[tsubaki]

Do like Destroyer said!
We have a couple of boats in the yard that have the hull numbers scratched into them the same way and they were from the manufacturer.

It is real simple to explain if there is ever any question.
You had repairs done in that location and the numbers became illegible.
Every boat MUST have hull numbers and you simply complied.

Get a dremel tool and start practicing.
Hopefully your numbers will be neater than ours that were from the factory.