<p>The Columbia River Maritime Museum will open its USS Shark Carronade exhibit to the public Saturday, May 24.</p>

ASTORIA On Presidents Day weekend in 2008, Oregon teen Miranda Petrone and her father, Mike Petrone, were beachcombing on the beach near Arch Cape in Clatsop County when she noticed a misshapen lump of rock and remarked how much it looked like a cannon.

That one moment kicked off the discovery of two 19th century cannons.

After years of restoration, the Columbia River Maritime Museum invites the public to an unveiling of the artifacts at 9:30 a.m. Saturday, May 24.

The cannons are a specific type called carronades, short-range naval weapons commonly used in the early 19th century. They were part of the 1846 wreck of the USS Shark, a U.S. Navy vessel that ran aground on the Columbia River bar as it attempted to leave the Northwest after surveying the territory.

Most debris sank, but some pieces floated 70 miles south, including one chunk of the deck with three cannons. A Navy seaman found them, but was unable to get any of them off the beach before they were lost to the sand.

In 1898, one of the three cannons was recovered and gave Cannon Beach its name. The cannon is normally on display at the Cannon Beach History Center & Museum, but is currently out for restoration work.

Then, in 2008, the other two cannons were found in Arch Cape, heavily encrusted with rock and sand. The Petrones found the first; two days later Sharisse Repp of Tualatin found the second. Oregon Parks and Recreation Department staff from nearby Nehalem Bay State Park helped members of the Arch Cape community recover them. OPRD contracted with Texas A&M University to conserve the cannons by removing the rock, desalinating the wood and metal, and covering them with protective coatings. The restoration work took six years.

This spring the two cannons were returned to Oregon and delivered to the Columbia River Maritime Museum, which already has some objects related to the wreck of the USS Shark.