On regular boats....10 to 15 feet of chain keeps the line on the boat and not pulling out. Guess what I am saying is that you ever anchor in 20 feet of water....50 feet might not be enough.
In the salt 1 1/2 boat length of chain is good. I have 30' of chain on my 18' Cuddy Cabin with 150 hp.
My nephew put 10' of chain on his 17' Boston Whaler.
Camping at Catalina his boat ended up on the beach. Lol.
DR