Anchor advice

[SR4]

Anyway I as of now I use neither, just bought a bargain shiny stainless steel folding one, I will keep my grapple one until I have tried and tested this, at less than half price it is worth a go, shame they don't do it in orange

Just need to source some stainless steel chain for it, I have a stainless 8mm shackle to attach it with but can't be having rough old galvanised chain now can I

Holt Stainless Steel Folding Anchor - Only £49.95 - Force 4 Chandlery

[wellhouse]

Originally Posted by tonto

Not exactly, although it does help.

The wieght of the chain causes the anchor shank to lie horizontaly on the seabed, (perticularly with an AC14, Danforth, Admiralty Stockless anchor etc, which then allows the anchor to hold at it's full power, which for a high holding power anchor is typically 1.7 times it's mass. (if i remeber correctly)

If the shank is lifted up from the horizontal, this causes the flukes (pointy bits) to pull out of the sea bed, and cause the anchor to drag.

So yes the chain is important, and is helping, but it is primarily to ensure the anchor is acting horizontally.

true - but interestingly if you take most merchant ships (i was on tankers upto vlcc's and production rigs/vessels) we used to drop the anchor from the waterline. The cable goes out so fast you end up with the anchor buried under a small pile of cable followed by a long length of cable laid along the sea bed with piles of cable every so often. The anchor didn't even have a chance to dig in let alone do anything. Latter it became the norm to lower the anchor to the sea bed then pay out the cable as the vessel went astern more often than not laid in a curve across the sea bed as the ship drifted/went astern slowly whilst 'laying' the anchor, if it ever got to the stage that the anchor was holding you, you haven't got enough cable out - you'd probably be dragging at this stage. In busy anchorages it wasn't uncommon for anchors and cable to be left behind (not ours) because they had got hooked up on something on the sea bed. As i used to be a ships diver, i occasionally helped on a friends salvage vessel recovering anchors and cable (amongst other things). Once we had dived down, you would normally find the cable had either hooked up on something or the anchor was buried under a pile of cable and had somehow picked up a loop around the anchor shank/fluke putting so much weight on it that the ships anchor winch couldn't lift the weight. Sometimes the shank was detached from the flukes. Unless you are at anchor for a long period, or anchoring in a strong tide or bad weather, i doubt that the cable ever stretched out straight. After you had turned at the first turn of tide it was probably laid in a circle anyway. In theory what you say is correct but in practice it is the weight of the cable and the friction from it on the sea bed that does the work. In most ship anchorages space/depth is restricted so you don't have the luxury of paying out the cable in a nice neat line from the anchor, it's normally a case of letting it go and put out enough to hold you (about 4 to 6 shackles depending on weather and depth) and hoping that no-one else anchored in your turning circle! Fortunately i don't have this problem on the rib

see this:

http://www.youtube.com/watch?v=3FJp6Ur5jeE

although i prefer the spoon type folding grapnel and i know it's not always a nice sandy bottom

http://www.youtube.com/watch?v=bhjdlKwTdv8

[tonto]

Originally Posted by wellhouse

true - but interestingly if you take most merchant ships (i was on tankers upto vlcc's and production rigs/vessels) we used to drop the anchor from the waterline. The cable goes out so fast you end up with the anchor buried under a small pile of cable followed by a long length of cable laid along the sea bed with piles of cable every so often. The anchor didn't even have a chance to dig in let alone do anything. Latter it became the norm to lower the anchor to the sea bed then pay out the cable as the vessel went astern more often than not laid in a curve across the sea bed as the ship drifted/went astern slowly whilst 'laying' the anchor, if it ever got to the stage that the anchor was holding you, you haven't got enough cable out -

I still am currently working on large ships!
hve recently been on VLCC's, and am currently on a 300M Loa LNG ship, and can see what you are saying, and agree to some extent.

VLCC's stopped dropping their anchors about 25 years ago as they kept losing them. the inertia was just too much for the brakes, and they would be unable to stop them running out, and hence they would loose the whole lot, and parts of the chain locker as well. They were also anchoring in deeper waters, consider this a VLCC is at least 20M draught loaded, so would be in 30+M of water, and that is a long way to drop 20 tonnes of anchor, plus about 10MT per shackle of cable.

We started walking it out in gear to prevent the uncontrolled running away, and still do, however....

