Post by Brian M on Jan 31, 2009 22:43:43 GMT
From: Downton1071s (Original Message) Sent: 16/04/2005 13:13
Hi all,trust you are well,just wondering if anyone can give me any indication of the weight of our 13/4? Somewhere near will do,we have a steep drive at home and it is a struggle to get the van back in after use,so I am toying with the idea of using a 12V winch to make life easier on me and the car.In theory its a sound idea,the problem coming with 1,the vans weight given its age, 2 its is going to be a dead pull so will need a winch with enough power to pull the van from standstill staight up the side of the white cliffs of dover (the drive realy is that steep!) without calling it a day after a few feet.The vin plate is still on the van but is now smooth so unable to read anything of it,so if anyone has a similar size van they could give me the info off it would be a great help in sourcing the correct winch.Many thanks for your time...Regards Paul&Deb.
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Recommend Delete Message 2 of 7 in Discussion
From: OliverShaw1 Sent: 16/04/2005 14:41
The 1980 Sales Brochure quotes the following data (amongst others) for the 13/4:
Average weight (sic - they of course mean mass) ex works 25.75 cwt (800 kg)
Maximum weight 19.38 cwt (985 kg)
Tyre size 155 x 13 reinforced
I have the subjective impression that the 1980 17/2 uses slightly lighter construction, at least of interior furniture and gas locker, etc, than the 1978 one, and the quoted maximum gross mass has come down from 1300 kg to 1275 kg; if this applies across the board one would expect earlier 'vans to be around 20 to 25 kg heavier than the equivalent 1980 models.
Can you measure the slope of your drive at its steepest point? Perhaps most simply done by using a long encased spirit level to set a horizontal, and then use any convenient straight-edges to set up a triangle; the bottom side on the slope, the top side horizontal, and the third side vertical; devise a means of clamping these in place and then measure the vertical and sloping sides.
Divide the vertical height by the sloping length (this is the sine of the angle of slope); if you multiply the answer by the weight of the caravan this will give you the tension in the winch cable. Alternatively, if you measure the slope in degrees of angle, the tension is the weight times the sine of the angle (mg sin a); scientific calculators will always have a button for the sine function, or ask your nearest tame GCSE maths student to work it out for you - if you can trust their reliability and accuracy!
If we assume a total mass of 900 kg (allowing a modest reserve for overloading), at a gradient of 1 in 5 - which corresponds to a seriously steep gradient when found on a road, steep enough to defeat many caravanners - this would require a cable pull of 180 kgf (400 lbf). At a gradient of 1 in 3 - which corresponds to the absolute maximum gradient which I have ever found on any road in the UK, over an entire lifetime - this would require a cable pull of 300 kgf (660 lbf).
(Just to clarify, 1 kgf - sometimes written 1 kg wt - is a force, the weight of a mass of 1 kg. 1 lbf - or 1 lb wt - is the equivalent for imperial units.)
Allow a generous safety margin on top of these figures; any given 'van may well in practice weigh a little more than its plated maximum (I know we shouldn't load them to that extent, but let's play safe by allowing for the possibility ... ), and you may feel you want a degree of reserve capacity in the winch. The quoted safe working load for a winch should itself embody a margin of safety, but I presume that that will be in terms of not breaking and letting the load run uncontrolled down the slope; not the same thing at all as guaranteeing to succeed in pulling the load up the slope.
You don't say whether you have a specific 12V winch in mind; there are a vast number to choose from. I have the impression that I have occasionally seen them advertised in the caravan press, and a very wide range - at a huge range of capacities - are regularly advertised in the Land Rover magazines. These latter are designed for use on a vehicle, but presumably they could be equally well secured to a wall (but the wall would need to be suitably strong!) or to a concrete plinth in the ground. Electric winches are also manufactured for use on yachts, as anchor winches, and although the demands of marine quality might make this an expensive route if buying new it is one more area to keep an eye on if you hope to buy secondhand.
There is a comparative survey of winches designed for mounting on vehicles in the current (May) issue of Land Rover Owner International (available from most supermarket magazine stands, and presumably many newsagents also). Be aware though that (as is made clear in that magazine) that the maximum line pull quoted refers to having only a single layer of the cable on the winch drum; as further layers are added the effective diameter increases, and this reduces the available line pull. With the drum full of cable, the available pull may be little more than half the maximum when there is only a single layer on the drum.
A possible alternative solution is an electric caravan mover, provided it will cope with your gradient, so you would need to either measure or alternatively ask for a site demonstration before buying.
