In June 1990 a small group of divers from the Potters Bar Sub Aqua Club, north of London, visited the site to survey the wreck. Under the guidance of archaeologist Margaret Rule, the team prepared to measure the wreck using the Direct Survey Method developed by Nick Rule for the Mary Rose project. However, bad weather limited their time on the wreck and they were only able to complete a basic photographic survey of the site with some measurements.
Using this data in conjunction with some information from the ADU, one of their members, Carol Rule, was able to create an isometric sketch of the Iona II. This was the first visualisation of the wreck remains and has been the basis of all subsequent illustrations.