My old (1940) house has a basement utility sink that has started to leak at the drain (shown in picture). Is there a way to replace the section that is rusted or do I have to rip the whole thing out and replace it? It looks like its a very different mechanism to modern utility sinks, it doesn't have a threaded base or a threaded drain strainer (just a hole). How do I go about fixing this?
Edit: From some googling, this is an old concrete tub and weighs and absolute ton.