Length of Chain

[Bluewaters2812]

If you have an anchor winch which will pull both, a solution is to go half chain, half nylon rope. This has several advantages: lighter, and you get a built-in snubber. If you are anchoring on rock or coral, however, the rope will chafe and may break.

Given the choice, I'll take chain.

[/QUOTE]

Am I sort of on the mark so to speak if I am planning on about 60metres of chain and 40metres of rode for a 44 - 48 footer? I would think that 60 metre chain will go deep enough to cover the coral sections down below?

[Seaworthy Lass]

Originally Posted by Amnesia II

People, 100m of 3/8" chain is VERY heavy, in the bows of a 36 foot boat while sailing in any sort of lumpy sea. In my opinion talking 8:1 & 10:1 is enormous ratios to apply when anchoring, normally 4 or 5:1 is very acceptable. Don't forget too a well sized anchor for your boat, equally important as amount of chain.

Yes, unfortunately this much chain is very heavy. We had 50m of chain and 50m of 28mm nylon rode previously, so as Carsten mentions, this is an option if coral is not a concern. The transition between the two is, however, a real pain if you are dragging and need to haul up in rough conditions.

For me, 7:1 is the minimum I am comfortable with at 40 knots (depends on the holding) and it is common to get this with the meltemi in the Aegean in summer. If you have 1.5m from the bow roller to the water, 50m limits you to anchoring in less than 5.5m if you want 7:1. Yes, many boats don't carry more than this, but also many drag once the wind picks up over even 25 knots. So length of chain carried depends not only on the amount of space in your chain locker, but also how much peace of mind you want if you are anchoring out often.

[GordMay]

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[carstenb]

Bluewater,

Do yourself a favor and read Peter Smiths website. It is the most comprehensive dissertation on anchoring I have seen. But, yes, generally a 60/40 will do it. However, if you have a calm day and the current changes several times, the rode will chafe on the coral below. Not a problem per se, but should the wind come up. Well, anything can happen.............

[Seaworthy Lass]

Originally Posted by Bluewaters2812

Am I sort of on the mark so to speak if I am planning on about 60metres of chain and 40metres of rode for a 44 - 48 footer? I would think that 60 metre chain will go deep enough to cover the coral sections down below?

Coral is like razor blades when it comes to rode. Coral bommies are common in many spots - little steep hills/columns that can rise off an otherwise sandy bottom. In some spots it is not uncommon to have one not far below your keel when you swing around at anchor. So the only safe amount of rode to use is a couple of metres - ie your snubber.

The transition between chain and rode can be more than annoying. Had a very nasty experience dragging in one 60+ knot blow a few years back here in the Med and trying to haul up a dragging anchor with chain/ rode combination (two up at night, zero visibility). Don't ever want a repeat of that!!!!

[Bluewaters2812]

Originally Posted by carstenb

Bluewater,

Do yourself a favor and read Peter Smiths website. It is the most comprehensive dissertation on anchoring I have seen. But, yes, generally a 60/40 will do it. However, if you have a calm day and the current changes several times, the rode will chafe on the coral below. Not a problem per se, but should the wind come up. Well, anything can happen.............

I am a risk taker but when it comes to the sea I don't push it before I try and get the odds in my favour if that makes sense. Perhaps 70/40 then? I would think a 44-48 footer should handle the weight?

[Bluewaters2812]

Originally Posted by Seaworthy Lass

Coral is like razor blades when it comes to rode. Coral bommies are common in many spots - little steep hills/columns that can rise off an otherwise sandy bottom. In some spots it is not uncommon to have one not far below your keel when you swing around at anchor. So the only safe amount of rode to use is a couple of metres - ie your snubber.

The transition between chain and rode can be more than annoying. Had a very nasty experience dragging in one 60+ knot blow a few years back here in the Med and trying to haul up a dragging anchor with chain/ rode combination (two up at night, zero visibility). Don't ever want a repeat of that!!!!

I guess then it might make sense to put out a stern anchor if you know there is coral that can cut your rode if you swing. Obviously there are a few conditions that this would not be advisable (like if there are others anchored nearby on a single anchor).

[Seaworthy Lass]

Originally Posted by Bluewaters2812

I guess then it might make sense to put out a stern anchor if you know there is coral that can cut your rode if you swing. Obviously there are a few conditions that this would not be advisable (like if there are others anchored nearby on a single anchor).

A stern anchor is an option, but it would get messy if you start to drag and need to reanchor. Also you tend to get tidal variations if in a coral region, so in practice it would be hard to get the slack right to keep the rode off the coral.

The most successful technique I have seen is to buoy the rode, but it is time consuming and really only suitable as an occasional measure in extreme conditions.

