Anchor dragging by night, 45 knots wind, 1.5 m waves, between 3 boats and the beach

[Oceanride007]

I got hit last night, similar event inside the Sandy straight, 100mi Nth of Stradbroke. Previously I studied the weather knowing the wind would change from Northerly to Easterly so I took protection behind Great woody Is, My anchor is also a CQR and its a dragger.
I new a weather event was coming up from SW but not having Simi 60 Experience (am not from here), did not know in what direction the wind would be once the front hit. No moon, plotter out in the weather, It was only 30 knots but a lea shore.


Early in the day, just after lifting the anchor, I hit a sand bank and the incoming tide was pushing me up the bank. I dropped the anchor it dragged, started the engine to hold ground, dragged more, more power, eventually I made ground but wary of running over my anchor, more power, chain to stbd, figured the best thing to do was drag the anchor behind me, rather than risk going forward to lift the anchor. Thankfully I didn't find deeper sand, I Broke free and then went fwd to lift the anchor.

Actually it was kind of nice not having a anchor that reset itself. But I've had it with the CQR looks like a Rocna Vulcan, as a hooped anchor collects to much crud, and allows a sprit. Wonder if I can drag a modern anchor behind me.?

Anyway the CQR did hold, but for 2 hrs, my sphincter muscle was working extra hard, hoping now, I learnt something, but not so sure.

[kriskro]

Originally Posted by Simi 60

And here's a picture

This was the pics when i checked the radar seing the little clouds coming on the horizon

[foggysail]

Originally Posted by boatman61

Always preferred the Bruce as my primary.. although happy enough with a CQR if that's all I have to work with and they are better with all chain.. tho' on my own boat it'd be the secondary.

I used Bruce for years on my long gone Hunter 30. I used both the 33# and later a 44#. But along came ell grass here in Massachusetts and the Bruce cannot be trusted in our ell grass infested harbors.

Sure, it feels as if the thing gets set just as it use to before ell grass. But put enough force on to rode and the anchor rips out a large divot of ocean bottom that takes what seems like forever just to clean the crap off the anchor. Now if ell grass is not found where you anchor, then the Bruce is a good choice. But be careful here in Massachusetts. You might find your boat on a beach with a Bruce.

[ericoh88]

I use excel sarca with 300' high tensile chain. One evening solo, I have dark clouds coming in. I decided to drop anchor at 30' mud bottom near Cape Rachado / straits of malacca. After 2 hours, wind started to blow 30kts gusting 40 spins my boat 360. Boat held her spot well.

Slowly let out all the chain while engine is in reverse. Always take time to slowly set the anchor backing the engine starting at rpm 1,000, 1,500, 2,000 , 2,500 and one minute at 3,000 rpm.

There was one time I dragged. I drop all the chain out and did not do the reverse test. The chain fouled the anchor naturally. My terrified wife asked why I did not do the reverse check. I just smile.

[peter57]

Originally Posted by Boatyarddog

I believe the OP said here:
Originally Posted by kriskro View Post
I was staying at tangalooma resort on moreton island, 27°09'58.6"S 153°22'13.9"E



4 meter depth when i dropped the anchor. not sure about the distance from the beach, but would say between 50m and 100m. I know there is a strong tidal current when the tide goes down. It may have played. Bottom is all sandy.



There is a little sand bar that it formed by the wreck and that shelter a little bit the anchorage area. But at high tide, it may let pass quite a lot the swell. Anchor is a CQR type, 25 lbs and i must have had 60 metres of chain (8mm) out is think...



The boat is 30 ft, about 5000 lbs i believe.



But basically, once it is too late and that you are already dragging , seems the only remaining option available is to let the anchor go (attach a fender if possible), and go with the wind instead of fighting it. if possible reach the open waters and not stay so close from other boats and the shore..
Cheers
SV Cloud Duster

Read post #65

[Alan Mighty]

Some excellent advice from experienced cruisers (Jim Cate, Boatman61, etc) and people with local knowledge (Simi 60 and a couple of others whose names I did not note, for which I apologise). And some not so good advice from others. Let me explain further ...

1. Anchoring in excessively shoal water is a thing.

Boatman61 made the early comment in this thread (#6 I think) that if the OP had 1.5 m waves around the boat, then the water was too shoal. In other thread, the OP suggested he aims to anchor in depths of 4 m (12' or thereabouts). I did once too. I now reserve such depths for fair weather only.

