"This is the German warship Augsburg, we are about to commence gunnery practice, please avoid the following coordinates..."
A panic shot round the crew as the radio crackled to life and they heard a thick accent announcing there was a military vessel only a couple of nautical miles away on our port side.
The crew radioed in for a repeat of the coordinates, frantically trying to calculate if they were within radius, and I was completely unaware of the potential imminent threat.
After a few minutes of uncertainty, the skipper confirmed our boat was not in Augsburg's path, but I was keen to speak to the crew about the impact this will have on marine life and how we need protected areas in place to ensure the regeneration and long-term sustainability of fish stocks.
Navies are going to have start thinking in terms of protecting natural resources.
Before that drama, I was joined by guest swimmers Matias Ola and Jackie Cobell (pictured above) - both of whom are renowned open water swimmers.
I had a strong swim in the morning, with fewer jellyfish than normal, but we are now on the neap tide rather than the spring tide, so with half a knot of current behind me it's much harder to make progress each day.
Matias joined me for the first hour and it was like swimming with a swordfish. He is Argentina's best open water swimmer.
Jackie joined for the last 10 minutes and was magnificent. I was thoroughly impressed by her style and perseverance.
She swam the longest Channel crossing at 28 hours and 44 minutes when she was 56 years old, and in my view, the person who swims slowest is the greatest as they need the most grit and are immersed in the cold for longest.
After the swim we transferred from the Aquila to the Princess speed boat to rush to Plymouth for the lord mayor's tea reception to welcome me home.
The sea state was slight to moderate, but combined with a force-three wind, there was kitchen cutlery and crockery flying everywhere and several people on the verge of being seasick over the side.
The nasty chop in the sea meant the transfer nearly ended with several crew members overboard, with many wet feet and a couple of green faces.
We are now all safely aboard the Princess and are speeding home to Plymouth ready for an afternoon of celebration.
Aquila is sailing behind us and will take several hours to reach harbour. Me and the crew will be using the Princess for the next few days to continue swimming, as it is much faster.
5.4 miles (8.7km)