Capt J We've been running everything from large cat gen sets to vehicle diesels perhaps under false information. Start, let the pressures all level out and as soon as temp shows any movement applying light load. No heavy load until normal operating temps achieved. Have we been ill-advised? Or are marine applications a different kettle of fish? 25 year old Cat D9 push cat with 15k+ hours that has been run this way since day one. Suppose I ought to check and see if there's been any work done to the powerplant but I don't recall any painful bills on it. Hydraulics at -40C are another story. BTW. The man that services these machines is a fanatic so I know that it's been maintained better than what is specified.
A light load should be ok. It is a little different in a vehicle application and a yacht application. I don't think anyone would advise putting a heavy load on a diesel when it is not at operating temp.
I know that big high performance diesels are also preheated up to 24 hours before startup. Not the preheating you do with the key, prior to starting the diesel, more like when you have cooling water heaters on cars in cold climates. This prevents the engine to smoke and build up carbon inside and of course it will allow for a shorter period before putting load on the engine. Perhaps DieselJoe can expand on how the preheating itself is made?