snort system question

kimwhite
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snort system question

Postby kimwhite » 22 Sep 2011 11:07

Attention: John S
Hi John, can you clarify a theoretical question I have on snort systems? See attached diagram. I am looking at the feasibility of doing a K Boat at some future time. The K Boat is a unique project and will have problems/opportunities not encountered by builders of "modern" boats with basic cylinders for hulls.

For instance, the K Boats all had substantial free-flooding superstructures which projected a long way out of the water (to house surface-firing torpedo tubes, a dinghy, and the funnels and mushroom air intakes. In K26, the last of the line, this superstructure (not including the conning tower), was 9ft high. The conning tower of course added another 10ft or so. That is a lot of top-hamper and, unless I make it in brass, potential extra buoyancy.

Now, I know that the standard practice for your models is to locate the TOP of the WTC at waterline, and ballast the sub so when the tanks flood it JUST has positive buoyancy, yes?
If I did that with a K Boat the actual hull would then be at "decks awash" state but the superstructure would still be well-clear of the water.

However, if the snort system can work on ballast tanks outside the WTC, you can see from the diagram that the superstructure of a model K Boat could actually work as an open-top box on which the sub would/could float until a valve was released to flood it in which case the sub would then dive. I guess that would mean a set-up where the sub is ballasted to "just" float once the WTC tank AND the "floating box" are flooded. Note that the potential volume of the superstructure on a K Boat may almost be as much as the whole of the WTC.

Now I know that nothing exact can be looked at until I eventually have a hull but, does that sound like a workable/sensible arrangement?
cheers
Kim
Attachments
KBoat.jpg
oztruck1
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Re: snort system question

Postby oztruck1 » 26 Sep 2011 09:45

Hi Kim, don't want to push in but I too was placed in the position of what to do about the waterline height of a model sub with a lot of superstructure. My sub is a WWII IJN B1 with aircraft hanger and catapult on the deck.

What I found was that everything above the waterline should be made as light as possible and made in such a was as to eliminate any places that air could get trapped when trying to submerge.

My sub I found had to have a lot of extra lead ballast as low as possible to make up for the weight above the waterline, if this isn't done the boat will tend to "FALL OVER" as it submerges.

The net result of the extra ballast weight and larger superstructure resulted in the the need for an extra large ballast tank. That means that the boat takes longer to dive or get to the correct waterline, in an old style boat that is not a problem.

I use a snort system on my boat but I have 2 air pumps, one to pump air in and one to pump air out.

The Caswell SUB DRIVER is a well made unit and from what I have seen work well but as I said you will need a larger than normal ballast tank to do the job.

Although I myself are new to subs I am happy to help as much as I can.

Cheers Chris McKay (oztruck)

Image

http://www.youtube.com/watch?v=MyHb3_KNfkk
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Re: snort system question

Postby SlatsSSN » 26 Sep 2011 18:23

Kim
as discussed on SD forum, when the time comes just order the Subdriver with a larger tank.
Again - you only need the one tank a Standard Gato type SD (perhaps) with a bigger tank.

As discussed I won't even setup Seawolf's BT until I have the sub built. You can use a variety of methods to get a good fix on BT size / volume. In fact I used peanut butter jars to experiment with size.

Bottom weight becomes even more of an issue when you diameter of the WTC is too low down, but we have covered this before.

Your boat like, Chris's fine example, and very much like the Gato will have a high reserve bouyancy, but this is a function of where the boat sits and not the free flood cavity of the upper hull / super structure.

Just build it mate before spending dosh on any ballast system.

Best
J
He who dies with the most toys, just dies...you can't take it with you.
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Re: snort system question

Postby scott154 » 26 Sep 2011 20:22

:offt: Chris I clicked on that YOU TUBE link at the bottom of your post. What a cool video both your sub's ran faultless and had the crowd on it's toes. Well done, and I like your message at the end. Scott :ninj: :ninj:
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Re: snort system question

Postby kimwhite » 26 Sep 2011 22:42

Hi Chris (and John)
I love that Japanese submarine! It looks great. I hear what you say about ballasting. Is all your ballast within the hull or have you some external ballast under it? I note that the K Class had quite distinctive keels - if I cast this in lead it would help lower the COG. Yes, your superstructure is very large cf a modern sub, or even a Type VII, so anything you encounter will be applicable to me too if I do build that K Boat. I will no doubt be asking you more!! But, as John says, "first get your hull". I am toying with the idea of a Deans Marine one but it really is not quite what I want, especially if I do K26. Still I have to get Glamorgan in the water first.
Now I will go download that YouTube of your boat.
cheers
Kim
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Re: snort system question

