Another fine Neverland Submarine concept:
The Stealth submarine "NS Sneekie".
The Sneekie has a regular old looking boat attactched to their periscope. When they are moving in on an enemy vessel, the raise the periscope and the boat to the surface. Put a couple sailors in civvies in the boat with some fishing poles and a cooler of beer, make them look all innocent and such, and they just casually and slowly "drift" towards the enemy ship. The periscope itself is disguised as a "mast" in the boat, maybe even put a silly
Kegger On Board flag on it. When they are in range, the Sneekie blasts the bejeebers out of the unsuspecting enemy with their bow mounted underwater laser cannon.