In the world of anchor chains, there are a few key players. All of these chains will be labeled with a number or letter stamped into the links metal. If you do not see any markings, the chain could be a cheap knockoff that might not be built to the same rigorous standards.
Chain also comes in a few materials, mainly consisting of galvanized or stainless steel. We will be focusing on galvanized chain in this post.
There are three main types of chain: Proof Coil, BBB, and High Tensile strength chain.
Proof Coil is by far the cheapest and weakest of the chains. The links in this chain are made from carbon steel and covered in a protective galvanized coating to ward off corrosion. Proof coil is identifiable by the markings PC, PC3, G3, or Grade 30. Upon construction, the chain is stressed to its breaking strength and then inspected every 10 links. It is not calibrated to work with the wildcat on windlasses, so it might not be as easy to retrieve as you might have hoped.
BBB is the next step up. Also made of carbon steel, it is inspected at each and every link upon testing. This means that the chain is strong and checked throughly before it reaches you, the consumer. The links in BBB are uniform and it will work with a wildcat on your windlass! Identifying marks on BBB chain are: BBB, and 3B. It tends to have the same weight per foot as PC chain, but it will work in your windlass and it was inspected more throughly before you bought it.
Hgh Tensile chain is made from heat treated and high tensile strength carbon-manganese alloy. It is much stronger than regular carbon steel, so a chain of the same strength can be made of much smaller links. This means that the chain will weigh less per foot and will upset your displacement and balance much less when fully loaded.
HT chains are marked as Grade 40, G4, and G43. These are manufactured under the same rigorous testing of BBB chain, but you get a much lighter product with the same strength. Higher strength chain is marked as Grade 70, G70, and G7. This chain is very light and very strong, offering the best strength to weight ratio. This will allow you to carry hundreds of feet of rode in your bow without weighing your bow down into the water.
While HT chains are favorable with their weight reductions, they do have one draw back over BBB, and that is the heat treatment that gives it strength. When a chain needs to be re-galvanized, the heating of the galvanization can damage the heat treatment of the chain. Grade 40 and 43 chain is more resistant to the process, but Grade 70 is very delicate and can loose its strength by regalvanizing.