After doing some research I found that in 1942 while in route from Algiers to Gibraltar off Oran the Maron was torpedoed and sank by a U-81. The survivors were picked up by HMS Marigold and landed at Gibraltar the following day. Would you know if your grandfather was on a different vessel in 1951?
Thanks for the additional information! I have a couple of sites I am working on. I'm going to recheck for another SS Maron.I went through the entire Blue Funnel site with the ship lists but will check again. While I am perusing that stuff you may want to look at the following site. It contains a good deal of info. on the Blue Funnel Ships, families, photos etc.and even though of Celtic background you may be able to find something recognizable within it's pages.
Blue Funnel Line, Collection, Home Page. Rhiw.com
A bit more Joseph....The first site is the UK/Ireland site that list all the records, medals, ships, coastguard records etc for the Merchant Marines.
GENUKI: UK and Ireland Topics - Merchant Marine
If you have not done and online researching or have not found the next site I think you're going to find it to be a positive step in possibly locating a picture of your grandfather. It the British Merchant Site. Joseph there are men listed with email addresses with whom you can contact and may have pictures of your grandfather or have known him and can give you more information on how to obtain a photo. When you get to the site, scroll down and click on the list of ships. I don't see the Bosnia listed but the Maron is listed. Click on the ship Maron. You'll then get a list of men that served on the ships, the Maron is listed, which area they served as well as the dates served. If you click on any of the names you'll be brought to an open email where you can contact that Marine and ask him if he knew your grandfather as well as anything else. Even though some of the fellows served a bit later he may have been there when your grandfather was.
And...there is also an area on the front page titled "Looking for a shipmate" You can then post a message in regard to information/pictures etc about your grandfather.
I hope this is a good start and I will continue to see if there is anything further I can find.
And lastly for this evening....a wonderful compliment of the archives of the BBC and the Royal Navy including pictures, diaries, archives...
BBC - WW2 People's War - Photo Gallery: Royal Navy
Enjoy! Have a good night. If you need anything more let me know and I will continue my search in the morning.