[PSUBS-MAILIST] Alec's test

Fri Apr 14 19:30:33 EDT 2017

This Vetus 6 bladed prop looks good but it does not match up with the MK
101 motor very well.   To get this thrust from this small diameter (150mm
or 5.9") they need to operated at higher rpm.  The MK 101 operated under
load at about 1500 rpm.  IT does look like it would work well for 3-D
printing.  Let us know how the new thruster motors work with this prop.
Which nozzle are you planning using.

Cliff

On Fri, Apr 14, 2017 at 5:40 PM, Alan James via Personal_Submersibles <
personal_submersibles at psubs.org> wrote:

> Cliff,
> have you looked at the Vetus 6 bladed prop rated for 35-55 kg thrust.
> https://www.vetus.com/set-spare-6-blade-prop-bow35-55.html
> The 35kg Vetus bow thruster has a 1500W motor. The rpm is 2600,
> but I am not sure if this is no load rpm. If it is, it would be about the
> same rpm as the Minn kota motor.
> The prop was designed by Marion & is designed for more of a static
> load as we see in our submarines, rather than for a faster lighter boat
> like
> the Minn kota prop is designed for. There could be some compromise
> in the diameter though, as they want to get the tunnel (nozzle) as small as
> possible to fit in to the bow of boats. The diameter could be an issue
> as it relates to the larger diameter of the Minn kota motor which would
> impede the water flow.
> One advantage is that it looks like it would be a lot sturdier when 3D
> printed than the 2 or 3 blade props. ( I have a collection of them now)
>    Even though the printed 3D props performed on the Yamaha 15hp
> outboard, their prop design was again a lot stronger than our 2 or 3 blade
> props.
>    Have you looked at the propeller on Graeme Hawkes Dragon submersible?
> I am guessing he is using high torque bike hub motors. He has designed a
> wide central nozzle with multiple fins off that. This would make for a much
> sturdier 3D printed article & avoid wasted thrust in to the body of the
> 101.
>   Testing the New DeepFlight Dragon Submersible in Lake Tahoe
> <http://robbreport.com/boating-yachting/testing-new-deepflight-dragon-submersible-lake-tahoe-video>
>
> Testing the New DeepFlight Dragon Submersible in Lake Tahoe
> The game-changing “hovering” recreational sub is so easy to use, almost
> anyone can operate it…
>
> <http://robbreport.com/boating-yachting/testing-new-deepflight-dragon-submersible-lake-tahoe-video>
>
> I am going to test the Vetus prop but have to wait about 4 weeks as I am
> having 4 new motors being made to my specs.
> BTW the prop shaft hole diameter in the Vetus is 13.5mm; I will be having
> to make up a sleeve to test it. Would be interested to know of any more
> test results.
> Cheers Alan
>
>
>
>
> ------------------------------
> *From:* Cliff Redus via Personal_Submersibles <
> personal_submersibles at psubs.org>
> *To:* Personal Submersibles General Discussion <
> personal_submersibles at psubs.org>
> *Sent:* Saturday, April 15, 2017 1:23 AM
> *Subject:* Re: [PSUBS-MAILIST] Alec's test
>
> Alec, thanks for posting the trip report on Shackleton.  I was interested
> in the testing you did on your printed Kort nozzle.  From the testing
> we did on the MK-101 variable pitch prop project, we found a pretty large
> variation in performance of different props with and without the nozzle for
> these MD-101 motors.  Just because you have a nozzle it does not guarantee
> better thrust.  As example, if you look at test results below, the 4" pitch
> open water prop that ships with the MK-101, the MKP-33 with out the nozzle
> generated 82 lbs of bollard thrust but when installed in the nozzle, the
> thrust drops off to 71 lbs.  This is not always the case.  Using the 5"
> after market Kipawa 80/01 prop when tested without the nozzle, the thrust
> was 80 lbs but with the nozzle it jumped to 90 lbs.  To me one of the big
> issues seems to be the tip shape. To get good performance you have to
> minimize leakage of pressure from the high pressure side of the blade to
> the low pressure side around the tip.  This is why all props on thrusters
> with nozzles have tips that are square off rather than rounded with a small
> gap between the blade and the nozzle.  I don't know the prop you were using
> but my guess is that it was an open water prop with rounded tip. Can you
> send a picture from the stern showing the prop in your printed nozzle?
>
> [image: Inline image 1]
> [image: Inline image 2]
>
> On Fri, Apr 14, 2017 at 7:41 AM, Alec Smyth via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
> Oh I'm not celebrating yet - the sub hasn't made any dives! I was just
> puttering around on the surface and only submerged in shallow water where
> there were still six inches of the CT showing when I reached the bottom. It
> might have been possible to dive, but I'd rather try it once the
> water-blocking issue in the plumbing is addressed.
>
> On Thu, Apr 13, 2017 at 11:24 PM, Alan James via Personal_Submersibles <personal_submersibles at psubs.
> org <personal_submersibles at psubs.org>> wrote:
>
> Congratulations Alec,
> How deep did you dive? Are you busy selecting a sound track for the video?
> I am wondering if you were turning toward the tunnel thruster because
> thrust can
> push out to the side without the restraint of a kort nozzle!
>    I have done a preliminary drawing for a solenoid operated ballast valve
> based on the top hat design that Vance gave out in Islamorada. With it
> being
> electrically operated you could control it with a gyro sensor using a board
> that controls quad copters. That way at the flick of a switch you would
> descend horizontally. (in theory).
> Did you use the new lights?
> Cheers Alan
>
>
> ------------------------------
