Im planning on having my runners take over a cargo freighter to steal the stuff required to make a nuke.

So I need some suggestions on ship size and NPC's and such. Like how many crewman and guards and also how many cyberzombies should be guarding the cargo bay .

Rigger 3 shows how many crew are needed to run any size ship (hull^2 + 3 I think). What I don't remember is weather there is a good example of a cargo frighter in the book so you may have to make up stats.
Anyway take the number you get from the book and multiply it by 1.5 to represent the night shift as well, if the ship is at dock the double the number again for loaders, customs officals, safety inspectors and so on.
In real life the hardest parts of a nuclear weapon to aquire are the Fissionable/Fussionable material and the tools to machine the material properly. Detonators and electronics will be (relatively) easy to get. So depending on what exactly is in this ship of yours I'd say anywhere from 1-3 Zombies on guard.
Gee, I hope the runners make it OK

I always though that all the major world Governments did all they can to track Fission/ Fussionable materials. To stop precisly this sort of thing....

Bah!!! Your use of logic only serves to enrage me.

Google gives you stuff on

+ Liberty ships (WWII medium freighter)

http://www.cascobay.com/history/libship/libship.htm (Scroll down for picture, data)


+ On 1960s freighters

http://www.biedekarken.de/bayernst.htm (That one is german)


Birdy

Try this.

No man, THIS is the best thread ever about taking over ships.