I live near the water and twilight is one of my favorite times of day--it's a very peaceful, calm time of day and the breezes have died down a bit so that the water surfaces are generally much more calm. Also, after the sun has set there is often a pretty afterglow in the sky. In this scene you can just see slight tinges of pink. That pink was actually stronger a few minutes before, but I wasn't set up in time to capture it. A friend of mine on Facebook commented on the geometry of this shot and I have to agree that when I shot it I placed that larger foreground boat carefully between the others. I think that being careful not to let the boats overlap helps to reveal the space of the scene and also helps maintain a feeling of balance
The photo was shot with a Nikon D90 and a 70-300mm f/5.6 Nikkor zoom. The exposure was 1/60 second at f/8, ISO 320. I captured it in both RAW and jpeg, but this is from the jpeg version--I will play with the white balance much more when I work it from the RAW file.