Snorts and external ballast tanks

[Weissman]

Hi, I am new to the forum and have plans to build a 1/72 scale model of a submarine that has fascinated me for 50 years - the WW1 K Class. I am thinking of doing K26, the last of the line. Now, from reading various threads I think a ballast/gas/snort system is what I will need. The boat will be about 58" long so will need lots of ballast??
In case you don't know what a K Class looks like I will try and attach a diagram.
What I want to know is, is all the ballast best placed in the WTC or can an external tank be used as well? With K26 there is a substantial superstructure projecting above the waterline (red in the diagram). I can envisage the WTC ballast tank being flooded yet the boat COULD still float on the air in the superstructure if it was designed as an open-topped box.
So, flooding the WTC would get the sub down to "decks under water" but "superstructure only half submerged", then a further valve could allow water to enter the bottom of the open-top-box which would dive the sub, or at least get it down to just having the periscopes above water.
Does that make sense, or am I better off having the superstructure totally free-flooding and relying on the WTC to flood down?
Either way, I think I will need Mr Merriman to build me a WTC with a BIG ballast tank!!
Any ideas, anyone?
Kim in Australia
aka Weissman

[Kazzer]

I'm pretty sure we looked at this recently. You need a Revell Gato Sub-driver either in kit form, or assembled. It has the larger ballast system.

http://www.caswellplating.com/models/sub-drivers.html

SD25G

Sub Driver 2.5"/2 Gato (Includes 2 motors, 1 servo, pushrods, seals, gas saver) - Snort Ready

or a kit

SDK25G

Sub Driver 2.5" KIT Gato (Includes 2 motors, 1 servo, pushrods, seals, gas saver) Snort Ready

Here's the hull

http://www.deansmarine.co.uk/shop/product_info.php/cPath/26_33/products_id/2251

Here are plans

http://support.caswellplating.com/index.php?/Knowledgebase/Article/View/275/40/british-k-class-plans--photos--1

and more

http://support.caswellplating.com/index.php?/Knowledgebase/Article/View/274/40/british-k-class-plans--photos--2

I have a kit with the dive planes and rudder too


What else do you need?

[oztruck]

Hi Kim and welcome aboard.

The ballast is as you said best kept in the WTC and as close to the centre as possible. Makes it easy to trim that way and when filling or emptying the ballast tank the boat still stays level in the water.

Looks like there will be a lot of boat above the waterline, I would suggest keeping what is above the waterline as light as possible. Makes for a better handling boat

There are a lot of very talented people here that can and will give you help and point you in the right direction.

Good to see another Australian here, we will outnumber to others soon. Where are you?

[jlday1256]

OK...I've got to know. I have searched about everywhere. What does PROJ on the Seawolf stand for?

[He Who Shall Not Be Named]

PROJECTION.

It's telling the tug and Pilot boat Coxswain's out there in submarine land to keep clear of the bow planes (which may, or may not be deployed).

David,

[jlday1256]

Ahhhhhhhhh, OK. Thanks.

[Slats]

Hi, I am new to the forum and have plans to build a 1/72 scale model of a submarine that has fascinated me for 50 years - the WW1 K Class. I am thinking of doing K26, the last of the line. Now, from reading various threads I think a ballast/gas/snort system is what I will need. The boat will be about 58" long so will need lots of ballast??
In case you don't know what a K Class looks like I will try and attach a diagram.
What I want to know is, is all the ballast best placed in the WTC or can an external tank be used as well? With K26 there is a substantial superstructure projecting above the waterline (red in the diagram). I can envisage the WTC ballast tank being flooded yet the boat COULD still float on the air in the superstructure if it was designed as an open-topped box.
So, flooding the WTC would get the sub down to "decks under water" but "superstructure only half submerged", then a further valve could allow water to enter the bottom of the open-top-box which would dive the sub, or at least get it down to just having the periscopes above water.
Does that make sense, or am I better off having the superstructure totally free-flooding and relying on the WTC to flood down?
Either way, I think I will need Mr Merriman to build me a WTC with a BIG ballast tank!!
Any ideas, anyone?
Kim in Australia
aka Weissman

Hi Kim,
welcome to the site.

