You could chock the planks 1/2 way on the span, I used to moonlight with the company flatbed at the lumber company I worked years back, moving cars, using spruce scaffold plank, the actual 2"x10" not nominal lumber. Without columns or braces it would load a car such as a early 70's or late 60's Buick GS, flex a little but I made up some short pieces and put them in the middle of the span, you just have to inspect the lumber you use, OSHA outlawed these for scaffold around this time or a little later.
You are probably so used to that crawler, loading and unloading, nosing over, probably does not scare or intimidate you, though the feeling of something dropping out from under you is always present. Our young foreman whom was in charge of us doing site work /excavation decided one morning real early to try his hand at or better himself on the JD 850 dozer we had on site. Just as I came up over a rise, with the tractor trailer-lowboy, I see him nose over a berm and get launched out of the seat onto the hood, just about kissing the stack, Phew....... glad he did not get hurt, good guy too, not the only tryst, I had to hand dig him out of a trench collapse once too, up to his neck, wind knocked out of him, some people have 9 lives.
Scariest crawler incident I had was on a Caterpillar 977-L. We had this nice addition to a private girls school outside of Morristown NJ, the site work, and had a huge pile of fill to remove, some days I'd just run the 977 loading others would be both, tandem dump and load yourself out each round. I try to align the trucks in a simple K pattern to the bank of the pile, easier on U/C wear, and the operator etc. So just as I get over the sideboards with the bucket, the ground collapses under the front end of the track frames, bucket now on the sideboards, back end up in the air, operator of the 225 excavator up above backfilling a retaining wall swooped down in a panic, the whole job stopped, and eyes were on us. I thought about what to do, and figured out what how I wanted to get out of this jam ! I carefully walked the 977 back until you could stand under the drawbar! No lie or bs, not my "schtick" to ham things up anyway. I wish I had a photo of this one. This gave me enough room to move the bucket which was still 3/4 full from being heaped up full, maybe now full but struck full. Point is its heavy, and with the combination of walking back even further and curling it all the way back, getting those teeth up, I was able to get it over the sideboards, and just ride the side of the dump box, which was old anyway, all the way down to the tires, which by then the bucket teeth wanted to dismount, I backed up further, the back end was a lot lower and got out without a hitch, apparently there was an unknown tank or void in this spot and I found it ! The other workers on site, hoot & holler, clapped as the performance was over and was back to work, was a little scary, cooler heads prevailed.
