Anchor chain comes either galvanized or in stainless steel. How strong the chain is depends on what grade and dimension it is.
The most common grades are, G30 (Low tensile), G40 (Medium tensile) and G70 (High tensile). Higher grade means stronger chain.
If you would replace a 10 mm G40 chain with a 8 mm G70 you would still have the same breaking load and be able to save weight.
Above is a simplified description, but basically what you need to make an intelligent choice. If you want to learn more about anchor chain click here
Why should I consider Stainless Steel chain?
The big advantage with Stainless Steel chain is that you can store more chain in the anchor locker. Stainless steel chain has less friction between the links. With less friction the chain will not cone up, and jam the hawse pipe. Another advantage is that mud will rinse of easier as the chain is more slippery.
If you decide for Stainless Steel Chain, you should check he quality before making up your mind. Good quality is essential and does not come cheap.
On Bella Luna we bought 100 m of the best stainless steel anchor chain we could find. It is the German manufacturer, Kettenwälder, who manufacturers a special “Cromox Duplex” chain (Grade 60) that is seawater resistant up to a water temperature of 34.5 C. Download Kettenwälder Cromox PDF and read on page 27, how seawater resistant other qualities are.
Test Cromox chain
As you can see from the PDF the breaking load for the Chromox Duplex 8 mm , 60 grade chain is 63 kN. The safe working load is 50 % of the breaking load.
A tip is to flush the chain with fresh water when leaving the boat in the marina. Temperature and humidity in the anchor locker can get quite high. High humidity, salt and high temperatures is corrosive for all types of chains.
How to connect the chain to the boat?
Never connect the anchor chain to the boat with a shackle. This can be dangerous, as it might be impossible to leave an anchorage in a hurry. Imagine having to open a rusty shackle in the bottom of the chain locker!
Instead secure the chain to the boat with a rope. It should be installed between the “bitter end” of the chain and a fixing point in the anchor locker.
This rope should end more or less at the windlass. The idea with the rope is to make sure you do not lose the chain, but also to make it is possible to cut the rope in case you foul the anchor. If the rope is to short it might still be difficult to cut the line if to short.
If you foul the anchor in nice weather it is not a problem. But as Murphy’s Law apply, it will happen a stormy dark night.
How to connect the anchor to the chain?
This is the weakest point. Make sure to use a tested shackle from a well-known manufacturer. Size should be chosen as big as your anchor chain could accommodate. Secure the pin on the shackle.
Stay away from all kind of swivelling fittings. To my opinion they are not needed and will weaken the ground tackle. In the specification you might read impressive breaking load numbers. But remember that those figures are under the assumption that the load is in a straight line. If there is a side load, they are not strong. If the anchor would be wedged in and the wind shifts, the load is not in a straight line any longer. If you anyhow want to use a swivel, at least avoid to connect it directly to the anchor. Instead use a shackle between the anchor and the swivel, in order to keep maximum movement to avoid side loads on the swivel.
The primary use of snubber line is to reduce the shock loads on the windlass and on the anchor chain. As a bonus it also reduce the noise from the chain over the bow roller.
Both the windlass and the anchor chain can be damaged by shock loads. The windlass is built to lift the anchor up and down, not to take the load from the weight of the boat. It is more or less impossible to damage the anchor chain by the load you can get from a constant pull from the boat. But the shock loads from snatching, can and will shorten the life of the chain.
Snubber lines should always be used when anchoring. Do not make the snubber line to short. If to short it will not flex and absorb the loads. Adding a mooring compensator to the snubber line is not a bad idea.