Born in 1917 in Mackay, Queensland, joined the navy at 17 years of age and served in World War 2. He spent 14 years in the Navy advancing through all lowerdeck ranks and was a commissioned gunnery-officer when he retired from the service. He began writing books while still in active service, his first book, Fleet Destroyer - a collection of stories about life on the small ships - was published by The Book Depot, Melbourne, in 1945. He published several books with Constable of London beginning with Valiant Occasions in 1952. Other publishers he had books printed through include:

The Children’s Press
Horwitz
Dent (London)
Ace
Signet New American Library

The last book I have been able to date is Requiem For A Destroyer (1989). This puts his writing career at over 40 years in length after 14 years of service in the navy (off course he still obviously wrote before he left the navy too). After leaving the navy he lived and pursued his writing career married to his wife Valerie in Sydney until he retured in 1988 and moved to the Sunshine Coast. He died peacefully in his sleep at a Buderim (Queensland) hospital in 2003. He was survived by his wife and his children Beth, Jane and Peter.

J E MacDonnell, wrote over 200 novels, in at least 7 different series's under his own name, as James Dark, James McNell, and apparantly he may have wrote as James Workman as well. according to the above website some of the names mentioned, where standard house psuedonyms. The series mentioned are:

The Sea Adventure Series or Horwitz Naval Series by Horwitz.
The (Gold) Collectors Series by Horwitz.
The (Silver) Classics Series by Horwitz.
Juvenile Books, published by Constable of London, The Children's Press, one reprint by Horwitz and one book by Dent (London).
The Medical Series published through Horwitz.
The Commander Carton Crime Series by Horwitz.
The Mark Hood International Espionage Series by Horwitz and Sygnet.

I researched for the three navy series's and rely on the collectingbooksandmagazines website for the other four series all though I have noted the books listed in the other four have come up in my searches time and again, but I havent totally cross checked them, as much as I have the three navy series, which where my first interest. According to the lists I have drawn up, there are 147 numbered books in the sea adventure series, as well as 20 not numbered published by horwitz, there are also 2 unnumbered books that fit that genre, both published by Sygnet with one under James Dark's Psuedonym.
this totals out to 169 books in my adding up.
The other 2 naval series, the Gold Collectors Series, and the Silver Classic Series both have 141 books in them as best I can tell, with but 2 differences other than sequence between them.
The Collector Series does not have the book "The Captain" in it and the classic series does not have the book "Don't Gimme The Ships" in it. Both of these series comprise books from the original Sea Adventure Series.

From the collectingbooksandmagazines website, there where seven books in the Juvenile Book Series.
Nine books in the Medical Series. Two in the Commander Carton Crime Series. Sixteen books listed under the Mark Hood International Espionage Series, allthough three are unnumbered and "mediterannean striker" has made me curious and I havent been able to confirm it. so counting the lists of confirmed series's my total comes up to 203, allthough I'm still trying to confirm the Mark Hood book.

In addition to the listed series there, I am fairly certain, my three lists of naval books do not include some novels as numbered including as far as I am aware at this point in my search, the novels "Subsmash!", "Commander Brady" and "Wings Off The Sea". As soon as I can work out how to input the long lists or input them manually I will add them in.