It's really useful only as a water transport. It has a good deck-gun that it can use to bombard shores and fight other ships. This allied vessel can't fire at land or water, but it's deadly against anything that flies. Use them against all enemy air threats. Dolphin These dolphins are specially bred for combat.
Dolphins can remove Squids from ships and they're deadly in numbers.
Carrier The Carrier is the most powerful allied unit. It's a very large ship with 3 Hornet planes. The Carrier attacks by sending its planes against the target. It has great range, but after attacking, the Hornets need to re-load. If a Hornet is destroyed, the Carrier will build a new one for free.