11-19U

Within modified proton ordering model of quasi-one-dimensional CsH$_2$PO$_4$ type ferroelectrics with hydrogen bonds with taking into account linear on strains $\varepsilon _i$ and $\varepsilon _4$, $\varepsilon _5$, $\varepsilon _6$ contributions into energy of proton system, but without taking into account tunneling, within the two-particle cluster approximation their transverse thermodynamic characteristics and sound attenuation are studied and calculated. At the proper set of the parameters satisfying quantitative description of the available experimental data for CsH$_2$PO$_4$ is obtained.