How long does it take marlow to repair his boat?

Marlowe doesn't know how long the repairs will take, other than it will be a matter of months.

"The manager repeatly questions Marlow about the boat repairs. In frustration Marlow states some months, no doubt. At this point Marlow hasn't even seen the boat so how could he give an estimate on how long it will be before the boat is repaired. The manager then states - some months, Well let us say three months before we can start. Yes. That ought to do the affair."