Another recent or current thread on CF makes the same point about shoal water anchorages. See posts such as that from Fuss at: http://www.cruisersforum.com/forums/...ml#post2569475

(a) the scope recommendations that we all take for granted have limits. One of them is shoal depth. The canonical scope recommendations do not work for a chain rode in water less that 4 m / 12' or for 6 m/18 ' for warp rode.

(b) tsunami. Have you noted that all the ports on the E coast (and probably other coasts) of Aus have updated their Port Procedures Manuals (PPM) to include a note about tsunami? Have you noted that this year the Pacific Rim of Fire is more active than a year or two ago?

I happened to be anchored in waters affected by the 2004 tsunami caused by the quake near Aceh. A heads up. Cruisers anchored in 4 metres on affected coasts had problems. Cruisers anchored in 8 m had no such problem.

Think I'm alarmist? Sure. But read the PPM for Moreton Bay and the port of Brisbane at: https://www.msq.qld.gov.au/Shipping/...dures-brisbane and you'll see that the port authority covers its rear end. One day, with much warning ...

2. Scope recommendations are for calm-ish conditions.

The OP was dealing with peak gusts of at least 59 knots. I know that because I was in a marina berth a few miles W of the OP. And that was the windspeed measured by a govt agency (and close to the speed measured by my masthead instrument as my awning tore apart). The OP may have had stronger windspeeds. Or not.

The canonical scope recommendations are not for storm conditions. They are for something like '25 knots or less'.

John Knox, a retired UK scientist who did some remarkable research on anchoring relevant to cruisers (as opposed to research relevant to naval ships or oil rigs) reckoned that once above 30 knots, a more sensible safe scope was something like windspeed multiplied by depth multiplied by a factor that ranged from 1.1 to 1.6 depending on the depth.

So for 4 metres/12' at 60 knots, Knox would have recommended a scope of about 66:1 (and that would be 66 times the drop from anchor roller to the bottom where you lay the anchor, not the depth under the boat).

And if the bottom were downward shelving (such that the anchor might drag into deeper water) in the direction of the wind, even that might be inadequate.

The 15:1 scope that one poster thought acceptable is not adequate for 60 knots of wind.

3. At some windspeed x, the substrate will fail.

Forget about being a proselytiser for MAX anchors (not available in the Aus market) or Bruce anchors (other than anchors for oil rigs, I've not seen a new Bruce in the marketplace for many decades).

Rex Francis's Sarca models are one of the few Aussie designed, Aussie made anchors (and jolly effective anchors, too). NZ designed and made Manson anchors are around too. Rocna anchors are available (designed by an NZer, made elsewhere these days) in a few marine supply stores.

Any substrate (except perhaps rock) will fail the anchor at some windspeed. And if the substrate doesn't fail, then a weak link in your chain, an anchor swivel, or a fitting on deck will fail.

Simi 60 posted (at #40 I think) photos of two boats that were stranded during the same storm. The OP's tactic of motoring in station worked. A well chosen strategy for the time and place.

The port authorities of Aus ports advise against cargo ships riding to anchor in storm conditions. I was not monitoring Brisbane VTS (VHF channel 12) that night, so I am not a witness. But I've heard Brisbane VTS ordering ships to weigh anchor and motor against the conditions in similar windspeeds.

Several other suggestions are just not practical in the OP's local setting.

(a) To drop the rode and chain and motor out of the anchorage would be crazy in that case: motoring to the S to get out of the Tangalooma anchorage would mean motoring into 60 knots of S with driving rain and a black sky. That's just a recipe for a low visibility disaster. That's if the OP's vessel can deliver enough grunt to the propeller and turbulent water to motor and steer against 60 knots of wind.

(b) same for weighing anchor in 60 knots of wind and rain. Crazy idea. Ten minutes before the squall hit, weighing anchor and resetting the anchor in deeper water and on a longer scope might have been good. Once facing 60 knots, you'd be a mug to try. I would not be happy to be downwind of someone trying to re-anchor in 60 knots.

(c) same for heaving to or otherwise dealing with the conditions in the shipping channel (East Channel) just W of the Tangalooma Anchorage.

