Top left of this page, under the Navyfield banner is GAME INFO, mouse over that and scroll over to components.

In that new window, select torpedo at the top, then select SN just beneath that.

You should now see the list of all SN torpedos and torpedo launchers, naval mines and torpedo bomber torpedos, including the space and level requirements for different launchers and what promotions they require. All the ones that say Hvy Torp require the Heavy Torpedo skill from Heavy Torpedomen.