anchor rode

W

Witchwood

Member
Joined
31 Jul 2009
Messages
37
Visit site
I need to replace the existing and aged anchor rode on a 25 foot Snapdragon 747 and would appreciate thoughts on the relative pros and cons of going for either all chain (8mm?) or chain and 12mm 3 strand nylon rope. I cruise the waters of the south west with the Exe as home.
 
Witchwood said:
I need to replace the existing and aged anchor rode on a 25 foot Snapdragon 747 and would appreciate thoughts on the relative pros and cons of going for either all chain (8mm?) or chain and 12mm 3 strand nylon rope. I cruise the waters of the south west with the Exe as home.
Click to expand...

6m/m chain is more than adequate for the 747 & personally for cruising would have 30m chain & add anchorplait warp after that if necessary
 
The argument goes something like:

A short length of chain plus good rope is theoretically stronger and more shock absorbing. It is also far lighter, important in a small boat.

Chances are you rarely anchor in more than about 7 metres of water, so 30 metres of chain plus rope means you will rarely use the rope anyway.

Boats on all chain rodes are far more stable in shifty winds. If you regularly anchor in deeper water, or only select 10 metres of chain, you run the risk of collision with other boats in crowded conditions when on rope.

It's a different matter for extended cruising, in which case I believe all chain to be better for a number of reasons.
 
Your required chain size depends on its grade and the anchor type and size. 8 mm seems a little over weight. Multi-braid rope is generally preferable to 3-strand if you care. Match the WLL to equal or exceed that of the chain, again talking about size is pointless without knowing specifics. If you're pulling it all in manually it seems unlikely you would want all chain, and it's certainly not necessary.

www.rocna.com/kb/Rode_optimizations
 
Anchor rode

Around here almost all boats of your kind of size use a few (5 or 6) metres of chain and then rope. However all chain seems far more normal in UK. With rope you get good spring action less jerking but need more rode for a given depth (5 to 1) for rope so need more swing room. good luck olewill

O dear we have argued rode to depth ration before. I believe it is all about angle of approach to bottom when rode is tight. 5 to 1 gives a smallish angle 6 to 1 or 7 to 1 does not significantly reduce the angle. (trigonometry) olewill
 
Vyv,

it's perhaps worth pointing out that a small cruiser - say 25' or less - will be crucified by the weight of all chain; if using part rope an 'angel' helps reduce sheering about in wind, and keeps the warp away from the keel - or a drogue over the stern reduces sheering better and also prevents sailing the anchor with the warp around the keel, but does increase pull on the anchor and put one out to maximum scope radius.

Once one is aware of these factors and plans accordingly there is rarely a problem.
 
William_H said:
Around here almost all boats of your kind of size use a few (5 or 6) metres of chain and then rope. However all chain seems far more normal in UK. With rope you get good spring action less jerking but need more rode for a given depth (5 to 1)
Click to expand...
Not you don't. Except in very deep water which I don't think the OP anchors in.

William_H said:
O dear we have argued rode to depth ration before. I believe it is all about angle of approach to bottom when rode is tight. 5 to 1 gives a smallish angle 6 to 1 or 7 to 1 does not significantly reduce the angle. (trigonometry) olewill
Click to expand...
Actually there are fairly significant benefits up to a point of diminishing returns around 8:1.
 
I won't pretent to any technical knowledge, but my Snappy 24 is an older version of the 747, so will behave in much the same way.

I have 17m of chain plus around 50m of octplait and, with a 10kg Delta, I sleep well at anchor. If the water's so shallow that I've got no rope out, I use a 10mm nylon snubber about 2m long with a rubber shock absorber to reduce snatching and the graunching of chain in bow roller. Chain hook one end and spiced loop the other to go over the Samson post.
 
After advice from other forumites and a fair bit of thunking, I've decided on the following for our 23 footer ...

10m x 7mm chain spliced to 30m x 10mm anchorplait
- this will flake down in the chain locker in the bows

30m x 7mm chain + shackles
- this will be stowed under the main cabin floor and brought up when needed

This is based on the expectation that we will normally be anchoring in pleasant weather and in shallow(ish) water either to wait out the tide (entrance to R. Roach for example) or overnight up a river or creek. I figure therefore that 40m of chain/warp should suffice under normal circs. I doubt we'll be keen on lying to the anchor overnight when it's at all rough or breezy anyway!

Another 30m of chain will give us options in deeper water and/or rougher weather and/or lying to all chain in a tight anchorage where we don't want to swing as much etc. albeit with the extra hassle of having to heave the chain up on deck and stow it away again afterwards but with the great advantage of having the weight stowed as low down as possible and in the middle of the boat (and the space under the floor isn't much use for anything else anyway ... 'cept maybe for keeping the beer cool)

I'll look at adding a snubber for use when lying to all chain if we find ourselves doing so sufficiently often to make it an issue.

