A man was travelling with his boat mounted on a trailer along the A179 towards Hartlepool when his trailer tyre suffered a puncture.
He pulled into a lay-by and left to try to organise a replacement tyre.
But while he was away, opportunist thieves hooked up the boat and trailer to their own vehicle before towing the vessel away.
They then stripped the boat of its engine and equipment before abandoning it and making off.
A spokeswoman for Hartlepool Police said: "While he was away someone approached in an old white Ford Transit pick-up, connected the trailer and drove off along the A179 in the direction of Hartlepool, having stolen the boat and trailer.
"The boat was found later that evening close to a sub-station just off the A179.
"The boat was found to be stripped of its motor, battery and boat equipment."
The theft happened sometime between 5.15pm and 6.15pm on Tuesday, April 18.
Anyone with information about the theft, or anyone who witnessed the man in the white Ford Transit pick-up truck, is asked to
telephone Pc Phillip Agar, of Hartlepool Police, on (01642) 302126.