The Maingon Blowhole has a serious warning sign ("anything that happens is your own fault" -type of sign) just before you get to it, and I think it's justified. It's a narrow slit in the earth, which drops some rather large distance into a heaving sliver of white water. The edges are sloping, crumbly, grassy and slippery, and a fall would undoubtedly be fatal. Well worth a look! I'm not sure if it actually "blows" in a heavy sea. I haven't been there before, having done this walk from the opposite direction in years past. Just beyond here, the rocky shore could be explored at length if time and sea conditions allowed.
The track then passes Mount Brown, a large dolerite protuberance, and a rough cairned track heads steeply up the hill. The views from the top are great; Crescent Bay, Port Arthur, Cape Pillar, Tasman Island and Cape Raoul make a dramatic 360 degree vista. Particularly spectacular is the view from the high western end of the hilltop, which is basically a 170m cliff. There are great views from here down onto Dauntless Point, which has its own dramatic and interestingly fractured cliff. I can say the dolerite on this headland is particularly gritty and sharp, having personally tested it with hands and knees when a rock shifted beneath me.
Descending Mount Brown, the track then heads down to Crescent Bay, which is a beautiful beach with high dunes. At the far end of Crescent Bay is Standup Point, which has its own blowholes. I only made it to the first one (apparently smaller) before my turn-around time arrived, enabling me to be taxi in Hobart later in the afternoon. Apparently these blowholes do blow spectacularly in heavy seas when I assume they become more difficult and/or dangerous to access. The amount of time that could be spent taking in the views and investigating the various sights along the way took me by surprise, and I found I ran out of time, which probably requires a return trip (Phil).
I found three Hooded Plovers on the beach, and a gaggle of angry and noisy Yellow-Tailed Black Cockatoos in the dunes. None of them were very pleased to see me. I'm assuming the plover with the blotchy head markings is actually a juvenile, perhaps hatched last spring.