covering plywood on carvel planking

[Landlubber]

alan,

I did say wet and dry, 360 w&d is quite agressive mate, used wet of course.

I would agree if it was done dry.

[alan white]

I see that now. My point was that a coarser grit will always work faster just so long as scratches don't telegraph through to a finish coat. Recently I built up the protection on my white oak coamings and 150 grit on a small random orbit worked very fast. My goal was to get down to a flat surface without any grain fissures remaining and then add a few (4-5) more coats. Until the grain was completely filled, I used only aggressive means to level the surface.
There is a difference, of course, between old and new varnish in terms of hardness. Softer varnish responds better to wet/dry.

[Landlubber]

...yeah understand, you are right, you want to get rid of the hollows asap, and coarser grades do that of course, just remember to never remove wood, only varnish in the process.