Too much rode ?

[billyfish]

New boat is the same length as the old boat but half the weight. Still with a long keel .at anchor I put out more scope when the wind picks up as it did last night in a storm . Only in 3mt depth had 20mt out old boat would just sit there. New boat with more wind age yaws all over the place finally disloging the hook from the bottom..can you put out too much chain I wondered

 

[RichardS]

You definitely can't use too much scope in terms of holding.

Richard

 

[Binnacle]

I think it may be easy to suggest some anchoring conditions when too much scope could get you into trouble, e.g. tangling with other nearby anchored boats, or as the OP suggests, enabling the boat to become frolicsome.

 

[Mistroma]

I think a more likely reason is that your new boat has more windage forward of the centre of lateral resistance.

 

[RichardS]

I think it may be easy to suggest some anchoring conditions when too much scope could get you into trouble, e.g. tangling with other nearby anchored boats, or as the OP suggests, enabling the boat to become frolicsome.

I'm not sure what tangling with other boats has got to do with holding?

As for frolicsome .... the opposite is the case.

Richard

 

[Tranona]

Suspect the cause of dragging was that the anchor was not properly dug in - either because it is a poor anhcor, the seabed was poor (or a combination of both) or you did not dig it in enough when you set it. Chain has little to do with holding power. It is not the yawing per se that affects the holding, but the rode being stretched enough to pull the anchor, and probably not straight pull because of the yawing..

Hate to say it but type of anchor, boat seabed and estimated wind strength might help give some better response.

 

[Jamie Dundee]

Could the lighter boat have failed to set the anchor as securely as the old, heavier boat?

 

[penfold]

You may benefit from a riding/anchor sail. @Neeves will be along shortly to fill in the gaps about matching ground tackle to boat.

 

[thinwater]

... It is not the yawing per se that affects the holding, but the rode being stretched enough to pull the anchor, and probably not straight pull because of the yawing....

Afraid not, or at least exactly. Active yawing, all other things being equal, can reduce holding capacity by 2/3 compared to a boat that yaws less than 30 degrees. I've done the side-by-side testing and published the same.

Yawing...

• Increases the tention on the rode, both because the wind sees the boat from the side, and in some cases, because slack comes out of the rode causing snubbing.
• The anchor can be wiggled, reducing consolidation around the fluke. Once an anchor starts to walk, it will eventuall trip when it hits a bad spot.

You need to stop the yawing. More than 30 degrees change in heading is too much. That long keel is pretenting a lot of resistance aft. A riding sail helps. If there is a dinghy on the foredeck, remove it. A large drogue from the bow or rode helps.

 

[Rappey]

My 16ft centre consol yaws like crazy on its mooring.. It had galvanised 10mm chain then some very large stuff on the seabed. Its also tidal but mostly afloat.
After nearly 6 years on neglect it failed but it was the shackle that joined the 10mm to the huge chain below that vanished...
Went a bit crazy this time and put what must be well over 20mm chain.
I noticed last night during the thunder and lightning the boat was hardly yawing at all !
So from my possibly useless post i would conclude if you put 3" chain on your boat it would stop yawing

 

[noelex]

New boat is the same length as the old boat but half the weight. Still with a long keel .at anchor I put out more scope when the wind picks up as it did last night in a storm . Only in 3mt depth had 20mt out old boat would just sit there. New boat with more wind age yaws all over the place finally disloging the hook from the bottom..can you put out too much chain I wondered

To calculate scope you need to include the bow roller height. Assuming this is about 1m (this is worth measuring) you had a scope of 5:1. This is more than enough in most conditions, but if this was storm force winds especially in a relatively shallow anchorage I would suggest more scope (assuming there is enough room to deploy this safely).

 

[V1701]

I know it's natural to but I don't think it's particularly useful to compare with what you think the old boat would have done in the same situation. Work with the information that you have, we'd need more info to be able to make suggestions that might prove useful. Out of interest may I ask what are the old & new boats?

 

[Refueler]

Lighter boat .... windage ... all can make a boat 'frittish' on the water at anchor.

You only have to compare a high top hamper MoBo with a lower structure but heavier sailboat of same LOA .... guess which yaws about more ...

This is something I have posted about before when people talk about anchors etc.

Too much rode ? The only possible problem is then swinging close to another boat .... but hold ? It should not reduce hold ... but improve it.

 

[billyfish]

Well lots to think about .cheers. in answer to a couple of questions my old boat was a Heard falmouth work boat 9 ton. New one a Degero 28 . A what ? A Finnish motor sailer , very civilised, heaters hot water fridge. Oh and it sails. I was in Newtown creek been going there for over 50 years holdings fine. But there was a lot of that thick green gunky weed I think that might have been a factor . With wind over tide as well ? it was 30 knots of breeze in the storm and the boat was going well more than 30 degrees at times. I think the hook and chain are fine 10kg Bruce. 8mm chain . Not been a problem before. Was in more breeze in Portland a little while back and it held fine and you know how a westerly whistles through there.. maybe I was just unlucky last night with top of the tide and big storm coming through at the same time. Hey ho keeps me on me toes ???

 

[Tranona]

Well lots to think about .cheers. in answer to a couple of questions my old boat was a Heard falmouth work boat 9 ton. New one a Degero 28 . A what ? A Finnish motor sailer , very civilised, heaters hot water fridge. Oh and it sails. I was in Newtown creek been going there for over 50 years holdings fine. But there was a lot of that thick green gunky weed I think that might have been a factor . With wind over tide as well ? it was 30 knots of breeze in the storm and the boat was going well more than 30 degrees at times. I think the hook and chain are fine 10kg Bruce. 8mm chain . Not been a problem before. Was in more breeze in Portland a little while back and it held fine and you know how a westerly whistles through there.. maybe I was just unlucky last night with top of the tide and big storm coming through at the same time. Hey ho keeps me on me toes ???