Guys Kim is from Australia, and is keen to learn about sub construction for his one off K class sub, and ballast systems.

Kim
in practice its easier to have the one ballast tank, centrally located at the COG.
Don't worry about space above the WTC this is free flooding and providing sufficient air holes are available in the subs top and conning tower, this area won't represent a buoyancy problem for you. So you won't need anything else apart from a fairly stock standard subdriver with the one tank and a standard snort arrangement.

Mike I previously suggested that to Kim off line that I thought the GATO 2.5 SD would be a good fit, but I reiterated to Kim, he needs to get the sub built first.

Hope this helps
Best

John

[Kazzer]

I'd be very interested in seeing this boat built, especially to see the retracting chimneys actually operate.

Its a good candidate for the model building competition methinks!

[Weissman]

Hi all,
many thanks for the encouragement and feedback. Yes, as John said I am from Victoria, Australia. It may be a while until I can start K26 as I am completing a 1/72 destroyer model - HMS Glamorgan - just now and expect that to take several months more.

Looks like the GATO subdriver will be the best choice. ATTENTION Mr Merriman - should the standard GATO one do the trick or may I possibly need a special one with bigger tank? I will wait until the hull is completed before actually getting one built, though!!

And, yes, I would like to see how the chimneys could retract. I was thinking of the same sort of mechanism some of you blokes use for retractable diving planes, does that sound reasonable? I need to check back, do you drive the gears from within the WTC or is there a separate waterproof servo?
One thing for sure, I cannot use fold down front dive planes as the K Boats did not have them - the bow planes slid in and out of a slotted recess.

One last silly question, if the boat is "driven" by the rear planes only, that means that to dive they will tilt UP, yes, and tilt DOWN to surface? ie opposite to what bow planes do??
cheers all,
Kim from Australia

[Slats]

Kim
all good questions and there are no silly questions from guys starting out.

My overall advice is get the basics sorted first. From a practical perspective you might find having the planes deployed always out might provide you with some surface stability - that is don't worry about too many functions first up and working bow planes will be sufficient as opposed to working and retracting.

Bow planes allow you to have good depth control, stern planes control the pitch angle of the boat and this is where a sub leveller IMO is a must. A boat driven off rear planes alone tend to have more rapid depth changes than the fine control you get from bow or sail planes.

I won't pre empt David's answer re the ballast tank size mate, but as I discussed with you previously, I think you need the boat first.

Best

J

[He Who Shall Not Be Named]

There are silly/stupid questions! So far you have not lofted too many of them.

Is this your first submarine? If so, don't start with the K; it's going to be too much of a hand-full for the uninitiated.

Yeah ... what John said. Keep it simple.

Before you order that GATO SD, build your model first and get all the mechanicals (linkages, control surfaces, running gear) installed and working.

Don't sweat the retractable bow planes and storable smoke-stacks yet!

The K's were very long, narrow beam boats with terribly long moment arms. Set up the stern planes and bow planes as John recommended -- this boat will be all too easy to broach or dig into the mud without positive control of the bow planes and stern planes, on separate channels.

Build that boat. Then we'll talk again.

David

[Albion]

I'm just starting on an M, its not my first sub, similar profile hull to the K but with not so much free board, but its still taking a lot of pre planning

[Weissman]

Hi Kazzer,
many thanks, I'm good for plans and photos, have been collecting them for years. I had a look at the Deans Marine jobbie but it is not 1/72 scale, which is the scale I want. The Deans one is too short by several inches for 1/72 scale.

I think I will have to build my own hull. I have a local bloke who is a fibreglass expert and I will be talking to him to see if he is willing to do the plugs from my master. If I could tell him he may be able to sell some hulls to cover his costs he would be VERY keen, I suspect.