> *From:* james cottrell via Personal_Submersibles <personal_submersibles at psubs.o
> rg <personal_submersibles at psubs.org>>
> *To:* Personal Submersibles General Discussion <personal_submersibles at psubs.o
> rg <personal_submersibles at psubs.org>>
> *Sent:* Friday, April 14, 2017 2:58 PM
>
> *Subject:* Re: [PSUBS-MAILIST] Alec's test
>
> That sounds great Alec! Congrats on a great build. I'm sure you'll iron
> out the minor venting issue.
>
> Greg
>
> ------------------------------
> *From:* Alec Smyth via Personal_Submersibles <personal_submersibles at psubs.o
> rg <personal_submersibles at psubs.org>>
> *To:* Personal Submersibles General Discussion <personal_submersibles at psubs.o
> rg <personal_submersibles at psubs.org>>
> *Sent:* Thursday, April 13, 2017 10:47 PM
> *Subject:* Re: [PSUBS-MAILIST] Alec's test
>
> Hi Greg,
>
> Well here's how it went - much better but there's one more issue to
> resolve.
>
> The change to a raft configuration for the MBTs has solved the surfaced
> stability issue. It was great, I could walk around to any edge of the deck
> without excessive list. The longitudinal trim was slightly down by the
> stern when empty, and trimmed out to perfectly level when a person was
> lying in the front half of the boat (stability was calculated for the boat
> with crew). She floats in water only just over waist deep, 38 inches, and
> the freeboard is 24 inches. The thrusters and their controls worked
> beautifully, and the "tank drive" is really, really intuitive.
>
> After launching I drove around on the surface a bit. I didn't get a
> measurement of speed but would say while slower than a K350 she's decidedly
> faster than Snoopy. I tested a prototype kort nozzle by mounting it on one
> of the stern thrusters only and then giving both thrusters equal throttle,
> to see which way the boat tracked. Surprise, the un-shrouded original prop
> was more efficient because the boat would turn toward the side with the
> kort. So I'm just going to put on standard prop guards, at least for now.
>
> Part of the surface running I did lying down and looking through the bow
> dome. The view is ridiculously good! From the CT it wasn't bad either, and
> I was surprised how the flat domes made objects appear closer, something I
> didn't recall from the flat bow dome in Snoopy. In this one, the leading
> edge of the deck as seen through the CT viewports seemed only a foot away.
> The dome is something else entirely, and optically seemed to have the
> opposite effect of making things appear further away, but maybe that was
> just in contrast to the CT viewports I'd been looking though moments before.
>
> And so here is the new problem. The raft MBT consists of a collection of
> aluminum tanks, each of which has SS tubing coming out the top and
> gathering at a manifold, which is piped to the ball valves on the CT. As
> some of the tanks are off on the edges of the raft, some of the tubing runs
> side to side at an angle (up to 90 degrees) to the centerline. When you
> start flooding MBT, invariably one side will begin to fill slightly faster
> than the other. The side that is flooding faster will be lower in the
> water, and the effect of this list on the opposite side is that the tube
> connecting tanks to their manifold is now sloping downhill instead of up.
> This blocks the high side from letting out air, which exacerbates the
> initial list. It's really obvious when you see it, I should have thought of
> this effect. But luckily the solution is obvious too. There are two ways to
> fix it; remotely actuated valves right on the tanks, or new manifolds that
> are high enough to keep all tubing going uphill at reasonable angles of
> list. My initial impression is that the simpler of the two methods is to
> modify the plumbing.
>
>
> Best,
>
> Alec
>
>
>
>
>
> On Thu, Apr 13, 2017 at 10:10 PM, james cottrell via Personal_Submersibles
> <personal_submersibles at psubs.o rg <personal_submersibles at psubs.org>>
> wrote:
>
> Did anyone hear how Alec's test went today?
>
> ------------------------------
> *From:* Alan via Personal_Submersibles <personal_submersibles at psubs. org
> <personal_submersibles at psubs.org>>
> *To:* Personal Submersibles General Discussion <personal_submersibles at psubs.
> org <personal_submersibles at psubs.org>>
> *Sent:* Thursday, April 13, 2017 9:34 PM
> *Subject:* Re: [PSUBS-MAILIST] Oil Compensator
>
> Jon,
> an easy solution is to take the thruster, or that section of the thruster
> in to a plumbing merchant or hydraulic repair shop & ask for something
> compatible with a barbed hose fitting. Sometimes a metric option will
> fit in an imperial thread, & so they may know of not so obvious solutions.
> Alan
>
> Sent from my iPad
>
> On 14/04/2017, at 12:53 PM, Jon Wallace via Personal_Submersibles <personal_submersibles at psubs.
> org <personal_submersibles at psubs.org>> wrote:
>
> Hi Hank,
>
> No, I don't have the shaft, I purchased just the lower head.  A 36 inch
> shaft is $28 but like you said, I really only need a few inches of it so
> don't really want to purchase it that way.
>
> Jon
>
>
> On Thursday, April 13, 2017 8:27 PM, hank pronk via Personal_Submersibles <personal_submersibles at psubs.
> org <personal_submersibles at psubs.org>> wrote:
>
>
> Jon,
> Do you have the shaft that used to screw into the motor?  if so, you can
> cut it down to a couple inches long and put a waterline compression fitting
> on that.   Then reduce from the compression pipe thread.  Or you can thread
> the inside of that stub shaft with a pipe tap and reduce from that,
> providing it is the heave fibreglass shaft.
> Hank
>
>
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