You cannot do that.

Brisbane is a 24 hour working port dominating Northern Moreton Bay.

The port authorities and Maritime Safety Queensland publish recommended routes for recreational craft and do their best to keep recreational craft out of the shipping channels and to have recreational craft to monitor Brisbane VTS on VHF 12.

You can download the recommended routes from several websites, including: Recreational Craft

4. Tangalooma Anchorage is a fair weather anchorage
Jim Cate and several local cruisers noted that simple and correct fact.

The wrecks were laid by govt in an attempt to make Tangalooma a better anchorage. It failed, as one or two posters noted that the wrecks do not offer protection.

Fear not, those who thought that anchoring on a ship wreck was a danger - the deal is that the wrecks were placed on a sandbar and are clearly visible. The anchorage is inshore of those wrecks.

The sad reality is that Northern Moreton Bay has precious few storm anchorages. Anything on the W coast of Moreton Island is a fair weather anchorage.

The canonical scope recommendations are for protected waters. Another of its limits.

In a Tropical Revolving Storm (TRS: a cyclone, hurricane, typhoon, or willy-willy) winds can come from most any direction. Same for a microburst, such as caused by the downdraft from a thunderstorm cell. Doesn't matter what direction the t-storm is moving. The downdraft hits the water and fans out in whatever direction (sure, it may fan out only 120 degrees not 360 degrees, but it won't necessarily come from the magic direction for which the fair weather anchorage offers direction).

Several cruisers noted that Tangalooma anchorage is great only for winds from the E. They are right. And the best storm anchorages, as several local cruisers noted, are several hours sailing or steaming away in Southern Moreton Bay or the W coast of the bay.

5. Several posters suggested two anchors in various arrangements.
Vessels at Tangalooma anchorage sit to the tide, which reverses, unless the wind is jolly strong (as it was on 11 Feb).

I would not use any 2-anchor technique in an anchorage that will be dominated by a 2 or 3 knot tide that is S-going on the flood and N-going on the ebb. That'a a recipe for a tangle.

And when would you set your second anchor? Before the squall or during it?

It's a different thing to use multiple anchors and lines to shore in a mangrove creek, a cyclone anchorage, or the like.

6. Other designs of anchor
I'm not a proselytiser for any particular brand of anchor. CQR anchors (especially while the hinge pin is not worn and slack) perform quite well in the clean quartz sand of Moreton Bay. So does most anything, for that matter.


CQRs do have weaknesses, including that once unset (such as by a reversing tidal current or wind in the opposite direction to that which the anchor was set) a CQR will be dragged out and happily sit on its side without embedding for ever and day.

More modern designs with greater fluke area for the same mass, such as the Rocna, do a better job including that a well-embedded Rocna will "shuffle around" while staying embedded in reversing tide conditions as Noelex 77 say.

I do agree with the several cruisers who posted recommendations that the OP (and everyone) work their way through Noelex 77's thread "Photos of anchors setting' (with very valuable contributions from SWL of course!) and Panope's thread "Videos of anchors setting".

Would a Rocna or Bruce, Max or anything else have held in the OP's situation? I don't know.

The sand substrate must have a mechanical limit. An anchor with a large fluke area would fail the substrate at a higher wind speed.

The substrate limit might be 60 knots. Or it might be 100 knots. Waves add load on top of the wind load on boat and rigging. A scope of 60:1 or greater might be have been required even for the best anchor. And such a scope might not have been practical for the OP in that anchorage.

[Arafura II]

Originally Posted by Simi 60

Way to hard
Better to just get a real anchor.
Since our upgrade setting the "one anchor suits all bottom conditions" supreme, we simply drop, spool out chain, put on snubber, make an adult beverage and let the weight of the boat do the rest
100% success rate in over 600 days at anchor.

When we first used it we did it your way and nearly fell over and thought we were going to tear something out of the deck due to the instant set.

What size Manson do you have? My boat is 47 foot 30t and came with a 60 pound stainless Manson supreme it seems to do the job. I nearly fell over when I saw the price when I was researching it. It also had 9 meters of stainless chain witch I ditched.

