By Leendert Dorst, contributing editor, Hydro International

This issue's product survey compares side-scan sonars. The product survey contains both stand-alone and integrated systems. From a number of manufacturers we received several types of sonars. In order to keep our overview manageable we have selected one product per manufacturer for the print edition. The online edition lists all the products. During the selection process, we tried to maintain the stand-alone and dual-use sonars that are designed for use in shallow water surveying. These are usually relatively small systems when compared to the demanding systems used for geological surveys in deeper waters. In cases in which the manufacturer indicated the sales per type, we listed the product with the highest sales. In many cases, these two criteria lead to the same product.

We have tried as much as possible to keep the list with specifications as close to previous side-scan sonar surveys as possible, allowing for a comparison with earlier product surveys. Often, the side-scan sonar is the limiting factor in the determination of the vessel speed during a survey. Maximum operating speed was added just below the horizontal resolution, as the two are often closely related. The demand for high operational speeds also translates into larger forces necessary to keep the fish at its depth close to the sea floor. Therefore, we also introduced some additional information on the depression technique.

Further, we would especially like to draw your attention to the data processing and imaging capabilities, as they show the most interesting differences. These capabilities range from not available to advanced graphical software that was developed by the manufacturer.

We believe that we have captured the details of all the major manufacturers in this product survey, thereby presenting you with a comprehensive overview.