[PSUBS-MAILIST] vertical thruster orientation

[Jon Wallace via Personal_Submersibles]

Valuable info.  Thanks Alec. 

Jon


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On Fri, 8/10/18, Alec Smyth via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

 Subject: Re: [PSUBS-MAILIST] vertical thruster orientation
 To: "Personal Submersibles General Discussion" <personal_submersibles at psubs.org>
 Date: Friday, August 10, 2018, 5:10 PM
 
 Another thing to consider is that
 the thrust developed by the vertical thrusters, regardless
 of direction, is rather small compared to the lift provided
 by an emergency blow of MBTs. At least for a conventional
 Kittredge-type sub. Shackleton has two 100lb Minnesota’s
 for vertical thrust. That’s nominal and I recall actual
 thrust being a considerably less. They’re angled to enable
 crabbing, which takes away some from vertical efficiency.
 Their prop wash goes through a grated deck, losing some
 more. The net vertical force is probably well under 100
 pounds between them - compared to 900 lbs from the MBTs and
 close to 200 from the drop weight. I’ve come to think of
 thrusters as tools for maneuvering, but not really for
 solving an emergency with brute force.
 
 Thanks,
 Alec