Two motorboats race down a twisting channel towards the sea, jockeying for the best line on the corners as their motors roar. I brace myself as our pilot swings into another tight turn, we nearly catch the larger craft in front, but it breaks out of the channel and skims off over the silver sea.

For a hallucinatory moment I am in an episode of Miami Vice, complete with high-revving speedboats on a sun-dappled ocean.

But my daydream is short-lived as our motorboat lurches to a very quick stop. The 200-horsepower outboard kicks up screaming, and flicks arcs of salty mud skywards as the driver fumbles the off-switch. The sound of lapping water slowly invades the sudden silence, then comes the murmuring from the 20-odd passengers behind me in the cramped boat.

Our west is filled by rolling grey Pacific. Our east is a line of green mangrove forest. Under us the hull is stuck fast on a hidden sandbank. We are well and truly encallado. Stranded. This never happened to Don Johnson.

“Get out and push, quick, everyone out, the tide is falling” says the boat driver, but no one moves. Now the driver is paddling around in the sea trying to find the deeper water.

He tries again: “If you don’t get out and push we’ll be stuck here for at least six hours.”

This warning galvanises the passengers. We all clamber out and start to rock the boat. The boat ahead of us avoided the shallows and is now a spot on the horizon. We are on our own and in a race with time.

Standing up to my ankles in the Pacific Ocean is a salient reminder that this wild coastline is hardly connected to the rest of the country. In fact, only two roads traverse thousands of kilometres of jungle, mangroves and beaches. It is not just physically cut-off, but culturally, and maybe emotionally too.

Ramshackle settlements built on stilts over the water seem to owe their design to Dr. Seuss. Towns like El Charco and Guapí, where I started my journey, cling to the banks like malignant water-creatures waiting for the next tsunami to wash them off.

Inland, rivers are being ripped up by illegal gold-miners, the hills sown with coca, all guarded by guerrillas and drug gangs. It is not an easy area to get in, and it’s often trickier to get out. Transport up and down the coast is slow and aquatic, with a variety of boats, canoes and small coastal freighters crisscrossing a labyrinth of estuaries, tidal flats and shallow sand-banked ocean.

Which brings me back to our current predicament. The tide is ebbing fast and we push, heave and slip in the mud.

“Push, all together,” shouts the captain, and we lean into the task until slowly the boat wiggles into deeper water and turns towards the Bay of Tumaco.

An hour later we arrive at the crowded wharf in the heart of downtown Tumaco and a port which has witnessed its share of violence. People seem surprisingly open to talk about the conflict, and my lunch companion at a local cevichería, is no exception.

Ajustando cuentas,” he says. Settling scores. An insidious phrase which hints that some or all of the dead were somehow into something bad and in that case had it coming to them. Or maybe “mala suerte” — bad luck, he says.

For a town facing metaphorical waves of violence and then, intermittently, actual ocean waves, Tumaco seems a remarkably happy place with an exuberance reminiscent of India or Africa, and quite the antidote to Bogota’s street-worn blues.

Most of downtown is a giant market but trade takes second place to more urgent business in the cafes where dominos, cards, money and cold beers are slapped down. Crowds gather at the tables where the games are hot and bottles of aguardiente make the round.

Tumaco is hemmed-in by sea and shaped by the tides. You only need to walk a few blocks in any straight line to hit water and you can smell the salt and fish long before you glimpse it through the maze of wooden poles propping up large parts of the waterfront.

The large tidal range — much larger than the Atlantic coast — and expanse of semi-submerged mangrove forests combine to form a nutrient-rich haven for marine life, which becomes a bewildering array of fish and shellfish dishes such as jaiba crabs cooked in coconut — encocadas — and served with patacones, which are large slabs of fried plantain.

Tapao is a fish stew with hot peppers and plantains. Seafood ceviches are marinated in lemon juice, onions and coriander (ask for the “natural” or they’ll ruin it with a massive glug of ketchup).

A ceviche mixto usually comes with piangua clams, small black and spongy which are a staple protein in coastal communities of the Nariño department, but also a source of income for piangueros — usually women — who root around in mangrove swamps digging them up.

On the streets you can buy large greasy chunks of smoked stingray, a favourite mid-morning snack.

I wander through Tumaco from one side to another. The island population is mostly Afro-Colombians, but in other parts of the coast there are mestizos and zambos (people with Afro-Colombian and indigenous heritage) and every combination in between.

On the street I am mostly ignored, but in cafes and shops people want to talk, and just buying a drink requires ten minutes of friendly banter.

My only surprise is turning a corner I bump into a platoon of wary-eyed soldiers edging down the street, a sudden reminder that I am in Tumaco, a most troubled town. The trouble is it just doesn’t feel like it.

Late in the afternoon I wander across the city to the long concrete bridge that links Tumaco to Isla Del Morro, a larger but more sparsely populated island with beaches and up-market hotels.

Fishing boats race in from the sea to make the harbour channel before the falling tide, their nets flapping in the breeze, and kids drop fishing lines from the bridge itself to haul in tiddlers for the frying pan. Out towards the surf-line the clam-diggers cast giant shadows on the sand flats as they walk out with the tide.

Tumaco’s tin roofs fuse in the last light of day and for a brief moment the Pearl of the Pacific is revealed in a lustrous glow, another one of Colombia’s treasures we hardly know we have. And as with any pearl, it takes a bit of mud and grit to find it.