The subject of maritime archaeological fieldwork is often an old shipwreck with its cargo and equipment. The sites are systematically documented by measuring and photographing. The work is done by diving and with the help of remote sensing techniques. The aim of maritime archaeologists is not to raise single objects but to record, interpret and understand each site as a whole. After the fieldwork, archaeologists write a research report, and if there are objects that were raised, these are conserved. Maritime archaeologists often use other branches of science to support their investigations. For example, the environmental factors at a site can be surveyed together with biologists.