About 13km, IIRC, but that’s not not much difference.

You have to read what I wrote in context. It was a response to the comment about landing craft with 120mm mortars. If you want that sort of close-in fire support (a different beastie from offshore fire support from a long-range naval gun), then a combination of CB90 (or a similar boat, e.g. the Finnish one whose name escapes me for the moment) with a rapid-fire mortar is probably superior to an ad-hoc fitting of mortars onto landing craft. IF.

I wasn’t proposing it as an alternative. It has advantages, but also disadvantages. In some circumstances, it may be a better option, in others inferior. A supplement, not a replacement.

Certainly a combination of CB90 variants would offer a nice initial landing and commando capability able to provide its own short range fire support capability.