Well its only 165km from end to end on my map so submerged is out of the question. If I was you I'd sneak up to Port Said undercover of darkness and surface about 5 km outside the entrance to the canal. Take a big breath and run the engines to flank and just go for it!! If you can maintain 15 knots you'll be through it in 6 hours
The important thing is to make it look like you belong there. Dont look anybody in the eye and make sure the bridge crew arent wearing lederhosen and you'll be fine
