Dumb Sheaves

[Wrinklybear]

I am thinking of replacing the dumb sheave system of rigging a 14' catboat w small standard rotating cheeked sheaves. These will be suspended from the original dumb sheave throughmast holes by cordage and will lie outside a glued-up hollow 3.5" dia mast.

Will this weaken the system by moving the centre of down force away from the mast centreline? Will it make enough difference to be critical?

Any theories (or better yet - facts) wld be welcome.

Bear