Option 3. Bring results ashore at the end of the day for processing

• This is the simplest option, but the slowest.
• Competitors will not see their results until well after everybody is ashore, by which time many of them may have gone home.
• You are likely to get late queries, probably the next day, from competitors who have only just seen the results.

Personal opinion. This option should only be used for club racing and very low-key events. Competitors will not be happy at an important event if the results are this slow.