Steve Cotterill believes it will take five years to rebuild Pompey.
The Blues manager reckons reconstructing the club from the wreckage of administration is going to be a lengthy process.
And he warned supporters the arrival of Convers Sports Initiatives (CSI) is not going to reap instant dividends.
Fans have been delighted by the CSI takeover from Balram Chainrai and Levi Kushnir at the start of the month.
It has allowed them to look forward with optimism after the club’s stagnation under the previous regime.
Cotterill has been buoyed by discussions with CSI, after meeting with Roman Dubov and chief executive David Lampitt at Fratton Park on Monday.
They have made it clear they want him as manager and the 46-year-old has reaffirmed his commitment to Pompey in the face of speculation linking him with Birmingham.
The new owners have made noises about seeing the Blues as a long-term business opportunity.
And Cotterill feels that is a realistic approach.
He said: ‘It’s going to take five years to rebuild this club.
‘I look at a year ago and all the work that has gone into building things up since I came here.
‘There’s been progress in that time but it’s only a small step along the way. It’s like having 20 holes in the bottom of the boat and there’s only 10 corks.
‘Wherever the waves go you have to plug that side of the boat. That’s certainly how it’s felt.
‘We managed to survive last year and not sink but these guys are here now to do things properly.
‘It’s very early days but they aren’t here to be stupid with the club – they are here to run it properly.’
Building a squad is the top priority for Cotterill and his new bosses, with the countdown on to Pompey’s return for pre-season on July 1.
David Norris is the first name through the door after Cotterill confirmed the Ipswich captain’s switch.
With a squad of nine at present, the man from Cheltenham knows it will take time for things to come together.
He said: ‘I don’t think because we have got owners and can get players in that it is going to flick a switch overnight. It’s not.
‘We need players and it’s going to take time for them to bed in. It will take time for them to find out who’s good at what.
‘All of that will go on for a while. That’s why pre-season is so important.
‘We need to get some more bums on seats for when we go away to America.’
The first round draw of the Carling Cup takes place this morning – with Pompey seeded in the southern section.
To see who they face visit portsmouth.co.uk from 10am.