Issues building a large battleship

Guys Im a bit stuck, having been out of GMod for so many years

Now I was last into GMod while version 10 was still quite new and I was into building large contraptions with alot of lag. So I took to building in GMod 9, using the VMF saver, putting the files into Hammer to save as a VMF to remove the lag and then it could be loaded into GMod 10

Iv built rather a large battleship using the parent tool to keep the lag down but I’ve hit some form of constraints limit. I am trying to add a bunch of AA guns I’ve built, by building 1 and duplicating it. Then parenting it to the ship. However its reached a limit by which when I spawn a duplicate it spawns the props but brings up a Null Entity error and none of the welds or no collides copy and it throws the props everywhere.

Now there must be a way around it Im just after some advice on the best route to take.

I’ve been trying to download a VMF saver for GMod 10 to get the ship into Hammer to see if theres hidden no collides and welds I can delete. But the only VMF Suite I can find, when I try to use in game comes up with another bloody Null Entity error when I try to select props

Any ideas fellow Facepunchers?

Heres what I am up against for prop numbers