I know that normal hydraulic stabilisers work like a pair of plane wings - they rotate on their axis dipping or raising like a dive or a climb in a plane. The faster you go the more effect they have as they rely on the velocity of the water over their surface to generate the lift or dive - underwater wings.
Gyroscopes tell the software what is happening and can actually learn the wave situation and anticipate the motion so that it learns the sea pattern.
These work I know from trying them out - you can go into a sharp turn at 25 knots and will not bank at all. They reuce rolling at sea a great deal.
Ok with that preamble out of the way, there is another use for stabilisers - at anchor. These stabilisers must act in a different axis and in effect flap up or down. I do not know, I am guessing - but this seems to be a very limited option - I mean once you have flapped down you have to get up again and this may not be convenient - you appear to also need a large surface area to have any effect.
I have used witches hats - lots of them to help dampen a boat at anchor and I cannot see even a largish pair of stabilisers being more effective than that. My guess is that they must use the same stabilisers but operate them in another axis. So they are not very large.
I am curious because at present I cannot see them being very effective. If they consisted of a circle of cup like ends on a wheel that could roate either way and hence create a lift or a dive type motion 0 a sort of underater windmill - they may work but as wings, I just cannot see it.
I have tied to find out how these at anchor systems work - google came up with nowt - does anyone out there know?