1/72 Victoria Class Submarine

[Slats]

Hi Guys

my Victoria Class sub kit is on its way from Jon Evan's in Canada.

I hope to start on it very soon.

Attached are some hull photos and the moulds that Jon has produced.

Lots of detail.









I plan to fit either a 3" SD or 2.5"SD (SAS capable) - I'll do some tests with the assembled boat to see.

J

[trout]

John,
That is really fantastic hull. Are you going to do a production run?

[Slats]

John,
That is really fantastic hull. Are you going to do a production run?

Nope
sorry - I'm just a humble kit assembler / customer.

I (and a few others here in Australia), have been twisting Jon's arms for about a decade to do this boat in this scale.

At this stage I don't think Jon plans on doing much more than filling the orders he took several years back. It was very much a project among friends.

J

[He Who Shall Not Be Named]

What a fine looking piece of work. So rich in detail. Keep us informed.

David

[Slats]

What a fine looking piece of work. So rich in detail. Keep us informed.

David

I intend to David.

Mike's team have the 1/72 Ark Kilo in the post to me now as well, so I plan on doing a side by side assembly of the two.

When I figure our the ballast tank needs of the two boats, stand by David for the order of 2 new SAS capable Subdrivers in 3" or maybe a 3" and 2.5".

J

[He Who Shall Not Be Named]

I have raw resin parts for the new 3" diameter SD in a bin now. Give me those figures and we'll fix you up, John.

You and Mark have waited nearly two years for that new diameter, have you not?

David

[Slats]

I have raw resin parts for the new 3" diameter SD in a bin now. Give me those figures and we'll fix you up, John.

You and Mark have waited nearly two years for that new diameter, have you not?

David

yep something like that but it's not a problem waiting David. No point in proceeding without a clear understanding of the ballast tank requirements.

If Mark's wanting it as an upgrade to the Albacore, the Ballast tank size is simply that of the previous system he had in play.

I'll need to get these boats assembled to have the best estimation as to what size I'll need.

Kilo will need a 3" diameter - but her tank size might need to be bigger than what you put the Albacore as she has higher reserve buoyancy.

For the Victoria class - I can fit a 3" and would like to, as it makes the tank shorter than a 2.5" regardless of the ballast required. But this leaves not much space above and below the SD, so a 2.5" might be a better bet. But again this little boat, very much like the Australian Collins has a high reserve buoyancy so I'll get these boats together and report in here with results when I have them.

Attached below is my grid exercise of the Victoria Class using Microsoft Excel
COG point is on the yellow line 54% of the distance from the propeller tip / 46% from the bow.



J

[He Who Shall Not Be Named]

If the thing has a high freeboard then we want a narrower SD so we don't put any ballast tank sticking up into the air where it becomes part of the problem, not the solution.

David

[Slats]

If the thing has a high freeboard then we want a narrower SD so we don't put any ballast tank sticking up into the air where it becomes part of the problem, not the solution.

David

Exactly which is why I'm thinking 2.5" for the Victoria. I'll have the boat soon and get to work.

J

[roedj]

If the thing has a high freeboard then we want a narrower SD so we don't put any ballast tank sticking up into the air where it becomes part of the problem, not the solution.

David

David,

I hope I'm not hijacking a thread here but your statement raises an issue I've had bouncing around in my head for some time now and why I believe larger-than-needed ballast tanks are really OK. - even if they're above the surface water line.

Here's how I trim a boat:

Part A
Put the complete (complete as in everything - batteries, electronics -everything) boat in water. Make sure ballast tank is completely empty. There are three possible outcomes:
1) Boat sits exactly at surface water line - you're really lucky (or a great planner) - proceed to Part B
2) Boat sits high - add weights as down low as possible until boat sits at surface water line - proceed to Part B
3) Boat sits low - add flotation (usually closed cell foam) below surface water line until boat sits at surface water line - proceed to Part B