Al-Ko (who bought out B&B Trailers, who had made the chassis for Safaris) caution most strongly against using the type that clamps to the A-frame, because this frame was never designed to take that sort of load, although mover manufacturers and many owners seem to feel that the A-frame is amply strong enough. Unfortunately both sides of that argument have vested interests, which makes it difficult for the layman to judge between them ... ...
At least two manufacturers offer caravan movers that work via the tow hitch, Mister Shifta and Powr-Wheel. That at least applies the force at the very point on the chassis that is specifically designed to accept it; however the hitches on Safaris are designed to rotate, so this rotation must be prevented in some way before that sort of mover can be used. There would appear to be possible ways of temporarily blocking this rotation, or you may be prepared to replace the hitch with a modern non-rotating type, but this is a problem that needs to be considered if you decide that a hitch-mounted mover is potentially the solution.
There are also at least two manufacturers offering caravan movers which are permanently fitted to the chassis, and which drive via the caravan wheels. As movers go, and subject to being man enough to cope with your gradient, this seems the most satisfactory option, but only if you have sufficient margin of payload. Be aware that this type of mover comes at a very substantial price (although if you later change the 'van you could always remove it first, and then either sell it separately or transfer it to the new 'van). Al-Ko's one is specified for their own chassis only; you would need to check whether it can be fitted to your B&B chassis. Powr-Wheel assured me over the telephone about four years ago that they could adapt their unit to any chassis if I took the 'van down to them, although in the event I found a different (and cheaper) solution to my particular needs at the time, although I may yet take them up if I have a need for it in the future.
Hope this is helpful.
Oliver
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Recommend Delete Message 3 of 7 in Discussion
From: OliverShaw1 Sent: 16/04/2005 14:46
Sorry: mea maxime culpa; put it down to a typing glitch.
Quoted average weight ex-works should have read 15.75 cwt (800 kg), not 25.5 cwt as I incorrectly stated.
Creeping back into my shell in shame ... ...
Oliver
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Recommend Delete Message 4 of 7 in Discussion
From: OliverShaw1 Sent: 16/04/2005 14:51
And to make matters worse, I used the 800 kg rather than the 985 kg as a starting point for my calculations ... ...
Suggest therefore that we assume a maximum loaded mass of 1100 kg, allowing a generous margin for possible overloading:
Hence at a gradient of 1 in 5 the required line pull is 220 kgf (485 lbf), and at a gradient of 1 in 3 it is 367 kgf (810 lbf).
Sorry about these errors.
Oliver
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Recommend Delete Message 5 of 7 in Discussion
From: Downton1071s Sent: 16/04/2005 18:06
Oliver,where would we be without you!! Thanks for all that,all that remains is to drag out the MIG & knock up a frame to attach the winch too and then we should be in business! Given all the figure,s & advice you have supplied the rest should be staight forward.Also on the upside ,since posting a neighbour has a winch for sale,only used it once for the same purpose but then purchased a mover.His drive does not have the incline of mine but his van is larger so will pop up to see him and work out if it is up to the job.Once again may I thank you for the advice & help,the ClassicSafariCaravanEnthusiasts comes up trumps again!!! Regards Paul
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Recommend Delete Message 6 of 7 in Discussion
From: Brian Sent: 16/04/2005 21:35
Paul
When I bought my first classic caravan it had a manual winch on the A frame, presumably so the previous owner could use it to pull the caravan up to the hitch on his car.
I took it off and a fellow caravanner saw it in my garage and was very keen to buy it to pull his caravan into his driveway. He particularly wanted a manual winch with the mechanical pawl ratchet, as he felt more secure than relying on an electric brake.
Just a thought
Brian Miller
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Recommend Delete Message 7 of 7 in Discussion
From: Downton1071s Sent: 16/04/2005 22:36
Good thought Brian,the main reason for the electric winch was realy a trade off of speed v the safety ratchet on a manual winch.Since looking at the figures supplied by Oliver and your mail it may be a good idea to look into the braking ability of a electric item.I will try and get a pic over the weekend of the drive itself so you can understand better the problem at hand.As we have put a lot of work into the van so far the last thing I want is for it to go off on an adventure of its own! A manual winch would need to be very low geared and as the van has to be turned through 90degrees a slow winch speed would leave it exposed to the idiots that use our little street as a shortcut,also a lot of the houses above me do not have drives which means they have to park on the road opposite to our drive so with the van positioned to winch up the drive the road would be blocked.Its something I am going to have to give some thought to , thanks for your input Brian will keep you informed of the outcome...Regards Paul
Hi all,trust you are well,just wondering if anyone can give me any indication of the weight of our 13/4? Somewhere near will do,we have a steep drive at home and it is a struggle to get the van back in after use,so I am toying with the idea of using a 12V winch to make life easier on me and the car.In theory its a sound idea,the problem coming with 1,the vans weight given its age, 2 its is going to be a dead pull so will need a winch with enough power to pull the van from standstill staight up the side of the white cliffs of dover (the drive realy is that steep!) without calling it a day after a few feet.The vin plate is still on the van but is now smooth so unable to read anything of it,so if anyone has a similar size van they could give me the info off it would be a great help in sourcing the correct winch.Many thanks for your time...Regards Paul&Deb.
