The duration of the entire scheme is ten weeks, but this is phased to avoid work during the school summer holidays and ensuring that road closures are kept to a minimum.
Despite advising the media late Friday afternoon that the floating bridge would be out of action from Monday morning, the IWC are now saying it is in service today.
Cowes Harbour Commission say the work will take place Tues-Thurs, but Isle of Wight council say the Floating Bridge will be out of action for five days.
Measures that 'may be introduced' in Portsmouth include vehicles registered before 2006 or diesel vehicles registered before 2015 faced with a charge to enter the city.