Why are the swimming pools so small?

I was also one of the lucky people who got to sample NCL Epic's launch party last week. The weather was fantastic and on Wednesday, I was able to chill out by the pool.


The main pool area, as shown in the photo above, consists of two separate swimming pools and lots of cooling blue tiles around it. It looked amazing and my colleague Sian and I enjoyed dipping our toes in the water. However there was a huge amount of wasted space and we questioned why they hadn't made the whole area into one giant pool. Individually you could probably fit around 20 people in each pool to cool off, and the ship holds over 4000 passengers.

This isn't just an NCL design fault but seems to be the case on many ships. This photo shows a pool area on P&O's Ventura - again look at the space of the pool compared to the deck area

What I'd like to know is - are the pools small because cruisers don't like to swim and would prefer to have more deck area? Or is it an economical reason - ie does it cost too much to keep maintained or to build? Or is it an actual physical limitation - does a large body of water weigh too much for a ship to sustain. Please excuse me if these questions sound a bit daft (you can see that I am blonde) but if anyone actually knows why cruise ship pools are small please let me know.