Despite great interest in wood boatbuilding as a form of craftsmanship, it’s a sad fact that the number of older boats, including many built of wood, is declining as these vessels age or fall into disuse.
Relatively few classic yachts, old workboats and small craft are preserved, sometimes by conversion to new uses; most older boats end their lives on the sea bottom, rotting on the shore or broken up for scrap.
The loss of a boat of traditional design, or one that has evolved over time to serve a particular function, can go well beyond an individual case. A few decades can mean the loss of all original examples of some designs; others live on only as reproductions.
Preserving the designs of significant vessels, particularly those for which no plans exist because they were built the old-fashioned way using half-models and a builder’s eye, can be expensive and time consuming.
Howard Chappelle, of the Smithsonian Institution, spent much of his lifetime measuring and preserving the designs of traditional boats, compiling his work in books such as American Small Sailing Craft, published in 1951. Others carry on that work, but many hull designs are still lost because no one has the time or the money to document them.
A boat-not an easy shape to work with in the first place-must be measured at hundreds of points before it can be reduced from three dimensions to two; and of course, if someone were to build a vessel from plans developed this way, the process would have to be reversed.
In Chappelle’s day all of this measuring was done by hand, with the likelihood of errors. In recent years, digital technology has come into use, increasing accuracy, reducing measuring time and making it possible to produce a 3-D image in a shorter time than it took by hand. Lasers entered the picture some years back, and most recently there has been interest in using “photogrammetry” to reproduce 3-D shapes.
Photogrammetry is defined as a three-dimensional coordinate measuring technique that uses photographs as the basis of measurement. It’s similar to triangulation, used in navigation and surveying.
“I don’t have experience with hand measurement but expect photogrammetry to be considerably faster and more accurate,” said David Cockey, a Michigan-based computer specialist who came to Southwest Harbor in March to work on a 3-D image of the Jacob Pike, the historic sardine carrier that now belongs to the Penobscot Marine Museum in Searsport.
The Pike had been hauled out at the Hinckley yard in Manset for the winter. Cockey, along with his wife, Katherine, and two other helpers, spent several hours placing “targets” on the Pike‘s hull so he could shoot digital pictures from various distances and angles. Back home, with the help of two computer programs, PhotoModeler and Rhino3D, he planned to produce an image of the Pike similar to what Howard Chappelle might have done by hand, 50 years earlier.
The Pike is important in Maine’s maritime history because it’s one of the few original examples of a large sardine carrier. The last of Maine’s longtime sardine canneries closed in April, meaning the Pike and others like her are going to pass from the scene.
“My observations so far,” Cockey wrote in an e-mail two months after shooting the Pike, “are the field work time for photogrammetry is roughly comparable to using a laser total station for an equivalent amount of information.” Actual time, he added, “depends on the size of the boat. With photogrammetry most of the field time is spent applying targets which takes longer with a large boat such as the Jacob Pike.” The Pike is 83 feet long.
The “targets” Cockey uses are black-and-white shapes, printed on sheets of white paper. In addition to affixing dozens of these to the hull, Cockey and his crew applied vertical strips of masking tape from rail to keel, spaced several feet apart the length of the vessel. Each target and strip of tape would provide a point of reference, and Cockey explained that together, all of the points allow the PhotoModeler program to locate them in space. Together, the points will allow him to produce a 3-D image that will “preserve” the Pike for the museum in a virtual if not an actual form.
The equipment needed for this sort of field work? “A reasonable quality digital camera and tape or other targets,” said Cockey. “It’s low cost to acquire and easy to transport.” And instead of referring to pages of field notes, one can always look at the photos taken at the scene-all in all, considerably simpler than lasers or hand measurements.
Ben Fuller, the Penobscot Marine Museum curator who arranged for Cockey to measure the Pike, points to “reduced field time and expense” over measuring by hand or working with a laser device. While he was in Maine, Cockey also measured a small dinghy in the museum’s collection.
Like many inventions and technologies, the PhotoModeler computer program wasn’t designed for the particular use Cockey and the Penobscot Marine Museum are putting it to. It was developed for accident reconstruction, building documentation, crime scenes (bullet trajectories, blood spatter and the like) and just about any purpose involving placing objects in space. One such object could be a dead body, as illustrated in the section of PhotoModeler’s Web site describing the various applications.
As for documenting the shapes of boats, Cockey is careful not to rule out older methods. “My expectation is the ideal method for measurement of a boat would be a combination of laser devices, photogrammetry and hand measurements,” he said.
David D. Platt is former editor of The Working Waterfront.