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Motorhome Hammock Mounting to Bike Rack


plop

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We have a homemade version of the attached hammock support which we've used for years to fix to one static item like a post or tree etc.

 

Winner.

 

Just made ot from some spare ally tube, very light and great.

 

I've been wondering how I could potentially fix it to the back of the 650 and was thinking initially of a right angled bracket right in the internal rear corner which would act as a backing plate then something similar on the outside bolting through so it was getting strength through both the rear and side panel.

 

However, I found the attached picture and thought that probably as long as I am running the guy line perpendicular to the length of the van, there is no pull load away from the rear panel (which is what the bikes and rack do), it is across the panel so distributing the load better.

 

I could just make a further support frame I guess and make it totally free standing.

 

I weigh about 83kg but mainly it is my wife who is 53kg.

 

Mountain bikes weigh approx 20kg each I am guessing so not that far off her weight and if not pulling the rear panel directly away from the vehicles it seems likely to be ok?

 

Anyone think this could cause issues with the rack/rear panel or have any useful thoughts?

9205227_hammocksupport.png.f5026fa4b1ef66666b9f00ce5e4adb7b.png

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I don't think I would have any issues with attaching to a bike rack. My Fiamma CarryPro is rated to a bike load of 60Kg and if you consider the shock loads on the carrier when in transit, i.e. going over rough roads and potholes, then it can obviously cope with quite a lot. I would though ensure that the load of the hammock was being taken by both sides of the mounting frame of the carrier, either attaching to a crossbar or using a webbing sling to distribute the load.
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plop - 2020-07-24 9:44 AM...……………………...

I weigh about 83kg but mainly it is my wife who is 53kg.

Mountain bikes weigh approx 20kg each I am guessing so not that far off her weight and if not pulling the rear panel directly away from the vehicles it seems likely to be ok?

Anyone think this could cause issues with the rack/rear panel or have any useful thoughts?

Definitely, yes!

 

I couldn't begin to calculate the actual stress at one end of a hammock, but here's a website that may help you work it out: https://tinyurl.com/lsg2eux

 

You then need to know if the rear panel of your van can adequately resist the resulting stress, and I doubt even the manufacturer could advise on that! :-)

 

More simply put, do not do this! :-D

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I got around 72Kg cable tension with a 80Kg body in the hammock, but obviously depends on the assumptions you make. I'm almost tempted to go and set up a test on my own van with a bit of rope and dial gauge to see what deflection there is on the back panel!

 

 

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Just had a rush of emails about all the replies - hammocks obviously generate a lot of interest!

 

SAlexander please do!

 

I'm just waiting on a new hammock to arrive (old one from Mexico got attacked by mice recently) and I will probably test it with my wife and see how it looks.

 

I'm not going to test it myself in case it goes wrong!!!

 

The forces with the bikes on the rack is pretty significant as the farthest one is levered out about 50cm and there are some damn bumpy roads around so the shock forces must be pretty significant when scooting along.

 

The hammock will be a pretty static force, especially once the first couple of bottles of wine are done with....

 

If a strap went across both sides with the hammock linked to it spread the forces between the 2 sides mounting points that should mean pretty low loads across the panel.

 

I'll see if I can look further this weekend and report back

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The primary force from the bike weights is vertically down, but those from a hammock are inline with its rope, not the same at all but more basically not likely to be what the "designer chappie" was considering in the calculations.

 

Then the bikes are singularly placed on the rack, not the same as a suddenly applied much larger loading as you flop into the hammock.

 

It may or may not work, it may or may not progressively yield and open up an ingress path, but whichever way it is not something I would even contemplate, where the consequences even forgetting a potential hazardous bumpy landing, could be pretty pricey to rectify.

 

Even as an engineer able to assess some aspects, there is simply too much unknown here, even if time has not already been degrading the capabilities from what they once might have been.

 

Here, on this one I am in the "Chicken Club".

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