Re: What is your preference safety cable or chain
99% of the time that isn't true...
Here is an experiment... Chain up, and then unhook the tow vehicle. Yep, tongue falls right into the cradle, it works great, when nothing is moving! Now chock the tires of the trailer, and pull your vehicle ahead... Once you get enough tension on the chains, they will end up parallel to the ground, and the tongue will fall right through the cradle. If it doesn't fall immediately, give the tongue a light kick, and it will drop through. (simulate a bump in the road.)
Now of course you say this isn't a real world test... What do you think the chains are going to be doing .5 seconds after the hitch comes loose? The drag of the boat going down the road is instantly going to straighten them out.
Don't believe me? Go try it! Best to use an old vehicle and a small/light trailer, if the trailer hops the chocks is going to come forward, quickly!
Crossing chains is good for other reasons (allows you to use the minimal length of chain without binding on turns), but as far as the cradle, doesn't happen and no real world benefit.
I think you missed a couple of other things while your at it.
If a trailer comes loose from the hitch/vehicle you have lost control of that trailer except for the trailer brakes (hopefully, they still work) as well for horizontal control!
If you had no chains BYE BYE trailer
This is not a perfect world but there are things we do to mitigate the amount of damage that can be done,
"This is Why We Cross Chains" when we are towing a trailer.
The amount of chain is the key to being able to keep the situation under control as well as the points that they are
afixed to the reach of the trailer, and how far they are spaced on the vehicle reciever.
The crossing of the chain does two things, front to back and side to side movement.
Front to back- at the time the trailer lets go either your trailer E-brake or your regular brake should be coming on,
their for all the trailers weight should be pulling to the rear of your vehicle and not sliding under, this is why you make sure that you do not have alot of slack in your chain.
As for side to side movement this is why we cross them so they drop into a cradle, think about useing just one chain, there will be "NO" control, crossed you have some.
Your experement is flawed I believe, because if your not set up right to begin with, you can expect the worse scenario to happen, I would try tightening up your chains a little and widening the cross at the vehicles reciever or the reach.