chips. But if you want to believe yours does not, that's just perfectly fine also.

dude! Take a chill pill. Life's to short and the world to small to have a hemroid over a chat forum.

I haven't been questioning whether it does nor does not have GPS. That's pretty well confirmed with Apple. What I'm questioning is the reliability of GPS on iPad, iPhone. And it seems that the GPS inbuilt is dependent somehow on the cell connection. BUT, you get it working fine 1000miles out, fantastic. Not sure why I can't get it to work in my back yard with the sim pulled out then. Maybe the satalites like you more than me.

[Palarran]

I'll illustrate one of the situations where an anchor alarm really helped me.

In Croatia there is a popular island called Hvar and the main town, also called Hvar. It is really crowded in the summer so there are a lot of boats anchored outside of the semi-protected harbor. The water depth is around 60 to 70' and we had no visability of the bottom. We dropped about 220' of chain down and set the anchor late in the afternoon.

Around midnight a Bora started to blow at 35 to 40 knots and kicked up a nice chop across the bay. We did start to drag towards the small island in the picture. Not only did we start to drag, but about every boat in the bay and harbor did also. Many of you have seen this situation where everyone's lights come on at the same time, spotlights are shining and even some are yelling to wake up neighboring boaters. It was very packed, enough so that even with the wind we could yell to our neighbors.

We didn't drag very far, maybe 40 or 50' then I let out all my chain (300') and stopped. Why I liked the alarm is that it alerted us quickly that we where moving slowly and allowed me to verify that letting out more chain stopped the dragging. All I had to do was reset the distance and confidently went back to bed.

Not everyone in this bay had an anchor alarm set and none of the boats dragged onto shore. Almost everyone woke up when the wind started gusting and their boat started dragging. I don't really think this is some special skill that is only learned by spending 40 years of cruising. Why I like a reliable anchor alarm is without it we have to stay up all night on watch or sleep very restlessly waiting to "feel" the boat moving. In regard to the "feel", that's not 100% either as Kenomac just experienced. Certainly a slow drag can happen in deep water where the movement of the anchor on the bottom is dampened by the time it hits the roller and goes unnoticed.

We also use it when stern tied to shore because there isn't very much room for error. In many of the bays it if very deep right up to shore and there are boats slid in one after another. Enough that you actually do need fenders not just in case. We set ours with a very small radius round the boat so if for some reason one of the lines are cut on a rock or the anchor should drag, we are warned.

I don't understand the mentality that one shouldn't need it, or if you do, your not a seasoned mariner. For those of us who have used the Vesper Watchmate it's probably unanimous 100% trust in the system. Why would you not take the 30 seconds of time to set it every time and sleep worry free?

My son pulls our tender up out of the water every night. A lot of friends will ask "why" and the answer is simple - we have never regretted pulling it up, but we have regretted not. That is again why we set the anchor alarm every time we anchor, regardless.

[monte]

Ted I Don't have a SIM card or wifi connection. If I turn on my anchor app and walk 10 m to the bow, the gps follows me and the location dot moves. I walk back, it follows me, it's very accurate. Simple. The extra software apple refers to is apps. Short for application software...
Also the compass works. If yours doesn't work take noëlex's advice and check your settings and if all fails your hardware.

[Rustic Charm]

Originally Posted by monte

Ted I Don't have a SIM card or wifi connection. If I turn on my anchor app and walk 10 m to the bow, the gps follows me and the location dot moves. I walk back, it follows me, it's very accurate. Simple. The extra software apple refers to is apps. Short for application software...
Also the compass works. If yours doesn't work take noëlex's advice and check your settings and if all fails your hardware.

I'm aware of what 'apps' stands for thanks!
I'm glad you can put your faith in it. Good for you.
Me, I'll stick to my chart plotter alarm and external GPS antenna. So far it's never failed me. During the day, I've now tried my wife's ipad as well as mine and my iPhone 4s. As soon as I pull the sim, I loose the ability of tracking. Perhaps it's the Navionics software.. But regardless, I'll stick with the chart plotter.

