I've thot about a washdown pump
cause where I anchor the most, Newport Beach, CA, the bottom is soft, sticky mud that scoffs at buckets and brushes. I was going to mount a washdown pump on a board, and make a plug-in to connect to my windlass power and equip it with a hose I could just drop overboard, but so far I havn't done it. I just use a long handled brush to get as much off the chain (I have all-chain rode) as it comes in, motor slowly with the anchor just awash for a bit, bring up the anchor, then do a more thoro washdown back in the slip.