I can tell you that Titanic was not badly built, she was the strongest ship of the time. This is a nice what-if, but how do you get the flex tape on those holes when she's flooding so fast? You'll have to get there, standing in the icey waters to apply it. Perhaps you will already be washed away and how will the crew allow some random strangers to do that?

Of course, this is a good question. Flex Tape being the almighty tape of memes afterwards. But, there would be a problem.

Problem: How is Flex Tape supposed to be applied?

We know she got struck on her starboard side and it began to take on water fast. So, how can it be applied? The watertight compartments were already flooded and the water was freezing cold. Even if it wasn't cold, you would risk drowning.

In conclusion: It's a maybe but not a certainty.

COOL. That sounds doable.