General Motors Detroit Diesel 6121T
 

Howdy, great to be here! I'm a former Navy Engineman, vintage1968-72. I currently do a lot of work on my son's 97 Dodge Cummins, though he hasn't signed the title over to me yet! So technically I am only a diesel wannabe owner! I enjoy your site, tho, I don't get here often. I especially enjoy checking out the tech sections. So now I digress back to 1969-70 when I was in Nam on a 35 foot fiberglass patrol boat powered by a Detroit Diesel 6121T, two .50 cal. Brownings, one 60mm mortar, 5 man crew, and I have 364 days to go before I can rotate stateside. I have long since forgotten most details about the boat engine, except that it was supercharged and turboed, and after cooled with sea water. The engine would have been produced early to mid 1960's and was related to the GM 6-71 series and may have been related to the 6-110 series. So I am trying to pin down, with documentation, the series and any other info on it. Our first boats arrived in Vietnam, late 1966 and early 1967. They were designated LCPL Mark 11's I believe, so any id help would be much appreciated, thanks. Hotz

General Motors Detroit Diesel 6121T
 

Bob,

Thank you for your prior service. I would suggest to try to google one of the larger Navy installations and search out there library. They should have a contact email or even a number. They just might have that info on the boat that your speaking of, or at least point you in the right direction.

oudive


Sent from my iPhone using Tapatalk....all while doing a whole lot of nothing

Welcome and thank you for your service. :hellox::tu:

:howdy: Howdy! Welcome to Diesel Bombers! Enjoy the Site! :)

Thank you for your service! :usa::usa:

Welcome to the site. That sounds like a pretty serious boat.

Bob, I was on the USS Vancouver in 1969 and we had two LCPLs and one was used for the Captain's Gig. He insisted it run fast enough to ski behind it. The 6121Ts in our LCPLs (Landing Craft Personnel Lighterage) were turbocharged but not aftercooled and used 75 cubic mm injectors instead of the 60 or 65 Cubic mm injectors that other 6-71s used and we set the governed speed up to 2,400 rpm from the original 2,100.

I later spent a year on PBR Mobile Base One, near Tan My on the Hue River. Our boats had twin 6V53s driving Jacuzzi jet pumps. They were also way too slow.