Sand/Offroad Ladders

[tuko]

I have had sitting behind the wood shed for several years a pair of ramps that I would finally like to put to good use. I would like to use them for the bases of a pair of sand/off road ladders, something that would have a multi function that could be used for sand if the need arises or for bridging when off-roading over stumps or boulders.

So here's what I have:

I'm looking for input/suggestions of how I can make these lighter, shorter and stronger so that they can carry the load of my series 3 hybrid.

Those ramps are long, so first question is what is the recommended or ideal length that I should cut these down to?

With the sides folded over that adds some strength but I'm not too sure if it would carry the weight of the hybrid so I'm thinking that a length of square tubing up the center on the bottom will work??? Or should I use two lengths of square tubing equally spaced?

Also I see that many sand ladders have lots of holes in them, should I do the same here with these ramps? What do those holes really do? Do they add traction but at the same time reduce weight or is it just cosmetic?

Cheers,

Todd.

[Maverik]

hmmm, now not intending to tiddle on ur parade, but my first thoughts would be to scrap the idea and just invest in some "waffle boards" or a purpose designed sand bridge/board/matt.

I work with steel/aluminium structures at work and i see what you want to do, but for the time and effort putting into converting them, you'd probably end up with something usable but probably a little on the heavy side.

Firstly are they Alu or steel checker plate, I'm guessing Alu?? the problem you'd have is they are pretty deep with those U sections hanging down, the shallower the matt the better (easier to get out the mud when it does sink in a bit) tubing or square profile would theoretically give it more strength but only if you can anchor it sufficiently to either end of the top plate, otherwise you'd have a bendy collection of tubes and plate not working together "structurally"

you could cut some holes down the centre partition, but again I probably wouldn't make them too big as you'd maybe get local buckling in the flat plate.. if it was slightly corrugated then it would be a different story. small holes will stop any sucktion when getting them out the mud.

Yeah i do have too much time on my hands, see i even did a wee sketch. hope this helps.

Mav

[David Sparkes]

Sand Ladders and Bridging ladders are two different things, having different design criteria. After understanding these you can design a composite unit, but like any compromise, it will never perform each function as well as a single use device.

Possibly better to change the terminology and call them Sand Mats and Bridging ladders, which of course open the design to the treaded rubber mats available.

Sand mats are supported over their whole length, and need to be substantially solid to spread the load over as large an area as possible. The disadvantage of the resulting low ground pressure is that there is little grip between the mat and the ground, thus the holes. While reducing the surface area the multiple edges dig into the sand and give the mat traction.

So, the holes aren't cosmetic.

If you put the term 'ladder' in it's more common usage, to enable a human to climb up a pole, house wall, or tree, etc, then you can see how such a design does not work well if used in sand. The holes are too big, and the surface area of the stiles and rungs is too small.

The same criticism could be leveled against waffles, although they would be better than simple ladders.

In terms of length, two short pieces that can fit between the wheels could always be useful, to give the trailing wheels something to grip, or at least to stop them sinking, but other wise 'as long as possible' will be best. Soft sand (or mud) is rarely only 4 feet long.

'Distance between the wheels'.

In these circumstances I'd say it's best defined by subtracting the tyre diameter from the wheelbase.

Thus 88 - 32 = 56, or 109 - 32 = 77. Inches of course. Anything longer and you could struggle to get one in place after you are stuck.

Bridging Ladders.

You have already highlighted the design criteria re carrying weight.

Length, I think the same critera apply as to sand mats; a short pair, no longer than the maximum length between the wheels, or possibly shorter, to fit in your designated storage space, as you won't always have the space to take a straight run at an obstacle. Another pair as long as you can carry on the vehicle without them getting in the way. These bridge longer gaps with better ramp angles. As there will be more length between the supported points, these longer ladders need to be stiffer than the short ladders.

Next Steps.

Starting from what you have, I'd be looking for an aluminium ladder, possibly second hand will get you commercial strength at a reasonable cost, as opposed to domestic strength, which in the UK at least, are too light (weak).

Lay the ladder 'inside' the ramps. Drill holes through the ramp and plug weld (or blind rivet) the two together along the stiles. Cut holes in the ramp surface as per sand mat design. Plunging the holes seems like a worthwhile exercise.

Use plate down as sand or soft ground mat.

Use plate up as bridging ladder.

The ramps may only be long enough to provide a long pair, but you will have some ladder left over to fold plate around to make a short pair.

HTH

[DefcoL]

Remember that someone has to get them off the truck, lay them in position,

get them out of the mud(most likely with mud that could easily double the weight)

relocate them on the truck ready for the next obstacle

Larger ones might seem logical to bridge wider/taller obstacles

but not on the weight side of the debate unless you have the hulk as a helper

Where would you mount your large ramps? how much would they weigh.....

Do your back a favor and get some waffle boards, someone on here should be able to recommend

where to get them from.

[mel]

Remember that someone has to get them off the truck, lay them in position,

get them out of the mud(most likely with mud that could easily double the weight)

relocate them on the truck ready for the next obstacle

Larger ones might seem logical to bridge wider/taller obstacles

but not on the weight side of the debate unless you have the hulk as a helper

Where would you mount your large ramps? how much would they weigh.....

Do your back a favor and get some waffle boards, someone on here should be able to recommend

where to get them from.

Hi,

I've got some 38mm and 50mm thick waffle boards here if you want some.

They're 1220mm long and 310mm wide with the heavy grit finish in a few different colours, give me a call if you're interested.

I'll add a post on the for sale board too.

