Typical visual range

[nats]

Whats the maximum visual range for direct weapons fire? I am thinking weapons like howitzers that can fire many miles but can only fire a limited distance accurately without a forward observer, ie firing direct using gunner targeting only. I am just amending my CT Book 4 the Field Artillery bit to allow for fire without Forward Observers and just wondered what the likely direct fire distance was. I believe the horizon is only about 10 miles away so it must be less than that.

Out of interest if using opitcs such as MBT obtics whats the likely max range of reasonably accurate fire?

Finally the energy weapons - A Guns and the like, are they indirect fire weapons or do they fire only directly?

Anyone?

 

[jawillroy]

I can't speak to actual visual ranges IRL. High Energy weapons, IIRC, are all only direct fire - like lasers in that respect.

 

[whartung]

Oh I dunno. Forward Observers are handy when you CAN'T see the target. When you can see the target, I guess it depends on whether you're using the Mark I Eyeball or a good pair of binoculars.

Clearly the large guns on surface ships were firing with effect without FO's on the open sea at, what, TL 5, yet they don't have to be as close as Man Of Wars ala "Master and Commander".

Granted, their hit -to- miss ratio isn't necessarily perfect, but it didn't really have to be. They bracketed a lot.

Add in higher tech devices like laser range finders, and you increase accuracy dramatically.

As I understand it, much of modern FO work is walking to a spot, noting the lat/long via GPS, siting the target, calculating ITS lat/long, and then sending those coordinates back to the guns. I'm sure it's different for smaller things like mortars.

But with modern location services, ballistic computers, and radar tracking of trajectories to help calculate drift at altitude, line-of-sight truly becomes a terrain limitation. And even then, not so much. If you can see it, you can hit it, accurately, with large guns.

Ballistics is ballistics. Not so much art any more, save for reading of conditions, just good solid math. Moving targets add to the challenge of course.

 

[D. Foxx]

The M1 Abrams has a range of 2.5 to 5 miles depending on the type of ammo, if that helps any.

 

[far-trader]

Whats the maximum visual range for direct weapons fire?

Yep, horizon as one limiter, which will vary with terrain (even the size of the world since we're talking Traveller) and the gun's elevation.

The Mark 1 Eyeball range question depends on what you're looking for and the quality of said instrument.

A match in the dark? Very very long.

A Marine in a Ghillie suit? They could possibly strike that match to light your fuse before you see them

A fast moving object? A slow moving object? Coming directly at you? Moving across your field of vision? Approaching with the sun behind it? Approaching in total darkness? etc. etc.

There are simply too many variables to make a hard and fast rule for sighting

 

[aramis]

Horizon Distance
d=√(h₁*(D+h₁))

Sighting Distance
d=√(h₁ * (D+h₁)) + √(h₂ * (D + h₂)

Both using
d= distance
h₁ = Observer Height AGL
h₂ = Target height AGL
D = Diameter of world.

 

[Icosahedron]

A lot of good points there. Technology has moved on a bit since LBB4 was written.

I'd say for TL8+, anything that isn't blocked by intervening terrain (or planetary curvature) can be hit, and smart munitions may even deal with interrupted LOS (not for lasers and energy weapons, obviously).

Even using optical sighting, the ability to use computers to network captured images from multiple sighting weapons would give you a virtual optical array that could pinpoint a target right up to the horizon. And that doesn't even touch the possibilities of satellite imaging and gps. FOs could well be redundant by TL9.

I introduced camera rounds IMTU. Similar to an illum round except that they gather light instead of project it (maybe both), they hang in the air under a parachute for several minutes and take the role of a FO to see behind terrain.

Speed, concealment and camouflage will still provide DMs of course.

 

[McPerth]

I think it would also depend on the target size.

IIRC maximum visual distance between WWII battleships was about 36 km (20 miles), but that was at sea (withour intervining obstacles), battleships were quite large and tall, and smoke told you where to look...

I think this last point is also important, because one thing is random watching and another to look directly at one point you know there's something, so using to maximum effect any optical (or electonic) aids you have.

 

[Vargas]

I introduced camera rounds IMTU. Similar to an illum round except that they gather light instead of project it (maybe both), they hang in the air under a parachute for several minutes and take the role of a FO to see behind terrain.

