TARTARUGA
THE STORY OF A TRUCK
WITH A HOUSE ON ITS BACK
THE STORY OF A TRUCK
WITH A HOUSE ON ITS BACK
election of a suitable winch for the Tartaruga project was not a simple matter.
How big, which rope, where, how......................... many questions?
I firmly believe that wherever possible, one must avoid drilling or welding a 4x4 vehicles chassis, and so with our vehicle I had to confront the dilemma of how to mount a winch.
I suppose rightfully I should say that before we could deal with the how, we had to deal with the where and the which.
As a process control engineer I have some experience of what it takes to move electricity down a wire, so in order to winch 5 tons of truck it occurs to me that rather a large copper cable would be necessary between my camper batteries and winch, and the camper batteries are Lithium, and sit in the middle of the truck, and as Lithium is considered by some to be unsuitable for heavy transient loads , and as I have had a dismal outcome when trying a Lithium battery as a main starting battery, my decision was to go with a PTO driven hydraulic winch.
In addition to the minimization of weight in terms of cables motors and contactors, an hydraulic winch has other prominent features, not the least of which is its gearing to engine speed.
Any experienced offroader knows that a winch is not used on its own to extract a vehicle wherever possible, one must put your vehicle in low range and if possible difflocks on, and use a gear suited to the speed of the winch rope. Use the engine and the winch together, the winch places huge electrical demands and mechanical demands on your vehicle (particularly the electrical demand on the vehicles battery and alternator) and so we use them as little as possible, and even though a stuck vehicle has little traction, every bit helps, and as soon as it does have traction, take the load off the winch.
With a PTO and hydraulic winch, a pump attached to a shaft, commonly on the transfer case, makes the hydraulic pressure and this turns an hydraulic motor on the winch mechanism. If the engine turns a bit faster, the pump also turns a bit faster so if you have your gears and wheel speed matched with your winch rope speed, accelerating a little or slowing your engine a little, is inclined to make the winch go faster and slower as well, by sending more or less oil to the winch motor, this coordination is more than useful and all helps to minimize stress on the engine transmission and chassis structure.
Clearly then we were after an hydraulic winch, these are also a little cheaper than electric equivalents and also simpler to control as no heavy cables and contactors are required, only a pair of solenoids sending the hydraulic fluid one way or the other, through the winch motor.
This dilemma is seldom considered, people are inclined to accept that a winch is installed on the front bumper, and usually the only reason why, is that the fitment centre sold you on the idea, which r=frankly they chose, because a front bumper mount is easier than anywhere else.
I have seen some installations where a receiver is mounted on the front and back bumpers, and the winch is in theory relocated to the most suitable end of the vehicle to effect the pull.
With a 5 ton vehicle, it is not going to be me that disconnects that winch from the front bumper and takes it around to the back to mount there, I am too old and too weak for this type of superhuman behavior.
It is my due consideration that a winch in the front, is used to pull a vehicle forwards, while a winch in the back is designe3d for the converse, now it is a fact that in the greater majority of instances a vehicle is driven forwards into an obstacle and becomes stuck, it is therefore entirely logical to me, that in order to free the vehicle, the best route is to return it to solid ground where it was still moving under its own steam, I therefore have a preference for the rear mounted winch.
It is also a fact that when badly stuck, you need to reverse to assist your winch for a recovery, and reverse gears are very powerful, but not designed to handle heavy loads for long periods of time and so not the best way to drive out of trouble, it is also a fact that when recovering a vehicle, it is much better to be able to see where you are going, and that is not out the back window.
It is also a fact that most often you will come upon another unfortunate soul who has gone a step too far and needs help, I have had to winch others out, ten times more often than I have been winched, if I recall correctly, twice I used a winch on my own vehicle, because I had no option, but I have pulled countless others out of trouble and it is known that I just cannot resist pulling a stuck landrover, but that is another subject for another day.
When pulling another vehicle, it is more than helpful to be able to watch carefully what you are doing, and that would be best out the front window not the back.
But all that having been said, I have a winch on my vehicle, as an insurance policy to pull myself out of trouble, this will be a last resort when no other tools I carry with me work, and it is my consideration that being in the wrong place and stuck, requires extrication from that place and the shortest route to normality, will be back out the way I came. So winch mount at the back.
I do still have the need to tow stuck landrovers, winch and rescue large firewood to safety, and pull camels out of wadis, so at some time I shall likely build a bulbar and put a small electric winch in front, but for my insurance policy for my truck, to get the wheels back on the road, my winch location is the back.
It is a common rule of thumb that a winch capacity should be 1.5 times your vehicles likely combined weight.
Winches are normally rated in pounds, my truck weighs 5 tons when loaded for battle and for the record there are 2.20462262184 lbs in one KG, 5000 KG x 2.2 = 11000 lbs and applying the factor of 1.5 this then indicates I should have a 16500 lb winch to pull my truck.
There is another theory that says the correct rating for a winch is the maximum weight x 1.5 plus another 0.5 to pull out of very deep mud, which has a tendancy to suck a vehicle into the hole it finds its unlucky self in, and therefore more power required to pull it out.
I am not sure any winch is always big enough to just magically lift a vehicle out of hades back onto the straight and narrow, recoveries are always a combination of tactics and tools and methods, and we all know what opinions are…….. everyone has one.
