Suggestions for lumber tie down

I am a novice when it comes to knots, but am hoping someone here can offer some advice. I need to transport two 16 foot long 2x4 boards on top of my Chevrolet Tahoe. The boards will be stacked on top of each other and shrink wrapped together. The vehicle has a roof rack and brackets for transporting a canoe that can be used to lock the lumber in place. I have 2 lines with brass hooks that connect to the front bumper and are normally used to attach to the bow of a canoe. In the rear for the vehicle I normally tie the stern to the bumper and use a loop in the line to tie it taught.

I am wondering if anyone has a suggestion for a way for me to fashion a hitch and loop system that I could tie to the lumber and use the existing system I have for my canoe. I am concerned about the line slipping off the lumber and I need to travel a long distance with the material.

Thanks in advance for any suggestions you might have.

Basically, would look at 1 line, Half Hitches at mid and ends;
can then feed to Trucker’s Hitches 3/1 each end to center of bumper etc.
.
Better would be same to rings on ends of rope on lumber, then instead of single anchor front/rear to truck
go for wide front/rear:
lace line from 1 side of bumper thru ring to other side of bumper, back thru ring to then make Trucker’s tension wide on ends for more stability

.
This is assuming, won’t flex or deform 2x4’s too much form narrow pedestal on roof to wide load.
Trucker’s Hitches tight enough that if wood flexes on impact over bump etc. not loose enough to give problems

Just a quick note to say that if the boards are tightly
lashed/tied to the roof rack, they shouldn’t be going
anywhere. Then, maybe a simple clove hitch of your
front / rear canoe lines could be make secure with a
extra line that connected the turns of these hitches
running along the boards --to keep the hitches from
migrating off of ends.

Cheers,
–dl*

Good day Mn_Dan and welcome.

A hitch that would work well at each end is the Scaffold hitch. http://www.surreyknots.org.uk/images/49_Scaffold_Hitch.jpg
Perhaps a little more complicated to tie, but interesting to learn.

SS

Just for a better picture;
2 x 16’x2"x4"
layed on how long a roof platform?
tied to points spread apart how far (bumper to bumper)?
.
Lease amount of flex would be 2x4’s side by side, standing tall, shrink wrapped.
.
If use the spread point tie down front/rear;
can then tighten more by bending the anchor lines to each other.