In article , Roger Long wrote:
[snip]

The last ones I was involved with were on a fleet of longliners. The tanks
were tuned by adjusting the level and designed to be about 20% full. After
the vessels were in operation, they were found full to the top on all of the
vessels and they were damn near about to capsize in some loading conditions.
The less stability a vessel has, the slower the roll. The slowest roll
possible is to just lay over and stay there. The captains found that the
boat just got more and more comfortable and rolled slower and slower as they
filled the tanks. They didn't understand the dynamic and the peril they
were exposing themselves to.

Sounds like the principle that makes a metronome work as it does. With
the weight low, the beat/tick is more frequent, the low COG righting
itself almost immediately it moves away from upright. Conversely, with
the weight high up, the beat/tick is much less frequent, but the
momentum of the 'roll' carries a long way passed upright before forces
kick in to bring it back upright.

I agree, it certainly doesn't sound like something you'd want to
over-use on a boat.

Justin.

--
Justin C, by the sea.