Fastgun tiedowns - tension vs camper weight

I don't want to hijack the thread, but a question occurred to me about using ratcheting, fabric tie downs, there are some pretty thick ones out there. Is there a reason the manufacturers have opted to go with hard-style tiedowns? Or perhaps even chains?

BG

Regardless of the weight of the camper the Fastguns when the lever is down should have ONLY an additional 1/4" of threads exposed as compared to when the lever is up. At that point there is 300 lbs. of load on each of the anchor plates for the camper or 1200 lbs. in total.

More than 300 lbs. and you risk damaging the camper with too much of a load on the plates, and this is not easy or cheap to repair.

macdale4 wrote:
Well when I wrecked my truck, camper and jeep last year the tork lift brackets mounted to the frame bent straight upward and the fast guns snapped like twigs. I don't think having the right tension would have made any difference. (The truck had a blow out and I shot between two guard rails. The truck had rolled over on the left rail and then slid sideways between the two rails and wedged tight. The inertia flipped the truck upright and it stopped but the inertia tossed off the truck camper which rolled once and landed upright in the road.)

So what your saying is we need some of them there NASCAR tires that don't go flat so quick. Did your insurance company attack the tire company and make'em pay. Hopefully no one was injured.

macdale4 wrote:
The truck had a blow out and I shot between two guard rails.

Sorry to hear about the wreck. Was it a front tire?

Well when I wrecked my truck, camper and jeep last year the tork lift brackets mounted to the frame bent straight upward and the fast guns snapped like twigs. I don't think having the right tension would have made any difference. (The truck had a blow out and I shot between two guard rails. The truck had rolled over on the left rail and then slid sideways between the two rails and wedged tight. The inertia flipped the truck upright and it stopped but the inertia tossed off the truck camper which rolled once and landed upright in the road.)

Having worked as a Mechanical Engineer in our litigious society I'm going to stick with the instructions provided by Torklift. Surely they want to cover their ars. And I do too.

"Yes your honor, (or Mr insurance man) my camper was in snug and all 4 fastguns were tightened to the recommended setting when the texting driver crashed into the back of me and my camper ended up on top of their car."

Another measure Torklift uses is 1/2 of the lock hole should be covered by handle when tension begins to be applied.

However, I have found my 2,400# camper rides just as nice and the tie down point is over stressed when I have most of the whole covered before tension is felt. This is a lot less than the tension specified by Torklift. Reason is not only is my camper lighter weight, but it also has a lower than usual center of gravity (COG). And yes, works just as well on the pavement and off-road.

As an engineer, I would say that the higher the COG, the more tension would be required to help hold the camper in place. Thinking is the hold downs are only put into play when kinetic energy (motion) creates enough force that it overcomes the natural force of gravity pulling the camper down into the bed. I.E., when you driver to fast coming out of a gas station with a bad dip.

As the Torklift is pulled on past the 300# pre-set tension, it starts to pull the harder against the spring. The more it moves, the higher the tension. This cause a slowly increasing counter-action to the camper trying to leave the bed. Purpose of this is the tie down point and camper (or any material) can with stand a slowly increasing strain much better than a sudden jerk. If you want, you can test this out by using some sewing string and weights. See how much you can pick up slowly and how much with a jerk.

Tiedowns have flexibility to prevent damage. To me it's kind of like safety chains for a trailer, the chains don't have to be tight all of the time to do their job.

The engineering of a fastgun or a chain & turnbuckle isn't such that it stops side to side movement but forward and back. Since there isn't a lot of stretch, it doesn't take much tension to accomplish this. For us boat owners, I compare camper tie downs to our transom straps. Their primary purpose is to stop bouncing or allowing the boat to slide forward on the trailer. "Snug" usually works for all these restraints.

I saw a photo of a rollover and the fastguns still held the TC in place in the bed. How much stronger do they need to be?

The tie downs aren't carrying the load of the camper, your truck is. They just hold it in place. As you should know, the tie downs are spring loaded, they aren't supposed to crank down on the TC anchors. So I'm not understanding the concern with this as they carry no weight and the weak point is the TC itself.