The ascent is a long way from the entry!

The following might give a better mental picture of what happens: The
entry is down a wall to the side of the lagoon entrance. The aim is to
drop quickly and drift with the current along the wall keeping below
the level of the lip of the entry to the lagoon. This lets you get past
the point where the entrance starts and prevents getting swept in too
soon. You continue the sideways drift below the lip as long as possible
(but there is now a rising component of the current too) then rise up
the wall to the level of the floor of the lagoon grabbing the lip as
you get pushed over it and before the full force of the current grabs
you. At this point the current is at about 4 - 5 knots. With fins
trailing in the current, and your head upstream, you maintain position
on finger-power, and can manouever around to chosen locations as there
are a good few rocky grab holds. This is all around the 25m - 20m level
as I recall.

When it's time to go - you let go! The current sweeps you into the
lagoon and whilst making a carefully controlled ascent you keep one eye
constantly on the computer as your only reference, and the other on the
rest of the dive party as the current can branch into occasional
gyrations that can split you up, and is prone to push up and down a bit
which needs reacting to. The dive operators appear to be well in tune
with the area and when we got back to the surface, the boat was not far
away - even though bubble following would not have been posssible.

This was the only dive we did in the area that needs a reasonable bit
of experience. For anyone going to Derewan/Sangalaki who doesn't fancy
this one you can be assured that there's plenty of excellent dive sites
for all capabilities and experience.