These 18 projects fall roughly into three categories: decorative, useful, and somewhere in between. Some, such as the astrolabe, are mainly for display. On the other hand, the sounding line is an important and practical tool for small-craft navigation, particularly in the absence of an electronic sounder. The cross-staff falls somewhere in between, equally at home in the den or the ditch kit.
Each of the devices discussed here--with simple, proven building instructions complemented by clear illustrations--has at one time or another been used for the practical business of navigation, and each is worth reviving for its beauty, historic value, or sheer usefulness.
Dennis Fisher has designed these projects with an emphasis on simplicity and reasonable cost. Everything can be scratch-built using easily obtainable materials and tools, and each is true to the spirit and function of the original instrument.