Here's my take on the question. There are a number of ambiguities in there

1. Since both LH and NY ships travel at the same speed and depart at the same time (ignoring time zones), they'l meet at a mid-day of the third day (Day 3.5)

2. Mid-day of the third day (Day 3.5) the LH ship that left at the beginning (Day 0) will cross with the NY ships that left on Day 0

3. The fourth day (Day 4) the LH ship that left at the beginning (Day 0) will cross with the NY ship that left on Day 1 since it's already passed the NY Day 0 ship

4. Mid-day of the fourth day (Day 4.5) the LH ship that left at the beginning (Day 0) will cross with the NY ship that left on Day 2 since it's already passed the NY Day 0 and Day 1 ships

5. Etc.

So my guess is 8, depending if port arrival on Day 7 counts as passing

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