Ratbag
Administrator
- Joined
- Jan 1, 2012
- Messages
- 7,474
- Location
- Bayside, Melbourne, Vic
- Car Year
- MY06, MY10
- Car Model
- Forester SG & SH
- Transmission
- 5MT/DR & 4EAT Sports
A basic rule is that if you are not sure what you are supposed to do: DON'T DO IT!!
This sort of thing should always be learned from those who do know what they are doing.
People happily talk about snatching another vehicle. Mostly they understand what they are doing, or have been doing it so often and for so long that it is second nature to them.
Snatching (and towing ... two very different things) can be extremely dangerous if you do not understand the safety precautions needed. When I say "dangerous", I mean that people can easily get killed; and have been.
Some other "rules" or guidelines that are worth knowing:
1) It is generally advisable to avoid snatching a vehicle that is much heavier than one's own. It can literally pull your vehicle out of shape if not done with great care.
2) If you MUST do #1, then always use shackles rated for the heavier vehicle's weight, while using a snatch or tow strap rated for the lighter vehicle's weight. Using a heavier vehicle's recovery straps may well deform the entire frame of the lighter car.
3) Recovery equipment that you buy should be rated - i.e. have stamped or marked on all components what its maximum load limit is.
These ratings come in two different classes.
"SWL" (Safe Working Load) means that the component is capable of being subjected to the marked load in a dead lift situation (i.e. lifting vertically off the ground).
"WLL" (Working Load Limit) means that the component is rated for the marked capacity as long as the load is rolling - i.e. much of the mass of the vehicle or load is being carried by its contact with the ground.
Items that have a WLL rating will usually have their Breaking Strain ["BS"] listed. By engineering convention, the BS is about double the WLL, and the SWL is normally 2/3 rds of the WLL; but these relationships can vary. I would be profoundly worried by (say) a load distribution strap that listed WLL = 4,000 kgs; BS = 5,000 kgs. My own LDS has a SWL of 4,000 kgs and a BS of 8,000 kgs.
Almost always, the "SWL" figure will be considerably less than the "WLL" figure when both are marked on a component. e.g. the "WLL" rating for my creeper winch is 2,400 kgs, and its "SWL" rating is 1,600 kgs.
4) A snatch strap should be rated at approximately double the weight of your vehicle. e.g. my snatch strap for my Forester is rated at a BS of 5,000 kgs. The bow shackles I have are rated at a WLL of 3,200 kgs.
One should never use a snatch strap for towing; or a tow strap for snatching. A tow strap has almost zero stretch in it. A snatch strap is designed to stretch (quite a lot ... ).
5) One should use a rated load distribution strap between the tie down points on Subarus that do not have a dedicated recovery point and recovery eye bolt.
When using a load distribution strap, the rated shackle should be attached to one vehicle tie down point with a rated bow shackle; the other end of the load distribution strap is then passed through the eye on the SNATCH strap; then the eye on the load distribution strap is attached to the other tie down point with the other rated bow shackle. IOW, one should never attempt to tie off the load distribution strap other than to the rated shackles attached to the vehicle tie down points.
UNDER NO CIRCUMSTANCES should the load distribution strap be attached to the snatch strap by any other method - e.g. by using a bow shackle; this latter would be a deadly mistake.
When using a recovery eye bolt on later Subarus, one must follow the instructions about fully screwing the bolt into the body thread, and tightening it according to the instructions in the Owner's Manual.
6) When winching using a tree as an anchor, one must use a tree trunk protector. This is a non-stretching rated strap with padding that must again have its two end eyelets joined by a rated shackle, or more commonly by the winch anchoring hook.
7) NEVER, NEVER use a tow ball as any kind of attachment point - NOT EVER. It is OK to use a rated bolt or shackle through the tow ball bolt hole in a removable tow tongue, or preferably to use a rated snatch strap attached using a rated bolt through the main tow bar frame in place of the tow tongue. The tow tongue retaining bolt is fine for the purpose, but ENSURE that the retaining split pin is securely in place.
8) A snatch strap should always be used with a 'dampener'. This can be a purpose built sand bag type thing, or something as simple as a blanket thrown over the middle of the strap before any load is put on it. Such a thing can absorb much of the energy if anything breaks ...
9) DO NOT ALLOW any person to stand within the maximum (stretched) length of the snatch or tow strap on either side - i.e. if the strap has an un-stretched length of 8 metres, onlookers should be a minimum of 16 metres away in all directions. This distance includes to the front and rear of the vehicles involved, and on all sides [Thanks, Mr T]. If the strap breaks, it will be like a guillotine. There is enormous energy stored in such a strap when under load. Specially if a shackle or bolt breaks and is still attached to the whipping end of the strap.
Keep the bloody spectators and children well out of harm's way ...
By now, you should be able to see why I said that one should learn this stuff practically from an experienced, careful and knowledgeable person. It is a big part of the value of forums like the ORS in that one can meet up with just such people and learn from them, both in the field and on-line.
