Allardyce was named new boss on Wednesday and will replace Paul Ince who was sacked earlier this week.
Gallacher told Setanta Sports News: “Six months ago I did not think Sam would be the right man, but now the ship is broken it needs a new captain to sail it again.
“I think Sam can do that. He did a good job at Bolton and I think he can do that at Blackburn.
“Paul’s style of play was very attacking minded and very open, that was upsetting the applecart. I don’t think the players were good enough to do that.
“Sam actually loves to fix things and make them go again. He is like a second hand car salesman: he gets a second hand car in and turns it into a first class motor.
“He has done that at Bolton with lots of players and you just hope he can do that with the Blackburn players and get some more out of them.”
