Anchor rode

[Silkie]

So what would you recommend for a rode for those of us who typically anchor in 5 to 8m?

[sahona]

I have nothing to gain from this thread, but need clarification of your last statement.
A boat at anchor will be driven back and to the side by a gust and waves.
This is the sheer to the side. As the anchor chain rises and slows the boat, it's head comes more to wind and eventually stops and comes through, That is due to catenery- the weight of chain lifted from the bottom.
The same catenery then pulls the boat forward on the opposite "tack" as the chain sinks, until the next gust/wave catches the boat and sends it backwards again. This is what a boat does at anchor and can be seen on a sensitive GPS (like a furuno) as a "dirty fingenail" when track is viewed.
If a 'springy' rope is added to the ground tackle, the angle of sheer is increased, but the snub shock on the anchor is lessened, therefore it is more likely to stay where it was set.
Please tell me where I am going wrong. I've done this many times, and it seems to work.
To clarify - I set anchor, put as much chain on the floor as space will allow, use a 3m 8plait snubber, then drop more chain to emulate the weight of an angel. - it works.

[Ancora Latina]

Please tell me where I am going wrong.

Hi Bill,

Same for me, I have nothing to gain if you use an all chain rode, rope or mixed line…

Your description of the catenary action of the chain is perfectly exact... With low wind, the chain will never be fully lifted from the bottom, and one may ask the question of the utility of the anchor??.. (and some do, saying that it is the chain which hold the boat!… not the anchor..)

But with LOW wind, who cares about the holding of the anchor?

My concern are STRONG winds, let’s say more than 25 to 30 knots... With strong winds, (and some wave action) your chain mooring rode is nearly bar tight,
When your mooring rode is nearly bar tight, this is when you also need the more ELASTICITY to dampen the peak of pulling forces (snub shock ) on the ground tackle system.. and then your chain line doesn’t have any more elasticity; and this is why I said « Chain catenary is there basically when you need it the least. »


A good mooring rode should have some ELASTICITY, and this is achieved either by using a mixed – chain / Nylon rope – rode, or if using an all chain rode, by using an efficient SNUBBER...

Below, you will find a suggestion for chain and rope:

SUPPORT HARDWARE
Anchor weight (kg) 5 kg 10 15 20 32 44 55 70 115
Proof Coil Chain in 3/16" 1/4" 5/16" 3/8" 3/8" 1/2" 1/2" 1/2" 5/8”
mm 5 6 8 10 10 13 13 13 16
Nylon Rope**
in 3/8" 3/8" 1/2" 5/8" 3/4" 7/8" 1" 1 1/4" 1 1/4
mm 9 9 13 16 19 22 25 32 32
Shackle Size in 1/4" 1/4" 5/16" 3/8" 7/16" 1/2" 5/8" 5/8" 3/4"
mm 6 6 8 10 12 12 16 16 19
** Rope must be in good condition - Rope recommendations are based on 25% of breaking strength.. (see: http://www.ancoralatina.com/acolhimento ... ction.html