I settled on a Come up winch HV 15 rated for 15 000 lbs
Layer of Wire RopePull by LayerTotal Rope on the DrumLine Speed at 60 l/min (15.9 g/min)kg / lbm / ftmpm / fpm1st6,800 / 15,0007.8 / 25.69.0 / 30.02nd5,673 / 12,50717.3 / 56.810.5 / 34.43rd4,867 / 10,73027.0 / 89.012.3 / 40.4
This was something short of the best solution, however, there are some significant considerations,
The power the winch could handle would not :-
Hydraulic winches, generally do what they say they can under all conditions, if they turn, they turn according to spec, so I was faced with the option to order and wait for the import of, a 18 ton winch from the same supplier, a rare item that had to be specially ordered, or compromise with the promise to myself that I would always keep a snatch block in my back pocket, never expect the winch to perform unless the rope was fully unwound and on the first layer, and I went for the smaller, lighter and off the shelf 15 ton unit.
I have seen some of the most beautiful looking bullbars on offroad vehicles, complete with concealed winch, just the fairlead and a rope and hook visible on the front.
Why? I always ask myself how do these fabricators expect you and I to remedy a crossed over winch rope on that enclosed drum, how do I get in there to extricate a rope turn from between two other rope turns below it, when the rope wasn’t correctly wound in on the underlying layers, indeed in some cases, how do I even reach the clutch to disengage the winch to run the rope out.
The next thing I look at is the thickness of the plate and how the winch is connected to the chassis of the vehicle. In most cases I found there was no insight into the forces generated by winching or the stress on the winch mounting points, or the distribution of the winch load onto the vehicle chassis.
A winch should be on an adequate base made from high grade steel and bolted to as many bolts directly on the chassis as possible, way too many are tacked onto a bulbar structure with a wish and a prayer, or enjoy a base made from 2mm thick mild steel plate.
All bolts should be of the best grade available that means a minimum of grade 8.8 bolt, and n particular, as attractive as the corrosion free environment may seem, never use stainless steel bolts.
A winch should neither use welding nor drilling of the chassis unless it is absolutely unavoidable, and then the procedure to weld or drill and make that modification, had best be discussed with the vehicle manufacturer or a competent mechanical engineer with a practical sense of offroading, AND strength of materials, (yes there are manuals, the Iveco Daily has “body builder instructions” to assist the fabricator to know what the chassis is designed to handle and where the designers envisaged such things to be installed and how)
I made the decision to mount at the back and the Iveco chassis has an underrun bar at the back with a series of bolt holes, but in my opinion all in the wrong place and unsutably positioned to be repurposed for a winch.
Fortunately the iveco ladder chassis has two really monstorous pipes cross in from left to right chassis rail, just in front of the rear cross member. I resolved to fabricate a pair of metal plates to bolt into the space between these two tubes and fabricate them accurately enough so that when bolted to gether they would grip both of these tubes and distribute the stress of the winch load overt the maximum area possible. I am satisfied that I could not come up with a more suitable are and method for this mount, and thus far it has only done one serious pull, but it did it with aplomb and I am satisfied I got it quite right.
I have worked in industry for 40 years and seen some horrific cuts and punctures in hands of the careless ones who chose to handle a wire rope without gloves.
Even with gloves, a wire rope has a penchant to snag, hook and kink, straighten it out, it has a weakness and sooner of later a wire strand frays and breaks. In continued service this strand finds its way to the surface where needle sharp, it lies in ambush for the unsuspecting user to grab it, or worse, let it slide through a bare hand.
It is never safe to handle any rope with bare hands, even the softest of rope can burn your hand straight into the nearest hospital.
So to minimise risk, we have opted for synthetic rope, there is still a possibility of serious damage to your hands, but severe hospital type damage is not at all likely, and the synthetic rope needs to be rested after use, not stretched out and then wound tightly around a hot winch drum covered in sand and mud.
A synthetic rope is perhaps 10 - 15 kg lighter than steel, not likely to be totally destroyed by kinking, can be repaired on site if you have the patience and skills, and if it was to break, you could just tie a knot in it and continue your recovery, not a good thing to do, but an option you do not find with a steel rope. We went for a rope size one up from the steel rope, it has a higher breaking strain rating than the steel one did, but remember, it can still pick up a thorn or a wooden splinter and if that drags through your hand, your will not forget your gloves again anytime soon.
Of course the winch is only half the story, the other vehicle needs to have a point to attach the rope for the recovery and/or the winching vehicle needs an attachment point for the end of the winch rope when using a snatch block to double rope pull.
These are difficult considerations when it comes to the back of the Iveco chassis, in my case, there just isn’t room for it, and I have yet to “get around to it” so for now, my vehicle cannot be recovered with a rear attached rope and can also not operate with a snatch block, I will edit this dialog when that happens one day.
The front of the Iveco chassis ends in two rails that have a welded end plate closing them off. There are two M16 bolts in the end which go into tapped thread holes in the end plate, on each rail, and as standard they serve no purpose other than to secure the front bumper/valence (or whatever else you may choose to call the almighty steel plate you have to remove from the front of the truck, to change the fanbelt)
I am happy that this end plate is substantial enough to tow the vehicle and indeed to pull it out of the hole when required, however I am not entirely happy about the end plates construction nor the threading of the M16 bolts into that plate. I decided to have a metal block cut with shackle attachment holes below, and to bolt this onto the front of the chassis rail end plate, my thinking here is that both bolts will then have to share the stress of the pull, the plate I fabricated cannot distort or bend, as the recovery point is below the chassis rail, the lower bolt will always do a bit more work than the upper, however as I used grade 10 bolts which can each manage well over 100 tons, I was substantially more concerned that the Iveco chassis could survive than the bolt or manufactured end plate.
I did find that the thread for the M16 bolt was either not tapped deeply enough or was welded closed somehow during construction, and I had to run a tap through each bolt hole and ensure that the new bolt could pass right through the hole, and out the other side, the standard hole depth was just too shallow for my liking and it didn’t need to be.
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