[gurps] [VEHICLE] of the week 731 ? Planetary Defense Battery

[Anthony Jackson]

Onno Meyer wrote:
> 
> Call it up to -20 or -25 for a sub at 500m in the deep ocean or near the 
> bottom anywhere else - as the bottom depth and hence the maximum
> dive depth goes up, the water becomes murkier, too . A ladar with 500 
> miles nominal range should do the job if there is no stealth.

Not exactly. That -20 is an obscurement modifier; it stacks with range 
modifiers. A 500 mile range sensor (scan 27) would have a minimum 
penalty of -34 (-14 for 500 yards range, -20 for obscurement) for a net 
modifier of -7, and that's if you already pretty much know the exact 
position of the sub.