A. The BOG OUT device is made from two main tow lines (plaited braid) crossed with webbing we call rungs (it all looks like a ladder). We designed the exact formula for these to cover a reasonable high expectation and then we doubled it.
BOG OUT is not a lifting device so does not require a SWL rating, instead we recommend a breaking strength. These are factory tested and we test again to be sure.
Each tow line breaks at 2160kg and there are two per BOG OUT, so 4320kg. We nominate the break strength as around 4 tonnes to allow for manufacturing variations. The web ‘rungs’ break at 2140kg and are specifically woven to be tear resistant, they don’t get nearly as much load as the tow lines. The rungs are attached via a purpose designed stitch pattern by modified industrial sewing machines and each connection receives five separate stitch patterns (two is sufficient), so if one is damaged, the whole lot won’t unravel. Each BOG OUT has 148 separate stitch patterns and each of those can hold 380kg and they are handmade in Tropical North Queensland.
The eyes are taper spliced and retain very close to full strength, if fact they have never broken during our destruction testing. The connector ties are the same material as the rungs and the knot we recommend (simple sheet bend) holds full strength wet or dry.
We’ve received many questions regarding the strength of the system and some compare BOG OUT with mounted winches. Winches pull at the chassis level and haul the vehicle through a bog or against an obstruction. They may even pull the nose of the vehicle down into the bog increasing load, depending on the anchor point angle.
BOG OUT pulls from the lowest possible point of the vehicle ie the bottom of the tyres and allows the vehicle to drive itself up and out of the bog. BOG OUT is also assisted by the traction of all the tyres, and even if that’s not much, still helps. Also the BOG OUT lays against the bog area which also carries some load.
There are a few myths around the force required to get a vehicle out of a bog. Some think that if a vehicle weighs 3 tonnes, then the winching strength has to be a least that or it would break. That’s not so. Think of it this way, if you climbed under your 3 tonne 4wd and tried to lift it in the air, you wouldn’t move it much, but if you got out and tried to push it down the road, you could. Cars are designed to move forward or backward even when bogged. We’ve tested many recoveries with accurate load cells and computers and the loads applied using BOG OUT are nowhere near the tonnes some claim are needed.
Once a BOG OUT is attached it becomes part of the vehicle’s drive train, and the whole system from engine to anchor is then as strong as the weakest part, which should be the clutch (once traction is resolved via BOG OUT) provided the vehicle is in good condition and without worn or damaged drive train parts.
It must be remembered that even large 4wd’s cannot supply much more than two tonnes to the ground (total all tyres) because the clutch lets go at that. One BOG OUT breaks at around 4 tonnes, twice what is needed, and two
BOG OUT’s offer a haul capacity of a massive 8 tonnes. Still the vehicle can only give out around two tonnes.
Torque also comes into play. An electric winch may be strong but has little torque compared to a fuel engine driving a large tyre through a 40 or so to 1 reduction ratio.
It’s difficult for a vehicle to break a BOG OUT from engine power alone, in fact we’ve never broken one, and we’ve tried. We have deliberately smashed them though to see how they break and to find their weakest point. This was done by tying one end to a large tree and the other end to the winch points and ramming against one on dry concrete.
BOG OUT is made of very low stretch (less than 5% even when wet) high strength and tenacity product and does not become a giant sling shot like some nylon products (up to 30% stretch). Also BOG OUT is laid on the ground and when it snaps it heads towards its anchor points ie the bottom of the tyres which is a lot safer than many other recovery devices.