Hi Formidable,
Was it the PS Consul, PS Embassy, or the PS Monarch, or possibly the PS Emperor of India (Withdrawn 1956)? I believe all four boats ran trips around the harbor at various times through the late 50's. By the early 60's PS Emperor of India, and the PS Monarch had been withdrawn, but by 1963 PS Princess Elizabeth joined the PS Embassy which was the last of the Cosens paddle steamers at Weymouth. PS Princess Elizabeth was withdrawn from service in 1966, and PS Embassy was withdrawn and scrapped in 1967.
Chris