Polyester Rode

[thinwater]

In the US the shouting would have begun with the title. Pure heresy. Only nylon should be used for rode (or chain, of course--let's not go there right now). Polyester does not stretch. But of course, it does, just not as much. The WLL of polyester is nearly double and chafe is about 2-3 times less.

How much nylon do you need to absorb surge? Or chain? Or polyester? The answer, of course, is that with the correct length, they can all work. In fact, it has been demonstrated that too much stretch an increase yawing, increasing rode tension.

A short length of polyester with just 3 meters of chain in shallow water is a jackhammer. Nylon is smoother. But what about deeper water where more chain and polyester would be deployed? Certainly, as a long extender on 200 feet or so of chain polyester would be a good choice. I wonder if the US habit is related to vast shallow areas, and lots of powerboats that don't use much chain, only a token.

It's difficult to even find polyester anchor rope in the US.

Discuss.

 

[B27]

Nylon used to more cost effective.
Now, for a long anchor rode, I can save money by choosing polyester a few mm smaller.
In the English Channel, the tidal range can mean deep water and long rodes.
For my boat, a dyneema halyard is cheaper than a nylon anchor line.

As I don't have a windlass, I can use a mixed rode and not have issues with splices on the windlass or whatever.

 

[Snowgoose-1]

Not a great fan of nylon. Seems to go quite hard over time. I used to keep a bight of nylon as a snubber but now use poly with a rubber mooring whatsit. Tried a nylon strop on a swinging mooring and the lay used to unwind with constant swinging with the tide. As mentioned, polyester is well priced now.

 

[Neeves]

For my boat, a dyneema halyard is cheaper than a nylon anchor line.

I don't quite understand this without knowing the yacht, height of mast, usual anchoring locations, depths.

 

[B27]

I don't quite understand this without knowing the yacht, height of mast, usual anchoring locations, depths.

A new anchor warp is the most expensive bit of string on the boat.
It's not unusual to anchor in 10m of charted depth plus 5m of tide.
Planning to venture to France next year, there is more tide.

 

[Zing]

Agreed. It should be fine. Shock loading is proportional to stretch, length of rope and load/breaking strain. So increase the length and / or decrease the rope diameter to equal the stretch you would have had with nylon. (Obviously paying regard to having sufficient strength). Dyneema is much stiffer than polyester even and works well as a shore line, because you use long lengths. I’ve also used dyneema halyards many times as a rode for my kedge with 60m out and experienced zero shock loading.

 

[Neeves]

A significant problem with dyneema is that it floats, Not a problem if you are combating strong winds but if the wind drops off, another yacht comes into the anchorage in the dark (not uncommon) ands gets your rode round his prop.

Suddenly you are rafted up and the other yacht is immobilised (in the dark).

Dyneema is fine as a kedge depending on what your understand is of the word 'kedge' - thinking Dyneema offers any elasticity is a joke - the very reason you use it for a halyard should underline - it has no elasticity. If you have 60m dyneema halyards - you have a very large yacht.

Dyneema can be useful as a shore line - as the elasticity of your other components, chain or nylon, offer the shock loading. Additionally if you use shore lines you are trying to immobolise the yacht - no movement, no shock loads

Here the anchorage, off Bass Strait, is tiny but the winds, an effect of a Storm, are bullets coming in unexpected directions. We have a bridle off the transoms to an eye and then one line to trees and have deployed two anchors off the bows in a fork. Blaze a UK yacht, making a circumnavigation, has 2 shores lines and one anchor.


Jonathan

 

[B27]

Agreed. It should be fine. Shock loading is proportional to stretch, length of rope and load/breaking strain. So increase the length and / or decrease the rope diameter to equal the stretch you would have had with nylon. (Obviously paying regard to having sufficient strength). Dyneema is much stiffer than polyester even and works well as a shore line, because you use long lengths. I’ve also used dyneema halyards many times as a rode for my kedge with 60m out and experienced zero shock loading.

Do you mean 'kedging against the tide' in no wind?
We've done that a few times racing, one boat used to carry a whole coil of that blue 'lorry rope' for the purpose.