[carstenb]

Bow and stern anchors are generally not advisable. If the wind shifts, say 90 degrees, your boat will be lying beam to the wind (broach situation), and will take a pounding. As seaworthy lass mentioned, you will also not "swing" as the other boats do and will end up bumping into each other.

[zeehag]

my formosa41 has 194 ft chain...is not marked.
i know when i have down the length i want --i count backwards from bitter end, which is secured below decks in my anchor locker. i use no rope rode--isnt safe when rocks are in the mix on bottom...i usually allow for 125-150 ft in rough anchorages, and depth of water where i anchor is usually around 25 ft in anchorage. when it is windy, i add to make 170 ft down.
i have yet to see or encounter anyone here using more than one anchor to hold boat in these anchorages. too many boats occupy anchorages for bow and stern anchoring.
practice before you go cruising--is a good skill to know---by the time you are ready to leave, you wont have to count chain anymore--and there will be less nervousness when you do anchor.

[Dockhead]

Originally Posted by Seaworthy Lass

When calculating scope, people often forget to take the vertical distance from the water to the bow roller into account (about 1.5m in our case).
So 8:1 with 100m of chain means maximum depth of 10.5m, not 12m for us.

In northern Australia we commonly needed to anchor in 15m (so 100m would give only 6:1) and the same applied in Tonga.

Here in the Aegean we are usually in water less than 10m, so we usually use less than 50m of our chain, but in summer it is nice to be able to anchor deeper a little further out to avoid the crowds, and if we want 10:1 when 50+ knots is forecast (usually a couple of times a year) 100m of chain still restricts us to anchoring in 8.5m or less.

You don't need as much scope in deep water -- see for example notes about this in the Rocna Knowledge Base. I think 10:1 is overkill anywhere; in 15 meters of water 5:1 or 6:1 is already at the edge of disappearing returns, as far as I understand.

Another factor to consider is what other people have out. 10:1 in the UK would get you into trouble swinging into other boats, as it is commonly believed here that 3:1 or 4:1 is plenty. I don't approve of that practice -- I like to have out no less than 6:1 unless in very deep water, and 8:1 in strong weather if there's less than 6 or 7 meters of water. But if I put out 8:1, I make sure I am very far away from other boats, because almost no one around here puts out that much under any circumstances. In more settled weather, I am ok with 6:1.

[Dsanduril]

OK, I've broken out the asbestos and Nomex, let the flame throwing begin

Even in the "third world" countries where we like to cruise and ignore regulation, if you are anchoring in such a way that you are damaging coral then you are likely breaking the law. Living coral is a valuable resource, not least because it brings in tourist dollars, but also because of the critical eco-system it supports. Just because your all-chain rode can survive getting wrapped around a coral head doesn't mean you should allow it to do so.

Our general practice, when we can't find enough sand for full swinging room is to go with a Bahamian moor. That way you swing with the wind but restrict the movement of your rodes to a very small area. Have also found this quite successful when we are in a crowded anchorage and I want to put down 7:1 or 8:1 and all of my neighbors are using 3:1 or 4:1. With a little slack in each rode we can mimic the lesser scope boats quite well. Yes, it means dealing with two anchors. Yes, the rodes can get twisted. Has the advantage that once dug in your anchor(s) never have to change direction/reset. I feel more comfortable leaving the boat when I know that even if the wind/tide shifts 180 degrees I have an anchor facing that direction, with sufficient scope, and yet by playing with the slack I can have the same swinging circle as the nearby boats and not ruffle any feathers.

[Bluewaters2812]

[QUOTE=Dsanduril;1065908]OK, I've broken out the asbestos and Nomex, let the flame throwing begin

Even in the "third world" countries where we like to cruise and ignore regulation, if you are anchoring in such a way that you are damaging coral then you are likely breaking the law. Living coral is a valuable resource, not least because it brings in tourist dollars, but also because of the critical eco-system it supports. Just because your all-chain rode can survive getting wrapped around a coral head doesn't mean you should allow it to do so.


I'm sure nobody deliberately or intentionally drags their chain across coral reefs. The discussion I am sure was in the event of it happening unintentionally or because of severe conditions.

[Dsanduril]

Originally Posted by Bluewaters2812

I'm sure nobody deliberately or intentionally drags their chain across coral reefs. The discussion I am sure was in the event of it happening unintentionally or because of severe conditions.

I'd like to believe that, I really would

[Cheechako]

Originally Posted by Stumble

An afternoon with two cans of spray paint tied up along a shore pier and the chain is vividly marked, and will last for years. Just alternate the colors every 25 foot, and count the number of color changes as it spools out.

....or even that bright flourescent yarn sold for fishing works well. Just mark your chain or rode in a convenient manner. I marked mine every 5 fathoms (30 feet)