The calculated distance (air line) between Kapelle-op-den-Bos and Ostend is approximately 64 miles respectively 103 kilometers.
By car or train, the actual journey to Ostend is certainly longer, as only the direct route (as the crow flies) between Kapelle-op-den-Bos and Ostend has been calculated here.
Air line (approximately)
103 kilometers
55 nautical miles