which one? single leg I strut or diverging leg V strut propeller bracket

can anyone help me about twin screw propeller brackets choice?

which criterias important about choice of propeller brackets that will be I strut or V struts. Because i saw lots of sail yacht, motor yacht (not high speed), motor sailers with different propeller brackets. can anyone explain this?

- motor sailer -----some i saw v brackets and also naca foil I strut.

- sail yacht----- naca foil I strut or sail drive

- motor yacht and trawlers----- diverging leg V strut also I struts

also i couldn't find any documents about ---which type of boat, which type of propeller bracket---.

 

It is all a mixed bag.

But it ostensibly revolves around 2 issues
1) Drag
2) Strength.

1) 2 legs have more WSA ie more drag, also more frontal profoile drag.
2) 2 legs have more stability i.e. strength especially for grounding or impacts with submerged objects.

There is of course a difference in cost between 1 leg or 2.

Thus what are the risks and how are they mitigated.

 

The potential for a single leg strut to resonate to hull vibrations would seem greater. Just a thought but I'd go w the V strut.