Meditteranean mooring stern to on the anchor. How tight should the chain be?

[tudorsailor]

So here I am in the Ionian. I am on the quay, stern to. I dropped the anchor about 4 boats lengths out in about 10 metres I have 70m of chain out and it is quite tight. Once tied up, I applied a bit of reverse and we do not back back further. I have swum over the chain and anchor. The chain hits the sea-bed about half way along. So I guess that with a lot of wind on the nose, the chain can come off the sea bed as we go back into the concrete. So how tight should I have the chain. The tightest it could be would be to be drum tight with no chain on the sea-bed, but that cannot be right can it?


Thanks

Tudorsailor

 

[RupertW]

Doesn't need to be too tight - except perhaps in strongish cross-wind.
ll
The main aim is to keep the boat fairly straight and the stern away from the quay. With 70m in 10m depth you have plenty out and needn't keep it bar taut at all. Basically if you cannot pull the boat back to hit the quay by hand then you are usually fine.

 

[Tranona]

Not sure one can be prescriptive about how tight the chain should be as it depends on so many variables. Tight enough to hold the boat in position - wind is usually not onshore, but often a cross wind so needs to be tight enough to stop the bow swinging. If it is likely to blow at night, best to slacken the stern lines and take the bower cable in to keep the stern away from the wall.

 

[Tony Cross]

I doubt your windlass is strong enough to pull the chain tight enough to get it all off the seabed.

I agree with the above, tight enough to stop you swinging back into the quay in the surges of passing boats but it rarely needs to be bar tight. You'd be happy enough with 70m in 10m depth if you were swinging to it for example.

As has been mentioned it's the cross-winds that are the main problem, often they get quite strong for an hour or so as the sun goes down. As long as your anchor was set properly I wouldn't worry about your anchor and chain. What you do need to worry about is a less experienced boat owner next to you not setting their anchor and putting out too little chain so that they drag down onto you in the late afternoon wind, sometimes in their panicked attempts to retrieve and reset their anchor they'll pull yours out too.

 

[vyv_cox]

When going astern to the wall I stop lowering the chain about half a boat length out to give the anchor a good set into the bottom. I keep motoring astern until I know that the boat has stopped moving. Once berthed to stern lines I pull the chain by hand as hard as I can to ensure as far as possible that the anchor has held. Unless the bottom is a difficult one this is usually enough that it will hold in cross-winds.

 

[chinita]

May help with cross winds if you use a chain hook with a bridle; each side of the bridle (with snubbers if you have them) made fast on port and starboard bow cleats.

 

[mjcoon]

... If it is likely to blow at night, best to slacken the stern lines and take the bower cable in to keep the stern away from the wall.

A useful precaution, if only to discourage unwelcome beasties coming aboard (see other recent thread!).

Mike.

 

[jimbaerselman]

How tight should the chain be?

Tight enough to stop the boat hitting the quay if any of the following events are possible:

(a) strong cross wind
(b) strong head wind
(c) surge due to passing ships, wind or swell

Test that by heaving the boat towards the quay by any suitable means (engine or rope to quay). Using maximum effort, you should be able to pull the boat within a few inches of the quay, and no more.

Now, how far away from the quay should you allow the boat to drift off once you've got the chain right. Answer; a little more than the fore and aft surge of the boat likely to be generated by the disturbances above.

The boat will also be a lot more comfortable in any surge if lines used to pull the boat to the quay are splayed as much as possible. This gives much more "spring", especially if you're using nylon. Splay also reduces any "pull in" towards the quayside in event of crosswind.

If you're rolling at all, consider if your cross-trees are aligned with neighbours. Nothing worse than a game of rutting stags when the midnight ferry arrives . . . good for masthead instrument vendors, bad for your pocket. And one reason I like bows to - keeps me out of line.

 

[Tony Cross]

Tight enough to stop the boat hitting the quay if any of the following events are possible:

(a) strong cross wind
(b) strong head wind
(c) surge due to passing ships, wind or swell

Test that by heaving the boat towards the quay by any suitable means (engine or rope to quay). Using maximum effort, you should be able to pull the boat within a few inches of the quay, and no more.

Now, how far away from the quay should you allow the boat to drift off once you've got the chain right. Answer; a little more than the fore and aft surge of the boat likely to be generated by the disturbances above.

The boat will also be a lot more comfortable in any surge if lines used to pull the boat to the quay are splayed as much as possible. This gives much more "spring", especially if you're using nylon. Splay also reduces any "pull in" towards the quayside in event of crosswind.

If you're rolling at all, consider if your cross-trees are aligned with neighbours. Nothing worse than a game of rutting stags when the midnight ferry arrives . . . good for masthead instrument vendors, bad for your pocket. And one reason I like bows to - keeps me out of line.

From what I read on here Jim, you're often "out of line".

 

[jimbaerselman]

From what I read on here Jim, you're often "out of line".

That comes from a career of assessing the ergonomics of machines, displays, processes, whatever - and then proposing changes to simplify the way they work - or the way they are used.

Disturbing for two groups of people:
(1) Those who have been trained to overcome design deficiences - Mantra: "a bad workman blames his tools"
(2) Stakeholders of accepted inventions/processes/products which are criticised - Mantra: "it works for me"

I've got a list of accepted yachting practices to question. Starts with centre cockpit mainsheets . . .

But that's another thread.