 

[jdc]

I use polyester 3-strand for the (extension to chain for the) anchor rode. It was recommended to me for the purpose by a man from English Braids instead of Nylon, and I've found it excellent over some 10 or more years. It seems to have enough stretch, certainly with 60m of chain, and it remains flexible and re-spliceable unlike Nylon. All round, the better choice I think.

 

[Zing]

Do you mean 'kedging against the tide' in no wind?
We've done that a few times racing, one boat used to carry a whole coil of that blue 'lorry rope' for the purpose.

A kedge being a secondary anchor can be used for many purposes. I mostly use mine for holding the boat to an angle, the wind or the swell, which is what I am referring to here.

 

[Zing]

A significant problem with dyneema is that it floats, Not a problem if you are combating strong winds but if the wind drops off, another yacht comes into the anchorage in the dark (not uncommon) ands gets your rode round his prop.

Suddenly you are rafted up and the other yacht is immobilised (in the dark).

Dyneema is fine as a kedge depending on what your understand is of the word 'kedge' - thinking Dyneema offers any elasticity is a joke - the very reason you use it for a halyard should underline - it has no elasticity. If you have 60m dyneema halyards - you have a very large yacht.

Dyneema can be useful as a shore line - as the elasticity of your other components, chain or nylon, offer the shock loading. Additionally if you use shore lines you are trying to immobolise the yacht - no movement, no shock loads

Here the anchorage, off Bass Strait, is tiny but the winds, an effect of a Storm, are bullets coming in unexpected directions. We have a bridle off the transoms to an eye and then one line to trees and have deployed two anchors off the bows in a fork. Blaze a UK yacht, making a circumnavigation, has 2 shores lines and one anchor.
View attachment 177601

Jonathan

Shore lines are always on or nearly on the surface regardless of the material of the rope, so your point is not applicable there. I would buoy it anywhere regardless however if there was a chance of someone running into it. If halyards are used they usually sink, because they normally have enough polyester in the cover to overcome the small amount of buoyancy of dyneema.

Dyneema has about a 2% stretch at 50% ABL. On a shore line that could mean 1m to 1.5m of stretch. That is not 'no elasticity' as you term it. It is sufficient in anything but severe conditions.

Note it is common for large ships to use only dyneema for docking or buoy berthing lines. I wouldn't advocate doing that on our little boats, but for ships it's different, because they don't move very much and it works for them. Horses for courses.

 

[thinwater]

Do you mean 'kedging against the tide' in no wind?
We've done that a few times racing, one boat used to carry a whole coil of that blue 'lorry rope' for the purpose.

Around here (Chesapeake Bay) kedging nearly always means pulling yourself out of the mud. You only need to use nylon once to appropriate the folly. But often it is all they have.

Good discussion. As I said in the opening post, the chandleries in the US don't carry polyester anchor rope. None. The recommendation page lists the reasons not to use it. Even ABYC only recommends nylon. Then again, with a small tidal range and generally shallow water, I've cruised the whole east coast, from the northeast into the islands, and only deployed more than 100 feet of rode a few times, and then only to get very long scope. I carried 100 feet of chain and only got the rope wet a few times. It's different.

 

[Refueler]

Note it is common for large ships to use only dyneema for docking or buoy berthing lines. I wouldn't advocate doing that on our little boats, but for ships it's different, because they don't move very much and it works for them. Horses for courses.

Never seen Dyneema on ships .....

Polyprop
Steel
Polyprop with steel core
Titan composite

Dyneema ?? Maybe under another name ??

 

[Aja]

A significant problem with dyneema is that it floats, Not a problem if you are combating strong winds but if the wind drops off, another yacht comes into the anchorage in the dark (not uncommon) ands gets your rode round his prop.

Suddenly you are rafted up and the other yacht is immobilised (in the dark).

Dyneema is fine as a kedge depending on what your understand is of the word 'kedge' - thinking Dyneema offers any elasticity is a joke - the very reason you use it for a halyard should underline - it has no elasticity. If you have 60m dyneema halyards - you have a very large yacht.

