Scarecrow, I'm not a designer, or even an engineer, but I did take some engineering classes....many, many, many beers ago.
Please draw me a force/vector type diagram and show me where the additional forces are applied when you step a mast on:
1. a dock
2. a heavy boat
3. a light boat
As I said earlier, if you put the exact same amount of rig tension on it, it has zero idea of what it's stepped to.
What DOES change, is the amount of WIND (generating lift force, sideways to the mast) it takes to flip a light boat, vs. a heavy boat, vs. a dock. In our little beach cat world, we usually flip over sideways long before the mast breaking point is reached.
Those clowns on Wild Thing broke their stick because they went out in too much wind. The added lead just let them keep the boat upright while it broke.
I think we are both saying the same thing, you are calling that force: "increased righting moment", I am calling it too much lift.
The end result is the same. But to answer the original question, will the HT mast work on an Inter 20?
Probably, as long as you don't put your wife and 4 kids and a barbeque on board and go out in 30knots.
;^)
Rig tension increases beyond your initial settings with wind power. As the mast/sail catches wind and creates lift/force, it pulls on the cables holding it upright and to the platform. These cables have a high degree of down angle to them...so...adding tension to the cables results in considerable downward force (compression) on the mast (pulling it harder toward the mast ball). The more the boat/platform/dock/concrete foundation resists the motion of the sail/mast/cables, more compression force is carried by the mast....until it goes pop.
I'm not drawing a diagram.
