Hi Stranger,
It seems strange that the variation in aluminum mast bend from mast to mast is coming into question at this time. The Tornado has been around for a long time and there has been no question about mast bend inconsistency. Even if we start the Tornado history with the Marstrom Tornado, there has been no question about variation in aluminum mast bend until recently.
Bill, I think there has always been this inconsistency...see the Marstrom website for a discussion. It's just never been discussed at length because there was no solution to it other than testing many extrusions until you found one that best matched your sailing style/weight range (ie. flex characteristics). Again, this was only ever a concern at the top levels of the class, where minute performance advantages are sought after. Of course at this level, budgets are less of a concern as well.
The bend in the top few feet of the mast is very small reguardless of taper because the bending moment is still small due to the short lever arm in the top few feet of the mast. The region of max mast bend occurrs in the region below the hounds and above the diamond spreader.
From looking at my alloy mast under spinny loads, a lot of bending is happening above the hounds and in a leeward direction...it looks ugly-scary. This is with the older Marstrom mast (pre-2000). They have reported failures in these older sections and have increased wall thickness of the web on current extrustions. There is also an untapered option offered...but I'm not convinced this increases strength above the hounds...just the flex characteristics and obviously buoyancy after a capsize.
If there is variation in aluminum mast bend/flex characteristics, it is likely in the extrusion die wearing out and allowing the mast wall thickness to increase. The solution is a new extrusion die.
This is exactly what Marstrom claims as a primary cause of extrusion variation...but that is can happen quite often and leads to basically no two masts being identical in flex performance.
As far as my comment about sailors specifying the mast layup, Scooby made the comment that sailors could "design their own masts to suit their needs".
And once it's "just right"...they can make that same unit for all boats they buy in the future and the build can offer it to other teams on demand.
