Yes, that’s right. The shifting / adding weights is covered in La Dage, I presume all stability books cover this subject.
In the section quoted from La Dage, the point is, from a stability standpoint, what is a dangerous list and what is a dangerous roll? According to the book the general rule of thumb used is a dangerous roll is about 1/2 the angle of vanishing stability or roughly about the angle of maximum righting arm.
The rule of thumb for a dangerous list is 1/2 the angle of maximum righting arm.
I’d expect trouble before then but with regards to abandon ship decisions, maybe helpful.
This is where deck edge immersion comes in. According to La Dage, DEI occurs, as a rule of thumb, roughly at max righting arm.
So as a guide, according to La Dage, dangerous roll is when the deck edge rolls under, dangerous list is half that.
Presumably this rule of thumb was meant as a guide for a mariner at sea, in trouble. YMMV, check your ship’s stability curves.
This is from the IMO
2.3.1 The ability ofa ship to withstand the combined effects of beam wind and rolling shall be
demonstrated, with reference to figure 2.3.1 as follows:
.1 the ship is subjected to a steady wind pressure acting perpendicular to the ship’s
centreline which results in a steady wind heeling lever (lU’i);
.2 from the resultant angle of equilibrium (<Po), the ship is assumed to roll owing to
wave action to an angle of roll (<pd to windward. The angle of heel under action
of steady wind (<Po) should not exceed 16° or 80% of the angle of deck edge
immersion, whichever is less;
.3 the ship is then subjected to a gust wind pressure which results in a gust wind
heeling lever …
EDIT: Stability aside at lists greater than DEI there is risk from hull openings that may not be sufficiently weathertight.