The remains of Ferriby Boat 1 (F1), the most complete find, consisted of a flat but rockered bottom-structure of three strakes: the keel-strake of two planks jointed amidships and with one end (and presumably the other) shaped with a steep upward curve; on either side of it were outer bottom-strakes, each a single plank 35 feet long and curved in plan on the outer edge. A short piece of the first side-strake was preserved on one side angled to the bottom at 128 degrees, but with the end shaped in three dimensions to fit into the space on the bottom-structure. There is good evidence that there were two more side-strakes making a total of three along each side. The bottom-structure was braced laterally by transverse timders passing through cleats shaped integrally on the planks. The planks of oak were mostly of 3-4 inch thickness, but increased to 6-8 inch amid-ships. They were stitched to each other with individual withies of yew-branch at 9-12 inch intervals. The seams were caulked with moss and capped by oak laths for watertightness. It is thought that a peeled branch of yew was fed in and twisted inside the thickness of the timber as the stitch was formed, to separate the fibres and make the withy flexible. The edges of the planks were shaped with a variety of interlocking seams, the main purpose being to 'bury' the stitching for protection against damage on grounding.

In 1963 part of a third boat was found and excavated next to F1. It consisted of a length of an outer bottom-strake and the associated lowest side-strake. Apart from minor differences of detail, it was notable for the absence of the cleats and transverse timbers found in the bottom of F1 and F2