robb and manderly's fleet

[TheNorth's1stKnight]

I know that manderly was building a fleet while Robb was off in the south so was there anyway that he could have sent ships to Robb? I remember Robb sent letters to Lysa to see if she would open the Bloody Gate and allow his army to take ships from Gulltown to White Harbor so he could return north and flank the ironmen and retake moat cailin. Since she never answered him why didn't Robb ask Manderly to send him some ships down to the Saltpans. Were the ships just not built yet, does anyone know more about this?

[A Bastard Snow]

Manderly has been spamming ships out since he was asked too and has continued to do so.

[Rhaenys_Targaryen]

I doubt enough time had passed in between Manderly being commanded to build the ships, and Robb´s death. Several of the ships might have been ready, but that would have been of little use, since Robb would need to either put his entire army on ships, or none at all. Splitting up his army into two small fractions, one on land, and one on ship, would make them vulnerable to the enemy, and the Lannisters would have crushed them.