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Re: [PSUBS-MAILIST] Dive planes
I was talking to Pete Hoffman about that just today. I think the dive planes were about 8 or 9 inches wide and maybe 15 or 16 inches long. They had nice chord sections and side plates, and were mounted to have the MBT flat surfaces alongside, which increases efficiency dramatically. The rudders were also chord sections, 12" X 36" (I had one of those in my hand, so it's a fairly accurate guess).
Keep in mind, the 12 boat class turned 36 X 36 three blade main props and produced a corrected bollard pull of something like 900 pounds at full power. That's a lot of water moving, and the big rudder didn't need much deflection to turn the boat. In mid water or on the surface, the subs would turn just about on their noses under hard rudder deflection and a solid goose on the motor.
The penalty was that there is just one hell of a lot of equipment to make that happen. The 10 hp Reliance motor weighed God knows how much, plus the gear reducing transmission, double bearing, double seal shaft seal housing, the prop itself (which weighs something like 135 pounds all by itself. rudder, beavertail, ring assembly, hydraulics...etc, etc, etc. We think it all weighed just about what it pulled, 900 pounds or so. You need some heft to carry that much gear in the stern, and to tote the nearly 4000 pounds of batteries that we carried to run it all.
Vance
-----Original M
essage-----
From: Hugh Fulton <hc.fulton@gmail.com>
To: personal_submersibles@psubs.org
Sent: Sat, Sep 12, 2009 8:22 pm
Subject: RE: [PSUBS-MAILIST] Dive planes
For the uninitiated what size were they? Mm or inches will do. A
pproximations gratefully accepted.
Would be helpful. 2 sq ft, 6 sq ft? approx length and breadth. Hugh
Vance,
While I agree with you that they do have some effect, one of the issues that came up in reviewing the Seehund design was how effective the control surfaces were. Through the short life of this sub, the surfaces kept growing in size. The Perry boats are probably
an order of magnitude in size as compared to the typical PSUB and there is an exponential factor (either squared or cubed…probably can squared , this is later in my classes) associated with increasing the size of a vessel and associated control surfaces. Would have to go back and look at it but if I remember correctly the Perry surfaces were quite large. This is not a detriment just an observation. And while Harbor Branch (i.e. Link) may have found control surfaces unnecessary, I am speaking more from the naval architect’s perspective (even though I am an HB intern product J).
R/Jay
Resepectfully,
Jay K. Jeffries
Andros Is., Bahamas
Save the whales, collect the whole set.
Spoken like a true Harbor Branch alumni. Dive planes and rudders are, in fact, astonishingly effective when designed correctly and incorporated into the vehicle overall. Hyco never used them, but we surely put a million miles underwater using them on the Perry's. Even the apparently small surface area of the dive planes were good at 1 knot and better, and could be used at any rate to help trim the boat or otherwise adjust attitude when operating on the bottom. The old flat planes and rudder are notably less effective than even the simplest chord design. We've been through this before and there
might be some good info in the archives somewhere.
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