A blocked or partially blocked view as this is more commonly known usually occurs in two instances.
The first is when the view is obstructed by a life boat, this means that the view will be over the top or usually under the bottom of the lifeboat.
The second is when the view is obstructed by a stairwell or piece of the ships structure. If you know the cabin number on the ship and go the Cruise Lines web site you can see the deck plans of the ship. Find your cabin on the plan and there will usually be a coloured coded dot which you can refer to on the plan. This will describe the type of blockage. The other option is to ring the cruise lines reservation center and ask the staff to describe the blockage in that particular cabin.