I'm sure you know that the new chain must exactly match the gypsy
on your windlass
so choosing the correct chain is critical.
There are two critical dimensions for chain.
First the size of the metal rod or wire used to make the chain. If you have 3/8" chain that means metal of 3/8" diameter was used to make the chain. This you can easily measure with calipers. Just make sure you measure a spot that is typical diameter and not worn thin or distorted, etc.
The other measurement is a little trickier and that is the size of the link. The most critical spec here is the length of the link. Different spec chain of the same size like 3/8" may vary slightly in the width of the links but the one that is important to fit in the gypsy is the length. Some chain may specify inside length and outside but at the end of the day the length inside is what matters.
To make thinks confusing you can buy a size chain, like 3/8" or 5/16" in different types like Proof Coil, HT, BBB and a few more. Each one can have different size links.
If any doubt the best way is to buy a 1-2' length and test it in your windlass
Regarding brand, Peerless is the standard in the US. I would be extremely
reluctant to buy Chinese chain. For saving a few hundred dollars you are betting your boat
and possibly your life?
Titan chain, I don't know off the top of my head
where it's made. Research
very carefully before you buy.
FYI 1st Chain Supply has very good prices on Peerless chain and will ship free to a commercial
address with a fork lift
on site if you buy a drum or maybe half drum.