46 CFR §272.25

1. (a)Repayment of M&R subsidy for compensated marine or other loss. If an Operator eventually receives compensation from an insurer or any other person for a marine loss or any other loss for which M&R subsidy has been paid, the Operator shall repay to MARAD an amount equal to the amount of subsidy paid with respect to that loss.
2. (b)Repayment of M&R subsidy for Improvements—three year service requirement. If, within three years after the completion of an Improvement for which M&R subsidy was paid, the Operator permanently withdraws the Eligible Vessel from the ODSA, the Operator shall repay to MARAD an amount equal to the amount of M&R subsidy paid with respect to that Improvement unless MARAD shall have determined that such action was beyond the control of the Operator.
3. (c)Repayment of M&R subsidy due to allocation of costs. If the allocation of total M&R costs required by § 272.41(e) of this part results in the allocation of a lesser amount of subsidizable M&R costs than were actually paid for during the calendar year, the Operator shall repay to MARAD the amount of ODS which was paid in excess of the allocated subsidizable costs.
4. (d)Administrative action. If an Operator fails to repay an M&R subsidy required to be repaid by this section, MARAD may either reduce any ODS payable by the amount of M&R subsidy required to be repaid by this section, or take any other action necessary to secure repayment.