The use of THz frequencies for radar remote sensing has provided a new set of applications, where short-range sensing for high-resolution imaging can be used. At the same time, radar imaging of physically large objects for understanding their radar signatures, which is based on long-range remote sensing, can be a cumbersome process and require significant financial resources. In this paper, we propose to explore the synthetic-aperture-radar (SAR) concept at sub-THz frequencies to scale a real-life scenario of long-range imaging of foreign objects down to short-range sensing in the indoor environment. The idea is experimentally studied on four downscaled marine vessels, where the SAR imaging system is based on a D-band FMCW radar that operates at frequencies 126-182 GHz, and the global backprojection algorithm with modified linear interpolator is used for the SAR scene reconstruction. The experimental results demonstrate the feasibility of the proposed idea.