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Re: Nissan Off Road Club - Berakah trail 24th May 2014

Posted: 26 May 2014 11:48
by ricster
Just to give David a gentle pull up the last bit of mineshaft. Highway tyres aren't good on rough rock... :redface:

The Sani drove up most of the rocks but needed the tug to get the tyres to bite onto the rock to get over the top.

Re: Nissan Off Road Club - Berakah trail 24th May 2014

Posted: 26 May 2014 12:51
by Alex Roux
Cedric

I think you can still call it a recovery because I could not see how the Sani could get out of there by any other means. There was no turning back either!

However what was interesting about this "recovery" was that Christo said the winch was not able to pull the Sani up on its own.
It needed the Sani 's wheels to turn, get traction and help along the bumps on the way up.
The hill was steep enough as it is, but with the bumps / rocks the winch could not do it on its own.
What happened as a result though was that every time the cable tightened, Christo's patrol shifted another few inches forward. There was also no space further back for the Patrol to move into. (note we also added rocks underneath the Patrol's wheels to anchor it better. But this did not seem that effective.
Eventually the Patrol had moved about a meter by the time the Sani was at the top (with Andre in the driver seat and his foot on the breaks!).

No recovery ever seem to be simple "vanilla" and by the book; and I am wondering what could have been done differently?
Besides the safety of adding a dampener / dead weight over the cable
You okes that went on the 4x4 training course can comment...

Re: Nissan Off Road Club - Berakah trail 24th May 2014

Posted: 26 May 2014 13:32
by Herrie
Was Christo standing outside the Patrol to use the winch?

It is much better and safer to have the door open, stand behind it or sit inside and put your foor on the brakes then the Patrol will not move when you use the winch. I have tested it like this a couple of times already!

Re: Nissan Off Road Club - Berakah trail 24th May 2014

Posted: 26 May 2014 13:59
by ricster
I was below the Sani on the side out of the way so didn't see Christo at all. I asked Christo to take charge as he is an experienced "wincher" and knows his equipment. I know there was someone standing on his brakes while he was winching. The problem was the angle was not pulling the Patrol into the ground, but more pulling directly forward or slightly up taking weight off the front wheels. Ground conditions was very loose gravel.

We needed to keep the Sani moving under its own steam. Due to the landscape and terrain, the Patrol could only safely recover from that position. However had the Sani NOT been able to climb under its own steam, an angled recovery would have needed to take place, with Christo's Patrol's winch pulling through a snatchblock attached to another fixed point ( 2nd Patrol ) to try change the angle of recovery. The other way would be to make use of a snatch block to double up the pulling capacity. This would also have worked as there would not have been the odd jerking on the winch cable making the Patrol inch forward. With this particular recovery we didn't expect the Sani to move forward in the stages as quickly as it did. The load on the cable was, I believe far under maximum strain, except when the winch cable caught up to the Sani.

A damper blanket should have been used no argument, but under the conditions of this particular recovery I don't think that there was a safety risk due to the winch doing more of an assistance to get the Sani up the last bit of the obstacle.

One thing that could have been handled slightly different, and this is a very valuable point, is that the Sani should have rather kept a more constant rpm. I would guesstimate around 1100 - 1300rpm. This would allow the tyres to slip less before traction takes place, and once traction is achieved the car doesn't bolt forwards then have to stop to allow the winch to catch up. However there are a few nerves and adrenalin pumping through the veins, which can make one not be as calm as one would like to be.

A valuable lesson learnt by all I hope

Re: Nissan Off Road Club - Berakah trail 24th May 2014

Posted: 26 May 2014 14:25
by bogeyman
Alex,
Post mortems are a good thing. You can think about the actions taken without the intensity of the situation causing potential disaster.

Two things I could have done better:
1) At the first sign of uncontrolled movement by the sani , I should have stopped. Better coordination between the winch pull and the sani driver would have been safer.
2)If a strong enough anchor point could be identified in line with the pull , we could have used a snatch block and double the pull power with the same strain on the winching vehicle. Not really safer though with the added possible points of failure and increased pull power.

The reason we had to pull so hard is due to the vertical rock steps in front of the sani wheels. By winching alone we would only move the Patrol forward , as it already stood on an incline and the laws of physics will not allow you to lift something vertically by pulling horizontally.

The only real concern I had was the uncontrolled backward movement of the recovered vehicle causing uncontrolled loads on the winch and cable.
Momentum is not your friend when winching and the winch could not take up the slack quickly enough to match the "spirited efforts" of the sani.

