Alum vs wood comparison...interesting

So I made a wood deck for my new boat (posted in the bowfishing boat section). Then just found out a guy just down the road welds aluminum. got me thinking about haveing him make me the same deck out of alum to save weight.

So i got online and found out the weights of wood and the weights of aluminum id use.

here it is.

wood:

3/4" plywood 68"x75"-36" for taper equals 5064" total wieght of 85 lbs.

2x4 frame total length of 477.5" rounded to 40' @ 1.21 lbs per foot total weight 48.4 lbs.

Total deck weight of 133.4 lbs for my super solid hold 4 people deck out of wood.

aluminum:

.125 diamond plate 68"x75"-36" for taper equals 68lbs

40' of 2x2x1/8 wall alum tubing @1.14 lbs per foot equals 45.6 lbs.

total aluminum version of the same deck would be 113.6

Difference in weight is 19.8 lbs.

I know i could use 1.5x1.5 alum instead but would need to run more bracing than i need for the wood so it would even out to the same as the 2x2.

I was shocked that the savings was less than 20 lbs and my deck is pretty big 5.5 feet x 6.5 feet.

I know there are alot of advantages to alum. but there are also advantages to wood too. so i tohught i would post this for people that want to use or are useing either alum or wood as it's pretty interesting.

very intersting that 2x2 alum vs 2x4 wood are almost identical. and that a 4x8 sheet of .125 alum diamond plate is only 14lbs lighter than a sheet of 3/4 plywood. and yet the alum is much flimsier and needs more support.

just food for thought if anyone is interested.

if my calculations are off or i made a mistake anywhere let me know. keep inmind i have never shot off of an aluminum deck let alone made one so my knowledge is 100% internet and math no personal.