Mud in Newtown is usually good holding. I anchored in Clamerkin last week and it reminded me of a time around 1983 Cowes week being stuck for 3 days because of the storms. Watching yachts going out to play racing and some coming back sans mast! Wind mainly westerly and the 25lbs CQR dug in on the west side of the channel and sitting on the mud on the east side at low tide. Real struggle to break the anchor out when things calmed down.

Anyway suspect your problem was the changes in tide and wind direction meant that you were at full stretch of chain on a less than straight pull of a less than securely dug in anchor. More or less chain would only change the position you dragged from.

 

[Neeves]

The yawing in itself is not an issue. Its the snatch at the end of the yaw that is the problem.

You set you anchor for what you consider is the prevailing wind and then your yacht careers all over the place at more than 30 degrees each side of the set direction - comes to an abrupt stop at the end of each yaw and you wonder why the anchor does to hold.

Imagine - your yacht rushes over to port and bashes the shank to one side, you then rush over and bash the shank on the other side - loosening the hold each time. No wonder you drag.

Manage the veers.

Veerring is debilatating for the crew even if nothing else.

Anchor ing in 'V' will reduce veering. If the yacht can accept a bridle, it will be in a 'V' it will reduce veering. Adding a snubber will reduce the snatch at the end of the veers. A Hammerlock can work, simply drop an anchor off the bow allowing it to drag across the seabed but not enough to set - it will slow the veers.

Read the July issue of Yachting Monthly - there is an article on snubbers.

A Snubber & Hook for all Occasions | Practical Sailor

How to: Dealing with Snatch Loads in an Anchorage

Anchor Snubber Tips

Know how: Expanding your Anchoring Repertoire

Know how: Ground Tackle

Shock load on mooring/anchor chain & fittings

I think this thread has an educational spread sheet from MathiasW quantitatively defining and underlining the value of a snubber.

That should keep you busy.

Jonathan

Whilst a better anchor might resist the yawing and be more secure the better anchor will not stop the yawing. As mentioned if the yacht is rushing about like a demented cow - you will not relax - focus on reducing the yawing, see Thinwater's post.

 

[William_H]

If htere was a lot of weed on the bottom that would explain the anchor failing. The weed just balls up around the anchor to allow it to skip across the bottom. The best anchor for weed is an old fashioned fisherman's anchor. The narrow fluke will hopefully dig through the weed. ol'will

 

[Neeves]

A close, modern, cheap and efficient alternative to a Fishermans is a Kobra. Used by a number of members here. Has stood up well in independent tests.

Its similar to a Fishermans is that it is a, very, narrow fluke (one reason to use a Fishermans) which will work its way through the weed bed, has no roll bar to clog and is applicable in other seabeds, such as sand. The fact it is also cheap, available in many UK chandlers, relatively easy to store (or carry on a bow roller) is also advantagous.

What's not to like?

Answering that

On the other hand the narrow fluke does not offer a large surface area - which is what you need in mud and then a Fortress stands head and shoulders above the rest.

So for mud, large surface area, for weed narrow fluke, small surface area..

Horses for courses - no anchor is perfect, they are all a compromise.

Jonathan

 

[Neeves]

Could the lighter boat have failed to set the anchor as securely as the old, heavier boat?

Its a crude analysis but most auxiliary engines can develop at full cruising revs the same tension in the rode as might develop for a 30 knot wind. Beyond 30 knots the tension will increase as a result of windage and should set the anchor more deeply. I've measured this using a load cell and its not 'accurate' for all yachts but a decent rule of thumb. At a typical tension at 30 knots and typical scope etc etc the rode will look straight, obviously not straight but as good as (and there is little or no catenary left). The other 'rue of thumb' again an approximation is that at a 5:1 scope in about 5 depth all your chain will have lifted off the seabed at around 17/20 knots - so its all 'catenary'. This all varies dependent on whether you chain size is 'about' right or over/undersized, whether its an 'untypically' deep or shallow anchorage etc etc.

However how many people power set (at all) their anchor at full cruising revs and hold at the tension for a minute or so is a different question.

Jonathan

 

[Laminar Flow]

A close, modern, cheap and efficient alternative to a Fishermans is a Kobra. Used by a number of members here. Has stood up well in independent tests.

Its similar to a Fishermans is that it is a, very, narrow fluke (one reason to use a Fishermans) which will work its way through the weed bed, has no roll bar to clog and is applicable in other seabeds, such as sand. The fact it is also cheap, available in many UK chandlers, relatively easy to store (or carry on a bow roller) is also advantagous.

What's not to like?

Answering that

On the other hand the narrow fluke does not offer a large surface area - which is what you need in mud and then a Fortress stands head and shoulders above the rest.

So for mud, large surface area, for weed narrow fluke, small surface area..

Horses for courses - no anchor is perfect, they are all a compromise.

Jonathan

We replaced a 35 pound genuine CQR with a16kg Kobra. The Kobra has a considerably larger and wider blade area than the former.

I have not yet had the opportunity to test the Kobra in weed, but the CQR which, apart from the swivel, has a similar configuration has the nasty habit of collecting a large clump of weed or kelp around it's shank which prevents setting.

That said, there is no comparison between the CQR and the Kobra when it comes to ease and speed of setting. Well satisfied with the upgrade.