Fakverk, or truss construction “consists of two-force members only, where the members are organized so that the assemblage as a whole behaves as a single object”.
Ester was built with longitudinal bracing, we’ll call trusses, wedged between an upper and a lower stringer. We’ll call these the deck stringers and the bilge stringers. The trusses increase the strength of the hull vertically. The effect of this is that the rig tension and stresses of the waves do not bend the boat too much. It leaves very little space inside for anything else.
The trusses found in Ester on the seabed were not indicated in any of Mellgren’s designs. For this reason, Bo has consulted Juliane Hempel as well as a specialist crane engineer to determine how best to install the trusses. This research has finally yielded some results and Bo and the team are now installing the metal flanges that hold the trusses in position.
Plesha, Michael E.; Gray, Gary L.; Costanzo, Francesco (2013). Engineering Mechanics: Statics (2nd ed.). New York: McGraw-Hill Companies Inc. pp. 364–407. ISBN 0-07-338029-6.