Each episode focuses on a new challenge both above and below the waterline as the team are tasked with fixing marina jetties, rescuing ships, clearing abandoned vessels snarling up one of Britain’s busiest ports and responding to emergency callouts to keep the ferries moving.
Alongside, the series also gives the audience an indulgent view and knowledge about how the waterways work from an insight from a harbour master to a day in the life of the tugboat captains.
EPISODE 1: TILTING JETTY
Brighton Marina's main jetty is on the tilt causing chaos for residents and shop owners. Coastal Defender's team of diving engineers devise a cunning plan with air bags to fix the jetty in record time. Young diver Kai tells us how fitness is key to the job they do and he faces danger when the low tide threatens to bring the concrete jetty down on his head.
EPISODE 2: TUGBOAT TYRE
In Britain's biggest port cargo grinds to a halt as one of the tugboats picks up a mystery object in its propeller and is out of action. It becomes man versus rubber in an epic battle to get the tug moving again. The Coastal Defenders dive team use everything at their disposal, even a kitchen knife, to try and free the propeller from whatever has been dumped in the river.
EPISODE 3: SHIP'S SURVEY
An oil tanker the size of two football pitches has new owners but must be inspected inch by inch before it's allowed to set sail. With the potential to carry enough crude oil to power a third of the country for a day it's vital the team don't miss anything that could mean a disaster if the oil spilled. A second team is also called out to repair a vital piece of equipment on a cargo ferry that is holding up the transport of vital supplies to a nearby island.
EPISODE 4: SUNS AND STORMS
A luxury floating hotel in London's docklands has a rusty bottom and the Coastal Defenders dive team are charged with making it ship shape once more. The team are then faced with danger on the water as they attempt to rescue a stricken cruise liner amid one of winter's worst storms. With a £300 million pound boat in the frame, the team take no risks on this job in fear of scratching the priceless vessel.
EPISODE 5: SAVE THE DOLPHIN
A mooring structure, known as a dolphin, has brought the Isle of Wight ferries to a standstill. In desperate need of repair, the whole ferry terminal must move to allow the Coastal Defender's dive team to swing into action and repair the seaworn structure. However, the team come across a mountain of discarded rubbish ranging from teacups to prams as they work day and night to get the job done on time.
EPISODE 6: MUSSELS MAYHEM
The Coastal Defenders team face one of their smallest but fiercest challenges - mussels. These small but deadly shellfish have blocked the pipes of a huge vessel stalling it in dock. The divers must blast the mussels out of their hiding places to allow the ship to sail once more.
EPISODE 7: FERRY EMERGENCY
Work never stops for the Coastal Defenders diving team and today they get a late call from a boat in peril. A missing lifeboat cannister means the ship can't sail causing chaos for the passengers that use the service for their daily commute. It's a needle in a haystack hunt in near zero visibility and local leisure cruisers create imminent danger for the diver under the water.
EPISODE 8: OPERATION ABANDONED BOATS
The Coastal Defenders dive team have been charged with clearing abandoned boats causing an eyesore and navigational hazard in a picturesque part of the river. Facing the threat of dangerous chemicals, metal boats and lots of mud the team must chase the tide in what is one of the most unusual daily commutes. Disaster strikes leaving the team stranded into the night on what is one of their most challenging jobs yet.