Watching my yacht drift out into the bay

[anacapaisland42]

I do like to drop a stern anchor with a limited rode.
Bill



[\\\QUOTE=Akapeterc;2294900]We were anchored in black wattle Bay just under the Anzac Bridge in Sydney the other day, a After putting out 30 m of chain and digging it in I was pretty confident that we wouldn't move. What a shock when we were returning in the tender from fish markets to see our boat drifting out into the bay. After we got aboard and pulled up the chain which I think had stopped us by then again, a catamaran which seemed to be where our anchor was, lifted their anchor and drove out past us. I can't understand how we drifted never happened before. So I assume that the catamaran must've pulled my anchor out of the mud. I said to them as they went past "we were lucky we came home when we did and they just said yeah and waved and kept going. Anyone else had an experience where someone just doesn't give a stuff about your boat after their actions cause something like this. So glad I decided to go back to the boat when we did or we could have lost our boat[/QUOTE]

[brownoarsman]

Originally Posted by a64pilot

I have an anchoring app on my cell phone that will send an alert to another cell phone if the boat is dragging, of course downside is it requires cell coverage and two cell phones

A suggestion. Google Fi has been discussed on the forum before, but what you may not know is that with your Fi plan, you can also order an extra SIM card linked to your account, and put that in whatever old phone or tablet you have lying around. You only pay for the data at a rate of $10/GB (no fixed monthly cost besides your $20/month unlimited voice and text package on the primary device) and only when the data is used. With your anchoring app, you would hopefully be paying zero as it would never send out the alert! Google Fi works in 150+ countries and basically all on the same $20/month plan.

[mowerandy]

Went diving with my brother once, years ago, and surfaced to see the (unmanned) boat about a mile away in a brisk breeze. We were at least a couple of miles offshore (swimmable but involving ditching a lot of expensive gear) so I gave chase, using my remaining air to alternate between surface and subsurface compass-swimming. After two hours I caught up with the anchor (large Danforth) flying along a couple of metres above the bottom with the flukes pointing upwards. Just enough air to dive down and grab hold, then another 15 minutes hauling up the line. Found my bro by dead reckoning about an hour later, just on dusk. Bit lucky whatever way you look at it!
Many lessons in this, mostly pretty obvious, but the anchor was well dug in last time we saw it at the start of the dive, and no other boats around at the time, so we didn't get to squint sideways at anyone else.

Blackwattle bay doesn't have much holding unless you snag junk - soft black stinking ooze which many anchors will just plough through ineffectively. I have dragged in similar places, once with three massive anchors set out, admittedly in more than 80 knots of southerly buster at the time.

[keepondancin]

Originally Posted by Shrew

About 8 yrs ago, I had been anchored in the same spot for 4 days. On our last night we dinghy'd into shore to go to a waterfront restaurant that had a dinghy dock. About 10pm I'm puttering through the anchorage and find a boat where my boat used to be.

I look upwind, downwind, port and Stbd, and I'm certain my neighbors are the same boats I've been looking at for the last few days.

Your dinghy never feels so tiny as when you're in the anchorage at night and your boat is gone. We tool around for some time while I try to calm the wife. Eventually someone hollers to ask if we're looking for a boat.

They directed us to the emergency mooring that the local tow boat secured us to. Chain had wrapped around a 'danforth' STYLE anchor and fouled it when the wind shifted and kicked up. (I use a NG anchor now and haven't had that problem since).

Block island? That is an everyday event there.

[knockabout]

the imitation CQR's made at Newcastle marine engineering works in Australia have a variety of shank lengths for different bottom conditions and seem to set well / the knock off bruce anchors have a different angle on the head and hold well in mud and sand /work better in deeper water with long scope / each anchor have their own types of habits and characteristics same as boats and us people all have different ways of interpreting their habits /

[Akapeterc]

I've got a Simpson Lawrence 44lb

[Akapeterc]

My Simpson Lawrence 44lb anchor

[brianlara 3]

In days gone by people would have killed for a genuine Simpson Lawrence CQR. But compared to the new gen anchors they, like all plows, are known to drag in mud. Maybe, just maybe, it dragged without help. If you want to drag there's no place like Blackwattle.
Save your bickies and buy a Rocna/Supreme/Spade/Mantus. Whitworths price for a 35lb Manson Supreme is $500. Rocna are dearer. (No valid reason, Whitworths have the buying power. The others...?
And for what it's worth a 35 pounder IS NOT overkill for your boat, depends where you go.
But with the all chain rode you used at BWB a Rocna/Manson would almost certainly never have pulled. Is your chain 5/16 or 3/8...8 or 10 mm? And how much do you have out of curiosity?
And in case you're interested, Net & Tackle Sales at the fishmarkets are the local Rocna agent.

