It would end, it would just awhile.

For example, lets say I quickly find a sink one of your ships - I will still have 5 shots, you only 4. I can then decided to keep shooting with my 5 shots, or place the captured boat which will then give me 6 shots, and you still 4 (that is if you sunk none of my ships)

Then again, I may not place the captured ship right away to keep shooting. But also, when I replace the captured ship, it could be placed where you have already shot - so it would make it even harder to find.