Scuba tanks. Uh-oh.
2 seconds sound clip from Scooby-Doo, Where Are You! - A Clue for Scooby Doo (S1E2).
You can hear this line at 00:14:50.623 in the Blu-ray version of the episode.
Quote context
[...]
- Look! What's that? Could that be Captain Cutler?
- It could be, but there's only one way to find out. Let's go inside.
- No. Look at that old-fashioned diving suit. He's been down here a hundred years.
- Scooby-Doo? Scooby-Doo, where are you?
- Hey, Shaggy? I found a clue! I found a clue!
- This cannon is loaded. There's a fuse in it. Fire!
- Like, no fire. I forgot matches don't light underwater.
- I am!
[...]