The pun in the original post is clearly not meant to offend or minimize the tragedy of 1,500 lost lives.
The “Titanic” disaster has entered the mainstream dialog in many ways – in 2007 people were referring to the New York Mets’ collapse as the “Met-tanic Disaster”, and “hitting the iceberg” or “not seeing the iceberg” are also expressions I’ve heard used.
Along the same lines, I’ve also seen a concession stand named “Custard’s Last Stand”, a soft drink called “Alexander the Grape”, and an arcade (or the like – I don’t remember exactly) called “Attila the Fun”.
It’s commendable to be sensitive, but in this case I don’t see the OP as objectionable.
P.S.
Full disclosure – I can be considered equally guilty of the same offense in this post: http://www.theyeshivaworld.com/coffeeroom/topic/inspiring-quotes#post-12372