Reply #3: Review the rest of Article 1, Section 8

[ProgressiveProfessor]

http://www.usconstitution.net/xconst_A1Sec8.html

Which says in part:

To define and punish Piracies and Felonies committed on the high Seas, and Offenses against the Law of Nations;

To declare War, grant Letters of Marque and Reprisal, and make Rules concerning Captures on Land and Water;

To raise and support Armies, but no Appropriation of Money to that Use shall be for a longer Term than two Years;

To provide and maintain a Navy;

To make Rules for the Government and Regulation of the land and naval Forces;

To provide for calling forth the Militia to execute the Laws of the Union, suppress Insurrections and repel Invasions

The way I read it there is no requirement to have a standing army but one to have a navy. No specific weapons systems, but it should be a safe bet to assume the navy would need boats/ships.

There are also some interesting things said about militias there as well.