Anchoring in heavy conditions

I suspect wire rope would relay a harder shock load to the anchor than chain due to it's lighter weight.

 

Possible. Fishing trawlers dont anchor that much.

The only time i see them anchored thy are stern too in port.

Wire rope is light so you could carry a very long length. But handling the stuff is so obnoxious that its not worth while.

Normal Sink rope....leaded rope ....also works well but again handling and storing the stuff is a nightmare.

Chain is the way to go if your boat is big enough to have an anchor winch

 

Actually I would guess wire would transmit less shock than chain. 7x19 has a good amount of stretch compared to the same strength chain. Not that it's great, but figure .5% the length of the wire. And chain cantenary is pretty meaningless in storm conditions, chain will get pulled bar tight by 20kn usually.

As mentioned the real problem with wire is dealing with it on board. Ideal bending radius for 7x19 is almost 50:1.

 

Its the catenary of chain that acts as a shock absorber. Unfortunately this centenary also causes boats to tack wildly on anchor .

Its possible that wire rope helps dampen tacking, sheering on anchor.

I have no experience.

Normal rope anchor rode has so many bad features that its not worth considering.

 

Reel winches are found on cranes and four-wheel drives the world over, though maybe not of marine quality. In principle, wouldn't they also work for an anchor rode?

Can you attach a nylon snubber to a wire rope?

Why does rode catenary cause boat veering?

 

The weight of the chain pulls the boats forward.

At anchor , put your engine in hard reverse...make the anchor chain stand up. Put engine in neutral and the weight of the straightened chain will pull the boat forward. Once you are moving forward the boat will have to tack port or starboard.
Gust of wind hits the boat..boat blows back, straightens the chain..gust ends chain weight, catenary, , pulls the boat forward.

Depending on length of chain the weight could be half a ton.

Thats a lot of energy

 

If you can't set lots of rode to take the shock loads, (ie: you are committed to a short scope, and rode has no catenary) fit a kellet or sentinel.

 

Adding weight to the anchor rode is troublesome.

Normally you only do it when you use a rope rode. The reason being that when a boat sails over its rope anchor rode and the anchor is now behind the boat , the rode , since it has no catenary will get tangled on keel or rudder.

Best to stay away from rope anchor rodes

 

Sounds like a good reason to switch to a lighter, cheaper wire rope with less catenary, then use a nylon snubber to reduce the shock loads.

 

Here's an article by Rocna on the use of kellets and buoys. They are of some use in specific conditions, but in the most severe situations, when the forces are such that the rode is 'bar taut', a kellet or a bouy will be of little use. Best then to have a large, efficient anchor.

http://www.rocna.com/kb/Kellets_and_buoys

 

Handling wire rope is not easy. A reel winch is a dangerous piece of equipment in the wrong hands.

Also with a reel winch the wet wire is stored on the drum. Corrosion issues.

Im sure its possible but it sounds troublesome on a small craft.

new style winches can handle soft rope anchor rodes http://www.batsystem.se/batsystem_ny_site/index_start_eng.htm

In conjunction with " sink line", lead core rope, these winches are popular in Scandinavia for boats that are too small to be able to handle the weight of chain.

http://www.commercialfishingsupplies.com.au/fishing-rope.php

This rope is used in the commercial fishing industry, many different styles and sizes.

 

Hello to all,

Thank you for your inputs.

At the moment I would be glad to get the links towards such cells to measure the effective load encountered by the anchoring line and thus get feedback regarding remarquable theorical calculations as follows, thanks to Alain FRAYSSES's work: http://alain.fraysse.free.fr/sail/rode/rode.htm

Some improvements are possibly in question.

Kindly.

Patrick

 

There are a few recreational manufactures, and a lot of commercial ones. I have never played with the commercial ones, but as I understand it they have more capability, but require a greater degree of understanding to really get them to work.

Recreational ones I know about generally start in the $2,000 range, and go up from there.

B&G - sheer pin type - http://www.starmarinedepot.com/b&g-loadcell-sensor-pin-12.7mm-1/2.html you need to have a B&G display to read the info
Spinlock - inline type https://www.spinlock.co.uk/en/load-analysis/zs-ropesense-2/10-tonne-wireless-load-cell

 

A quick search shows a 10,000 pound S load cell for $160. The sensor (strain gauge) is typically encased in epoxy so I would expect it to be reasonably resistant to spray. I made my own amplifier (one chip and a resistor) for $5 and this provide several volts of analog output.

As the reference says "an all-chain rode is both dangerous for the anchoring tackle and prone to dragging."

 

Hello to all,

Thank you for yours inputs.

Do you know such cells used on a sailing boat in the range 30 - 50 feet that produced measurements especialy during heavy conditions and the relative published literature ?

Following my thread, these data are to be compared to calculated ones.

I wish you all calm and secure anchorages.

Kindly.

Patrick