Anyone know of a "Standard CN MkI 5inch rocket"?

[Alex van de Wetering]

Is anyone familiar with the "Standard CN MkI 5inch rocket"?

According to the "working instructions", these rockets were used to launch the canvas tube of the mine-clearing Conger carrier.

Nigel Watson and I were making jokes about this "standard" rocket last week, as no one seems to know this rocket.......So how standard is standard? Most rockets seem to be 2inch, 3inch or 4.5inch.....

Is there any simmilarity with the Land-matress maybe?

Alex