Originally Posted by PCP
I guess that everybody knows that weight for weight Aluminum is considerably stronger than steel.
Originally Posted by AlaskaMC
And, offshore it is the same thing. Weight AND durability is the issue. These things take MAJOR beatings that a fiberglass boat would not even make it 100 yards from the launch.
Durability is a broad subject. The specific issue of durability I refer to is one of fatigue strength. This has little to do with other metrics of strength. Many who think aluminum is stronger than Steel invariably compare alloy aluminum with mild steel. Clearly alloyed steels can easily be 5-10 times stronger than aluminum.
Fatigue strength, on the other hand refers to a stuctures ability to resist bending/vibration. Even the alloyed aluminum is rarely a match for steel in fatigue strength given the same size.
I have also seen an interesting
discussion of impact resistance of fiberglass versus other materials. It argues the point impact such as a rock hit or bowling ball or sledge hammer is representative of the distributed force of a wave on a hull. Seems to mirror your discussion. The way I see it, they are unrelated. Besides the problem of point impact not translating to distributed force by a reasonable model, in the very least, such tests fail to consider fatigue.