Not picking nits, I actually like the concept, but wouldn't a UAV of some sort be a more persistent, cost effective solution?

 

[nats]

Thanks.

I have since found out that the distance to horizon for 2m sighting height is only 5 miles, not much at all. At 50m the range increases to 25 miles and at 100m is 35 miles. But it isnt too relevant to energy weapons using direct fire as they would pop up on grav vehicles to fire anyway so their sighting range isnt too much of an issue the range of the Z gun at 31 km would equate to the maximum sighting range at that tech level probably.

Regarding optics the laser sight for an M1 tank has a designation range of 10 miles and targeting descrimination range of up to 20 miles. But it's gun has an armour piercing range of 3-4 miles using HEAT. Of course it could probably throw HE ammo a lot further using indirect fire.

So it looks like the maximium sighting range for a direct fire gun using pop up or firing at an elevated target would be around 20 miles, but only 5 miles to same-level ground based targets. Thus the need for a forward observers.

I was just trying to relate the 11+ throw in the Book 1 Forward Observer rule to the 7+ throw in the Book 4 Merc FA section and was thinking that the latter could be considered direct fire throw only within typical sighting range and the former would be for any other indirect fire. I probably now have enough to compile my own FA/vehicle combat rules for my Traveller.

 

[fiat_knox]

The Mark 1 Eyeball range question depends on what you're looking for and the quality of said instrument.

A match in the dark? Very very long.

A hand mirror, say from a ladies' compact? Line of sight, anywhere up to the local horizon.

 

[far-trader]

A hand mirror, say from a ladies' compact? Line of sight, anywhere up to the local horizon.

On a clear day with the sun in the right place

 

[whartung]

A hand mirror, say from a ladies' compact? Line of sight, anywhere up to the local horizon.

http://en.wikipedia.org/wiki/Heliograph

I learned that they use these in the US Army in the late 1800's when I visited a fort ruin in Arizona. Yes, here it is, Fort Bowie. http://www.nps.gov/fobo/index.htm

 

[Icosahedron]

Not picking nits, I actually like the concept, but wouldn't a UAV of some sort be a more persistent, cost effective solution?

Depends on the relationship between camera cost and delivery medium cost, and the survivability of the delivery medium. You might make the same argument for a searchlight UAV over an Illum round.

If the camera costs pennies, can perform its task in seconds and can be despatched in seconds to its target area, why spend (tens of?) thousands on a delivery mechanism that takes several minutes to reach the target area and is at greater risk of being shot down, before, during or after its task, thanks to its size, speed and ongoing usefulness.

 

[nats]

A hand mirror, say from a ladies' compact? Line of sight, anywhere up to the local horizon.

Of course, you wouldnt be wanting to fire an MBT main weapon at a hand mirror would you? I am of course talking about attacking military targets and getting adequate feedback on the accuracy of your shots, I thought I had made that pretty obvious. There is always one.

 

[Craig67]

Speaking as a serving gunner, field artillery (for me,105mm howitzer) can attack anything the gun detachment commander can see via direct fire or anything an observer can see via indirect fire.

Accuracy is usually measured in the lethal radius of the round. For 105mm HE M1 this is 30 meters. So if you land a round within 30 meters of a soft target (Infantry, trucks etc) its a "hit". Remember, most casualties are caused by shrapnel, not the explosive force of the round. Actual mechanical accuracy of a field gun is about the same as a good rifle ie 1-2 MOA.

Hard targets (Armoured vehicles, bunkers) require direct hits. This is accomplished by a special type of fire mission called a "Destruction Mission". In this type of fire mission, more rounds will be fired to ensure direct hits. It can take a long time depending on a host of factors. (Up to date Met info, current M/V's of each gun etc)

hope this helps,

Craig

 

[Patron Zero]

Mind may not be applicable but I didn't see mention of radar guided-directed artillery as beyond 'line of sight', fair example being such depicted in the 1961 film The Guns of Navarone.

That said, there are also the proposed but uncompleted cannons of the late Saddam Hussein, massive fixed artillery specifically targeting Israel.