It's not uncommon to find uncharted
reefs between
Tonga and
Fiji. Cruisers usually avoid sailing through this area because it is too risky with uncharted
reefs just below the surface. Occasionally a new volcanic island forms in the same area. Rarely in the uncharted expanses of the southern oceans, unfortunate sailors have
lost their yacht on an uncharted reef.
Some nautical
charts display the lines along which soundings were taken in the construction of
depth contours. When I sailed from
New Zealand to
Fiji, the chart showed that most of the seabed was not sounded in the construction of the chart.
Now that we have satellites surveying the oceans, I suspect that the
government knows of even the tiniest pieces of oceanic real estate.