No that is your claim. I am nkt claiming they adopted it and changed it. I am saying they used a symbol of a ship, with the widely held view it represented the canal that opened the same year. Just because a ship was used elsewhere, doesn't make it the same meaning.
Ships existed before they were used in that period that involved slavery. And long after. As all symbols, they can be used to symbolise a variety of things.
That is not gymnastics, that is just basic awareness.
They didn’t use a ship, they used the Manchester coat of arms.
If it was a random ship, you could definitely argue it’s got nothing to do with the Manchester coat of arms, but they literally copied the coat of arms exactly.
Obviously ships can mean lots of things, and they can represent lots of things, but a ship put on a crest in 1840 can’t represent a canal that wouldn’t be built for 50 years.