[PSUBS-MAILIST] bow thruster

[Rick Patton via Personal_Submersibles]

I haven't posted in ages and can't seem to post a new thread for some
reason so am attaching this to Sean's last post.
I am planning on attaching a VHF antenna on top of my hatch and was
wondering what I need to do to water tight where the co-axle cable goes
into the antenna?

Rick

On Fri, Mar 25, 2016 at 5:06 PM, Sean T. Stevenson via
Personal_Submersibles <personal_submersibles at psubs.org> wrote:

> The counter rotation is a function of the design of the gearbox. It is
> possible to do it either way, but having e.g. one right handed prop on the
> forward shaft and one left handed prop rotating in the other direction on
> the after shaft counters wasted energy from discharge thrust that is
> circumferentially accelerated. Of course, there is some wasted energy
> associated with the gearbox, so it's not all positive, but I think I'll
> come out ahead in my specific application.
>
> I wasn't going to vector one big thruster through a large range of motion,
> but rather have thrusters mounted on either side, with some degree of
> movement in order to selectively optimize the thrust direction depending on
> commanded ahead/astern, lateral, or rotary movement.
>
> Any such scheme has to carry all of the thrust through to the vessel, so
> it requires some thought on how to best arrange.
>
> Sean
>
>
> On March 25, 2016 8:36:11 PM MDT, hank pronk via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>>
>> Autorotate, maybe wrong word, I meant both props turn opposite
>> directions.  Are you thinking of vectoring in multiple directions or
>> rotating 360 degrees.
>> I was once working on a single thruster design.  The thruster could point
>> in any direction so the sub only needs one thruster.
>> Hank
>>
>>
>> On Friday, March 25, 2016 5:12 PM, Sean T. Stevenson via
>> Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>
>>
>> It will be similar to a surface vessel bow thruster, only instead of a
>> thruster tunnel in a hull, it will be housed in a symmetric nozzle which
>> itself can be vectored with an actuator.  I'm designing the gearbox from
>> scratch - a few off-the-shelf spiral miter gears, tapered roller combined
>> load bearings, shafts, seals and ports for oil circulation. Not sure what
>> you mean by autorotate? They will not freewheel, if that's what you mean.
>> Zero output on the hydraulic servovalve will lock off fluid flow (and thus
>> lock out motion), although the gearbox will still be pressure compensated
>> from the discharge side.
>> Sean
>>
>>
>> On March 25, 2016 3:59:31 PM MDT, hank pronk via Personal_Submersibles <
>> personal_submersibles at psubs.org> wrote:
>>
>> Hi Sean,
>> It sounds like you are going for something like a hydraulic bow thruster,
>> I am not sure if the props autorotate.
>> Hank
>>
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