Harke from SY Serendipity is requesting advice about charts for cruising the Louisiades and the Solomons.
He has C-Map? charts from 2009 which cover the northern part of the Louisiades.
Harke, as I understand it, the C-Map? charts have been compiled from the Australian Admiralty charts for the PNG region. We carried both the latest C-Map? charts and the latest Admiralty paper charts with us in 2009, and found them to be reasonably consistent - i.e. they generally agreed with each other.
On the other hand, we found several errors on both the C-Map? and the Admiralty charts, such as the location of numerous bomboras and the position of the entrance to Panasia Lagoon.
Unfortunately, I don't think you're likely to find anything more accurate than this, as hydrographic survey is an expensive exercise, and is generally only conducted with a high level of accuracy in areas of significant shipping movement - and a hundred odd cruising yachts a year don't really count!
My advice would be to use the current C-Map? and/or Admiralty charts, but take into account the zone of confidence (from memory they have a horizontal accuracy of +/-200m and depths +/-10m throughout most of the Louisiades). This means never rely on the chart to find coral passes etc, and avoid navigating between afternoon and late morning when underwater visibility is impaired due to the angle of the sun.
Also, beware of Google maps. I believe they are often airbrushed to compensate for problems with the original image. I have seen an example from the Louisiades where the satellite image from Google shows a distinctly different pattern of reef than in real life due to this practice.
Good luck, and safe sailing!