Double Bridging

[CharlieB]

Sometimes one bridge just can't do the task!

This one was at night so I may have to let the engineers off. However the first Biber did fall into the river trying to cross!!!!

[Tacbat]

I don't think I've ever seen a "double" bridge before. I'll tuck that tactic away for a later date.

[CharlieB]

I believe it is a technique tought to our Royal Engineers - you have to do it manually though. Means you can cross where the river is wider than one pixel. Other end can be submerged.

[Tacbat]

Rgr that. I'll have to rememeber to add a few extra bridgelayers to future missions so that this option will be available to the appropriate side. At least that will give them more areas in which to conduct their crossing.

[Ssnake]

In real life it is even possible to use three Biber bridges for a river width of about 30 to 40m (should look like an "A" upside down). I haven't tested that in SB, and it may not work if the air intake point of the Biber is set too low.

[CharlieB]

Having just run a quick test scenario...

Wadi:

1 or 2 Pixel (P) no bridge required

3 P - Double bridge required, 3rd will improve angles

4 P or greater cannot be done.

River:

1 P 1 x Bridge.

2 P 2 x Bridge

3 P Cannot be done.

This is with the Biber.

Going to attempt with the MT55 as it has a greater span.

UAV Pics to follow.

Wait out...

MT55 did not perform to well see below.

Images of the 3 pixel Wadi crossing below.

Hope this helps.

Edited April 28, 2009 by CharlieB
Mistake!!!!

[GH_Lieste]

I have successfully bridged a 3 pixel river, but required 4 bridges to do so. The river depth is excessive for the width though, so any bridges layed from the dry banks disappear.

Judging how deep you are from the driver's position is tricky as the model is always in front of the water layer - from external view it is much easier to check progress into the water.

[CharlieB]

I think I would consider using bridges that can't be seen because they are totally underwater as a little un orthodox.

[GH_Lieste]

I think I would consider using bridges that can't be seen because they are totally underwater as a little un orthodox.

Think of the first one as engineer preparation/reconnaissance of the banks/bed

The above shows the final bridge - not the neatest, but perfectly usable by a 6 vehicle platoon to cross on a route without going for a swim

[CharlieB]

Perhaps you could try and re do it in a wadi and we can see what that 4th bridge is upto.

[GH_Lieste]

Perhaps you could try and re do it in a wadi and we can see what that 4th bridge is upto.

It is horizontal (ish) across the bottom of the deep bit. Makes the depth more compatible with the stream width, and gives something for the 'first two' bridges of the triple bridge to rest on - they tend to lie on/under the slope with their lower end in the bottom of the 'v' without it.

This is actually harder to accomplish in a Wadi than in the River, as you have no clearly defined datum, but getting it wrong matters less... The Wadi was successfully bridged on by the first Biber, so the additional three only serve to improve the entry angles and to make the River crossing.

[Tacbat]

Good research guys.

[CharlieB]

I have to say your bridge laying is much neater than mine! Engr Tp Comd slot for you then!

[Hackworth]

It is horizontal (ish) across the bottom of the deep bit. Makes the depth more compatible with the stream width, and gives something for the 'first two' bridges of the triple bridge to rest on - they tend to lie on/under the slope with their lower end in the bottom of the 'v' without it.

This is actually harder to accomplish in a Wadi than in the River, as you have no clearly defined datum, but getting it wrong matters less... The Wadi was successfully bridged on by the first Biber, so the additional three only serve to improve the entry angles and to make the River crossing.

i messed around with this last night for a few hours trying to double and triple bridge...you can command my engineers any day Lieste. :thelmuts:

[Hackworth]

with these wadis... and so deep....furious syrian engineers at work... tank traps. ok. who's going to create an updated golan heights mission?

[GH_Lieste]

i messed around with this last night for a few hours trying to double and triple bridge...you can command my engineers any day Lieste. :thelmuts:

That was the first triple bridging attempt in the linked picture, and the third (after two successes on rivers) for the Wadi image.

I have since done several more 'triple' bridges, but the four pixel river/wadi is too much for sensible numbers of bridges.

In total I lost two Biber on the river crossing during the first experimentation, one lost into the depths, and sadly gone for ever, and one recovered from the span by an M88 after it moved a little too far for the laying of the far side exit span (but after it had layed it's bridge). I also lost the first Biber into the Wadi while 'finding' the equivalent water line, but it could be recovered/drive out.

The double bridge was completed on the first attempt without loss.

The main downside is that you cannot recover the near side bridge and move on - you might be able to pick up the 'deep' bridge with a bit of luck, but I haven't tried. You have to use the 'correct' Biber to recover each bridge, which is a nuisance. 'Fancy' bridges also cost lots of time... about 30 minutes including movements from hide position to the bridging site, possibly a minimum of 20 minutes if security is not an issue.

[Hackworth]

you probably cannot recover the deep bridge. the biber/mt-55 doesn't like to fish in the water for the bridge. they just look at you funny when you ask them to.

[GH_Lieste]

you probably cannot recover the deep bridge. the biber/mt-55 doesn't like to fish in the water for the bridge. they just look at you funny when you ask them to.

It probably can, if you can remember where you put it

Using small terrain features to assist in positioning the bridges helps a lot... And should assist recovery operations as well.

I think I should be able to get all four bridges back, and three of them on the far side of the crossing... Now I need to test it… Curses, you fiend…

:biggrin:

Ok, four bridges laid over a 3 pixel river, three bridgelayers and an ARV passed across the span, and all four bridges recovered in a hair over 30 minutes. Three bridging elements ready for further bridging efforts, the fourth stuck until a permanent bridge is secured.