Hi, here's the straight goods, PM me for more info if required/wanted:
6 weeks long.
physically tougher than most Navy courses, by a long shot. To stand a reasonable chance of succeeding, you should be able to run 1.5 miles in under 10 min, do at least 30 pushups (in a row, and by the end of course you will be able to do much more) 30 situps (same goes) chinups.... seem to be falling out of favour, but a solid 8 will definitely help. Your swim test is 6 lengths of the pool any stroke, but then on course you "surface swim" approx 1 km/ day with fins and wetsuit during PT. During course, you will conduct PT every morning, and will progress to running 8-10 km , 50+ pushups, 50+ situps, 8ish chinups,1.5 miles <10 min and the swim in under (often well under) 20 minutes. It is amazing to see how far a person can progress in a relatively short period of time when given the proper motivation, ie the "standby">
courses are run approx 4 times a year, depending on Naval requirement.
IMHO, PADI cert is an asset, as it will at least provide some knowledge of subsea environment. Fear of the unknown fails a lot of candidates. The techniques are definitely different ie, your first dives on course are conducted with heavy lead boots and vest, with no buoyancy compensato. you "plod" along on the bottom, and ascend, descend by climbig on a weighted rope fastened at the surface.
Hope this helps