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Sand anchor size


VViCKiD

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What you have should be plenty,If you want you can upgrade the chain to whatever thickness you like eg:10mm but try letting out more rode first.

It sounds like your not letting out enough to suit the conditions causing the flukes not to bite in to the seabed.

The more Wind,Current,Swell,Depth

The more rode you need to let out to get the correct lay on the rode/chain to allow the anchor to set correctly.

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No worries mate,another thing Is always lower your anchor over the side smoothly, don,t just throw it over in a big lump as the chain/rope can tangle around the anchor which will prevent the flukes from digging in.

Cheers.

Edited by Fab1
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Thanks Fab1. Ok I'll test it out again.

I think the previous day was windy. I'll try let out more rope before making any purchases

Cheers !

The rule of thumb is 3 times the depth. This can vary depending on the conditions , on calm days 2 times may be sufficent but 2 - 3 is the normal practice.

6.0mt of chain is heaps so suggest this is not increased. I have a 4.9mt boat with a 10lb anchor with only 1.0mt of chain but use the 3 times rule & never have a problem.

Geoff

Geoff

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Does that rule only apply to sand ? I normally just use 2 times when using my reef anchor.

As reef anchors catch on or lock into a crevase or hole in the rocks , depending on sea conditions , 2 time is normally enough.

Sand being softer & the need for the anchor to remain flat , longer rope is better so the rope / chain act as a shock absorber as the boat moves up & down but the anchor is not being disturbed.

Geoff

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  • 2 weeks later...

I had the same problem. Research revealed that it is recommended to have a length of chain the same length as the vessel. I did this and haven't had a problem since. True that the longer rope you use, the better too.

Sent from my iPhone using Tapatalk

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I had the same problem. Research revealed that it is recommended to have a length of chain the same length as the vessel. I did this and haven't had a problem since. True that the longer rope you use, the better too.

Sent from my iPhone using Tapatalk

I read that the chain needed to be the same length as the vessel, too, so swapped the metre or so that came with my new boat for 4.5 metres. It's a pain in the proverbial sometimes but I'm sure it helps hold better.

Baz

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Guest Aussie007

I tried letting a bit more chain out and it lessened the problem. But we still managed to drift about 50m or so over 3 hours. Perhaps I will add another meter or so of chain and connect them with a shackle.

the length of chain helps greatly as boats pass u by creating small waves it tosses your boat about and slaps the chain on the sea floor the longer the chain the better as it will only lift so much of the chain, when u have a short chain theres not much to lift before it pulls the anchor out of the sea floor the chain does all the work

my little tinny weighs bugger all it had a short length of chain from memory around 1-1.2m in length and it just wouldnt hold bottom at the hawkesbury, i lengthen the chain and now it doesnt budge

a mate has the quintrex bowrider 5.3m we tried anchoring same place in the hawkesbury it wouldnt hold so my mate who owns the boat works in a nut and bolt factory and purchased 5 meters of high tensile chain worked a bloody treat even on the most windiest days she doesnt budge but i s... u not that chain is a back breaker to pull up lol its gotta weigh around 40-50kg adding the original chain and anchor plus add some mud and it takes 2 people to pull it up fun times :biggrin2:

the only down side is chain isnt cheap and anchors are often lost so it can be costly

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I tried letting a bit more chain out and it lessened the problem. But we still managed to drift about 50m or so over 3 hours. Perhaps I will add another meter or so of chain and connect them with a shackle.

Your chain is not the problem.

Its all in the technique used that determines the hold. Before lowering your anchor, hold the chain just above it and make sure the ring and whatever else is all in the same position you want it to be when the anchor is set at the bottom. Lower the anchor with slight tension on the rope so it stays in the correct position until it hits the bottom.

The way anchors work, the more rope you let out the stronger the hold. Think about the angle the rope is pulling on the anchor as its on the bottom. With not much more rope out than the water depth, you are basically pulling the anchor straight up. Let out heaps...

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Yes, the chain length should be a minimum of the LOA of the vessel it is on. As for how much rode to let out for the anchor and chain to work as intended depends on the conditions. In calm conditions 3 x the depth is a minimum on average it should be 3-5x the depth. In moderate conditions 5-7 x the depth. In rough conditions 7- " as much as you have or need". You can never have to much rode out if the conditions aren't great. This is a general rule of thumb for all anchors in all types of seabeads.

Your anchor chain should never lift off the sea bead for its entire length, if it does you haven't let enough rode out. Only the first 10-20% max, of the chain should.

The more rode you have out the greater the holding power of the anchor and chain. The scope is very important if you think about the angle the anchor pulls into the sea bed it's either going to bury it self and hold you in position or if the scope is to great you"ll continually break the anchor out of the sea floor. Don't throw the anchor over the side, lower in in a controlled manner and make sure it doesn't end up in a tangle heap on the bottom. Make sure it's stretched out and then the vessel is bought up on on the anchor. A good tradesman never blames his tools, this can be applied to most anchoring problems too.

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What type of Sand Anchor are you using? There is a vast difference in the holding power of the full range of anchors.

As to the length of scope I use a lot more than two times the depth.

Cheers

Paikea

Edited by Paikea
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