[PSUBS-MAILIST] Minn-Kota Shaft Seals

Mon Apr 10 21:30:12 EDT 2017

I agree, that Parker suggestion makes sense so long as one can get ALL the
air out of the gap. No idea if that's easy, but I guess I'll be finding out
soon. I wonder what Karl Stanley did with his seals?

:)

Alec

On Mon, Apr 10, 2017 at 7:12 PM, Cliff Redus via Personal_Submersibles <
personal_submersibles at psubs.org> wrote:

> I think this could work Alec and it does fit the KISS principle but I
> don't think it an optimum solution.  I like the feed back I got to day from
> the Parker seal guy to pull both seals and reset with the inbound set to
> resist high internal pressure and the outbound seal set for higher ambient
> pressure and grease  in place of the dead air space.  This is going to be
> the arrangement I try next.
>
>  I don't have a good feel of how much  differential pressure across a
> backward facing lip would cause it to leak air.  I really think we need to
> put one of the Minn-Kota 101 units in a controlled test chamber and try out
> some of these variables, test them to depth and then tear them down for
> inspection.  Seem with psubs, there is always one more thing to research.
>
> Cliff
>
> On Mon, Apr 10, 2017 at 4:57 PM, Alec Smyth via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
>> That's a good conundrum. Let's assume the pressure compensation is to a
>> very small pressure above ambient (one could also compensate slightly below
>> ambient, but I suspect everyone goes above). With the seal in the direction
>> to keep water pressure out and in the wrong direction for the internal
>> pressure, it could leak air - but the question is how many psi it would
>> take for that. On the other hand, if you were below whatever threshold that
>> is and there isn't any leak, I actually still like the idea of having the
>> seal oriented to keep water out, as it's better than nothing in the case of
>> a compensation failure.
>>
>> I still have both seals in and am scheduled to test Shackleton later this
>> week. These are going to be very shallow dives, so the air gap between
>> seals isn't an issue I've bothered with yet. But I think at the end of the
>> day, if all is working well and we've got some dives in, I'm going to go
>> ahead and drill the outer seal of one of the thrusters and just see if any
>> bubbles escape. My pressure compensation is set at 5 psi over ambient. If
>> that turns out to be below the reverse blowout threshold, I like the idea
>> of drilled outer seals for its simplicity.
>>
>> Best,
>>
>> Alec
>>
>> On Mon, Apr 10, 2017 at 5:29 PM, Cliff Redus via Personal_Submersibles <
>> personal_submersibles at psubs.org> wrote:
>>
>>> Inbound functioning seal will be facing the wrong direction for a
>>> pressure compensated unit if you left the seal set in place that comes with
>>> the unit.
>>>
>>> Cliff
>>>
>>> On Mon, Apr 10, 2017 at 3:17 PM, Alec Smyth via Personal_Submersibles <
>>> personal_submersibles at psubs.org> wrote:
>>>
>>>> What if we just drill a little hole in the outer seal, and leave it in
>>>> place?
>>>>
>>>> Best,
>>>>
>>>> Alec
>>>>
>>>> On Mon, Apr 10, 2017 at 3:11 PM, Alan via Personal_Submersibles <
>>>> personal_submersibles at psubs.org> wrote:
>>>>
>>>>> Jon,
>>>>> just be careful you don't damage the seal seat ( bore) or future
>>>>> seals may leak.
>>>>> You could try threading an over sized bolt in to it & pulling on the
>>>>> bolt with a hammer. Maybe hit the bolt in to get it started.
>>>>> You could also heat the housing around the bore first.
>>>>> There is a plethora of tools if you google on image search; but
>>>>> these are on the small size.
>>>>>  I have said before that there is a use to the outer seal as a "dust
>>>>> cover" function to keep muck away from the more important inner seal.
>>>>> A cheap protective seal that is easy to replace!
>>>>> Alan
>>>>>
>>>>> Sent from my iPad
>>>>>
>>>>> > On 11/04/2017, at 2:32 AM, Jon Wallace via Personal_Submersibles <
>>>>> personal_submersibles at psubs.org> wrote:
>>>>> >
>>>>> >
>>>>> > Ok, what's the secret here?  Poking around one of my MK101 lower
>>>>> units to get familiar with it and I have hacked up the outer seal trying to
>>>>> remove it.  I assumed these things were entirely rubber fabricated and just
>>>>> fit tightly into the cylinder that surrounds the shaft.  However, it looks
>>>>> like they are rubber over metal and press-fit into the aft section of the
>>>>> motor housing.  Anyone removed these things?  I can't find anything on the
>>>>> internet with instructions on how to remove them.  I can't just pull them
>>>>> out with plyers...tried that and now I'm going to have to purchase new
>>>>> seals.   :)
>>>>> >
>>>>> > Jon
>>>>> >
>>>>> >
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