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[bobk]

Ever since seeing a shipwrights model of a K Class submarine in the Imperial War Museum, many many years ago, and avidly reading everything I could about these unique boats, I have always wanted to build one.  So much detail and working parts.
Having found a source for the 53" long hull mouldings (Deans) and detail plans (John Lambert Plans) it is finally looking to be a realistic goal.   I would like to ask anyone out there who has travelled this road some questions please. . . .

a)   With the very narrow beam (4.25") & hull height of 3.5" is it possible to fit a Engel type static diving system?  If so which one would you recommend.
b)   Has anyone fitted RC retractable funnels to a K Class? Any info appreciated.
c)   I would love to track down that original 1914 shipwrights model again, anyone seen it?

Many thanks

[Albion]

Will be watching this with interest, ive got the same plan set as you, and also looked at that hull. In mean time im awaiting delivery of an M1 hull which is similar size.

I think it will be near impossible to get Engel tanks in her, you will need some other ballast system, at that scale. I have been working on the Revell type VII for some time and had difficulty getting a RCABS system to work well, so ive bitten the bullet and going for a gas based system using D&E miniatures (Dave M) sub  driver. Once i have both in my hands im going to measure what displacement the M1 needs and see how that compares with the Type VII sub dirver. I suspect im going to fall a little short of achieving scale a waterline, will let you know once i have the hardware. I'm then going to decide whether to accept the shortfall or get a second larger subdriver. Others may be able to offer some other constructive advice, but form what ive found in long  narrow hulls the gas system seems the safets route. YMMV

As fas as top sides you of course have the funnels to worry about, i have the big conning tower and gun.

 

[bobk]

Thank you Albion.  I thought the hull looked narrow, despite it's 53 inch length, but could not find any dimensions for an Engel (or similar) static diving system.  This looks to be a real challenge, especially as I want to keep to realistic looking speeds then dynamic diving is out.

Your M1 project sounds wonderful, please keep me up to date with progress.  I understand that M2 was converted into an seaplane carrier, and M3 a minelayer.
PS: I see you are in Singapore.  I have many fond memories of my visit there

[DavieTait]

Give Big Dave in the USA a shout http://www.frontiernet.net/~bwelch/

He sells WTC kits and he was going to be building a K class sub a few years ago so should be able to help out

[Albion]

but could not find any dimensions for an Engel (or similar) static diving system.  This looks to be a real challenge, especially as I want to keep to realistic looking speeds then dynamic diving is out.

Glad you enjoyed Singapore, i came here for a two year stint, and have been here 13 years now!

The Koryu, Japanese sub in my avatar uses a piston tnak, but whilst not engel, it is similar size, that menas a 75mm OD piston. the drive motor is offset and adds 12mm to the max diameter. they have a new design which is fitted to the new Type 212, and that has the drive motor within the piston tank diameter, saving space, but still too big (77.5mm)  to really fit into a 1/72 hull of this era. There is a company called Piranha who are producing small diameter pistons tanks, which might work.

[Davy1]

A very interesting project.
The only working K class I've seen was brought to the Barrow in Furness MBC a couple of years ago. It worked very well but I don't think it had retractable funnels!
I placed some video footage of it on the Association of Model Submariners Facebook site and the Forum site.

Sorry I don't have a link for it but contact me if you have trouble finding it.

David

[bobk]

Many thanks Albion, I will try to find more info on the Piranha systems for this very 'slim' hull shape.
Thanks also to Davy1, some really iteresting info on that Facebook group, which I have now joined. I have not found the video yet, but will keep trying.
Thanks to Davie Tait.  I will email Big Dave as you knidly suggested.

At least if I do succeed in completing this K project I probably will not see dozens at the first sailing meet I go to !
Once embarking on a 1.35 m model of a stem powered submarine how could I not consider retracting the funnels before diving, that would look SO cool. 

[Mankster]

Piranaha's small diameter piston tanks (45mm dia) only go up to 200ml as they are designed to be trim tanks. Thomas will make you any size you like but the tanks going to be rather long at diameter to hold any useful volume. I'd go with a sealed ballast tank like what Sheerline uses or a water pump puming into a badder. You can easily but this together your self for little expenditure.

[tobyker]

K1 quote from Officer in bow compartment on telephone to Officer in engine room "I say, No 1, my end's diving - what's yours doing?"
Also remember the battle of May island.

[bobk]

I found those videos from Association Of Model Submariners:  Thank you.
http://www.facebook.com/home.php#!/video/video.php?v=1177076634979&oid=42806976104 
http://www.facebook.com/home.php#!/video/video.php?v=1240054369383&oid=42806976104 
Really nice, very realsitic.  Great job!
On seeing how it answered the helm I was reminded of another quote from 'K Boat's in which there were described as "having the turning circle of a battlecruiser, but with the navigational facilities of a picket boat".  Looks like it will take both skill to build, and skill to sail.

[Albion]

Looks like a bit of a CG problem, heels over a lot in the turns.

Thanks for info Ramesh, i think it might be possible to squeeze two in, but so many compromises to make that work in this size of hull

[Subculture]

As this boat has a lot of freeboard you could look at a hybrid ballast system.

A snort system would work with those natty little diaphragm air pumps you can get for a few beans. You could combine this with a small trim tank sized to 10-15% of your overall volume required. That could be based in any number of technologies, a small piston tank based on a syringe is one possibility.