Bru
 
Witchwood said:
I cruise the waters of the south west with the Exe as home.
Click to expand...
... as do I. I don't agree with the post that suggests that you won't anchor in more than 7 metres, there's plenty of places in the SW that you might choose to. There are dozens of threads about anchoring, but no doubt this one will lengthen as people argue about which is best - all chain or chain and rope, and if so how much rope, and how much rode to put out ...

I suggest that you read the threads and make up your own mind, taking into account that 30 metres of 6mm chain weighs about 24 kg, of 7mm about 37 kg and of 8mm about 43 kg.

I'm an all-chain if I can man, so in my 28 foot wooden boat I carry 50 metres of 8mm. It's a fairly heavy boat, and a tad over 70 kg doesn't put the bow down.
 
brup said:
After advice from other forumites and a fair bit of thunking, I've decided on the following for our 23 footer ...

10m x 7mm chain spliced to 30m x 10mm anchorplait
- this will flake down in the chain locker in the bows

30m x 7mm chain + shackles
- this will be stowed under the main cabin floor and brought up when needed

This is based on the expectation that we will normally be anchoring in pleasant weather and in shallow(ish) water either to wait out the tide (entrance to R. Roach for example) or overnight up a river or creek. I figure therefore that 40m of chain/warp should suffice under normal circs. I doubt we'll be keen on lying to the anchor overnight when it's at all rough or breezy anyway!

Another 30m of chain will give us options in deeper water and/or rougher weather and/or lying to all chain in a tight anchorage where we don't want to swing as much etc. albeit with the extra hassle of having to heave the chain up on deck and stow it away again afterwards but with the great advantage of having the weight stowed as low down as possible and in the middle of the boat (and the space under the floor isn't much use for anything else anyway ... 'cept maybe for keeping the beer cool)

I'll look at adding a snubber for use when lying to all chain if we find ourselves doing so sufficiently often to make it an issue.

Bru
Click to expand...

is there a 7m/m chain ???
 
Many thanks for your varied thoughts on this one. It's obviously down to preference and size of boat, cruising area and budget.

On a related matter, i seem to remember hearing some disparaging remarks about chain from China, and that grade 30 chain wasn't good enough - should be 40. Is this just insubstantiated and anecdotal or pretty well accepted 'fact'?

Thanks again for opinions!
 
Witchwood said:
Many thanks for your varied thoughts on this one. It's obviously down to preference and size of boat, cruising area and budget.
Click to expand...
It's down to a rational assessment of the requirements.

Witchwood said:
On a related matter, i seem to remember hearing some disparaging remarks about chain from China
Click to expand...
When you buy chain you're essentially dependent on the reputation of the manufacturer. Anchor chain should generally be calibrated, tested, and certified. If you don't know anything about the generic no-name junk bought from the sale bin at Dodgy Chandlery Ltd, it's irrelevant if it was made in China or Essex.

Witchwood said:
and that grade 30 chain wasn't good enough - should be 40. Is this just insubstantiated and anecdotal or pretty well accepted 'fact'?
Click to expand...
The grades are just strength figures. Size for size, G30 is 25% weaker than G40, and less than half that of G70.

Lighter is better, nobody likes unnecessary weight on a boat, so stronger chain lets you use a smaller size. It's that simple.

Everything you ever wanted to know about anchor chain: www.rocna.com/kb/Chain
Well possibly that's a slight exaggeration.
 
craigsmith said:
Anchor chain should generally be calibrated, tested, and certified.

Lighter is better, nobody likes unnecessary weight on a boat, so stronger chain lets you use a smaller size. It's that simple.
Click to expand...

Witchwood. If you plan to pull in your chain by hand, which seems likely on your boat, don't waste your money buying calibrated chain - you will add an unnecessary 10% to your bill. But tested and certified is a pretty good idea.

You might take the view that a heavier chain will have a more effective catenary than a light chain and so think that the weight is not unnecessary - but that argument is in many other threads already.
 
Last edited:
Witchwood said:
On a related matter, i seem to remember hearing some disparaging remarks about chain from China, and that grade 30 chain wasn't good enough - should be 40. Is this just insubstantiated and anecdotal or pretty well accepted 'fact'?
Click to expand...

I'm currently researching chain from a wide variety of suppliers. It seems it is now quite difficult to find chain that is NOT made in China, with a couple of exceptions. Doesn't mean it's no good provided quality control is carried out to known standards.
 
You must log in or register to reply here.

Other threads that may be of interest

mogmog2
Maxwell windlass 10 VW looks interesting (to a windlass noob)
2 3
Replies
59
Views
1K
mogmog2
mogmog2

Share this page

Top