Scratch-built 1/96 Oscar II

[KevinMC]

This weekend was largely consumed

This weekend was largely consumed by marking drain/flood hole locations with small pieces of electrical tape. I first had to cut the tape down into little squares (or rectangles) of the appropriate size, which after a while really makes your eyes go crossed! Having cut out all the pieces though, I could get down to figuring out where they all belong on the hull.

I started with the line of limber holes just under the Granit missile doors. I already have pencil marks on the hull to show where to line everything up but based on photos I've decided they need to be "adjsted" a bit higher. To be sure that all the holes have a perfect vertical alignment, I temporarily layed down a strip of tape to mark the bottom edge of where all the holes should line up.



Next, I layed down another temporary piece of tape, used as a horizontal spacer, to ensure that all the pairs of holes will have exactly the same distance between pairs.



Now in the upper left and right corners I place my square of eletrical tape that marks the location of the flood hole on the hull.




First pair down, move the veritcal spacer tape over to where the next pair of holes go...



...And work along like that until all the holes are marked. Once completed, pull up the tape and admire. (Very important step!)




Using the same process, I also marked the upper hole locations on the "soft case". (For those who are wondering, "soft case" is the term the Russians use for the outer hull.)







That's all the "big" holes in the upper side of the hull. I still have to do the ballast tank vents on the upper surface, but I'll proceed to mark the companion "soft case" vents on the lower side of the hull first. (I'm doing this because I want to leave the smallest masks for last as they have the least amount of "stick" keeping them in place.)

[KevinMC]

Michael,

Thanks for posting that. Indifferent

Michael,

Thanks for posting that. Indifferent to the nomenclature, I thought only the Delta IV had that style of fin. Wayne- is this a III or IV?

[elec_tech]

Kevin,

looking good! I look

Kevin,

looking good! I look forward to more progress..... your build combined with Steves has been very helpful!

Thanks
Dan

[Antoine]

You are right Kevin, its

You are right Kevin, its a Delta IV. Typical rudder fin.

Great job on the Project 949A !

[Antoine]

Kevin, I cant read my

Kevin, I cant read my PM, if you want to contact me, use the email function (antoine.lenormand@N0SP@Mwanadoo.fr) remove N0SP@M from my address

Antoine.

[KevinMC]

Email sent!

Email sent!

[Guest]

Very interesting ballast system you

Very interesting ballast system you have outside the hull. Do you use fluorescent bulbs to control buoyancy?
Art

[KevinMC]

Groan! Actually it's part of

Groan! Actually it's part of an elabourate hull stabilization system. I call it "Heavy weight make hull not move!"

[wayne frey]

The exterior hull of the

The exterior hull of the Soviet submarines is actually called the "Easy Case" instead of the soft case.
Yep, the rudder design is a common one for the Russians.
Delta IV's can be quickly seperated from a III by the lack of holes at the base of the missile turtleback and the longer lenght.
The Delta IV should be built. It represents the mainstay and backbone of the Russian submarine SSBN fleet for the next few years.
Like the VW, they are so ugly they are interesting. I think a 1/96 (which would be roughly 69 inches long) would look cool surfacing for a launch at a regatta. As long as a Typhoon, but without the width. An interesting boat.
Fine job on the Oscar Kevin.
I want first dibbs on hull number two out of the mold.

[KevinMC]

Thanks Wayne, I knew you'd

Thanks Wayne, I knew you'd be there to keep me on the straight and level.

Not much to say but "More little squares?!?" I've completed placing the lower easy case flood holes on the front half of the hull.

[KevinMC]

I seem to batting my

I seem to batting my ususal with these flooding holes- three steps forward, two steps back. After much deliberation and comparisons with photos, I decided that the flooding holes I'd layed down on the top of the hull were a little over sized. So, all the squares that were down were lifted up and replaced with new ones, a hair smaller this time.



I also wasn't satisfied with the location of the lower flooding holes, so they were lifted as well and shifted further up the side of the hull.



I'm not certain if there also ought to be more flood holes along the very bottom of the hull, but unfortunately I cannot locate any doccumentation refuting this. I'd briefly considered taking an educated guess as to what might be there, however I've reconsided that idea in favour of not marking anything further. My rationale for this is simple, and based on two ideas. 1.) In the absence of doccumentation proving that more holes ought to be added, I think it would be worse to mark something wrong and add to the plethora of mis-information floating around, than to add nothing further until such a time as doccumentation "surfaces". 2.) It seems clear to me that this ship has been designed to be bottomed out- perhaps there are no holes on the very bottom of hull to avoid having them filled with "muck" upon hitting bottom? (Any readers with opinions on this are encouraged to share them!)