I've also found an ebay source for small, brushless centrifugal pumps, which are used in coffee machines of all things. With a  vented main tank and smaller trim tank these could work well, as they shift a lot of water very quickly.

So you can blow or suck depending on your preference.

To improve turning consider a removable front rudder. If you make it from lexan or acrylic, it will be invisible in the water and will greatly improve agility. Some people use thrusters, but they only work well with the boat stationary, and look most unscale like for a model of this vintage.

[Davy1]

Hi Bobk,

Sorry I my have confused you about the K class. I have posted videos of two of them. One is at Edinburgh MBC and is owned by Andrew G. The other one was brought to the Barrow MBC sub day in 2009 and was just brilliant.

I've reposted the video for you on the AMS Forum:
http://www.theassociationofmodelsubmariners.com/t293-k-class-r-class-and-type-ix-at-barrow#1119

She handled very well I think. Nice turning circle with only stern rudders. She had a gas ballast system (nothing complicated) and an epoxy hull. Hence light and easily carried.
The R class is my own humble attempt!
Best of luck with your K project.You wait for one and then 3 come all at once!

David

[Subculture]

Here's a link to the little centrifugal water pump I mentioned in my previous post- http://cgi.ebay.co.uk/Mini-Water-Coffee-Pump-24-GPH-P-25A-DC-12V-/250722722777?pt=Small_Kitchen_Appliances_US&hash=item3a603d23d9

The same outfit do a whole range of brushless centrifugal pumps in various capacities. Could suit just about any size of boat. Prices are very competitive I think.

[bobk]

Many thanks everyone, some really useful information.  I know a lot more now than a week ago.

I think I need to explain where I’m at :-
I used to love scratch building models, from a fully sectioned Apollo Command / Service module (from plans & photos), some unusual slot racing car replicas making my own vacuum formings, and a nearly 3 ft long wood hulled model of HMS Cressy powered by a Mamod marine steam engine.  However, that was many years ago.

I hope I am not 'out of my depth' here, never having built a submarine, or even seen one except on video clips.  Maybe I need to go to some events and meet submariners.  Whilst I have every confidence in building a very detailed ‘dry’ display model of a ‘K’ I would really love to build it as a fully operational boat, without replicating the first voyage of the K13 (lost on trials).

It appears that I may have to design and build a complete bespoke static dive system and ‘tech deck’, rather than adapt an existing professional system.  I reckon I could need around 1.5 to 2.0 litre ballast volume.  At least it’s fortunate I have a very large Koi pond for testing purposes.

[Mankster]

I think 1 litre should be plenty, as long as your not building it as a dry hull. A lot will depend on your desired waterline and how low you can mount your water tight container.

[Albion]

I dug out john Lamberts k class plans, and you are going to need the WTC to fit between frames 151/170 back to 69. Thay gives you a length of about 600mm, maybe a tad more, but really limiting the od to 2" (50mm, 60mm at a stretch). Anything larger than this will be above the waterline, and not offer any benefit. I have similar limitations, but probably not so much to lift.

[Arrow5]

Albion, you have a PM.

[dreadnought72]

...a fully sectioned Apollo Command / Service module (from plans & photos)

Bob, I would love to see that. Any chance of some photos in a new chit-chat thread?

(Though with the Apollo CM capable of floating, perhaps it could pass muster as "a boat"!)

Andy

[Subculture]

I reckon I could need around 1.5 to 2.0 litre ballast volume.  At least it’s fortunate I have a very large Koi pond for testing purposes.

That sounds like an awful lot of volume for that size of boat. I'd have thought  500-750ml would be nearer the mark, unless you are retaining a lot of dry space above the waterline.

If you're going for a vented tank, you could build a centre tank that utilises the hull, this will maximise width and reduce length- you'll get a lot of volume in a small footprint.

[bobk]

Sorry, I never kept photos of HMS Cressy, It got as far as pond trials (without superstructure etc) when I found the steam engine drove it far too fast, despite being sized well over the "suitable for boats of 2 foot or more" quoted. With only RC rudder control I never was able to limit its speed record attempts.
Attached is my 35 year old Apollo 13, the CM of which was an ocean going vessel - of sorts.


 

Whilst a fully sectioned 'K' would keep me occupied for a very long time, I would prefer a working version.  Totally different challenge.
PS:  That Dreadnaught is Awesome !!!

[dreadnought72]

Bob, that CSM is lovely.

I remember seeing one CM (Apollo 10's?) when it toured the UK in 1970-something, and I - as a young boy at the time - remember most vividly just how small the thing was. It's remarkable, on reflection, that 60's technology got off the ground, let alone to the Moon.

Thanks for the kind words on the Dreadnought. Building will recommence once I've got Racundra sailing.

Andy

[allnightin]

Is this the model you were talking about - I was more interested in the landing craft at the time but the K class does have its attractions?

[bobk]

That looks like the shipwrights model I saw !  Where did you see it please?  It does not appear to be on display at the Imperial War Museum any longer.

PS:  A perhaps naive technical question.  If I have one (or two in parallel) ballast tubes with plungers, if they start off full of air, what happens to the boats trim when the plunger is half in and the 50% at the front end is full of water whilst the rear 50% is still full of air.  How do you stop the boat nose diving?

[Mankster]

Turn one pluger around 180 degrees to balance out the other.