[GALAWA]

Apple Ipads come in several versions .
Marketing folks misleadingly mention GPS features of Ipads which have no GPS chip inside but use GSM base station data to compute an approximate position.
I did return my own Ipad when I found that it had none of the claimed GPS feature and got an Ipad with GPS proper and 3G modem (GPS chip and 3Gmodem come together in Ipads)

[noelex 77]

Originally Posted by estarzinger

How many times a year, or a decade, do you drag?

Since I have been cruising full time, with the Rocna I dragged once in 5 years and before that with my CQR copy I dragged lots (it was a remarkably consistent anchor - it never dragged below 30 knots, but never held above 45 knots). My previous sailing was only intermittent cruising (a couple of months a year) and there were only a few drags.

My solution to the problems with the CQR copy was not to rely on an anchor alarm, but to get a better anchor. For the residual risk that remains with the best gear, an anchor alarm is a good insurance policy.

When a good anchor is used with sound technique and judgment, the risk of dragging is low, but the consequences are serious. Personally I see the cost/benefit ratio of the anchor alarm strongly in favour of setting this warning each time I anchor.

If we compare the cost/benefit ratio of other safety equipment and practices, I believe the anchor alarm would compare favourably. I carry a life-raft, EPIRB, PLBs etc. I have only been on one yacht that sank (fortunately not mine) and that is one more than most people have experienced. Nevertheless, I buy and maintain this equipment despite an extremely small chance that it will be needed. I clip on offshore despite never having experienced a MOB. I have never even met a sailor that has mentioned a genuine MOB on a cruising yacht (although in my racing days there were a few). In contrast, most cruising sailors that anchor consistently have scary dragging stories.

It is also important to realise that people starting cruising, or on a boat that anchors infrequently, will drag far more often than we do. The rates of boats dragging even in anchorages with private cruising boats is abysmal. When I dive on anchors and see anchors performing poorly or set in bad substrates I do worry for their wellbeing. I often hope they have an anchor alarm set up. So forgive me for labouring my belief that an anchor alarm should be used.

[noelex 77]

Originally Posted by rwidman

Instead of tying the trip line to the buoy, run it trough the buoy (this assumes a ring of some sort on the buoy) and small weight to the end. The weight will keep the line pretty much vertical over the anchor. Of course it's important that the weight be small enough not to trip the anchor loose.

Yes, that is a good option, but it does not eliminate the problem of the boat traveling directly over the top of the anchor, as can happen.

The incident with the anchor float was in Croatia, which is virtually non tidal and there was not much slack in the trip line rope. I don't use an anchor float often, but I have solved this problem with a weak link below the surface, but still in a position where the rope prior to the weak link can be accessed if the trip line needs to be used. Other solutions are to lead the trip line back along the anchor chain.

The greatest danger of unexpected dragging is not these bizarre events, but just unusual substrate problems. Only a few days ago I anchored on sheet rock thinking it was sand. A small fissure could have conceivably held my full reverse setting and test force, but let go with a slight change in wind direction.

A drag in only light wind would have been possible on the smooth rock despite my oversized anchor and adequate scope etc

[StuM]

Originally Posted by tedsherrin

I'm aware of what 'apps' stands for thanks!
I'm glad you can put your faith in it. Good for you.
Me, I'll stick to my chart plotter alarm and external GPS antenna. So far it's never failed me. During the day, I've now tried my wife's ipad as well as mine and my iPhone 4s. As soon as I pull the sim, I loose the ability of tracking. Perhaps it's the Navionics software.. But regardless, I'll stick with the chart plotter.

Get an android device

I've used the GPS capabilities of several android phones and tablets many miles out of cell phone range and never had a problem.

[estarzinger]

Originally Posted by Palarran

For those of us who have used the Vesper Watchmate it's probably unanimous 100% trust in the system.

Well, I in fact have a vesper!

I mentioned it in a post above. I turn either it or the furuno on if I want to see a 'cloud' of track points to watch what the boat is doing.

