Yep, most Oxalic acid type cleaners will be what you want although some hull cleaners that contain this are less effective than others, I have just finished cleaning a boat that has never been cleaned in 9 years and used a French hull cleaner, yellow bottle from Force Four Chandlery (sorry, thrown away the bottle and can't recall the name), it was excellent but I ran out just before finishing and purchased a different one that was not so effective. With a jet wash and scrubbing I'd be still there until next year. I think Muriatic acid is also good for cleaning hulls from what I've heard. On You Tube you'll find some vids from the US showing products being used with both types of acid.
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