[EDITS] fixed up the confused and wrong description of use of a load distribution strap, and clarified a few other points.
And fixed a couple more bits ...
[end edit]
This sort of thing should always be learned from those who do know what they are doing.
People happily talk about snatching another vehicle. Mostly they understand what they are doing, or have been doing it so often and for so long that it is second nature to them.
Snatching (and towing ... two very different things) can be extremely dangerous if you do not understand the safety precautions needed. When I say "dangerous", I mean that people can easily get killed; and have been.
Some other "rules" or guidelines that are worth knowing:
1) It is generally advisable to avoid snatching a vehicle that is much heavier than one's own. It can literally pull your vehicle out of shape if not done with great care.
2) If you MUST do #1, then always use shackles rated for the heavier vehicle's weight, while using a snatch or tow strap rated for the lighter vehicle's weight. Using a heavier vehicle's recovery straps may well deform the entire frame of the lighter car.
3) Recovery equipment that you buy should be rated - i.e. have stamped or marked on all components what its maximum load limit is.
These ratings come in two different classes.
"SWL" (Safe Working Load) means that the component is capable of being subjected to the marked load in a dead lift situation (i.e. lifting vertically off the ground).
"WLL" (Working Load Limit) means that the component is rated for the marked capacity as long as the load is rolling - i.e. much of the mass of the vehicle or load is being carried by its contact with the ground.
Items that have a WLL rating will usually have their Breaking Strain ["BS"] listed. By engineering convention, the BS is about double the WLL, and the SWL is normally 2/3 rds of the WLL; but these relationships can vary. I would be profoundly worried by (say) a load distribution strap that listed WLL = 4,000 kgs; BS = 5,000 kgs. My own LDS has a SWL of 4,000 kgs and a BS of 8,000 kgs.
Almost always, the "SWL" figure will be considerably less than the "WLL" figure when both are marked on a component. e.g. the "WLL" rating for my creeper winch is 2,400 kgs, and its "SWL" rating is 1,600 kgs.
4) A snatch strap should be rated at approximately double the weight of your vehicle. e.g. my snatch strap for my Forester is rated at a BS of 5,000 kgs. The bow shackles I have are rated at a WLL of 3,200 kgs.
One should never use a snatch strap for towing; or a tow strap for snatching. A tow strap has almost zero stretch in it. A snatch strap is designed to stretch (quite a lot ... ).
5) One should use a rated load distribution strap between the tie down points on Subarus that do not have a dedicated recovery point and recovery eye bolt.
When using a load distribution strap, the rated shackle should be attached to one vehicle tie down point with a rated bow shackle; the other end of the load distribution strap is then passed through the eye on the SNATCH strap; then the eye on the load distribution strap is attached to the other tie down point with the other rated bow shackle. IOW, one should never attempt to tie off the load distribution strap other than to the rated shackles attached to the vehicle tie down points.
UNDER NO CIRCUMSTANCES should the load distribution strap be attached to the snatch strap by any other method - e.g. by using a bow shackle; this latter would be a deadly mistake.
When using a recovery eye bolt on later Subarus, one must follow the instructions about fully screwing the bolt into the body thread, and tightening it according to the instructions in the Owner's Manual.
6) When winching using a tree as an anchor, one must use a tree trunk protector. This is a non-stretching rated strap with padding that must again have its two end eyelets joined by a rated shackle, or more commonly by the winch anchoring hook.
7) NEVER, NEVER use a tow ball as any kind of attachment point - NOT EVER. It is OK to use a rated bolt or shackle through the tow ball bolt hole in a removable tow tongue, or preferably to use a rated snatch strap attached using a rated bolt through the main tow bar frame in place of the tow tongue. The tow tongue retaining bolt is fine for the purpose, but ENSURE that the retaining split pin is securely in place.
8) A snatch strap should always be used with a 'dampener'. This can be a purpose built sand bag type thing, or something as simple as a blanket thrown over the middle of the strap before any load is put on it. Such a thing can absorb much of the energy if anything breaks ...
9) DO NOT ALLOW any person to stand within the maximum (stretched) length of the snatch or tow strap on either side - i.e. if the strap has an un-stretched length of 8 metres, onlookers should be a minimum of 16 metres away in all directions. This distance includes to the front and rear of the vehicles involved, and on all sides [Thanks, Mr T]. If the strap breaks, it will be like a guillotine. There is enormous energy stored in such a strap when under load. Specially if a shackle or bolt breaks and is still attached to the whipping end of the strap.
Keep the bloody spectators and children well out of harm's way ...
By now, you should be able to see why I said that one should learn this stuff practically from an experienced, careful and knowledgeable person. It is a big part of the value of forums like the ORS in that one can meet up with just such people and learn from them, both in the field and on-line.
[EDITS] fixed up the confused and wrong description of use of a load distribution strap, and clarified a few other points.
And fixed a couple more bits ...
[end edit]
Last edited:
.
.
:iconwink:.
.
).