The vesper is nice kit but as an anchor alarm it only can 'drop' the anchor where the boat is. It does not have the capability (unless its been added since I updated my firmware) to place it's anchor waypoint where the anchor actually is (as some of the iphone apps do). This will lead to false positive alarms. Also if I want to see 'the cloud' of track points in relation to the land detail, I use the plotter rather than the vesper.

You can in theory activate the vesper, while you are lowering the anchor; but #1 this is not very practical double handed unless the unit is mounted at the helm (ours is not, it is mounted in the nav station, and that is a whole another discussion) and not very practical at all single handed (as I have been the past few years), and #2 even if you do that you probably still don't always get the anchor way point where the anchor actually is because if it is at all windy you will be moving as you lower the anchor and even once the anchor hits the bottom that is not necessarily where it will set. The anchor can very easily end up set 50' away from where you were lowering it down.

I believe I have access to almost every anchor alarm available. My current favorite is "Anchor!" on the ipad. It does allow you to place the anchor waypoint where you think it actually is, but I still get false positives with it, from a couple different sources.

Originally Posted by Palarran

Why would you not take the 30 seconds of time to set it every time and sleep worry free?

#1 I personally find that fatigue is the greatest enemy of safety and I find that false alarms increase fatigue.

#2 You can make this 'why don't you just have it' case you are making for almost every piece of purported safety gear. My opinion, perhaps based on being at the KISS end of the spectrum, is that one should make a hard noised risk/value assessment before adding gear and tasks to routine procedure. And for me, the risk/value assessment says very clearly no, not every time I drop the anchor, for anchor alarms. I just simply don't drag 'unexpectedly' more than about once a decade.

#3 and in those few cases of 'unexpected dragging', most often an anchor alarm would not have helped in any case - the last time was in Newfoundland a couple years ago where the anchor let go suddenly after holding for 2 days, we dragged back very quickly for about 2 boat lengths and then it caught firmly again. I knew full well when the anchor let go because the boat turned sideways, and the boat re-caught before I had time to do anything other than get on deck.

Originally Posted by noelex 77

Only a few days ago I anchored on sheet rock thinking it was sand. A small fissure could have conceivably held my full reverse setting and test force, but let go with a slight change in wind direction.

Except, it the real world, it did not. And even if it had you would have dove on the anchor and seen what was going on.

Again, I see this sort of reasoning time and again for purported safety gear. You can always construct some hypothetical scenario where you might really want it. But (I think) you really have to make a 'real world' assessment of the risk/value, not make up hypothetical cases. Otherwise you end of with a pile of mostly useless gear on board (or going to a stupid war).

But if you like and are happy with your anchor alarm - that's terrific. All power to you. I am just annoyed by the perspective that 'everyone should use one, you must be stupid not to'.

[noelex 77]

Originally Posted by estarzinger

even if you do that you probably still dont get the anchor way point where the anchor actually is because if it is at all windy you will be moving as you lower the anchor and even once the anchor hits the bottom that is not necessarily where it will set.

That will tend to make it better not worse. (Unless it takes 2x longer to set than the distance between the bow and the GPS aerial). The key to a reliable anchor alarm with no false positives is to have the centre of the alarm over the anchor.

With a unit that does not allow you to do this independently you have to adopt a fudge where you record the waypoint, move backwards the distance between the bow and GPS aerial and drop the anchor in this spot. It is not a very satisfactory solution. This assumes instant setting. If the anchor takes some distance to set you need to drop the anchor earlier to allow for this. The position does matter because the error is doubled on the other side of circle.

It also seems that the anchor alarm apps are giving many more false positives than my marine unit. Perhaps the lack of an external aerial is part of the problem with a multi-path error, or perhaps there are some software glitches and conflicts that are occasionally triggering the alarm.

With my anchor alarm false positives are very rare. The only time they occur is when I set very tight parameters on the alarm because the anchorage has very little room.

