Taking good action pictures of porpoising penguins or dolphins, of birds in flight, is hardly possible unless you use a camera with a fast auto-focussing technology, and a lens that quickly responds to the body. Simple (point-and-shoot) camera typically have an annoying delay and are not suitable for this type of photography.
All shags show a typical hestitation just before they dive under - the Antarctic Shag dives with an elegant bow.
Always anticipate on what you expect or hope will happen. You will have one or two seconds only most of the time. Follow the direction in which animals are heading, continue to follow that direction even if they are briefly out of sight.
Chose a spot where your view is not hindered by obstacles (other people or the ship's construction).
Set simple cameras to sport mode. For SLR's, select an iso value (corresponding film or parameter on digital camera) that allows you to obtain fast shutter speeds.
A few more suggestions for photographers using an SLR:
Select a large aperture (2.8, 3.5, as large as the lens allows) allowing for a fast shutter speed (for example 1/500 or higher). If the shutter speed is not fast enough, you can increase the iso value on digital SLR's.
Set the camera to auto-focus continually (instead of once). Of course the lens should be set to auto-focus.
Use a tripod or use a stable background for support.
If you try to shoot birds in flight, start by zooming out if you use a tele-zoomlens to make it easier to find them. Once you have them in focus, you can zoom in a bit.
Next