Cat C18 1015 vs 1150 hp

Huh? Low speed diesels are 600 RPM max, could this possibly what your talking about? I've never encountered any 3500 series motors as such.
Low speed diesel 600 RPM
Medium speed diesel 700 t0 1200 RPM
High speed diesel 1800 and up

Anyway, In the process of finishing the installation of two C-18's @ 1150 and looking fwd. to the sea trials. This will be my first experience with these 6 bangers.

The c18 1150 HP run very good, very torquey. I've run LOTS of them. I just don't see as big of a difference in speed between them and the 1015 HP in the same boats, except 9gph more....... I guess the 3500 series are medium speed then? It's been ages since I've worked on yachts with them, and I wasn't a Captain then, but I thought cruise rpm with them was around 1100 rpms?

Yeah, I recon a 3516 would be considered a medium speed diesel with max RPM @ 1800 so my estimate of 7 to 1200 RPM's for medium speed would be off a bit. I'm just used to MWM and Wartsila mediums @ 1200 max. I mentioned the 16v399 or just 399 because it was the precursor to the 3516 just as the 379 was the precursor to the 3412 Cat motors. You mentioned MTU's so maybe the 399 threw u off as to think I was speaking about the MTU 16v- 396 series that your not fond of.

Medium speed Diesel engine caps out no greater than 1400 rpm wot.

1800 rpm wot diesel engines are considered high speed.

Thank you, My first thought from memory was closer for Med. speed RPM. I stand corrected. Never thought I'd see a diesel turn 3500 + RPM or so like Yanmars do. I hear that their good motors but have zero experience with them. A lot of people don't realize that Yanmar manufactures commercial ship engines and high HP mediums also @4600 bhp @ 1100 RPM's. Oh well, getting off topic here.

Yanmars are good motors, some of the Volvo's also turn 3600 +/- RPMS and cruise around 3000 rpms. They seem to stay together without any issues.

Another thought; I learn more here with my friends. Nix that other web site.
Thx all.
,rc

They did have some recent c18 acerts popping off (breaking) high pressure fuel lines a year or two ago. I know of it happening on 3 different boats under 100 hours. Have not heard of this happening with the older ones or newer ones.