Todd Alleyn's boat started taking on water after a crack appeared in the hull, eventually it capsized leaving him stranded in Jervis Bay on Thursday, March 9.

"Took my tinny out near the tubes, got out there and then realized I was taking on a bit of water," Mr Alleyn said.

Mr Alleyn said he knew he had to head straight back to the boat ramp at Callala Bay when the water started coming in but it was five-and-a-half kilometers from his position in Jervis Bay.

"Bailed out my boat three times and each time more and more water was coming on and then on the fourth time ... way too much was coming onboard and I just had to make the phone call then to Marine Rescue," Mr Alleyn said.

Before he knew it his boat capsized.

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"Like one minute, pretty much hung up the phone, started to get my things together and then just felt the boat roll, like it was no time whatsoever," he said.

Marine Rescue was called at 8.30am and rescue vessel Jervis Bay 20 was sent to the scene, assisted by MV Sycamore which was out in the bay on a training exercise.

Marine Rescue NSW Zone Duty Operations Manager Glenn Sullivan said the man had the presence of mind to hold his phone above the water and was able to use it to talk to the crew on JB 20.

"He gave our crew his location in reference to MV Sycamore which enabled our volunteers to perform a swift recovery," Mr Sullivan said.

HMAS Creswell also tasked a rigid inflatable to the rescue area but JB 20 reached the fisherman after noticing the sun's reflection coming from the overturned vessel's hull.

He was picked up by Jervis Bay Unit Commander Kevin Hill and volunteer Adam Breau at 9.18am.

"He did everything right, he stayed with the vessel, he had his life jacket on, he remained calm, it was a good outcome," Mr Hill said.

Mr Alleyn and his damaged vessel were taken back to the Callala Bay boat ramp.

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