A full-size decoy convincing enough to imitate a warship could require nearly the same construction effort as the real vessel. It could even become more complicated and costly. Under that assumption, buying an operational warship would make better use of the money.
Notable Point · 2:42:30-2:42:44
The cost of a convincing full-size warship decoy
A convincing imitation could approach the cost and complexity of the real vessel.