you have to remember though, a monster doesn't have sonar detection like a submarine...
but, you could blast ultrasonic noises into the water, thereby driving anything inside it crazy, and you'd see very quickly if there was anything in there. WHOO!! a foolproof plan
oh, and of course, you need the salami (i think it was?) on a stick. i mean, once nessie comes up, she'll be hungry and want to eat something

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