[Simi 60]

Originally Posted by Arafura II

What size Manson do you have? My boat is 47 foot 30t and came with a 60 pound stainless Manson supreme it seems to do the job. I nearly fell over when I saw the price when I was researching it. It also had 9 meters of stainless chain witch I ditched.

150lb on a 60 ft twin decked 70 tonner

Usually anchor with 10ft under us at high +6ft draft +10ft to roller =26ft say 7m
Up to 20 knots we anchor 25m say 3:1
Expecting over that we spool out 50m say 7:1
All 13mm chain, no swivel (had one but not needed)
That has held us in 6 or more 50+ and a brown pants 80+ blow.

Stainless are expensive that's for sure, a regular getting around these parts runs a 180lb s/s ultra, I think they are around $11k

[RaymondR]

There is an adage stated by yesteryear aircraft pilots which goes, a good landing is any you walk away from. You did the marine equivalent, congratulations.

We make judgement calls all the time when cruising and one of them is in using the available anchorages. It works out most of the time but thunder storms in less than perfect anchorages are a fact of cruising life and you can congratulate yourself that you handled it well.

[NevisDog]

Originally Posted by Alan Mighty

...I would not use any 2-anchor technique in an anchorage that will be dominated by a 2 or 3 knot tide that is S-going on the flood and N-going on the ebb. That'a a recipe for a tangle. ...

Not necessarily. I guess maybe you have never tried any of the various tandem anchoring techniques - suggest you read up on this on the Rocna website, or here on CF. Done right it cannot tangle.

Not my favourite technique - I prefer to lay out the Fortress to windward, where it will not tangle in a short blow. Try it before you knock it.

[Alan Mighty]

Originally Posted by NevisDog

Done right it cannot tangle.

Not my favourite technique - I prefer to lay out the Fortress to windward, where it will not tangle in a short blow. Try it before you knock it.

By definition, anything "done right" must be wonderful, I'm sure.

But what're the chances that anyone would do it right just before a 60 knot blow?

How many times would someone have to practise to get it right before a 60 knot gust?

[NevisDog]

Originally Posted by Alan Mighty

...How many times would someone have to practise to get it right before a 60 knot gust?

Once.

[Alan Mighty]

Originally Posted by NevisDog

Once.

Great.

Please post a Panope-style "videos of anchors setting" test to show how well it works after, say a 60-knot blow followed by sometime in the early morning a tide reverse. And then show how easy it is to retrieve and weigh anchors.

Or perhaps a more scientific test: two similar boats anchored side by side, one with your preferred tandem anchor setup and one just sitting to a storm anchor with storm scope, subject to 60 knots. Noelex 77-style "photos of anchors setting" still photos of the result would be enough to convince me.

I'm sure you've cruised more sea miles than me. Crossed more oceans and seas. And anchored more times than me. But I'd like to see the video of tandem anchoring standing up to a 60 knot squall first.

[NevisDog]

For anyone interested in the most simple and totally reliable tandem anchor arrangement I suggest you go to the Rocna anchor site. Simple, reliable - no more difficult than a single anchor but easier to retrieve than a storm anchor. As I said, not my preferred method but a good start to using the equipment you already have on board - every yacht carries a second anchor, right? So why not use them if you are trapped in a blow? Would anyone seriously advise us leave their second (and third) anchors on deck if threatened by a 60 kt gust? That sounds kinda stupid advice.

Deploying the Fortress to windward on a separate rode is equally simple - just raise it before the wind dies completely and it won't have tangled. I see nothing even remotely complicated about this, for anyone with a twin bow roller, regardless of the oceans crossed and sea miles ticked off. Please don't continue with the put-downs - it kinda reflects badly on ourselves.

[boatman61]

Originally Posted by foggysail

I used Bruce for years on my long gone Hunter 30. I used both the 33# and later a 44#. But along came ell grass here in Massachusetts and the Bruce cannot be trusted in our ell grass infested harbors.

Sure, it feels as if the thing gets set just as it use to before ell grass. But put enough force on to rode and the anchor rips out a large divot of ocean bottom that takes what seems like forever just to clean the crap off the anchor. Now if ell grass is not found where you anchor, then the Bruce is a good choice. But be careful here in Massachusetts. You might find your boat on a beach with a Bruce.

We do have grass weed over here in some anchorages but I just look for a sand patch and drop my hook there.
It rarely coats the bottom completely.