I wonder, is there a market out there for up a few hulls? And, would the demand be for a K Boat "as designed" or with the swan bows? I really want to do K26 (at 351ft) but if an earlier boat was likely to generate a few takers I would go for the 339 ft version.

Just seeing if there is interest!
cheers
Kim

[Slats]

Kim,
I know how much you want to do this boat and for how long you have had that motivation. I would not write off the Dean's Marine hull yet.

http://www.deansmarine.co.uk/shop/product_info.php/products_id/2251

It looks like that hull pans out at 1/76 scale (339 ft version) as you point out you'd like the 351 and in 1/72....but I think given you want to get this boat done, the Dean's marine might be the way to go. That said I have no idea to the quality of the kit, but I am thinking primarily of you're enthusiasm for this boat. Suffice to say it looks cheap and cheerful and with a lot of work, and some scratch building and detail it may just be fine. You have scratch built target structures and detail, so this might be ok for your skill base. However, building it to get it running might be a big baptism of fire.

First - I know you and I live in a continent surrounded by 72nd scale fleets. But of the guys who run subs, we run in the main with other subs of all scales. When we do mix it up with our skimmer cousins, I doubt there would be a target driver anywhere that is going to know you boat ain't quite 72nd scale. Secondly for the sub guys you will sail with who will value and admire the boat far more than a skimmer, they won't give a toss at all about scale. And thirdly what constitutes 72 scale over the years at TF72 I can tell you is hardly an exact science and a lot of tolerance to round about that scale is across the fleet.

Finally and most importantly you have in the Dean's kit a basic model that is not overly expensive that you can buy now. I can see from our many discussions pre you joinning this site that you're itching to go. Even if you do secure your kit maker to make a kit, this takes time - lots of time. Have a look at the development of the 1/72 Foxtrot spanning YEARS by a professional who has built subs before and you'll see where I am coming from.

You also have to realise that the K boat - should you be looking for a market for hulls, will be made up of people who are primarily sub enthusiasts who unlike the 72nd skimmer die hards don't care really much about what scale the boat comes in and in this regard your competing against a product that can be purchased right now. It may not be the most "scale" in terms of its fidelity but it is cheap and there are a lot of cheap *******s in this game. The guys like me that shell out big cash for kits spend it on the most scale like representation, and for that the expected standard is very high, as is the kit's all inclusions. I don't mean to put you off, I am just trying to be realistic.

As David alluded to a K class is a problematic boat, particularly as a beginner. But starting out either having to get a kit made, or doing your own, and I think your adding a big factor in time and expense that may not be worth it.

I think you will find the Deans kit quite a challenge but I think if this is a one and only sub for you it might be the most practical way to go...but there are many many easier subjects to model, particularly first up.

Best
John

[Kazzer]

Hi Kazzer,
many thanks, I'm good for plans and photos, have been collecting them for years. I had a look at the Deans Marine jobbie but it is not 1/72 scale, which is the scale I want. The Deans one is too short by several inches for 1/72 scale.

I think I will have to build my own hull. I have a local bloke who is a fibreglass expert and I will be talking to him to see if he is willing to do the plugs from my master. If I could tell him he may be able to sell some hulls to cover his costs he would be VERY keen, I suspect.

I wonder, is there a market out there for up a few hulls? And, would the demand be for a K Boat "as designed" or with the swan bows? I really want to do K26 (at 351ft) but if an earlier boat was likely to generate a few takers I would go for the 339 ft version.

Just seeing if there is interest!
cheers
Kim

Aha! The 64 million bucks question. Would I be able to sell a few hulls?

Answer = who knows! You'll get a lot of folks say 'Yes, I'd like one! " but when it comes to parting with their money, that's a different story. Then, there's actually marketing and advertising. How are you going to reach the big market and get enough exposure? Have you allowed for these costs? Most people (and that includes many of the current suppliers) forget there is a cost of sales that needs to be included. So, you take your chances and invest in a few hulls - then take the risk.