Mark

07525943842

[David Sparkes]

Remember that someone has to get them off the truck, lay them in position,

get them out of the mud(most likely with mud that could easily double the weight)

relocate them on the truck ready for the next obstacle

Larger ones might seem logical to bridge wider/taller obstacles

but not on the weight side of the debate unless you have the hulk as a helper

Where would you mount your large ramps? how much would they weigh.....

Do your back a favor and get some waffle boards, someone on here should be able to recommend

where to get them from.

You make some very good points, BUT, I've never considered waffle boards as light, and certainly not when filled with mud. What thickness do you recommend for bridging? ISTR most people here say 50mm rather than 38mm.

This reinforces my point, trying to use one item for two purposes is a compromise that offers reduced performance.

I don't think a plain waffle is good in sand or soft ground, as it doesn't present sufficient surface area.

If I was starting from scratch, and Tuko could do this as well, IF waffles are available at an economic price in his country, is to go down one thickness in waffle and wrap, fully or on three sides, the waffle in aluminium no thicker than 5mm. This reduces the dry weight, stops the mud being trapped in the waffle, gives a good surface area for soft ground, with the combination giving enough stiffness for bridging.

HTH

[David Sparkes]

Hi,

I've got some 38mm and 50mm thick waffle boards here if you want some.

They're 1220mm long and 310mm wide with the heavy grit finish in a few different colours, give me a call if you're interested.

I'll add a post on the for sale board too.

Mark

07525943842

OK, about 48" x 12" x 1.5" or 2".

Just to have some numbers in the discussion, what is the weight of these, in both thicknesses?

Thanks.

[tuko]

Hej Guy,

I made this post in the middle of the night so as you have already pointed out my terminology was off to say the least. Lets consider this a "Lets make the best out of what I have" project. Years ago I enjoyed getting buried on the mud and getting hopelessly bogged down in loose sand but nowadays I prefer hard trails with technically challenging routes, ie: well placed roots or boulders on the track, inclines etc. I find it more enjoyable to see what man and machine can do over impossible terrain.

So getting to the alu ramps that I have that are around 2m long, I want to make them into an all round tool that will do a job when they are called upon. Of course strength is a factor, lightness and size. I don't as of yet have a roof rack so these ramps would be carried in the back of the hybrid, so overall length certainly plays a roll.

As for strength I can get my hands on a few lengths of high strength alu. trusts that were used in our warehouse for stacking pallets on. They are relatively light and would be even lighter once cut to size. Off the top of my head I think that they are 5cm x 8cm with rather robust wall thickness. I was thinking with just one running the length of the ramps (cut down to about 48") in the center (bolted, no pop rivets). This combined with the sides folded over should give me a fair amount of strength.... or will it ??

Then the idea of drilling holes, this would make them lighter and possibly add a bit of additional traction. As mentioned earlier going crazy with too many 22mm or larger holes will weaken the ramps so trying to figure out the fine line of too much or not enough should be interesting.

Then I was thinking about the ends, should they be left flat or should I try to create teeth on a folded lip to add better grip on roots or rocks for the ramps?

Hope I made myself clearer and many thanks for the input so far, I certainly have a bit to think about.

Cheers,

Todd.

[HoggyN]

Adding holes would reduce the weight. If you swaged the holes you wouldn't lose any stiffness and might improve the grip too.

[David Sparkes]

Adding stiffening ribs, of the same (or very similar) material is the best way to go, because they will have similar bend / flex characteristics. Personally I'd be looking to get the sheet material welded to the box.

My concern about a single beam is what happens when the tyre goes off centre? Then you are only using half the beam, the other weight is taken by the folded edge; will it take it, or will the sheet just fold around the side of the beam, dropping the wheel?

You need to be able to rely on the edge of the ramp being able to support the weight, otherwise you are carrying a 12" ramp but saying 'I can only use the centre 8"' (300mm ramp but only using the centre 200mm) :-)

If you put two beams under each ramp the concern is that the ramp folds down the centre, as the wheel runs down the centre.

The ladder idea has cross beams (rungs) to stop this happening!

I'd only put holes in the plate, swaged as suggested. I wouldn't put holes in the beams.

I think a lot depends on how much strength there is in the ramps. Could you conduct a test, say supporting the ramp on two 3" (75mm) blocks at 4' (1220mm) centres and driving onto it? You could put a 2" (50mm) block at the midpoint to stop the ramp flexing beyond it's point of elasticity. There is no point is destroying an asset through carelessness.

Clearly I like the approach "Lets make the best out of what I have"- we are just discussing details and options :-)

HTH

[hobson]

It seems to me whatever you make won't do either job as well as the proper item, wether waffle board or sand mat.

if you start puttin holes in chequer plate even 4mm stuff it will bend and warp, you could weld support ribs under/over and swage the holes but it's going to be a lot of work.

an easy option is look on Ebay or at Anchor supplies and get some PSP matting, it's heavy but pretty indestructible, and it'd do both things....

i think it's about 40 quid for two 2.5m lengths...

[bishbosh]

Light, strong, cheap.

Pick any two.

For any bridging work for vehicle wheel loads you are better off with waffles really. Mantec do some very expensive Ally bridging ladders but I can't see any advantages of them over waffles.

38mm or 50mm? Depends on how far you need to bridge. 50mm gives you more scope, but a lot more weight.

I would leave the trailer ramps alone and go get some waffles. Fabricating something in metal will either be heavy and clumsy or very expensive and exotic.

[tuko]

Ja Waffles sound great, there's no argument from me when it comes to them.

The fantasy prices here are the big turn off, then buying over in England it's the shipping that kills ya!

That's why I dug out the ramps and thought that maybe something can be done with these suckers.

Todd.