Maritiem;
Doubt this is the reason as the Jumbo game was finished (more or less) before the summer period and also before the shipyard was announced. So Vstep could have announced the Shipyard later in order to have more ships available, I think the main reason is the holiday season.
I do know now that a lot of time is needed to convert ships to the VStep system. Altough we had our ship in autocad and 3dmax already it was still necessary to do a 'redesign' in order to make it sail smoothly. Building a completly new ship from scratch is a tremendous effort.
Also lot of different people are needed for the various aspects like wire-model, textures, ships behaviour etc.