Logosol M8 - Manual (Page 10)

Carve the diameter of the hot tub in
the bottom boards: Mark the centre
of the temporary board, which is now
covering the centre of the cross. Check
the measurements of the outermost
bottom boards. Hold the compass
slightly angled and carve around the
bottom.
Cut along the line with a jigsaw: Make
sure that the saw blade can cut freely,
and that you do not cut into anything
under the bottom boards. This is to
prevent the saw blade from breaking.
Do not forget to move the planks, on
which the bottom rests, when you have
reached them with the saw. If the saw
cannot pass the temporary board, you
can stop and wait until later when you
have turned the bottom over. Then
you can cut the last part from below.
Be careful. Cut slowly so that the saw
blade cuts as straight as possible
through the bottom boards. Angular
misalignments over 3 mm should be
sanded with the belt sander (until the
deviation is at most 3 mm).