Coming into Pulau Harapan this morning at around 0430 it was still dark o'clock, Libby was sleeping and I was on watch. I slowed Aquarius down so that we could enter the anchorage with plenty of light at an easy pace. the chart showed lots of coral but we knew our friends on Taipan had anchred there last year and had written glowing reports about the people and the place. We started to make our approach around 0800 and found that the buoyage marks were very misleading and not always present - normal for this part of the world. We didn't have any waypoints as such and were really flying by the seat of our pants. First error was to follow the first set of channel markers into the anchorage. Things were going well with the depth slowly reducing on an even gradientI took my eyes off the instruments for 2 seconds to maintain visual on our approach, looked back at the depth to see it at 0.4m under the keel....and with full astern we touch gently the reef and immediately are off and going astern. Ok, obviously the wrong channel approach. Back out into the main channel and edge down to where another set of markers are positioned. As we approach a local boat comes out of the marked channel and indicates the channel as the way we should enter. Libby is up the ratlines watching the water for obstructions and in we go. depth tis time seems fine with 7 metres under the keel but I'm not happy because the channel is very narrow with little escape if things turn to custard.and they do! Libby calls 'Stop!!!!!' I see the depth go to 0.3m and we again go hard astern - there in the middle of the channel, right between the entrance markers, is a large and shallow coral bommie. We manage to back up and somehow squeeze a multi-point turn and head out again. We have had enough. We decide to continue on to our next intended anchorage at pulau Kali on the west end of Java near the entrance to the Sunda Strait. So we spend the day motoring in no breeze and arrive finally at sunset. The anchorage isn't how we had pictured it with rocky reef all around so we opted to anchor in safe water on the edge of deeper water to the north of the islet. A welcome cold beer after a very, very, long day.