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Old 13 May 2007, 10:15   #1
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tow ropes for slipways

i reckon the vipermax weighs around 1500kg

i am going to get some tow ropes made up that are 5m in length (i can have different lengths if i desire) and have loops in the ends with reinforced galvanised loop inserts that will fit over a tow hitch, plus some d link shackles

the rope capacity i am going for is 7.5 tonnes, but there are 10.5 tonnes ones

my thoughts are that 7.5 is plenty for dragging the boat up a slipway even if on gravel etc and if i get three of them i should be fine for most slipway layouts

has anyone got any views on the rope capacity in tonnes or what works out the best lengths of rope they use and where they connect the rope to their trailer

any hints and guidance would be appreciated

this is for the saab and the motorhome if needed but probably also a useful thing to have anyway

cheers

Hugh
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Old 13 May 2007, 10:33   #2
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Dunno about how you work out if its strong enough. I just use the big stuff. Seems to do fine for me.

I think you should look at getting a minimum of a 50 meter length and if possible go for 100 meters.

I have a loop in each end. The trailer end is wrapped round the upright with the pulling handles and winch on it. The car end goes over the tow hook but I try and keep it away from the ball as thats all greasy. Most times because the rope is way to long we wrap it around the tow hitch a couple of turns ang get some one to hold the loose end. Makes it easier to release it.

Don't forget to make sure your trailer handbrake works well or take some chocks.
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Old 13 May 2007, 10:34   #3
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You can work out the tension in the rope if you know the angle of the slipway.... basically only the component of the mass of the boat acting parallel to the slip will be seen in the rope so 7 tonnes will be more than enough. For the maths geeks the component of the mass of the boat in the rope will be 1500sinƟ where Ɵ=angle of the slip from horizontal.

Bung it in Excel and for various angles the tension in the rope should be:

Code:
Ɵ (degrees)	    Effective KG
5			131
10			260
15			388
20			513
25			634
So with a rope rated at 7500kg you have a very healthy safety factor to take into account wear, shock loading etc.
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Old 13 May 2007, 10:45   #4
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Originally Posted by Mrs Jardon View Post
i reckon the vipermax weighs around 1500kg

i am going to get some tow ropes made up that are 5m in length (i can have different lengths if i desire) and have loops in the ends with reinforced galvanised loop inserts that will fit over a tow hitch, plus some d link shackles

the rope capacity i am going for is 7.5 tonnes, but there are 10.5 tonnes ones

my thoughts are that 7.5 is plenty for dragging the boat up a slipway even if on gravel etc and if i get three of them i should be fine for most slipway layouts

has anyone got any views on the rope capacity in tonnes or what works out the best lengths of rope they use and where they connect the rope to their trailer

any hints and guidance would be appreciated

this is for the saab and the motorhome if needed but probably also a useful thing to have anyway

cheers

Hugh
Hugh,

I think you said in another thread you tend to set up your trailer with very little nose weight. It can be a bit dodgy towing on a rope with little nose weight - any loose water on board will ship to the back when you start moving forward... ...when you try to stop (or even slow down) the tension on the rope is reduced and the front of the boat / trailer can flip up... at the very least check what will hit the ground if you tip the trailer up - but ideally increase the nose weight before starting... and certainly drain as much water as possible...
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Old 13 May 2007, 10:49   #5
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If I where to pick your Rig up gently with my Helicopter and it weighed 1500kg's, then any rope or strop that was rated at 2000kg's would be fine. I would say that 3/4000kg's would be all you need and still give you a healthy marging, unless of course you're going to accelerate up the slipway at the rate of a F1 car
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Old 13 May 2007, 11:26   #6
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Quote:
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I think you said in another thread you tend to set up your trailer with very little nose weight. It can be a bit dodgy towing on a rope with little nose weight - any loose water on board will ship to the back when you start moving forward... ...when you try to stop (or even slow down) the tension on the rope is reduced and the front of the boat / trailer can flip up... at the very least check what will hit the ground if you tip the trailer up - but ideally increase the nose weight before starting... and certainly drain as much water as possible...
Andy,

Good point about the nose weight. I always thought mine was wrong because I can't lift the hitch on to the tow ball. I even struggle when there is no boat on the trailer. Guess RIBCRAFT knew what they were doing when they set the trailer up.
If I remember correct the nose weight should be 50 KGs on a caravan. Is it different for a boat.
I don't get the boat pulling the car around when I'm towing so it pulls well. I wouldn't want to have the jockey wheel collapsing on me on sand or shingle though. It would need jacking up to get it back on the car.

NR.
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Old 13 May 2007, 11:33   #7
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really helpful replys thanks

haha i was thinking just the same, if i dangled the boat over a cliff and it weighs 1500kg then if i got a rope with a breaking strain of at least that i should be fine, !! some logic in there somewhere, and i was thinking that i doubt if ever 1500kg effort would be needed to put the boat up a slip even if it was gravel and quite steep, the 7.5 tonne ropes seem quite cheap so they should be fine and will probably look safer if you know what i mean

with the nose weight issue, if i keep the engine trimmed up (which it hopfully always is when pulling the boat out) then the rear cradle of the trailer touchs down first so we are fine there.

i am not sure i would ever need 50 m but maybe a 5 m, a 10m and a 20m might be the way to go so i have a rope for most occassions and slip lengths

also getting a thicker heavier duty cable will be of comfort when dragging along the ground over the crest of a slip

the mrs does not want another landy and wants to keep the saab so ropes look like the best option and a lot cheaper. she does not want me to get a cheap landy to replace the td5 for those odd occasions
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Old 13 May 2007, 11:39   #8
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Quote:
Originally Posted by Biggles View Post
Andy,

Good point about the nose weight. I always thought mine was wrong because I can't lift the hitch on to the tow ball. I even struggle when there is no boat on the trailer. Guess RIBCRAFT knew what they were doing when they set the trailer up.
If I remember correct the nose weight should be 50 KGs on a caravan. Is it different for a boat.
I don't get the boat pulling the car around when I'm towing so it pulls well. I wouldn't want to have the jockey wheel collapsing on me on sand or shingle though. It would need jacking up to get it back on the car.

NR.
by the sounds of it you may have far too much nose weight on the trailer especially if it is single axle, a double axle can be tough to lift due to the two wheels but a single should be possible to lift up by a person like yourself.

i keep mine on the lighter end of ok to stop too much weight on the beemer back end but enough to stop it rattling and maintain a positve downwards force on the hitch
you may need to move the boat back or possibly move the wheels forward a bit.
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Old 13 May 2007, 11:41   #9
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I need 100 meters at times because I use Warsash. If your faced with a good slip even this can be tricky if the tides going out and its wet and slippy and you've only got two wheel drive. With a 100 meter rope you could get the car on the flat where it will have no problem towing. Its suprising how short 20 meters is.

A final point is to be aware of people around and between the trailer and car. Might seem like common sense but its amazing how many kids will quite happily get in the way when your not looking.
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Old 13 May 2007, 11:53   #10
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100m!

We have actually had an OAP drive over a rope whilst we were retrieving!

He deviated course to go around the tow vehicle which was just starting to poke out onto the road (as the tide was very high)... instead of waiting he drove down the top of the slipway to go around the back of the tow car and straight over the rope!

We were very lucky the rope went under his car (jag XJ12) and didn't snag on the front, it twanged back and left me with a perfect rope welt across the back of my hand (I was holding the handbrake on the trailer). The boat got pulled up a couple of feet and then rolled back again as the rope slackened.

The old boy got out of his jag and gave us a load of abuse and was noticeably slurring his words.
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