Can you explain your reasoning as to them being similar ships? I fail to see how that would affect anything. To answer your question, the reason the Olympic didn't aid in the rescue attempt was due to advice from the Carpathia that anyone who had had a chance of surviving both the sinking and the freezing water had already been rescued. Plus even as one of the closest ships after the Carpathia, she was still many miles away, ad by the time she reached the wreckage, would have been of no use. Hope this answers your question, but some background to it would be nice, if just to satiate my own intrigue/confusion.