For < 0.5 amp Hella = 125CFM, Caframo = 270CFM.
Nothing moves air for modest electrical comsumption like the open-bladed (cageless) Caframo fans. At higi air velocities, evem a minimal cage does make a difference.
Each time I bought a Caframo, I moved it around so much that I quickly bought another. I have 3, now, the earliest of which has lasted through over 1,000nm on my last boat and almost 6,000nm on my present one.
I did drop one and break its soft blade. Cost me < 10 bucks to get a replacment blade and it's back to like-new.
Be aware, however, that they don't have inline fuses and depend on your boat's circuit breakers in case they ever found some way to short or overheat.
They are the best fan for the money I've found. (They also make a very efficient cabin heater, which I love.)
No connection with the company, but I like these two products.
Fair winds,
Al