noun
torpedo boat
A small, fast naval vessel armed with torpedoes, used historically and in some modern contexts.
水雷艇は夜陰に乗じて敵艦に接近した。
The torpedo boat approached the enemy ship under cover of darkness.
魚雷艇 is a more modern term for a torpedo boat, while 水雷艇 is the older, traditional term.
Compound of 水雷 (torpedo) and 艇 (boat). The term is a direct translation of the English 'torpedo boat'.