With regard the first part of your question, you could search the GRDH products of the same AOI, by filtering this product with the scihub esa search products,
Source: The Sentinels Scientific Data Hub
In case the GRD is not available, it’s possible to convert the SLC to GRDH please take a look at the following post,
Basically any stable object (in general) within two passes of radar SAR, could result a coherent object, if this the case, the stable ship could be detected as coherent object within two passes or more, however the shape of the object is important to eliminate the shape represent other things especially close to the port.