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.

;^)