If any qualifying vessel operator sells or disposes of any qualifying vessel in an otherwise taxable transaction, at the election of such operator, no gain shall be recognized if any replacement qualifying vessel is acquired during the period specified in subsection (b), except to the extent that the amount realized upon such sale or disposition exceeds the cost of the replacement qualifying vessel.
For purposes of this section, the term “qualifying vessel operator” includes any person who would be a qualifying vessel operator were such person a corporation.
In the case of any replacement qualifying vessel purchased by the qualifying vessel operator which resulted in the nonrecognition of any part of the gain realized as the result of a sale or other disposition of a qualifying vessel, the basis shall be the cost of the replacement qualifying vessel decreased in the amount of the gain not so recognized; and if the property purchased consists of more than one piece of property, the basis determined under this sentence shall be allocated to the purchased properties in proportion to their respective costs.