First Previous 2-7 of 7 Next Last Delete Replies
Reply
Recommend Delete Message 2 of 7 in Discussion
From: OliverShaw1 Sent: 16/04/2005 14:41
The 1980 Sales Brochure quotes the following data (amongst others) for the 13/4:
Average weight (sic - they of course mean mass) ex works 25.75 cwt (800 kg)
Maximum weight 19.38 cwt (985 kg)
Tyre size 155 x 13 reinforced
I have the subjective impression that the 1980 17/2 uses slightly lighter construction, at least of interior furniture and gas locker, etc, than the 1978 one, and the quoted maximum gross mass has come down from 1300 kg to 1275 kg; if this applies across the board one would expect earlier 'vans to be around 20 to 25 kg heavier than the equivalent 1980 models.
Can you measure the slope of your drive at its steepest point? Perhaps most simply done by using a long encased spirit level to set a horizontal, and then use any convenient straight-edges to set up a triangle; the bottom side on the slope, the top side horizontal, and the third side vertical; devise a means of clamping these in place and then measure the vertical and sloping sides.
Divide the vertical height by the sloping length (this is the sine of the angle of slope); if you multiply the answer by the weight of the caravan this will give you the tension in the winch cable. Alternatively, if you measure the slope in degrees of angle, the tension is the weight times the sine of the angle (mg sin a); scientific calculators will always have a button for the sine function, or ask your nearest tame GCSE maths student to work it out for you - if you can trust their reliability and accuracy!
If we assume a total mass of 900 kg (allowing a modest reserve for overloading), at a gradient of 1 in 5 - which corresponds to a seriously steep gradient when found on a road, steep enough to defeat many caravanners - this would require a cable pull of 180 kgf (400 lbf). At a gradient of 1 in 3 - which corresponds to the absolute maximum gradient which I have ever found on any road in the UK, over an entire lifetime - this would require a cable pull of 300 kgf (660 lbf).
(Just to clarify, 1 kgf - sometimes written 1 kg wt - is a force, the weight of a mass of 1 kg. 1 lbf - or 1 lb wt - is the equivalent for imperial units.)
Allow a generous safety margin on top of these figures; any given 'van may well in practice weigh a little more than its plated maximum (I know we shouldn't load them to that extent, but let's play safe by allowing for the possibility ... ), and you may feel you want a degree of reserve capacity in the winch. The quoted safe working load for a winch should itself embody a margin of safety, but I presume that that will be in terms of not breaking and letting the load run uncontrolled down the slope; not the same thing at all as guaranteeing to succeed in pulling the load up the slope.
You don't say whether you have a specific 12V winch in mind; there are a vast number to choose from. I have the impression that I have occasionally seen them advertised in the caravan press, and a very wide range - at a huge range of capacities - are regularly advertised in the Land Rover magazines. These latter are designed for use on a vehicle, but presumably they could be equally well secured to a wall (but the wall would need to be suitably strong!) or to a concrete plinth in the ground. Electric winches are also manufactured for use on yachts, as anchor winches, and although the demands of marine quality might make this an expensive route if buying new it is one more area to keep an eye on if you hope to buy secondhand.
There is a comparative survey of winches designed for mounting on vehicles in the current (May) issue of Land Rover Owner International (available from most supermarket magazine stands, and presumably many newsagents also). Be aware though that (as is made clear in that magazine) that the maximum line pull quoted refers to having only a single layer of the cable on the winch drum; as further layers are added the effective diameter increases, and this reduces the available line pull. With the drum full of cable, the available pull may be little more than half the maximum when there is only a single layer on the drum.
A possible alternative solution is an electric caravan mover, provided it will cope with your gradient, so you would need to either measure or alternatively ask for a site demonstration before buying.
