Do I need to buy an Egyptian SIM card, or is hotel WiFi enough?

Hotel WiFi is usually fine for messaging and browsing, but can be slow for video calls. A local SIM (Orange, Vodafone or Etisalat, all available at the airport or in town) costs very little for a generous data package and is worth it if you want reliable maps and WhatsApp on the boat, though signal does drop once you're a few km offshore.