The park had a soft (unpublicized) launch of the new River Safari Cruise this week. It is a 15-minute ferry ride in the reservoir bordering the park, as opposed to the Amazon River Quest which is runs along an artificial channel. There is a captain and a guide on board each ferry, along with recorded commentary.
Leaving the dock, the ferry turns towards the Singapore Zoo. The first exhibit visible is the White Rhino, but you can only see a small part of the enclosure. Moving along the Giraffe exhibit is seen. Most of the enclosure is visible so seeing the giraffes should be guaranteed.
Passing the giraffes, the ferry heads into 'open' waters. The guide will bring out specimens - ostrich egg shell, giraffe hair and dried poop, cotton from a huge Kapok (Ceiba petandra) tree which is pointed out during the ride - for passengers to have a feel.
The ferry then makes a loop back towards the dock. On the way back, the ferry passes the Asian Elephant exhibit that was specially created for the cruise. It is a simple enclosure, basically a clearing fenced off by hot-wire. There are several views into the enclosure. During my ride 1 of the 3 elephants was in a far corner of the enclosure largely out of sight.
After the elephants the ferry returns to the dock and the cruise ends. It is a lot more natural than the Amazon River Quest, but it still doesn't give you more than a few seconds of seeing the animals. I hear there are plans to add more exhibits along the way but for now it's just the 3 species (and perhaps the free-ranging storks or occasional wild bird - there was a lovely purple heron perched beside the rhino exhibit during my cruise).
The cruise is an additional charge on top of the park admission. Tip for passengers - sit on the left for good views of the animals. Photos pf the cruise are in the River Safari gallery.