The Trustees next asked the civil engineer John Rennie to assess the state of the project. His inspection was carried out in the presence of the Trustees on 13–15 December 1791, and he produced a report within a week. He reported that the section from Stowmarket and Needham Market, the other main town on the waterway, was almost complete, but advised that the towpath would need to be raised in places. There were three turf and timber locks, but he suggested that further locks should be made of brick. He felt that while Jessop had laid out the plans prior to the obtaining of the initial Act of Parliament, there had been a failure to adequately survey the river and detail the works that would be required to construct the navigation. He particularly criticised Lenny's lack of accuracy, and recommended that a new survey should be made, so that the work needed could be identified.