We took a boat out the following day to Isla Rosario and immediately wished that we had taken one of the speedboats. Our clunky big two story ship was overcrowded and painfully slow, and I was not in the best shape to begin with, suffering from a bad back and muscle pain. Instead of the 45 minute trip to Playa Blanca on a speedboat, (which our hostel had advised against) it took us around four hours, and included a stop at a crappy little island with an aquarium and marine show that we were not bothered to pay to see. Seasickness abounded on the top deck, and streaks of vomit coated the windows of the lower cabin.
We finally got to Playa Blanca (apparently the best beach in Colombia) and were a little underwhelmed, particularly after the beautiful beaches at Parque Tayrona. To be fair, the sand was nice and white, and the water an incredible aqua colour, but it was swarming with people, and boats came and went in a constant stream.
After barely touching the lunch provided, I hired a beach chair and canopy and had barely sat down before being talked into a beach massage. This was definitely the highlight, as my back was killing me at this stage and I was desperate for some pain relief. I sunk down into the sand and let the relaxation pour over me, unsurprised when my spine let out three almighty cracks midway through the massage.

Feeling rejuvenated, I went in for a swim and nearly broke a toe on the hidden reef in front of us.

Drifting to a sandy area further down the beach, the water was a beautiful temperature

and things were looking up. Grabbing a coconut from a passing vendor I settled back into my beach chair with a book and looked forward to a relaxing afternoon.

My plans were rapidly scuttled with the rude interruption of our ships fog horn calling everyone back to the boat. Far from the promised 3 hours on Playa Blanca (the speedboats give you barely any time there said the hostel), we were being hurried off after just over an hour.
The back ache returned on the lurching journey back to Cartagena, and I miserably tried to sleep through the trip along with everyone else. Having left at 8am and not getting back until 6pm, with only a measly hour at Playa Blanca, it definitely was a trip we could have done without. In future, speedboats all the way!