dyneema anchor rode

[rpackard]

I occasionally anchor my 5500lb sailboat on SF Bay. The seabed is a very sticky mud that makes a mess on deck when retrieving the rode. i have no wash down pump and do not wish to install one.Where I anchor there is no wave action and very little wind.

I am thinking about making a rode consisting of 25ft of chain backed by a suitable length of 1/4" dyneema. The dyneema (actually amsteel) is slightly less dense than water so would float off the bottom yet not really lift the chain. The working strength is more than strong enough. Since there is no wave action and not much wind there is no need for elasticity.

The only negative I can imagine is that another vessel crossing in front of me might have its prop get caught in the floating line.

Can others comment on this plan.

[Foswick]

As you may know, there are broadly two kinds of rope: static and dynamic. A dynamic rope is designed with some elasticity, whereas a static rope is designed to minimize elasticity. For anchoring, you need a dynamic rope ... maybe.

Think of rock climbers. They climb using a dynamic rope to catch them if they fall. This is because, if the rope does not have some stretch, the shock of being arrested by that rope could be extremely jarring and damaging. Conversely, if you are rappelling, you want the rope to resist stretch and not give you a bouncy ride as you start and stop.

If you were to use Amsteel as a dock line, the repeated shock to your cleats would put undue stress on them because the Amsteel has very little shock absorption.

But, you don't have quite the same problem when anchoring. The ground tackle has some inherent "boing" to it when you lay out a good length of chain. So, this might be adequate shock absorption. Someone else would need to do the math on this - I'm not up to it tonight.

If I were to use Amsteel, I think I would be inclined to incorporate a snubber just to be sure. I honestly doubt it would transmit much shock to your equipment except in particularly rough conditions. But, it would probably add some safety and comfort to add a snubber.

[fxykty]

Originally Posted by rpackard

…
The only negative I can imagine is that another vessel crossing in front of me might have its prop get caught in the floating line.
...

This is the problem, unless you are anchoring very shallow such that you have enough scope with your length of chain plus 2x the depth of water of Amsteel. If you need more than 2x depth of water of Amsteel to provide sufficient scope then you are going to be a menace to every boat that goes past. And even your own boat as it circles around with the tidal currents when there’s not much wind.

And, as mentioned, you will need an elastic snubber to protect your windlass and/or bow cleat when it gets windy.

[s/v Jedi]

“
I need a deck wash pump but I don’t want to install one so I come up with an untested plan that could potentially cost me my boat or at least bring other boats in trouble with my rode in their props, but my dislike of installing a deck wash pump is of greater importance to me than that so I push ahead and ask the forum if it’s okay to find support and suppress my gut feeling of it being a bad idea. It doesn’t matter what people post because nothing will change my mind and I’ll go ahead anyway because nobody will prove that it doesn’t work, so it will work
“

Just an impression for entertainment purposes only

[GordMay]

An earlier discussion [2017]:
Dyneema Anchor Rode ➥ https://www.cruisersforum.com/forums...de-191436.html

Dyneema/Spectra* Anchor Rode for Drum Winches
1/4” Orange Dyneema w/8900# tensile, spliced into 1/2” Double Braid Nylon Shock line, spliced into 1/4” Grade-40 Hot Galv. chain. We can make any combination of lengths, sizes & even offer stainless steel chain.
➥ https://www.arcticwirerope.com/awr-p...-drum-winches/

* Ultra-High Molecular-Weight Polyethylene [UHMWPE]

[Benz]

Quiet water, short scope, decent snubber? I'd give it a try and see how it feels.

[malbert73]

Originally Posted by rpackard

I occasionally anchor my 5500lb sailboat on SF Bay. The seabed is a very sticky mud that makes a mess on deck when retrieving the rode. i have no wash down pump and do not wish to install one.Where I anchor there is no wave action and very little wind.

I am thinking about making a rode consisting of 25ft of chain backed by a suitable length of 1/4" dyneema. The dyneema (actually amsteel) is slightly less dense than water so would float off the bottom yet not really lift the chain. The working strength is more than strong enough. Since there is no wave action and not much wind there is no need for elasticity.

