Fourth arm of Defence

[Capt_Phoenix]

Plus smaller vessels simply do not make sense to use as they require different facilities to load and unload (ie no ramps)

True, but an OSV can go places deeper ships cannot and can get alongside and tie itself up without any assistance from tugs.

and their very poor economy of scale makes them fiscally unattractive to use.

For shipping cargo across an ocean I agree, unless they’re all that’s left.

Frankly I see no way whatsoever that the DoD would consider small vessels for a surge sealift or at least not until every other form of transport was in use

I’m not in disagreement. Although I could see them maybe using a handful for select services.