We will lay the cable out, more as a consequence of how we anchor, rather than thrying to achieve a neat line of cable. I have been doing this job over 27 years and I have not lost an anchor yet, or been on a vessel that has, baybe we were lucky. We have brought it up with flukes bent, and also with the cable looped round the shank, but never lost one yet. We anchor in upto 80M of water, and 4 or 5 shackles would not hold you there at all.

It is still the holding power of the anchor ultimately that hold you, as the cable will just slide easily over the soft muddy bottom. The catenery (bow ) in the cable ensures that the cable is pulling horizontally on the anchor. If it was just the wieght of cable you can be sure the shipowner would save the 1/4 million bucks a pair of anchors cost, and just put smaller ones on.
If you dont have enough cable out, this will cause the anchor stock to be raised at an angle to the seabed, thus breaking it out, as most crowns and flukes only move up to 30 degrees, so if the shank is raised off the horizontal by more than that, the flukes are not even digging in.

I have dragged a number of times, and each time was during heavy swell/seas, and winds, which cause the cable to be pulled tight, lifting the stock off the sea bed, thus breaking it out.

I have anchored in areas of rock covered by sand, and this has resulted in dragging, no matter how much we put out, as the flukes cannot dig in, and thus are innefective, irrespective of the wieght odf the cable.

[Josh_P]

Originally Posted by SR4

I would say user error with the grapnel rather than no good, I wonder why so many are used and sold, does make you wonder doesn't it

In all the 40yrs of my boating I have never lost a boat yet, maybe it's just luck

Couldn't agree more, do yours not have the age old simple slide twist and lock... it can't close itself... user error 100%.

If you are swayed into going for a bruce I would recommend getting and anchor bag and seperate chain bag, saves you have 20 metres of chain rope and anchor tangled, and installing some little plastic hooks and bungey chord to hold it down, or alternatively put all your heaving lines on top, holes in the fibreglass don't bear thinking about...

[Josh_P]

Maybe a little unfair, I use a grapnels mostly as they are easy to stow and carry on and off the boats and will easily take a 6.5m RIB or a 3.8 and 6 dinghies...

We use a slightly different type of grapnel than sold by Force 4, it was bigger flukes on it for gripping mud and is truly versatile, however we do have 2 metal split/holding pins attached to hold the casing open especially on some of the cheaper anchors available.

Danforths and Brittanys with their hinges around heavy plates and sharp edges are a liability for getting fingers trapped and opening inside the locker making getting them out a pain... Similarly fixed design anchors like the Delta or Bruce are cumbersome and a pain as they often swing under the tubes as you lift them out of the water.

For all round ease of use, stowage and general performance I would have to vote grapnel with decent flukes and a decent design... Especially for the mix of anchorages we have in the UK and the storage space available to you in a small RIB...

[wellhouse]

Originally Posted by tonto

I still am currently working on large ships!
hve recently been on VLCC's, and am currently on a 300M Loa LNG ship, and can see what you are saying, and agree to some extent.

VLCC's stopped dropping their anchors about 25 years ago as they kept losing them. the inertia was just too much for the brakes, and they would be unable to stop them running out, and hence they would loose the whole lot, and parts of the chain locker as well. They were also anchoring in deeper waters, consider this a VLCC is at least 20M draught loaded, so would be in 30+M of water, and that is a long way to drop 20 tonnes of anchor, plus about 10MT per shackle of cable.

We started walking it out in gear to prevent the uncontrolled running away, and still do, however....

We will lay the cable out, more as a consequence of how we anchor, rather than thrying to achieve a neat line of cable. I have been doing this job over 27 years and I have not lost an anchor yet, or been on a vessel that has, baybe we were lucky. We have brought it up with flukes bent, and also with the cable looped round the shank, but never lost one yet. We anchor in upto 80M of water, and 4 or 5 shackles would not hold you there at all.

It is still the holding power of the anchor ultimately that hold you, as the cable will just slide easily over the soft muddy bottom. The catenery (bow ) in the cable ensures that the cable is pulling horizontally on the anchor. If it was just the wieght of cable you can be sure the shipowner would save the 1/4 million bucks a pair of anchors cost, and just put smaller ones on.
If you dont have enough cable out, this will cause the anchor stock to be raised at an angle to the seabed, thus breaking it out, as most crowns and flukes only move up to 30 degrees, so if the shank is raised off the horizontal by more than that, the flukes are not even digging in.

I have dragged a number of times, and each time was during heavy swell/seas, and winds, which cause the cable to be pulled tight, lifting the stock off the sea bed, thus breaking it out.

