The major refit of the Ben my Chree will see the flagship ferry back in service just a week before TT.
Steam Packet bosses say the margin is wide enough to allow for any issues which come to light during the scheduled overhaul to be dealt with.
She sailed into Cammell Laird shipyards last Tuesday (29 April) and is due back on 20 May.
The Ben's biennial overhaul in dry dock has traditionally been much earlier in spring.
The later slot was agreed so a charter vessel could be secured to carry the Ben's freight on the Douglas to Heysham route - and increase the fleet during TT.
Steam Packet chief executive Mark Woodward says chartering a ship for two crucial periods was a top priority:
Clip 1