For the second time in recent days, a Canadian warship has intervened to protect ships in the Gulf of Aden from pirates.

Canadian sailors seized several weapons, including assault rifles. (CBC)

A Sea King helicopter from HMCS Winnipeg chased two suspected pirate boats, which split up and sped away after the men on board spotted the aircraft.

Both the helicopter and warship caught up to one of the boats, about 80 kilometres off the coast of Yemen.

A boarding party seized several weapons from the boat, including AK-47 assault rifles, ammunition, an M-16 rifle and a rocket-propelled grenade launcher with two warheads, said Cmdr. Craig Baines, captain of HMCS Winnipeg.

The three-member crew of the skiff had dumped a large aluminum ladder overboard, which was recovered.

"That kind of ladder would typically be placed alongside a merchant vessel in these waters where so many merchant vessels have been hijacked," the CBC's David Common reported from aboard the Canadian navy patrol frigate.

The ship stopped the second skiff less than an hour later and found several more weapons, many of them tucked under the engine.

In total, six suspected Somalian pirates were questioned, relieved of their weapons and released.

Under international law, the Canadian sailors were not able to hand them over to authorities on shore for prosecution because they were not actually hijacking any vessel.

Last Friday, HMCS Winnipeg, which is part of an international fleet of warships that protect merchant vessels navigating the busy shipping route, intervened to protect two ships threatened by pirates off the coast of Somalia.