Under title 10 U.S.C., section 1475, the Secretary of the Navy shall have a death gratuity paid immediately upon official notification of the death of a member of the naval service who dies while on active duty, active duty for training, or inactive duty training. The death gratuity shall equal six months' basic pay (plus special, incentive, and proficiency pay) at the rate to which the deceased member was entitled on the date of his death but shall not be less than $800 nor more than $3,000. A kind of special pay included is the 25% increase in pay to which a member serving on a naval vessel in foreign waters is entitled under 10 U.S.C. 5540 when retained beyond expiration of enlistment because such retention was essential to the public interest.