Part B
Completely flood ballast tank. There are four possible outcomes:
1) Boat sinks to slight positive buoyancy - just a tip of sail out of water - if this is what you want, proceed to Part C
2) Boat sinks to just below water line - let's call that neutral buoyancy - if this is what you want, proceed to Part C
3) Boat sinks but there's still a lot of boat out of the water. Two choices:
a) Leave it like that. You've created a sort of dynamic diver - run it full throttle - dive planes set to dive - proceed to Part C, or
b) This not what you intended - add more weight as low down as possible until just a tip of sail is out of water - you'll have a lower than desired surface water line - but it will work - proceed to Part C
4) Boat sinks like a rock. Two choices:
a) Remove all the internal works - paint nicely - place on mantle - all done - Do NOT proceed to Part C, or
b) Add more flotation above the surface water line until boat is slightly positively buoyant - just a tip of sail out of water - proceed to Part C

Part C
Go run boat - have fun.

Actually I prefer situation Part B, 4), b) - boat sinks like rock. That way I can, by adding foam above surface water line, raise the center of buoyancy above the center of mass for a more stable boat when submerged. In this regard, I like bigger-than-needed- ballast tanks.

How crazy or wrong am I?

Dan (loins girded)

[He Who Shall Not Be Named]

Dan,

Most appropriate to this thread, if John agrees, that is. His thread.

You're methodology works fine. However. If you start the trimming process submerged, the only thing you have to change, once you empty the ballast tank, is the vertical location of some or all of the foam to achieve designed waterline. All that providing your ballast tank is either of the correct volume, or is bigger in volume than what you need.

Agreed: a slightly bigger than needed ballast tank is a good thing. Just a bit more energy is required (and wasted) to empty it completely, that's all. And, of course, you have the extra real-estate in there to accommodate it.

We now rejoin John's VICTORIA project ... now in progress.

David

[bcliffe]

John A,

John E has been keeping me up to date on this project over the course of time. The detail he has put into the boat is incredible. I believe these images are of the hull enroute to you. Enjoy. Look forward to seeing your project come together.

[Slats]

Yeah he does nice work.

Dan - no problems - I like good technical discussion.
I have to agree with David however. It is so simple to start trimming submerged.
It's also far better to work out the diameter of the SD before you start buying gear. In my early days, the required WTC size - was what I could buy to fit inside the boat. My early boats were too darn heavy. A lot of that weight had to do with not only dealing with a Ballast tank that was too big and buoyant (read, lead required at surfaced to make her stable), but the diameter of the buoyant tube above the surfaced water line and also that diameter down low added to more stability issues and more lead required.

Matt Thor I owe my early education too in regards to mass momentum in the water. Matt's message - the more weight, more momentum in a straight track, the harder it is to turn.

In summary, the more your WTC diameter fills the inside diameter of your boat, the more your boat behaves like a dry hulled submarine, thus loosing a fair bit of the weight / maneuverability advantage/s that the wet hull approach offers.
If your WTC extends down too low you have a buoyant area down low that causes stability issues requiring lead. Up top if you have a the WTC venturing over the surfaced waterline, you have a buoyant area requiring the Ballast tank to overcome this buoyancy as well as the sub material itself above the surfaced WL.

In conclusion - from the plans I have seen of the surfaced WL in respect to the centre axis of the boat around the prop shaft line. A 3" SD will venture some 8mm above the surfaced WL. A 2.5" will be 4mm below it.

David the 2.5" will be the go for the Victoria Class.
I just need to try and work out the ballast tank size.

J

[alad61]

Struth I reckon I actually understood all that!! By the way John that is a damn fine looking hull. The modeler in me would love to detail n weather that kit. Not to mention assemble and play with the finished article. You sir are a luck man.

[Slats]

Struth I reckon I actually understood all that!! By the way John that is a damn fine looking hull. The modeler in me would love to detail n weather that kit. Not to mention assemble and play with the finished article. You sir are a luck man.

Your grammar sucks too Alec, but that is coming from a "luck man" as you put it, whom fights dyslexia daily!
Glad you understand Alec - that is about as technical as I can get. Still electrically challenged.

I do hope to see you at the Central Coast Regatta in October.

Best

John