LVT-4 Heavy Mortar - Close Fire Support - Done !

[perttime]

A mortar crew does not need to see the target. A mortar crew does not WANT to see the target.

A mortar crew needs either a visual reference at a little distance, or a very precise mechanism on the vehicle/platform.
For a visual reference, a vertical stick at 50 meters, on a precisely known bearing, is about as good as it gets, while keeping it simple. Less will do in a pinch. It can be either forward or back fron the mortar itself.

[PR19_Kit]

It's called 'Indirect Fire' in artillery terms, so I guess it'd work just as well for a mortar crew.

[buzzbomb]

Thanks gang !
As far as how Mortars target, I think I have learnt stuff with the contributions to the thread.
I was in the "Map, Protractor and Sighting pole" line of thought.

So just another day in uber lockdown in Melbourne, so hammered out the LVT.

Last of the mods, the raised superstructure.


Paint went on yesterday, today was decals and slight weathering and some paint jiggery pokery.



Cobbled together a crew as well. Probably short one dude, might find a suitable one at some stage


All up, came out all right, pretty much how I envisaged it, which is a nice refreshing change.

[Old Wombat]

Dog's dangly bits, BT!

[perttime]

...
I was in the "Map, Protractor and Sighting pole" line of thought.

...

- A map should tell you where you are, and the forward controller tells you where he wants the shells to land.
- The protractor (perhaps with a ruler pivoting on the center) gives you a bearing.
- The pole gives the aimer a reference

An accurate compass can give you an adequate measurement for the bearing from mortar to pole  - when you aren't shooting too many kilometers away. Aimer adjusts the sight, so that aiming at the pole gives the mortar the desired bearing.

---------
Actually, we used "millimeter paper" at firing position, instead of map. Just thinking co-ordinates. One for each platoon, and one for the company. The company guy on the co-ordinates and protractor would confirm that the platoons got it right.

When distances got longer, we used more elaborate manual methods to obtain accurate location and bearing for the mortar platoons.

[zenrat]

Excellent work Buzzo.



You do need to add the obligatory "crouching turned away with hands over ears" crewman as seen in all mortar photos.   

[perttime]

You do need to add the obligatory "crouching turned away with hands over ears" crewman as seen in all mortar photos.   

Mortars aren't necessarily all that loud. Firing an 81 mm to just a few hundred meters is just a "thump" With longer range and bigger charges it gets a bit noisy. These guys (with 120mm) have been issued ear protection:


http://www.suomensotilas.fi/tulivoima-kasvaa/

[rickshaw]

I was wondering if a sighting pole, attached to the front of the LVT would work?

Mortars are rather noisy and can lead to hearing loss if used over a long period.  Hearing protection should be issued to all crew members.  I've only ever fired 81mm mortars and they were sufficiently noisy to need hearing protection.

What I'd like to know, what is the routine for a misfired 107mm mortar?  I know the 81mm is alarming enough and requires a set of calibers on the end of a line to go down the barrel and "grab" the round and extract it delicately.   Not fun at all.

[perttime]

....

What I'd like to know, what is the routine for a misfired 107mm mortar?  I know the 81mm is alarming enough and requires a set of calibers on the end of a line to go down the barrel and "grab" the round and extract it delicately.   Not fun at all.

With our 120 mm, a device that you lower into the "tube" was the way.

Before that, the mortar leader was to pull the trigger string twice. If that didn't help, the assistant aimer (leveler) would lower the tube a little, grab the bipod assembly from behind and shake it hard a few times (there's a spring in the system), and then the mortar leader would try the trigger again, twice. If that didn't help......

With light ones like 81mm there's another way. You separate barrel, base plate and bipod. Then you turn the barrel over horizontal and slide the round out.

We had an instructor, former combat diver, who was famous for a number of things. One was shooting an 81 mm mortar from the hip. A practice round, only, I believe.

[NARSES2]

That's come out very well 

[Rick Lowe]

Nice work on that, seems there's an LVT family that could be in the works...

WRT indirect sighting, wouldn't a Periscope be the answer?
You could always cobble up an extended sight mounted on the mortar itself.

'Sides, the FOO would be able to correct your shots and the crews would have been trained enough to work out the mathematics of "We're here, the observer is there, he wants the shots over there..." trigonometry.

[NARSES2]

'Sides, the FOO would be able to correct your shots and the crews would have been trained enough to work out the mathematics of "We're here, the observer is there, he wants the shots over there..." trigonometry.

When I was at school in the early/mid 60's our maths master set all our trigonometry questions in terms of either navigation, surveying or artillery observation questions in order to keep our interest. And in a boys school it worked It was only after we'd taken our O Levels that we realised he'd done his National Service in the Royal Artillery 

[perttime]

... the crews would have been trained enough to work out the mathematics of "We're here, the observer is there, he wants the shots over there..." trigonometry.

The crew doesn't need much math. The platoon and company levels can use protractor and ruler to  get a bearing and distance, using coordinates marked on paper. Mechanical devices for that can be a little cumbersome, so better keep that with a dedicated team, apart from the single mortars. Then, apply a table for wind corrections and another table to find out suitable charge and elevation.

The mortar crew then needs a precise enough reference to get the right bearing from mortar to target.

The optical aiming devices that I used had dials to adjust them precisely horizontally and vertically. Then, aiming at the "pole", that was at a known bearing, would get the shell going at the desired bearing. Like, the calculator guy would call a setting that sends the shell 15 mils left of the "pole". The aiming device also had two bubble levels: one gets the right elevation and the other ensures that everything is square on the bipod. The "assistant aimer" would turn two cranks to keep them level, while the "aimer" would focus on the "pole".

[Rick Lowe]

'Sides, the FOO would be able to correct your shots and the crews would have been trained enough to work out the mathematics of "We're here, the observer is there, he wants the shots over there..." trigonometry.

When I was at school in the early/mid 60's our maths master set all our trigonometry questions in terms of either navigation, surveying or artillery observation questions in order to keep our interest. And in a boys school it worked It was only after we'd taken our O Levels that we realised he'd done his National Service in the Royal Artillery 

Useful way to keep the interest of a pack of schoolboys. Using what you have to get what you need.