What were the issues for the production company during the production phase?

was it an easy shoot? if there were any difficulties what were they?

Q. Can you talk about some of the logistical problems of shooting on water? Richard Curtis: In fact, filming on the boat was fantastic because it’s such a fantastic set. It’s an actual three-dimensional set so everywhere you put the camera there’s some sky, sea, rust, funnel… all that kind of stuff. Also, the great thing about filming on a boat is it was quite close to what we were filming – here were 12 men of a certain age out in the middle of a boat with loud music smoking a lot so it made it quite easy.
The logistical problems, such as they were, would tend to be if you got in slightly stormy seas, the boat would drift dramatically back towards land. You would be in the middle of a take when a very loud alarm sound would go off and they’d say if we do one more take we’ll hit the rocks.
Then, of course, you have to stop and sail back out again 40 miles. So there were some problems with tide but all the Jaws/Waterworld stuff didn’t occur. I think the only problem was people arriving on the small boat did tend to get … I think January Jones in her scene – she may look like an angel but she felt like a dog. And I think Emma Thompson also found it a nauseating experience – but don’t use that quote.

this is what i found on the internet. answering the question was the writer himself.