Today is the highlight of my trip and it doesn’t disappoint; we are doing a partial transit of the Panama Canal. It’s a southbound transit – in general, ships travel northbound through the locks north in the morning and south in the afternoon – so we are picked up by a minibus around midday.

First, we have time to watch some of the Panama Ironman (without even having to get out of bed), with the cycling discipline passing by our hotel. The event started with a 1.2 mile swim in the canal, which really doesn’t look like the colour for water you’d want to immerse your face in. Then a 56 mile cycle up and down the flyover – by the now the temperature has reached 32 degrees – rounded off by a half marathon on the causeway. That’s quite a feat – I overheat just leaving my air conditioned hotel room!

Once the triathlon is over and the roads reopen, we are picked up and driven 20 miles to Gatun Lake where we board our boat – the Pacific Queen, and set sail for the Pacific Ocean.

We pass through the huge Lake Gatún (an elevated artificial lake created by damming the Río Changres and flooding a valley) and into the Culebra Cut (a 12.7 km artificial trough blasted through the continental divide).

After passing under Centennial Bridge, where the Pan American Highway crosses the canal, we reach our first lock; Pedro Miguel. To economise on water, we must buddy up with a bigger ship – out buddy is a car container, the New Century 2. Once we are in position, which is fairly easy as we’re only small, it’s time for the huge container ship to be manoeuvred into place. Ships pass through the locks under their own power, tethered to locomotives on either side which keep them centred. With only around 45 cm margin for error, it’s a slow and skilful job.

Once the ship is in place, the lock gates close and we drop 9 metres to reach the height of the next lake; Miraflores. The process takes around 10 minutes and displaces over a million litres of water.

Time for a quick bite to eat during a lull in the action; a packed lunch and soft drinks are included in the tour. As is the very informative bilingual commentary, hence all the nerdy facts…

Sandwiches dealt with, we head back on deck for Miraflores Locks. Here, there is a double lock with two sets of 9 metre locks to negotiate. This time we are buddied up with an oil tanker – the Elka Hercules. The same routine, only times two; we get into position, wait for the container ship to be manoeuvred into place by the tugs and locomotives, water displaced, lock gates open, move forward and repeat. By the final lock, there is less jostling for position at the bow (most of the American tour groups have retired to the air conditioned bar) and I can actually get a better view of the process.

We are sailing through one of the two original sets of locks which measure 320 metres x 33 metres; to our right is the third set which form the canal expansion deal with even larger ships. We pass alongside two enormous fluorescent pink cargo ships (the One Motivator and One Maxim) which can carry 14,000 containers each.

After the locks, we continue under the Bridge of the Americas (when it was built, it was the only thing linking the American continents) towards the ocean, sailing parallel to the Amador Causeway. The causeway joins three former islands to the mainland and was created with spoils from digging the canal. Here, our 5 hour canal journey is over and we disembark into the minibus waiting to take us back to the hotel.

It’s been an exciting but tiring day, just time for a pizza and a couple of beers before retiring for the night.