Finally happy with what I had, I also completed the flood holes on the side of the hull.



There are now a total of 276 flood holes marked on the hull. And that's just the big holes! Still to go are the recessed parts of the retractable cleats and the MTB vents along the very top of the hull.

[KevinMC]

I've also been going through

I've also been going through the interesting exercise trying to calculate the diameter of the lower torpedo tube doors. Since I do not have any good (trustworthy) front-view drawings that include torpedo tube door information, I've had to work with some photos and mathematical trickery. (And might I add very good photos at that- Thanks again Wayne!)

The first photo I used (below) shows the OSCAR in drydock, weathering clearly demarking the outline of the four lower tube doors. Another important clue in this photo is the open Granit missile doors, which open parallel to the long axis of the sub. The fact that very little of the top surface of these doors can be seen here suggests that this photograph was taken with a fairly long focal-length lens. This is a key observation as it validates the assumption that (within the context of this photo) dimensions lifted from the partially open torpedo room access door will have approximately the same scaleing factor as that of the torpedo tube doors that are 2-4 meters (6.5 – 14 feet) closer to the camera.



Taking relative dimensions in the photo above, I find that the diameter of the torpedo tube doors (not including the “flatted sides”) is about 90% of the width of the torpedo room access door. On it’s own this is not a particularly useful figure, but when we introduce the second photo (below) we can begin putting some numbers to the equation.



By virtue of other objects in this photo with “known dimensions” we can come to a reasonable estimate for the width of the torpedo room access door. The weapon being loaded most certainly has a diameter of 650mm (25.6”) at the aft end. To my eyes the “fat” part of this device looks as though it would occupy about half of the width of the access door. This would place the door width at 2x650mm, or 1.3m (51.2”) across. Another “known dimension” can be taken from the man standing next to the weapon, for which a figure of about 1.8m (6’) in height seems reasonable. Once again taking some relative measurements (and taking an educated guess at the slant angle of the door with respect to the camera) I guestimated a door width of 1.25m (50”).

Now knowing that the torpedo room access door spans approximately 50”, we apply our relative measurement that the outer torpedo door has a diameter of 0.9 of the access door width. This gives a torpedo tube door diameter of 1.1m (43”). This seems awfully large for accommodating a weapon that is only 650mm (25.5”) in diameter, but it’s hard to argue with the numbers…

Scaling this down by 1/96 for my OSCAR, I'm looking at a tube door opening of 0.45” in diameter. With this dimension in hand I'll be making up a tool in the next day or two to cut correctly shaped masks for my tube doors.

[adriaticsea]

Hi KevinMc,

first of all, there

[color=#000000]Hi KevinMc,

first of all, there aren't enough words to describe your wonderful work on this 949A, both on the model and the thread]

[adriaticsea]

Hi Kevin,

was re-reading your thread

Hi Kevin,

was re-reading your thread and, regarding your doubt on the bottom flood holes, maybe I can say something.
Undoubtely the flat bottom of the 949As makes me think that they're designed for bottoming operations, and it's right to think that the bottom flood openings could fill up with mud, but, also to consider is that russian boats usually differ from USA submarines in the design of their MBTs.
While USA (and West, as far as I know) submarines use MBT with OPEN (no valves) bottom flood holes, and keep the water out by mantaining the upper vents closed and low-pressurizing the tanks, the Russians have valves (so called Kingston valves) at the bottom holes.
This is to avoid water entering, thus eliminating the need to pressurize the tanks and achieving also a faster filling of the MBTs, but could also be very useful on the bottom-you simply close the Kingstons, and no mud can clog the bottom holes.
BEST REGARDS MAURO

[timothy guest]

Regarding documentation on the lower

Regarding documentation on the lower hull flood holes, I have an Oscar II display model that I purchased several years ago from a Russian vender named Pormosky Souvenir. The model is in my office at work (I'm currently at home) but I recall there being flood holes below the waterline and possibly on the very bottom of the hull. When I get back to work next week I'll take a look, see if there's anything worth mentioning and get back to you.

I also recall that this model's manufacturer was located in Severodvinsk and regularly viewed Oscar hulls in drydock... so there may be some level of accuracy reflected in the model that's better then an educated guess. Again, I'll take another look and get back to you, if you're interested.

By the way, you're doing a fabulous job. Please let me know if you plan to pull any copies off your hull. I'd definitely be interested in reserving a hull/kit.

Regards,

Timothy Guest
SC Member #1617