A multi-attribute concept design procedure, as developed at the University of Zagreb, is applied to the small craft. Specialized concept design models of several generic types, e.g. mono-hull ferry, catamaran ferry, fishing vessel, fast SAR, patrol and paramilitary craft, were developed and included into a multi-attribute design procedure. In the present paper we address concept design model of the fast mono-hull type service vessels. Calibration of the model is an important task if reliable results are expected. Here we will deal with the reliability of attribute prediction. Practical parametric equations for attribute prediction, based on the previous work, were developed from published empirical methods, from analytical first principle methods, and from the study of selected database vessels. The results of attribute prediction were systematically com-pared to database values. Best fitting equations are presented in order to make them widely available to small craft designers.

We make use of the classical correspondence between Kekulé structures and lattice paths to obtain explicit formulas for the Pauling bond order of edges in benzenoid parallelograms. These formulas are further used to establish the average π-electron content of hexagonal rings in such benzenoids. We then compare this quantity with the atom-based π-electron content of rings, and study the local and the asymptotic behaviour of their difference.

We review basic mathematical properties of the augmented eccentric connectivity index. Explicit formulas are presented for several classes of graphs, in particular for some open and closed unbranched polymers and nanostructures. Asymptotic behavior is explored and compression ratios are computed for those polymers.