All the talk of wake reduction and vortex vanes suggest they are talking about high speed props and loads of cavitation. I suspect that is the case. Proper kort nozzles are used in lots of places, including many high volume pumps, but always in low to zero cavitation, as they are close tolerance items and vibration is the enemy.
On the big end of that are the reactor coolant pumps used in primary loops at some commercial nuclear power stations. Westinghouse unit RCPs pump about 65K gallon/min each. Of course, it does take a 5000 horsepower motor to turn one, which is just outside our requirment range, if I had to guess. The pump rotors alone (iron core motors) where I worked weigh 44 tons apiece. Hell, the power cables alone weigh more than most psubs!
At any rate, I suspect the closed (non-slotted) Kort at our kind of rpms will be the ticket.
Vance
-----Original Message-----
From: ShellyDalg@aol.com
To: personal_submersibles@psubs.org
Sent: Tue, Feb 9, 2010 4:12 pm
Subject: Re: [PSUBS-MAILIST] Kort nozzle
Hi Hugh. That looks very interesting. There's a 9 inch model too.
Rated at 5 HP.
The Minnkota's have an 11 inch prop but much less HP than the 35 HP rating on the 11" model.
Very cool link. Thanks.
Frank D.