Irene, I can't guarantee if a place is totally 'safe' or totally 'unsafe', but I can tell you about what's happening so you can decide for yourself.
Even at the height of the violence in Egypt (centered on Cairo) the Red Sea resorts, including Sharm el Sheikh, remained calm. At that time the UK government made a point of excluding them from its advice to stay away from Egypt. Of course things are much calmer still over all of Egypt. I can't find any reports of ships in the Suez canal being under threat at the time of the revolutionary troubles.
However.... US, UK and Australian governments, while recognising that public order has been restored in tourist spots like Luxor, are still saying everyone should defer non-essential travel to Egypt because of the unstable political situation.
Just a week ago 19 people died in 2 separate clashes in Cairo. There are next to NO police on the streets (especially in Cairo) and local communities have set up ad hoc protection units (which tend to shoot first and ask questions later). There is a nationwide curfew between midnight and 6am which applies to tourists too.
So, on a scale of 1 to 10 I'd figure that standing in Tahrir Square at 1am wearing an "I heart Mubarak" t-shirt would be a 10.... being on a cruise ship off Sharm el Sheikh is a 2 (I'd say 1, but ships hit things and sink sometimes).
If you decide to go; when you get off the ship at stops, check on the security situation with staff first.
Stay away from any demonstration or large public gathering (don't go and have a look!). Watch out when around central squares of towns - that's where protests usually erupt and also where tourists gather.
Call your tour provider and ask them what extra security measures they have in place (especially while travelling the Suez Canal) and what their plan is if things deteriorate. if they don't have any plans maybe pick a different provider who does!
Keep across news and events and be prepared to cancel at the last minute if it suddenly goes pear shaped.
Only you can decide how risk averse you are. If you feel unsafe about the trip, why not ask your travel provider if you can put it off for a while? over 9 years ago