The older terms of service and FAQs mentioned using the in-motion dish on a boat, but it was not in all places, and wasn’t a resounding “approval” that you could use it on a boat in any condition.
With the recent launch of Starlink Roam, which replaces the RV plan, there is a lot of confusion around acceptable usage including whether it is OK to have a dish on the Starlink Roam plan on a boat, and the very clear messages in their FAQ that these plans are now geofenced to land only.
Standard RV dishes have had service outages even before the Roam plan. I have one that routinely stops working as soon as I pass 8 knots, which they started enforcing a number of months ago. I have two others that work fine, and I have a mix of customers and friends who have the same result - some working, others stopping at 8 knots.
No one has said that an RV/Roam dish of either the rectangular or flat high performance kind isn’t working when at rest, whether in a marina or at anchor.
Are you hearing of reports of folks seeing these dishes not working at all unless they are firmly up on land, or just while underway?