Postby oztruck1 » 27 Sep 2011 09:56

Kim, life is too short to build something you don't want. The fun is in the building and building what you would love to have. Build the boat you want. The ballast idea sounds good to me. :wlr:
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SSN21 USS Seawolf
K-123 Alfa Class Soviet SSN

Merchants:
MS Bremen -Expedition Cruise Ship Hapag-Lloyd Cruises.
MS Christina O.
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Re: snort system question

Postby SlatsSSN » 27 Sep 2011 10:20

oztruck1 wrote:Kim, life is too short to build something you don't want. The fun is in the building and building what you would love to have. Build the boat you want. The ballast idea sounds good to me. :wlr:


True.

But Chris, as per Merriman et.al's advice, Kim could not have picked a more difficult subject for a first sub.

The Deans Marine kit will still be a challenge but scratch building a sub first time up of this class - well its a bit like a guy who wants to fly a F18 ducted fan with no RC flight experience.
The Deans kit will still be a hard entry - require lots of skill development and allow Kim to cut his teeth on a ballast system. Its also cheap and will get Kim away from theorising and onto doing.
Kim even if you bin the DM kit and go on to scratchbuild your own, it won't necessarily be a waste.

I have built a few target hulls now, some challenging, others straight forward but without a doubt the hardest scratch built I have had is the Collins upper hull. I never had a more time consuming project and a bastard to get right.
J
He who dies with the most toys, just dies...you can't take it with you.
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Re: snort system question

Postby kimwhite » 27 Sep 2011 18:39

Hi Chris and John,
yes, I know the Deans kit is cheap and ready-made but I think, as Chris says, its best to go with what I really want. And, it is only semi-scale and that would niggle me too much.

I think scratch-build is the way to go and even if the bloody thing won't sail I will still have it as a display model. I intend to have hull-plating detailing on it anyway so can best do that by DIY. Still deciding if I will build K26 or one of the war-time jobbies.

Chris, downloaded your video and it was fun but I never got to see the boat, just a camera-eye view of where it was going. How about another one showing close-ups of the boat and showing it from an "outside" view?? Would LOVE that.

BTW, you were talking about slow diving times........ a K Boat took 4-5 minutes to dive so I'd have plenty of time!! :D

cheers
Kim
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Submarines:
HMS Talent S92 - Trafalgar Class SSN.
HMS Conqueror S48 -Churchill Class SSN (Falklands 1982).
SSN21 USS Seawolf
K-123 Alfa Class Soviet SSN

Merchants:
MS Bremen -Expedition Cruise Ship Hapag-Lloyd Cruises.
MS Christina O.
MV Titan Uranus - Harbour Tug
Harbour Tug - (James Slater)

Warships: (Under construction) -
HMS Liverpool D92 -Type 42 Batch 2 (1983)
HMS Iron Duke F234 - Type 23 (2019) (James Slater)
HMS Dragon D35 (Daring Class Air Warfare Destroyer)
HMS Broadsword F88 - Type 22 Batch 1 (Falklands 1982)
FGS Elbe A511 - Modern Germany Navy Submarine Tender
HMS Clyde P257 - Offshore Patrol Vessel (James Slater)
HMAS Flinders - Hunter class FFG
Location: Adelaide

Re: snort system question

Postby SlatsSSN » 27 Sep 2011 21:15

kimwhite wrote:Hi Chris and John,
yes, I know the Deans kit is cheap and ready-made but I think, as Chris says, its best to go with what I really want. And, it is only semi-scale and that would niggle me too much.

I think scratch-build is the way to go and even if the bloody thing won't sail I will still have it as a display model. I intend to have hull-plating detailing on it anyway so can best do that by DIY. Still deciding if I will build K26 or one of the war-time jobbies.

Chris, downloaded your video and it was fun but I never got to see the boat, just a camera-eye view of where it was going. How about another one showing close-ups of the boat and showing it from an "outside" view?? Would LOVE that.

BTW, you were talking about slow diving times........ a K Boat took 4-5 minutes to dive so I'd have plenty of time!! :D

cheers
Kim


Your choice and your boat Kim, but Merriman and myself don't give bum steers. Its going to be a long hard slog. There are far easier subs to assemble let alone scratch build.
With greatest respect to this website, post your scratch build of this on the SD forum, you'll get Merriman and a host of other guys who have built countless subs and developed sub kits helping you along the way.

