The mortar and set up you have I am familiar with ;)

At a slow speed, in theory I think I could do it!

If its used in the direct role, piece of cake!

In the indirect fire role, sight it in, and if the movement is not so fast and you take into account the movement, and more or less lead the target you could be on target, remember a mortar is an area weapon, and if the rounds land close to the target it counts just like horseshoes and handgrenades. A moving platform would possibly act as a traverse fire mission, where the rounds land more or less in the line of travel, going down river, keeping in mind that a minor distance on the sight will be a greater distance down range, so, firing at a rapid but steady and unhuried pace could give a similiar effect as a traverse mission. Again, this is theory and oh to be on a gunline again to test it, as it does sound interesting.

If the mortar gunner can actually see his target, he could also do a direct lay -- that would be much easier than standard indirect fire. (In direct lay, you are sort of using your mortar sight to aim at the target; direct lay is tricky, takes a good gunner, and you are still going to have deviation, but it's not as much deviation as standard indirect fire and the gunner can function as his own spotter. The downside is that if you can see your target, the enemy can probably see you...)

Thats it! Direct lay! I was thinking boresighting, direct lay, thats the term I was trying to come up with the last several days. And that is how I would do it. Like I said, in theory it could work and the results would be like a traverse fire mission along the route of travel of the vehicle.

Of course the issue I would worry about is stability especialy after the first round throwing off the gun with the rocking, this could make following round go wild, as well as strong waves, sharp turns and evasive manuvers, again, these could toss the rounds to go way off!

However, the precident does exist of firing mortars and artillery from boats, this was done durring the British attack on Ft. McHenry which inspired Francis Scott Key to pen "The Star Spangled Banner." As were mortar barges and rocket ships common, and in the amphibious landings in Europe and the Pacific many vessels had 105 and 75mm howitzers firing on them or mortars and of course rockets. The Rangers attacking Pt Du Hoc fired mortars from their craft to launch the ropes and ladders which they scaled the heights with. And I seem to recall some units in the Delta of Vietnam had 105s on LSTs or barges firing, so it is entirely possible.

Again, having been a mortar magot once upon a time, the idea is something I would love to test.

I would say impossible (for indirect). You almost never drive in a straight line, and once you've turned just a little, that's it. It its a few kilometers away, the bomb's deviation is magnified sooo much, they're be no point in even trying.

If it were possible, it would definitely be the norm.

Assume the mortar is located on a boat and travelling through this sort of environment in predawn without sonar equipment to prevent grounding.
The boat would need to make sudden turns and stops without more than a few seconds warning.
The mortar crew also cannot see the target area although do have a general idea of it's location (as they should anyway).
Only a handful of rounds are available but an FO is on hand with an unobstructed view of the target area.

Given those details, how likely is it for even one round to strike the target zone?

http://mw2.google.com/mw-panoramio/p...ium/892293.jpg

Like I said, all the guncrew needs is distance and direction, then it is up to their data, they can dial in the gun and make sure it is dialed or sighted right. After that it is up to the winds, the gunsite being half a mil off or even a quarter or even the recoil of the gun as it fires as well as the round how well it leaves the barrel, how heavy, how well balanced how old, the charges did they burn right those are all some of the factors that can cause the unknown to happen.

But, they can do everything on their end, get it sighted in and the direction and make sure the data is right on their end. I am figuring they will aim for point X and firing from a moving target going at about 6 knotts they may hit target X plus 30m in the direction they are traveling, they may be a little closer, it depends on how fast their guncrew is. And then the rocking of the vessel from recoil may cause a checkerboard pattern of impacts, firing on the uproll the roads go inland and on the down they land closer, which may be cool since you could cover the target area nicely depending on the size of the round.

As for being common, they do the math for modern naval gunnery so it can be done, it just takes a good amount of math.

Remember, a mortar is not a point target weapon, can you hit the target directly SURE! I have done it many many times back in the day. But it is an area target weapon so if the round lands within the casualty radius area then it is considered a hit.