What ship? What do you mean?
The ship they use to get to Dressrosa. The guy said this whole thing could have been done in secret, but they can't. They're known to the public. For them to do this whole thing in secret, they'd have to enter Dressrosa without being seen. If they did that, that would mean they would leave the island shortly afterwards, but it seems like Oda has more planned for them becausee they're casually strolling around. When Law saw CP0, he did notice there was something off with the whole thing but he didn't expect DD to trick everyone just to get 10 people. I hope that makes sense.
–- Update From New Post Merge ---
Chapter 700 they get the paper and call DD. Law says meet us at Greenbit in 8 hours. So yes it would just be 8 hours of waiting untill the new newspaper came out. I dont see how that would be more trouble than potentially letting the secret slip. They are loyal and love DD. They would spend atleast 8 hours trying to figure out why he quit. Heck he could just say he will address the country at 4. Or something that would calm them down some without spilling the beans.
CP0 and the WG is what printed the false report. Not DD. Therefore, CP0 showing up to Dressrosa was because of DD. He knew they were coming and knew what they would say. Oda coulda have itroduced them in a flashback with Dofla talking with them in the castle along with generals. I dont see how that is worse than the way Oda did it.
Oda has more planned for them. That's why they are still on the island casually strolling around.
I also want to add: It's only logical DD's out of nowhere resignation caused an uproar. He didn't want that so CP0 came to calm then down, but that would mean his plan could fall, right? Well, DD's words last chapter explains that. Law did feel something was off, but he didn't think Doflamingo would fool the world just to catch 10 people.