Dyneema can be useful as a shore line - as the elasticity of your other components, chain or nylon, offer the shock loading. Additionally if you use shore lines you are trying to immobolise the yacht - no movement, no shock loads

Here the anchorage, off Bass Strait, is tiny but the winds, an effect of a Storm, are bullets coming in unexpected directions. We have a bridle off the transoms to an eye and then one line to trees and have deployed two anchors off the bows in a fork. Blaze a UK yacht, making a circumnavigation, has 2 shores lines and one anchor.
View attachment 177601

Jonathan

Refuge Cove?

 

[Roberto]

I wonder if the US habit is related to vast shallow areas, and lots of powerboats that don't use much chain, only a token.

It's difficult to even find polyester anchor rope in the US.

America is a vast country, plenty of space air land sea, no need to anchor stern-to concrete walls as canned sardines

 

[Neeves]

Refuge Cove?

Correct. I did not mention it as the name is largely irrelevant for the majority.

Most of the time its empty, being a bit too far from Melbourne. But holiday times it can be packed - which comes as a bit of a shock. There is an enormous open bay just to the south, whose name I forget, that offers shelter from the west and south west.

Jonathan

 

[Neeves]

America is a vast country, plenty of space air land sea, no need to anchor stern-to concrete walls as canned sardines

Similar to Australia - I've never seen stern to anchoring here.

Jonathan

 

[Neeves]

Never seen Dyneema on ships .....

Polyprop
Steel
Polyprop with steel core
Titan composite

Dyneema ?? Maybe under another name ??

Common place on, at least some, cruise ships.

J

 

[Neeves]

Shore lines are always on or nearly on the surface regardless of the material of the rope, so your point is not applicable there. I would buoy it anywhere regardless however if there was a chance of someone running into it. If halyards are used they usually sink, because they normally have enough polyester in the cover to overcome the small amount of buoyancy of dyneema.

Dyneema has about a 2% stretch at 50% ABL. On a shore line that could mean 1m to 1.5m of stretch. That is not 'no elasticity' as you term it. It is sufficient in anything but severe conditions.

Note it is common for large ships to use only dyneema for docking or buoy berthing lines. I wouldn't advocate doing that on our little boats, but for ships it's different, because they don't move very much and it works for them. Horses for courses.

In the picture I posted of Refuge Cove (thanks Aja ), copied again below, with ourselves and Blaze with shore lines and multiple anchors


We arrived late having just crossed Bass Strait from Three Hummock Island. There was a Storm warning issued for that night and the next day. We were obviously a bit jaded as we only made Refuge as the wind was building. Its a 36 hour crossing and a tight reach all the way, and it was getting dark. Blaze was the only yacht in the anchorage, thoughtfully anchored to one side. But Blaze must have arranged their lines at high tide and we arrived at low tide and their lines were slack. We had no idea they had shore lines, they appeared to be using one anchor. We went to go round their stern, close to, to ask how much rode they had deployed. In the dusk their slack lines were invisible. Fortunately they had seen us approaching and ran out, husband and wife, in a panic to warn us off - what they were screaming about was not obvious - and our attention was on them - not the lines lying on the dark water surface and slackly snaking up the beach to the trees (where there was large notice 'Do not tie to the trees').

They had no buoys nor lights on the shore lines.

We got the, or a, message and reversed our from our intended course.

Don't assume people will have buoys or lights for shore lines.

The reality is that shore lines in Australia are very uncommon. They are used in Tasmania, because Tasmania has a Storm warning at least once a month, through the summer (and presumably more frequently in winter). But Tasmania is not the preferred destination as Bass Strait is a major obstacle. We used them, anywhere, as we could anchor quite close to shore. We carried short lengths of retired chain for shore lines round rocks.

Jonathan

 

[Refueler]

Common place on, at least some, cruise ships.

J

Maybe ... I don't Superintend Cruise Ships - but I can soon ask my Brother if I was really that interested .. who conducts Classification Society Inspections of them in Florida.