[senormechanico]

I would never use a danforth style anchor as a primary in any waters around the PNW for the very reason posted here.
They're only dependable in a straight line pull, not reversing scenarios.
That said, I use an aluminum danforth style for a stern hook.
It's great for tight anchorages when shallow and not a lot of space in which to set.

[Akapeterc]

I've got 8 mm chain 85 m of it

[brianlara 3]

Nice. You are of the few boats around able to anchor in deep water with all chain. Pays dividends.
I'm 75 metres and often use every inch. Leaving Sydney for Tassie tomorrow and all that chain may well prove to be pretty useful.

[Connemara]

Few days ago... anchored 3 metres in Tutukaka harbour with 15 metres of chain down and a Rocna anchor.

Didn't seem too firm, so we reset. Still seemed dicey so we changed our location and reset, this time with 20 metres out. That seemed to be holding so we went to lunch.

Came back to find the boat had clearly dragged and was perilously close to some rocks.

Hauled up the anchor again, and headed for a new spot., Then I looked down to see that the anchor had attached itself to what looked like a rolled up blanket filled with mud. A few seconds with a boat hook and all was well.

Connemara

[Uncle Bob]

Originally Posted by Connemara

Few days ago... anchored 3 metres in Tutukaka harbour with 15 metres of chain down and a Rocna anchor.

Didn't seem too firm, so we reset. Still seemed dicey so we changed our location and reset, this time with 20 metres out. That seemed to be holding so we went to lunch.

Came back to find the boat had clearly dragged and was perilously close to some rocks.

Hauled up the anchor again, and headed for a new spot., Then I looked down to see that the anchor had attached itself to what looked like a rolled up blanket filled with mud. A few seconds with a boat hook and all was well.

Connemara

Out of curiosity did you remove the offending item to shore or did you merely drop it for some other poor soul to discover ?

[noelex 77]

Originally Posted by Connemara

Hauled up the anchor again, and headed for a new spot., Then I looked down to see that the anchor had attached itself to what looked like a rolled up blanket filled with mud.

There is often a lot of debris on the bottom of even relatively deserted anchorages, both man made and natural. I think it occurs more than realised. The offending debris will frequently drops off the anchor as it is retrieved, leaving no clue as to the cause of the problem.

It is a good reason to use a healthy lot of reverse to test the set. This is not foolproof. Sometimes the debris can allow the anchor to partially set with enough grip to hold full reverse. The debris may also hinder the anchor shuffling resulting in the anchor letting go if there is a change in direction of force despite holding adequately with a straight line pull. It is also important to realise that even a lot of setting force is only equivalent to 25-30 knots of wind so above this level the anchor is untested.

However, most debris will prevent the anchor digging in well, so it will fail the test of holding full reverse.

The other guard against this problem is having an anchor that will set rapidly. Even if they hold reasonably ultimately, some anchor designs can take a long distance to set, greatly increasing the chance of picking up debris. I think the other take home message is that if the anchor does not hold, raise the anchor to the surface to check for debris rather than simply partially lifting the anchor and re-dropping.

Oh, and secure your towels and swim trunks etc well if you are leaving them on the guardrails to dry. These items are the cause of most of the man made rubbish on the bottom, although there other hazards.

[GordMay]

Originally Posted by noelex 77

... It is a good reason to use a healthy lot of reverse to test the set. This is not foolproof...

Indeed.
For instance, a 25 HP engine can only develop about 500 Lbs of thrust, roughly equivalent to a 25 Ft boat in 30 Kts of wind.
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