Oh and when I forget to turn off the alarm and leave the anchorage

[estarzinger]

Originally Posted by noelex 77

Only a few days ago I anchored on sheet rock thinking it was sand. A small fissure could have conceivably held my full reverse setting and test force, but let go with a slight change in wind direction.

Except, it the real world, it did not. And even if it had, we know you would have dove on the anchor and seen what was going on.

Again, I see this sort of reasoning time and again for purported safety gear. You can always construct some hypothetical scenario where you might really want it. But (I think) you really have to make a 'real world' assessment of the risk/value, not make up hypothetical cases. Otherwise you end of with a pile of mostly useless gear on board (or going to a stupid war).

But if you like and are happy with your anchor alarm - that's terrific. All power to you.

In the big picture I am annoyed by (what I think is) the 'safety gear" fallacy (and 'fear based' marketing/assessments). I think it is a poor decision making process, and does the community a dis-service. (really you should tether up and clip on EVERYTIME you go on deck by this same logic). Specifically re anchor alarms, I disagree with the perspective that 'everyone should use one, why every would you not, you must be stupid not to'. I personally think there are very good reasons for me not to 'every day', as there are good risk/value reasons for me not to carry a defibrillator, and for me not to clip in every time I go on deck. If you want to do these things, perfect. But do realize I have tested almost all the available gear, and reached a (I think) thoughtful risk/value conclusion for me and my approach to cruising.

[Palarran]

Evans,
I know you have a Vesper as you mentioned it earlier in this thread and the "Too many targets" one. False positives - that is really the wrong term. If the alarm goes off it's because you set it wrong or moved. Ours is located at the helm, which is probably where it should be, and is easy to coordinate with lowering the anchor.

Fatigue for me would be much, much more extreme sleeping super lightly waiting to feel a strange movement in the boat compared to soundly and being woke up once per month (or never) due to the alarm going off for no reason.

The concept of never dragging unexpectedly is interesting. I guess you could go into any anchoring situation and rate the chances. Then if it happens, you expected it, and therefore have never dragged - except when you expected it. Your skills are really beyond question but from observation most boats who anchor in different harbors continuously will at some point drag. Maybe like your example and mine, it isn't far or catastrophic, but most do. Really I've seen over a hundred boats drag anchor so far but none have ended up on the rocks or a beach.

[estarzinger]

Originally Posted by Palarran

Evans,
If the alarm goes off it's because you set it wrong or moved.

Well, perhaps I can learn something. Say you are anchoring in 30kts in 40' of water. How do you get the anchor way point to be actually where the anchor sets - or even within 50' of it?I have never been able to do that (even with the phone/pad apps I can take right to the bow), as the boat moves as I am lowering the anchor, and the anchor moves before it is set. I personally think there are clearly better alarm feature sets/software available today than the vesper.

Ours is located at the helm, which is probably where it should be, and is easy to coordinate with lowering the anchor.

First, how can you see it at the helm if you are under autopilot? Do you sit back there while under autopilot? Second, this would not help me much single handed, But third, even double handed, as I said, that is another discussion. On Hawk I don't mount such gear at the helm. They go under the hard dodger both to protect them from weather/uv damage and because that is where we sit under autopilot, which is most of the time. So I find your 'should be' a bit narrow decision making (yes purely for the anchor alarm but no for the ais and durability) at least for the way I equip and use Hawk.

Really I've seen over a hundred boats drag anchor so far but none have ended up on the rocks or a beach.

Well, that simple observational fact SHOULD effect your thinking here about the risk/value.

I might also just say you gave Anne a hard time, but your posts have a similar tone of preaching 'you set it wrong', 'it should be', 'I don't understand the mentality'.

[sailorboy1]

Seems to me based on the thread that even though there are lots of anchor alarm apps and other methods like GPS/chartplotter ones, that as a whole the cruiser community doesn't feel there is a good one.

[Wotname]

After 6 pages it might be a good time to revisit post #6 (Alan Mighty). The app. he mentioned did appear to cover all requirements (except it requires an Android device).