Waveless Stab stabilizers

But why not merely seek to upgrade the hydraulic system itself via fins and command unit as opposed to converting an existing hydraulic system to electric?

Perhaps I'm hijacking the thread by focusing on the concept of conversion from an existing hydraulic to an electric system.

He doesn't already have stabilizers, it's a new install. Electric is supposed to actuate faster than hydraulic.

Ok, I need to learn. My experience was that "electric stabilizers" were operated by an electric hydraulic pump that sat apart from the mains. I guess I'm at the back of the class on this...

They were on the Siepner website (parent company of sidepower). For some reason the website has issues right now.

Electric fins have no Hydraulic at all, they use Electric motors/actuators to move the fins.

Electric motors have much less torque at low rpms than they do at higher rpm, even AC motors with VFD's. I don't have stabilizers on my boat but if I needed torque at low rpms from any system it wouldn't be electric.

Boatpoor, aside from being wrong also from a theoretical viewpoint (as leeky already mentioned), I assume that you never went snorkeling around a boat anchored with electric fins turned on, to see how they work in practice.
So, here's a strong recommendation for you: whenever you'll have an opportunity to do that, do NOT go anywhere near them.
The speed at which they can shift from standstill to their maximum rotation must be seen to be believed.
They could literally kill someone swimming close enough to be hit by them.

The Sleipner website does have a fins stabs section (click).
And it seems to be working just fine, but there's no mention of any electrical evolution of their fins.
I also checked a few other European websites where all new products are mentioned, also when still just at announcement stage, but couldn't find them.

Capt J, aren't you possibly mixing them up with Humphree, which are mostly known for their interceptors but also entered in the fin stabs market with a fully electric system?
Whose actuators are in fact similar to CMC ones, albeit much more limited in size, because they can "only" drive fins up to 1.50 square meters, as opposed to 4.50 (no less!) of CMC. Which btw are in another league also compared to Sleipner, whose fins are theoretically available up to 2 sqm, but I'm not aware of any of their installations above 1.50.

There was a full electric line on their site 2 months ago when I previously looked at it. It's not showing now. I think it was on the side-power site. But don't see them now.

If you're going to go gyro, go seakeeper. Quick is air cooled and that presents A LOT of heat related challenges. You basically need to air condition the unit. Gyro's work well anchored and up to hull speed, they only help about 20% over nothing at all above hull speed.

I'm not familiar with the CMC fins, but I believe they're curved. I have a lot of experience with the side power curved fins and they were the best in every aspect, including anchored over a gyro.....they were incredible fins.

The installations I've seen with the Quick required an A/C duct blowing directly on the unit. Otherwise they'd overheat the space they're mounted in and de-rate to 50% power.

Yes they are, but don't be mislead, ALL fins systems are very effective, whether curved or not.
You will hear that curved ones are better from two sources: one is Sleipner, which is hardly surprising of course. And the second are folks with some kind of vested interest with them.
If you look for scientific tests of some kind comparing (with the same boat, same conditions, same fin size, etc.) straight vs. curved fins, you will find none.
OTOH, as a matter of fact ALL very large yachts are equipped with straight fins, also because the largest curved fins available from Sleipner are less than half the size of those produced by CMC (and also ABT and Naiad, by the way).
So, if curved fins would be as good as Sleipner pretend they are, why aren't they building and selling them to the upper segment of the market, which is where money is no object?

Regardless, all that aside, going for electric rather than hydraulic is a total no brainer when retrofitting, due to the much lower complexity of the whole system.
In fact, while CMC was the first to start building electrically actuated fins, several other builders are now following.
In your boots, I'd rather check out and compare some other electric fins on top of CMC, without wasting any time with an hydraulic installation, also because I don't think you already have (and neither need) any other complex hydraulic systems onboard an ST52.
Talking of which, I'd rather have fins than ANY gyro, on a boat like yours.