I have anchored in areas of rock covered by sand, and this has resulted in dragging, no matter how much we put out, as the flukes cannot dig in, and thus are innefective, irrespective of the wieght odf the cable.

nice to see there are still some employed at sea! i came ashore about 20 years ago as the british vlcc's started to flag out or go to scrap. Glad we agree on some things ref anchoring. Most of the vlcc's i was on were 22m loaded draft and most of the anchorages in europe/persian gulf/singapore occasionally mexican gulf around 40m. 1 shackle is 90ft (about 28m) and depending on weather/tide it used to be about 3 to 4 times depth of water (sometimes more) for cable length, don't know about now but most ships only carried about 12 shackles due to the space required to carry more, this restricted anchorage depth to a max of about 60m in reality to get required cable out (plus contingency). Also if you had 8 shackles out plus the length of ship in singapore you would have a swinging circle of nearly a mile across, (our ships were about 384m) and you would quickly run out of space in the anchorage at that rate. I'm not saying that on some occasions anchors don't dig in (they obviously do if the ground is right and you get the right circumstances when going astern or you haven't got enough cable out and you get to the stage that you are about to drag - i would have let more cable out or left the anchorage before then) but you would have to 'set' the anchor and in most anchorages ships don't have the space or time to mess around going backwards and forwards to set the anchor. it's lay it and hope - or try again (rarely). Most of the anchors that i've been involved in recovering have not been 'set' (flukes in) and that's the point i make (an observation) not that anchors don't do anything. I wouldn't recommend only carrying cable and no anchor for instance. Certainly for ribs with virtually no chain and require a quick hold you need a decent anchor (see you tube dems
i put up earlier) After 20 years at sea, i never ran aground as a result of anchor dragging so must have got it right. It was interesting to see what the cable and anchor was doing underwater on those that we recovered because as a seafarer you just assume the anchor is set, from a divers perspective they rarely were.

[jyasaki]

Originally Posted by Josh_P

For all round ease of use, stowage and general performance I would have to vote grapnel with decent flukes and a decent design... Especially for the mix of anchorages we have in the UK and the storage space available to you in a small RIB...

I know grapnels don't work in sand (which we have a lot of here), the flukes don't dig deep enough nor present enough surface area to keep the anchor from dragging along the bottom. That's from experience, having seen my anchor pass me while diving for halibut.

In uneven rock, they tend to lodge themselves in a manner that needs to either be pulled out backwards (which is what the little hole on the nose is for), or dove on to free it.

A small Bruce or Bruce knockoff (like 4 to 6 lbs), or a 3 -5 pound Danforth should suit well with a decent length of chain (I'd suggest 10 -12 feet or so of fairly heavy hot dip galvanised chain, about 1/4" mininum size.)

Then again, I'm not familiar with the bottom compositions you have in the UK, so this is guesswork based on my experience on the US west coast.


jky

[wxmrich]

I lost my 2kg Bruce this weekend, first outing with it!

They're not very giving if you get a bit unlucky with rocks it seems.

[prairie tuber]

Originally Posted by wxmrich

I lost my 2kg Bruce this weekend, first outing with it!

They're not very giving if you get a bit unlucky with rocks it seems.

Sorry to hear that, but you certainly can't blame the anchor for that! Sounds like it was doing exactly what an anchor should do. Now whether the chain, rope, splicing, or shackles were sufficient is another question. At least one of them obviously failed on you.

[prairie tuber]

Originally Posted by SR4

Anyway I as of now I use neither, just bought a bargain shiny stainless steel folding one, I will keep my grapple one until I have tried and tested this, at less than half price it is worth a go, shame they don't do it in orange

Just need to source some stainless steel chain for it, I have a stainless 8mm shackle to attach it with but can't be having rough old galvanised chain now can I

Holt Stainless Steel Folding Anchor - Only £49.95 - Force 4 Chandlery

Very interesting. I haven't seen that design before. Looking forward to your field reports on it.

[SR4]

If you want one I can buy one for you and it can be dropped off in New York next Monday You just need to arrange onward shipping to Canada

[C-NUMB]

Big or small rib/sib, the usage pretty much dictates what anchor to use. If You only want something that keeps to boat in palace during good weather fishing or a supervised coffee break, a grapnel would be fine. They are particular strong at two things, price and storage.
As anchors grapnels are IMHO the most unreliable type. Can't recall having problems with the mechanism(but i don't consider it safe) however they let go pretty easily and would never do some serious anchoring with one. Danforth or Bruce type have been working well for me, in combination with long chain and sinking anchor line. I am not sure if cheap replicas works as well as the originals, might be some difference in performance?

