Three generations of the same family were winched to safety after they became stuck in marshland off the Isle of Grain.
A 13-year-old boy, his father, 58, and grandfather, 72, tried to reach dry land after their vessel broke down at Stoke Creek on the River Medway.
Thames Coastguard said they raised they alarm on Wednesday evening after they became disorientated and stuck in mud.
A rescue helicopter was scrambled and they were all winched to safety.
The group used a red laser pen to guide the aircrew to their location.
Simon Milnes, of Thames Coastguard, said: "Fortunately the weather has been in their favour this evening.
"During the mobilisation of the rescue units, the lad became increasingly anxious about his situation, and we maintained a dialogue with him via the mobile phone to calm his fears.
"Just before 11.00pm [Wednesday] all three had been found after the red laser pen had been spotted, and they were assessed for any hospital treatment."
He added: "Our advice would have been to stay with the vessel and call the coastguard.
"Stretches of marshland in the dark can be notoriously boggy and sticky underfoot, and also sound deadens around you, which can give rise to fear and disorientation."