WASHINGTON -- There have been at least 16 incidents involving amphibious boats around the world in the last 20 years, including one on a lake in Arkansas in 1999 where the boat sank and killed 13 people.

The basic safety rules, according to the Coast Guard, are the ones that apply to all boats. Check the weather forecast, and don't go out if there's a thunderstorm warning, like there was in Missouri. Make sure there's a life vest for everyone on the boat and don't just leave it in the bin, put it on when the boats on the water. If the boat has a life ring, that's a plus.

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DC Ducks runs amphibious boat tours around Washington and out on to the Potomac every hour on the hour from 10 a.m. to 4 p.m., except in the winter. The Coast Guard said it does not have any record of any trouble with DC Ducks, but the company that owns the tours the boats did not return phone calls, and a captain declined to talk to WUSA9, except to say that he doesn’t go out if there are high winds or thunderstorm warnings.

The captain is required to be Merchant Mariner certified and be licensed by the Coast Guard.

WUSA9 talked to a bunch of people who took the tour Friday afternoon, and they said they were not nervous, did not wear life vests – and had a blast.

The boats are old, originally built to ferry troops during World War II.

And ironically, after one duck boat pulled out a Gravelly Point on Friday, it's brakes failed. The captain pulled off in the parking lot, and the passengers had to wait for someone else to pick them up and take them back to Union Station.