Despite a long chain, You need to have a good anchor, its very easy to test, try to anchor with only the chain and rope, not much resistance there. But a long chain still reduces the load on the anchor by keeping the angel of the load in more favourable direction and taking some of the load also.

Drift anchors are cheap, light and easy to store so that is something would take along also on a smaller boat in addition to the hard anchor.

[prairie tuber]

Originally Posted by SR4

If you want one I can buy one for you and it can be dropped off in New York next Monday You just need to arrange onward shipping to Canada

Thanks for the offer SR! I have to hold off for the time being, but am interested to hear how it does.

Another interesting anchor I just came across is this:

Boat anchors for yachts, jet skis, inflatables, fishing, diving, cruising, sailing, or tinnys and Kayaks boats - Cooper Anchors

[jyasaki]

Why try and reinvent the wheel? Get a Danforth (or solid copy), or a Bruce 9or, again, a solid copy), and you're done.

jky

[awa154]

Afew years ago, Morris Marinas were very popular as anchors, unfortunately, they only lasted a season before rusting away from the chain completely.

Just joking , I have used the folding grapel type in the lakes for years and never had any holding problems.

In our lakes, we have a major problem with lake weed, Great for fish but a pain for boaties. I found the simplest anchor for the weed beds was a plastic milk bottle filled with sand, tied to a length of light rope. Does the job but wouldn't be silly enough to rely on it in a current or tide.

[jezza2011]

this is good

Anchor Selection Guide: Choosing an Anchor Type

I have a danforth and not had any problems its light and fits nicely into my anchor box.
I haev also used grapples and as long as you lock the ring in place I have nevefr had any issues with them , Appart from recovery in rocky bottoms. But thats the same for all anchors.

20 years of using my danforth without issues :-)
simple light and east to store. 3m of chain onto 18mm box braded rope. gives when under strain but very very strong, doesnt tangle up easily infact its almost anti tangle. :-)
just comes straight out of the box over the side.

nice easy way to stop your boats bow getting pulled under during rought seas when moored is to attach the anchor to the painter.
I pop a bowlin in the painter and a quick release not to that using the anchor line. SIMPLE.
boat rides over the waves and does not get pulled down like they do it you put the anchor line directly over the Bow.

[rik_elliott]

I used a grapnel for a while. It was alright, but dragged in any real current, no matter how carefully I set the thing. Now, the Bruce, that's a real mans anchor. bit more awkward to store, but welds itself to the sea floor a treat. So it's a trade off, convenience vs holding power. If you are going to be sat in a sheltered bay on nice days fishing then a grapnel is probably fine and a lot easier to store in a boat the OPs size. If you intend on more adventurous anchoring (I doubt you do!), get something that presents a greater surface area to the seabed and use plenty of chain.

[Cooper Anchors]

Originally Posted by sebrobinson

Hey what sort and size anchor would be suitable for a 3m Avon rib? any advice would be great! Thanks

Hi Sebrobinson good news
The Cooper Nylon Anchor is now avalable direct from their only offical UK/International Web Site about $49 AD including postage in UK, USA and AUS.
The Cooper Nylon Anchor Home - Cooper Anchors International Site

[Cooper Anchors]

Originally Posted by prairie tuber

Thanks for the offer SR! I have to hold off for the time being, but am interested to hear how it does.

Another interesting anchor I just came across is this:

Boat anchors for yachts, jet skis, inflatables, fishing, diving, cruising, sailing, or tinnys and Kayaks boats - Cooper Anchors

Hi Prairie Tuber

That site is our Aus site.
Our only official international site is www.cooperanchors.com Our Nylon Anchors are now where housed in UK & USA. and for the moment we are selling direct to keep the price as low as possible.

Cheers Larry

[IanH]

I really like the look of the Cooper Anchor. Anyone have any experience on one on an airfloor sib approx 3.6m long, (ie just past recommended boat length of 3.5m) on southern UK waters, bays and rivers?

I don't care that it reinvents the wheel. Many a modern material has been used to better traditional materials and I don't see why anchors should not benefit in the same way.

Whilst I'm on subject, recommended length/size of chain and rope would be useful to know if someone could assist. Its a 3.6m sib in inshore/river waters, not the titanic. I think the Arun harbour entrance is about 1.4m with 5.5m tidal range so I guess I need nearly 50m which sounds a lot to me.