J
He who dies with the most toys, just dies...you can't take it with you.
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1/16 LCM built.
1/16 drifter
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1/72 IJN Type A midget sub, building.
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Re: snort system question

Postby oztruck1 » 27 Sep 2011 23:24

Here you go Kim, another video just for you.

Cheers Chris

http://www.youtube.com/watch?v=uzGdGuw4Gds
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Re: snort system question

Postby kimwhite » 28 Sep 2011 15:05

Hi Chris, now THAT is what I was after. Magnificent model, the paintwork is brilliant!!! I especially like the way you have dirtied up/weathered the model, it is exactly the result I want for Glamorgan once she is completed, that "lived in" look. All too often otherwise excellent models don't get that touch of dirt which lifts them from excellent to exceptional but you have not fallen into that error. I love it! Now, I want another video showing it actually sailing and diving/surfacing, all close up work of course!!!

Hey Chris, I saw a post on another model website where the bloke had a 1/144 aircraft carrier and he had built some very light balsa gliders (basic ones using just sheet balsa so they were only "silhouette" models) and he was able to catapult them off the ship using a rubber-band catapult. I reckon you could do something similar on your submarine?? Just imagine catapulting off the seaplane then diving? Awesome! BUT, it looks awesome anyway so not something you would want to rush into.

Now all we need is someone to build HMS M2.............BTW, If I DID build K26, she was only 5ft shorter than your submarine so I can definitely learn from your experience in building her.
cheers
Kim
oztruck1
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My Ship Yard: 1/72 IJN B1 type submarine i25
1/72ish Alfa sub
1/50 French Naval tug "Tenace".
1/16 LCM built.
1/16 drifter
1/72 Soviet rescue sub, 80%
1/72 IJN Type A midget sub, building.
Location: Adelaide

Re: snort system question

Postby oztruck1 » 28 Sep 2011 21:17

Kim I will work on another video, how about a "Sea Trial type with the i25 going through its paces? :wlr:
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Re: snort system question

Postby kimwhite » 29 Sep 2011 18:14

Yes please - as much close-up work as you can do. That "meet the boat" video was excellent, you could see the lot.
cheers
Kim
oztruck1
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Posts: 55
Joined: 04 Feb 2011 21:50
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My Ship Yard: 1/72 IJN B1 type submarine i25
1/72ish Alfa sub
1/50 French Naval tug "Tenace".
1/16 LCM built.
1/16 drifter
1/72 Soviet rescue sub, 80%
1/72 IJN Type A midget sub, building.
Location: Adelaide

Re: snort system question

Postby oztruck1 » 30 Sep 2011 17:42

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Submarines:
HMS Talent S92 - Trafalgar Class SSN.
HMS Conqueror S48 -Churchill Class SSN (Falklands 1982).
SSN21 USS Seawolf
K-123 Alfa Class Soviet SSN

Merchants:
MS Bremen -Expedition Cruise Ship Hapag-Lloyd Cruises.
MS Christina O.
MV Titan Uranus - Harbour Tug
Harbour Tug - (James Slater)

Warships: (Under construction) -
HMS Liverpool D92 -Type 42 Batch 2 (1983)
HMS Iron Duke F234 - Type 23 (2019) (James Slater)
HMS Dragon D35 (Daring Class Air Warfare Destroyer)
HMS Broadsword F88 - Type 22 Batch 1 (Falklands 1982)
FGS Elbe A511 - Modern Germany Navy Submarine Tender
HMS Clyde P257 - Offshore Patrol Vessel (James Slater)
HMAS Flinders - Hunter class FFG
Location: Adelaide

Re: snort system question

Postby SlatsSSN » 30 Sep 2011 17:53

Chris
fantastic video


oztruck1 wrote:
Cheers Chris :wlr:


Kim, what Chris said.....build away. I am sure it will be everything you want it to be

J
He who dies with the most toys, just dies...you can't take it with you.
oztruck1
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Posts: 55
Joined: 04 Feb 2011 21:50
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My Ship Yard: 1/72 IJN B1 type submarine i25
1/72ish Alfa sub
1/50 French Naval tug "Tenace".
1/16 LCM built.
1/16 drifter
1/72 Soviet rescue sub, 80%
1/72 IJN Type A midget sub, building.
Location: Adelaide

Re: snort system question

Postby oztruck1 » 01 Oct 2011 19:18

Thanks John. Luv your work.

Chris :wlr:

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