I was telling my coworker about forthcoming Spain/Morocco trip, and he joked, "So, what, you're going to bike across the Strait of Gibraltar?"

Fact: There do, in fact, exist bikes on the water. They are... paddleboats!
Fact: The Strait of Gibraltar is eight miles long.

Okay, fine. It doesn't have to be Gibraltar, and in fact should probably be something (1) closer to where we live, and (2) not a major shipping inlet/outlet for a first run. However, the idea of a paddleboat caravan across a significant oceanic feature is buried in my head, and I shall be trying to bring it to live sometime in the near future. What's the exchange rate between road bike speed and paddleboat speed, d'you think?