'Belvidere' off Flushing RMG PY8465

'Belvidere' off Flushing
'Belvidere' is shown in port broadside view, entering port in a stiff breeze, and identified as such by name plate both at her bow and rear bulwark, and the signal “First 8 5 9” flown from her mizzen, which in Marryat’s system stands for "Belvidere". At her maintop she flies a red and white pennant with a black ball over the white half, a house flag which has so far eluded identification.
'Belvideres ensign is a variation on the Stars and Stripes, with the stars arranged to form a pentagram, this being repeated on the foretop flag. Although not entirely legible, the flag design appears to feature one single larger star at its centre, which is suggestive of the 26-star ‘Great Star’ flag in use between 4 July 1837 and 3 July 1845 (after Michigan joined the Union, and before Florida).
Eleven members of the crew are depicted on deck and aloft the rigging, among them four black men. The picture also shows Antwerp Pilot Cutter No.2, which – along with the schematically drawn church spires and windmill in the distance at left – suggests a scene in the Scheldt.
A vessel loaded with cotton from Charleston named ‘Belvidere’, P. Colon captain, visited Flushing en route to Antwerp on 29 May 1840. The best match for this is the ship-rigged entry of that name listed in that year’s Register as belonging to Fife & Co. of Charleston, plying a Liverpool-New York route. A dating for this painting of c.1840 therefore seems likely, and is not contradicted by the apparent ensign design.
Signed “J Spin” bottom right. Jacob Spin was a prolific Amsterdam-based sailor turned ship portraitist active during this period.

Belvidere sailing vessel off Belgium?