It’s easy to see which way the tide’s going in Cochin’s harbour as huge clumps of vegetation float downstream and out to sea. Yet the Indian stopover port for leg 2 of the Volvo Ocean Race has a particularly strange characteristic. At low tide the harbour is littered with what looks like huge clumps of weed drifting out to sea, huge lines of it snaking across the harbour. But at high tide the shoreline appears to change, as if parts of the dockland have fallen prey to a malicious and secret landfill operation.

Having witnessed weed on a giant scale in China during the Olympics, my first assumption was that Cochin was facing a similar problem, only with chunkier, shrub like growths. As it turns out, weed has nothing to do with the part time greenery.

Water hyacinth, (Eichhornia crassipes), washes down the various rivers that feed into Cochin and parks up in the harbour when it meets the flood tide. Back eddies gather up the thick green vegetation until the ebb tide opens the gate and flushes the harbour clean.

But, having motored out to sea in order to catch the Volvo fleet finishing, there was no sign of the water hyacinth.

‘The salinity in the harbour is low after the monsoon, around 1015 to 1018″ explained the media boat captain, referring to the specific gravity of the water. “When the plants hit a more normal 1025 out to sea they wither and sink. But the seeds still remain active and if the currents bring them back towards the shore and into an area of less salinity, the plants can re-generate and pop back up to the surface.”

“It’s a real problem for us,” he continued. “The plants block water cooling inlets frequently and we often have to stop engines and flush the plants out.”

The more immediate problem would appear to be with some of the many new visitors to Cochin looking to take a short cut out to the pontoons.

Note to self: always take the long route home.