Used the hourglass and attempted to attack, but the matchmaking was still taking too long even with the new changes so we decided to defend instead. We finally were attacked by a ship of the opposite faction (it was already in our server) and won, but before their supplies and loot even reached the surface of the water, another match was coming up out of the waves.
To be fair, they were a very skilled crew so we probably would have lost anyway, but they definitely had caught us in an unprepared state and it blew my mind that we were given another opponent so quickly after defeating the last one. This is why I'm thinking that there should be a cooldown between invasions when you're using the hourglass and defending. It wouldn't need to be more than a minute or so.
