Sailors' Society's Crisis Response Network (CRN) provided support to its 100th case this week, with piracy, death at sea and abandonment accounting for almost two-thirds (59 per cent) of those supported.
More than a quarter (26 per cent) of seafarers seeking crisis response were affected by piracy.
The international Christian charity, based in Southampton, set up its rapid response team in South Africa in 2015 to provide trauma care and counselling to survivors of piracy attacks, natural disasters and crises at sea.
The CRN has since expanded to Europe and Asia to keep up with the need for its service and now has 52 chaplains trained to offer crisis support to seafarers around the world.
The high level of piracy cases reflects the rise in piracy reported by the International Maritime Bureau for the first six months of this year, which saw 107 actual or attempted attacks, up from 87 in the same period of last year, with Nigeria and Indonesia the main piracy hotspots.
Just this week, 11 seafarers were seized by pirates off the coast of Nigeria. The charity has reached out to the shipping company to offer support.
Sailors' Society's CEO Stuart Rivers said: 'Piracy, and the fear of piracy, is a massive issue for seafarers.
'Survivors of piracy and kidnappings are exposed to violence and terror, which can have a devastating impact on them and their families for years to come.
'That such a high number of those seeking support from our Crisis Response Network have been affected by the trauma of piracy is sadly not surprising.'
Indonesian fisherman Adi Manurung is one of those to receive support from the CRN.
Adi had been held captive by Somali pirates for almost five years, before being released in October 2016.
He was supported by Sailors' Society chaplains, who accompanied him on visits to the psychiatrist, provided counselling to him and his family and provided financial support.
Adi said: 'I thought that I would die. There was no hope.'
The CRN also supports seafarers who have been imprisoned, often through no fault of their own.
After he was held hostage by pirates for 10 months, Ukrainian captain Valentin Dudnik decided to help the fight against piracy by leading the crew of the Seaman Guard Ohio, carrying security guards to protect ships in pirate-infested waters.
But the CRN had to come to his help instead when he and his 34 crew members were sentenced to five years in jail in India for allegedly transporting arms without the correct paperwork and illegally obtaining fuel.
While in prison, he was diagnosed with prostate cancer.
He said: 'After four months in jail, I fell ill. The pain was terrible. The doctors wanted to operate on me. I had lost 35kg of weight, I couldn't eat and could only drink water.'
In hospital, Dudnik underwent multiple bouts of radiation and chemotherapy.
'This was the most horrible period of my life. Time passed and we were still in prison and then I fell ill. My health was affected by the prolonged stress, it was the cause of this disease,' he said.
Back home in Ukraine, his family suffered a great deal.
The crew were acquitted in November 2017, tragically too late for him to see his dying mother.
He said: 'Three months after returning home I gradually began to walk, but the nightmares continue.'
Rivers added: 'By coming alongside these survivors and their families, we can work with other agencies to help them come to terms with what has happened and give them financial, physical and psychological support to help them pick up the pieces of their lives.'
Emergency contact details for the CRN are available here.
