Could you post briefly if your kids have done the Titanic, saying their age and the class they were in when the did? Would also be really helpful to know where you are in the UK, in case this makes a difference to curriculum guidance.
I'm asking because our kids' Class 4 (in Scotland, so 8 year olds) have just been stopped half way through their project on the Titanic because one parent has complained, saying that it's age inappropriate.
I'm trying to address the procedural issues around one parent being able to affect the curriculum for 33 kids separately, but it would be hugely helpful to get an idea of what age the topic is commonly done as well. A quick google of online curriculum resources looks to me as if it's a perfectly common topic for primary aged kids, and I've heard anecdotally of other teachers (in the same school and others) doing it with this year group too.
I'd be very grateful for your help!