Vessel-Bottom Cone-Stiffeners

Dear all,

I have a vessel having bottom end as toriconical cone, middle as shell and upper end as torispherical dish.

The vessel external design pressure is full vacuum.

Is it permitted to put stiffeners at midlength on cone and to consider it as line of support?

This will help reduce the unsupported length at one side of stiffener which will reduce the shell thickness.

(since vessel is suported on legs, i cant take large end as line of support)

Regards

ASD23789