From: Rabbi Moshe Sofer
To: Unknown recipient
The Chasam Sofer rules that Rizel, whose husband drowned in water without a visible end, may be permitted to remarry. The Torah-level prohibition of eishes ish is removed through the non-Jewish ship owner's mesiach lefi tumo testimony, and the remaining rabbinic stringency of mayim she'ein lahem sof is overcome through a combination of a distinctive nose sign, tevi'as ayin in the clothing, and combined garment color patterns serving as a siman emtza'i. The ruling is conditioned on the agreement of another prominent rabbi.
Source: Shu"t Chasam Sofer EH I §48