Jacob had an arterial bleed after a tonsillectomy and without several blood transfusions, he would have died.

The near loss of his son, almost two-years-ago, got John looking for ways he could return the favour and becoming a blood donor was the obvious thing to do.

"They could not stop Jacob's bleeding and they were concerned he would not survive the flight through to Sydney," John said

"Jacob had to be given a lot of blood - seven or more units.

"Luckily some very clever emergency staff at Shoalhaven Hospital were able to sort it out for him and stabilise him so he could get sent to Wollongong.

"It really hit home. I had never given blood before then and had just never thought about it."

He now donates every three months and just loves the notifications he gets from the Red Cross Blood Service telling him where his donations go.

The well-known Shoalhaven resident and NSW Fire and Rescue Station Captain urges other people to donate and says you just never know if one of your family members or yourself will be in need of a blood donation.

"Half an hour before we had to rush Jacob to a hospital, donating blood was not a thought," he said.

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John remembers sitting in the hospital with his wife Kylie and thinking how quickly their lives took such a dramatic turn.

"It came down to a lot of generous people doing the right thing and donating blood," he said.

Jacob needed two months to recover before he was back to full fitness

"He bounced back very quickly being a fit young fella," John said.

Jacob is now a blood donor and is a big advocate for the cause, while his dad is coming up to his ninth donation.

Jacob is now serving in the Royal Australian Navy.

Australian Red Cross Blood Service spokesperson Nicky Breen said they always welcomed more donors.

"Many of us may be surprised to learn that while one in three of us will need blood or blood products during our lifetime, only one in thirty donate," she said.

"It takes just an hour of your time to donate blood and every donation can help save up to three lives.

"If you're aged between 18-70 and are in good health call 13 14 95 or visit donateblood.com.au to make an appointment."