Hi there,
I had the same problem and I found the solution on the SINS Homepage (Forum).
You have to delete some files on the original Sins Mesh Folder.
I had to delete 3 Mesh files for some frigates. Looks like that the update forgot to delete them. It´s very easy and you will be able to play in one minute. 
Here is the link to the solution and the files you have to delete: https://forums.sinsofasolarempire.com/?aid=341480
Have fun, Ed 