The only negative I can imagine is that another vessel crossing in front of me might have its prop get caught in the floating line.

Can others comment on this plan.

Dyneema = terrible idea because it floats. Others are at risk (and hence you when they cut free) and also if you have light wind and swing around you will also wrap the rode around your rudder and keel.

I anchor in chesapeake bay with muddy bottom and now rarely commission or use my installed deck wash. My bow is fairly raked and I have an electric windlass with foot buttons. I use a boat hook to shake the chain vigorously as I raise it by pulling aft and releasing again and again. I’ve used both this and my deck wash and this method is faster and cleaner for me. When I get into a rhythm I don’t need to stop the windlass.
If you have a plumb bow this may damage your stem.
Without a windlass you could just shake the rode as you raise it.
A good quality stainless steel chain will shed mud much better but is super expensive and could also not be as strong unless you buy the high end type

[Kettlewell]

On a boat that small I would first try going for just a short length, say 6 feet of chain, and then use an all-rope rode. Double braid nylon holds much less mud than three-strand too.

[thinwater]

Originally Posted by Benz

Quiet water, short scope, decent snubber? I'd give it a try and see how it feels.

How do you attach the snubber? Any friction hitch will slide.

[thinwater]

Originally Posted by Kettlewell

On a boat that small I would first try going for just a short length, say 6 feet of chain, and then use an all-rope rode. Double braid nylon holds much less mud than three-strand too.

I used climbing rope on my first cruising boat on the Chesapeake bay (sticky mud). It has a very tight weave, compared to yacht ropes, to resist snagging on rocks and chafe. It has the right stretch characteristics, is very durable, has a good hand, and does not pick up much mud. The main downsides are:

• Price. Mine was very lightly used, with 15 feet cut away that had been damaged on one end (crampon strikes). Too short for climbing use, but still 140 feet + some chain.
• Can't be spliced. But it takes knots with less loss in strength than other ropes.
• Not compatible with a windlass, but I'm guessing you don't use one.

[leecea]

We use a cordless power cleaner and it does an OK job of reducing (not eliminating) the mud in our chain. Nylon rode would be easier to clean. After use, we run about 1/3 gallon of fresh water through it.

[Tupaia]

What about a floating buoy attached to the rode, at a distance just less than the depth, from the rope chain connection. Commonly used to protect the rope on a chain/rope combo from chaffing on coral by holding the rope vertical. Any force on the boat simply sinks the buoy. In a crowded area there is still the possibility of someone snagging it but less likely than a free floating rope. It is still much closer to the boat than an anchor buoy would be.

[Foswick]

Originally Posted by s/v Jedi

Just an impression for entertainment purposes only

That is unfair. They asked a legitimate question. This is not a common solution, they are considering doing it, they want to know about possible pros/cons they may not have thought of.

Dyneema is relatively new to the landscape and people are still finding new places that it does and doesn't work well on boats. It seems a perfectly reasonable inquiry.

As it happens, I don't think it is a good idea because what you would need to do to mitigate the problems it brings would offset any benefit you might gain. But, that doesn't mean someone shouldn't ask the question.

[Foswick]

Originally Posted by Tupaia

What about a floating buoy attached to the rode

If a person were to use a floating rode, I think a better solution would be to use a kellet near the boat-end of the rode. Better to try to sink the rode than to help it float.

A kellet would bring its own set of risks, though. I can see a situation (with shifting currents/winds/tides) where the kellet is dragged close enough to the anchor that it creates slack between the kellet and the anchor. If this slack floated it could foul a prop.

[Benz]

Originally Posted by thinwater

How do you attach the snubber? Any friction hitch will slide.

A slipped fishermen's anchor bend to a hook spliced at the end of the snubber.
Mind you, I wouldn't want a Dyneema rode in this situation myself, but I'm not against spitballing off-the-wall solutions. Who knows what might develop?