Al-Ko (who bought out B&B Trailers, who had made the chassis for Safaris) caution most strongly against using the type that clamps to the A-frame, because this frame was never designed to take that sort of load, although mover manufacturers and many owners seem to feel that the A-frame is amply strong enough. Unfortunately both sides of that argument have vested interests, which makes it difficult for the layman to judge between them ... ...
At least two manufacturers offer caravan movers that work via the tow hitch, Mister Shifta and Powr-Wheel. That at least applies the force at the very point on the chassis that is specifically designed to accept it; however the hitches on Safaris are designed to rotate, so this rotation must be prevented in some way before that sort of mover can be used. There would appear to be possible ways of temporarily blocking this rotation, or you may be prepared to replace the hitch with a modern non-rotating type, but this is a problem that needs to be considered if you decide that a hitch-mounted mover is potentially the solution.
There are also at least two manufacturers offering caravan movers which are permanently fitted to the chassis, and which drive via the caravan wheels. As movers go, and subject to being man enough to cope with your gradient, this seems the most satisfactory option, but only if you have sufficient margin of payload. Be aware that this type of mover comes at a very substantial price (although if you later change the 'van you could always remove it first, and then either sell it separately or transfer it to the new 'van). Al-Ko's one is specified for their own chassis only; you would need to check whether it can be fitted to your B&B chassis. Powr-Wheel assured me over the telephone about four years ago that they could adapt their unit to any chassis if I took the 'van down to them, although in the event I found a different (and cheaper) solution to my particular needs at the time, although I may yet take them up if I have a need for it in the future.
Hope this is helpful.
Oliver
Reply
Recommend Delete Message 3 of 7 in Discussion
From: OliverShaw1 Sent: 16/04/2005 14:46
Sorry: mea maxime culpa; put it down to a typing glitch.
Quoted average weight ex-works should have read 15.75 cwt (800 kg), not 25.5 cwt as I incorrectly stated.
Creeping back into my shell in shame ... ...
Oliver
Reply
Recommend Delete Message 4 of 7 in Discussion
From: OliverShaw1 Sent: 16/04/2005 14:51
And to make matters worse, I used the 800 kg rather than the 985 kg as a starting point for my calculations ... ...
Suggest therefore that we assume a maximum loaded mass of 1100 kg, allowing a generous margin for possible overloading:
Hence at a gradient of 1 in 5 the required line pull is 220 kgf (485 lbf), and at a gradient of 1 in 3 it is 367 kgf (810 lbf).
Sorry about these errors.
Oliver
Reply
Recommend Delete Message 5 of 7 in Discussion
From: Downton1071s Sent: 16/04/2005 18:06
Oliver,where would we be without you!! Thanks for all that,all that remains is to drag out the MIG & knock up a frame to attach the winch too and then we should be in business! Given all the figure,s & advice you have supplied the rest should be staight forward.Also on the upside ,since posting a neighbour has a winch for sale,only used it once for the same purpose but then purchased a mover.His drive does not have the incline of mine but his van is larger so will pop up to see him and work out if it is up to the job.Once again may I thank you for the advice & help,the ClassicSafariCaravanEnthusiasts comes up trumps again!!! Regards Paul
Reply
Recommend Delete Message 6 of 7 in Discussion
From: Brian Sent: 16/04/2005 21:35
Paul
When I bought my first classic caravan it had a manual winch on the A frame, presumably so the previous owner could use it to pull the caravan up to the hitch on his car.
I took it off and a fellow caravanner saw it in my garage and was very keen to buy it to pull his caravan into his driveway. He particularly wanted a manual winch with the mechanical pawl ratchet, as he felt more secure than relying on an electric brake.
Just a thought
Brian Miller
Reply
Recommend Delete Message 7 of 7 in Discussion
From: Downton1071s Sent: 16/04/2005 22:36
Good thought Brian,the main reason for the electric winch was realy a trade off of speed v the safety ratchet on a manual winch.Since looking at the figures supplied by Oliver and your mail it may be a good idea to look into the braking ability of a electric item.I will try and get a pic over the weekend of the drive itself so you can understand better the problem at hand.As we have put a lot of work into the van so far the last thing I want is for it to go off on an adventure of its own! A manual winch would need to be very low geared and as the van has to be turned through 90degrees a slow winch speed would leave it exposed to the idiots that use our little street as a shortcut,also a lot of the houses above me do not have drives which means they have to park on the road opposite to our drive so with the van positioned to winch up the drive the road would be blocked.Its something I am going to have to give some thought to , thanks for your input Brian will keep you informed of the outcome...Regards Paul