It looks nice. Expensive but would allow you to stay out there with a bit less reliance on the outside world.
Just putting some solar panels on a used ship is one way to achieve station keeping (ie propulsion just fast enough to counter currents and wind).
It wouldn’t be optimized for speed obviously, but if you only need a knot or so it probably needn’t be very expensive. Put an efficient propeller on an electric motor and you’re done. No need to mess around with anchors in deep waters.
The ad says it has a 3300 kW engine but it is probably 33000 kW. Let’s assume the top speed with this power is 20 knots.
Drag is equal to speed squared. The square root of 33000 is 182. We want a PV-powered speed of 2 knots. 182 / 10 = 18. 18 squared is 324. We need 384 kW of PV power.
One watt of PV is around a dollar I think. So the panels would cost 384000 USD. Let’s say 500k with the motors and propellers and other miscellaneous stuff. A bit over 5 million all told for a dynamically-positioned container house seastead.
That’s all you need really. Everything else that people need for their lives or businesses, let them import or produce it for themselves or each other as they see fit. Auction out the container spaces on Ebay.
Engineers or physicists are welcome to torpedo my energy calculations above, of course :-).