All is well that ends well and we live and learn.

Re: Nissan Off Road Club - Berakah trail 24th May 2014

Posted: 26 May 2014 14:41
by bogeyman
Herrie,
I know it is safer behind the door , but in this recovery I had a better view of the cable and movement of the other vehicle from where I stood.
It was a long pull and I could then also see the winch cable in case of an overwind. In fairness , I was at least 2meters away from the direct line of pull.

Cedric,
I wrote my response before I read your post , but it seems we agree on all points. A safe point for a snatch block would have been a challenge. Another vehicle would also have shifted and I don't recall any leadwood trees in line with our work.

Re: Nissan Off Road Club - Berakah trail 24th May 2014

Posted: 26 May 2014 15:04
by ricster
Yeah, there was noting solid to anchor to, and again as you said the recovery was in essence a safe recovery, except for the unexpected spirited Sani and lack of damper blanket. Decision made at the time is unchangeable, but hindsight can be learnt from by many people !!!

Re: Nissan Off Road Club - Berakah trail 24th May 2014

Posted: 26 May 2014 15:22
by davidvdm
I just saw this discussion now, and as it was my vehicle on the other end of the recovery, I suppose I should have taken charge of the driving. Emil had jumped in, and besides not having much off road experience, has hardly put any time in behind the wheel of the Sani, and obviously even less in the "being recovered" situation.

He seemed to struggle to get the power delivery balanced to just keep the wheels turning constantly. As soon as the revs started picking up, the turbo would come in and the revs would run away with him. He feels bad enough about it, but I think, lesson learned.

As I was not driving, I can't vouch for the traction or lack thereof after the ledge was cleared that stopped the initial progress.

As the other D21 HB made it up there with lower ground clearance than what Hillbilly has, I can only think that it could be the tyres and/or the driver (me). These wranglers were disappointing me the whole day with hardly any grip and lots of sideways slide. I returned the favour and exercised my revenge by splitting one of them open from tread to rim on the very next corner after this recovery.
2014-05-24 16.31.48a.jpg
2014-05-24 16.31.48a.jpg (78.01 KiB) Viewed 1788 times

Re: Nissan Off Road Club - Berakah trail 24th May 2014

Posted: 26 May 2014 15:44
by ricster
Ha ha ha.... Dave... You are a better driver than many.... and I'll tell you why.... My Patrol has big tyres, massive articulation, 6 cylinders and big cubic inches. Does the patrols make easy work out of most obstacles..... ooooooh yes. Is it the driver of the Patrol...... hmmmmm I say no. Patrol drivers are "lazy" drivers. We don't choose a line to ensure that we get up with minimal hassle..... we just go, so the vehicle is the king. I learnt to drive 4x4 in my green Sani, with also no difflock or LSD. Just a straight forward kick ass Sani. In that vehicle I learnt to drive, and choose a line and try protect the Sani as much as possible. You haven't learnt till you get stuck. 10 out of 10 to Emil. He took the bull by the horns and did his best. I guarantee next time this happens he will know exactly what to do, more so than most of us as he has physically experienced the sensation. He must definitely NOT feel bad !!

Just on a lighter note..... Andre with Leeuloop did a few of the obstacles in 2 wheel drive.... and not just 2 wheel drive..... front wheel drive !!!!! :surprised: :surprised: :surprised: Low Range !!!. And what makes this even more unique is that he didn't even realize he had stripped his rear diff. There was no big bang, just after the braai, put the hardbody from 4L into 2H and couldn't pull away.... only sound from the diff was a rather quiet (for a stripped diff) rumble at the rear pumpkin.
Now that shows that even under some pretty tough obstacles ( as we don't know where this happened) Andre had full and total control of his hardbody, not once loosing control down some rather hair raising decents on rough rock and loose rock. He told me that he thought that it must be time to change his Kumho tyres as the grip seems to be getting less and less as the tyres wear out !!!

Well done to everybody.

Re: Nissan Off Road Club - Berakah trail 24th May 2014

Posted: 26 May 2014 16:36
by Alex Roux
ricster wrote:Patrol drivers are "lazy" drivers. We don't choose a line to ensure that we get up with minimal hassle..... we just go, so the vehicle is the king....
And that is my problem
I never learned how to drive 4x4. I just bought a Patrol
Imagine how lazy I will get with front lockers!

So if I want to learn how to drive 4x4, what vehicle would you recommend?1