The issue with submarine diesels is their ability to handle running under a snorkel in transit. This places them under lots of pressure as their air supply is frequently being cut off as waves cover the inlet. The Hedemora V18 diesels (1.4 MW from their generators) for the Collins class came from an OEM who had never built submarine diesels so big and had supplied previous submarine diesels to a Navy that rarely used them for transit operation. So they are not robust enough for long term operation under these conditions without an extensive maintenance regime. The French generators and motors have not earned many laurels.
MTU of Germany have a good reputation for building submarine diesels resilient enough to the snorkel transit challenge. However they don’t build them big enough for the typical three diesel-generator per SEA 1000 fleet submarine size (>2 MW). There have been proposals (BMT) to build a new fleet submarine with four MTU (<2 MW) diesel-generators so as to leverage these off the shelf MTU submarine diesels. The Japanese use Kawasaki V12 engines (<2 MW) after previously using Mitsubishi/MAN V8s. The Japanese have lower transit speed requirements to the RAN so have never packed in the same level of internal combustion power as our requirements.
But of course Admiral Moffat wasn’t just talking about diesels but the whole generator, motor setup. The Japanese have been using an interesting tandem Toshiba motor set up that produces more power than the single legacy motor on the Collins. Having two motors would appear to offer a lot of redundancy and advantages for tailoring the output to transit (one motor) and sprint (two motors).
MTU of Germany have a good reputation for building submarine diesels resilient enough to the snorkel transit challenge. However they don’t build them big enough for the typical three diesel-generator per SEA 1000 fleet submarine size (>2 MW). There have been proposals (BMT) to build a new fleet submarine with four MTU (<2 MW) diesel-generators so as to leverage these off the shelf MTU submarine diesels. The Japanese use Kawasaki V12 engines (<2 MW) after previously using Mitsubishi/MAN V8s. The Japanese have lower transit speed requirements to the RAN so have never packed in the same level of internal combustion power as our requirements.
But of course Admiral Moffat wasn’t just talking about diesels but the whole generator, motor setup. The Japanese have been using an interesting tandem Toshiba motor set up that produces more power than the single legacy motor on the Collins. Having two motors would appear to offer a lot of redundancy and advantages for tailoring the output to transit (one motor) and sprint (two motors).
