Seehund Scale 1:35

[MFR1964]

Thanks, it will take some time and a checkup now and then to monitor the progress, for now she is committed to the next 5 years to see if it will return, after a 5 year period they say you are cancerfree.

Manfred.

[MFR1964]

Well, i did some testing in the kitchen sink, that went not so good. i started with a weight of 325 gram and with 5 miniutes the weight was 332 gram. leaving her iside the water gave her even more weight, took her horizontal positioned to the cave and started to opening her up.
Lots of water in the hullpart and some in the sternpart, it seems she is leaking through the O rings, sealing those inside their settings with RTV can be the solution, first she has to dry.
Yet again i fried the servo of the torpedomechanism, probably water had come inside the servo, the idea is to seal it with RTV as much as possible.


While waiting for the water test i made this, on the right the standard key with the crewmember which was allready made in the past, on the left a key which can be used during the first stage of the boat in the water, it has to set due to the temparture difference between the land and water, this second key gives me room to ventilate the boat.


Also made this, a stand for the Seehund, had some H shaped copper left.



The Seehund will fit snuckly between the rubber pads, this stand is a bit inspired on the transport lorry they used to get the boat at the desired location


Here i stand now, opened her up to dry, had to fiddle out all components, the flange of the sternpart was loose, used 2K epoxy glue to get it back on, it's secured it with tape while drying


Those are the parts i had to remove, the sternpart is stripped from all it's components, the servo for controlling the torpedo's is still inside the hull, when dry i can take her out.

Manfred.

[Subculture]

Machine an aluminium bayonet seal?

[MFR1964]

At this scale you need all the room to stuff things inside, for cilindrical hulls it's a good option, but this hull is a bit shaped as a upside down eight, leaving you with lesser room to stuff things inside using a bajonet seal.

Manfred.

[MFR1964]

Done some work this week, just as i suspected the O rings where the issue, ended up sealing them with RTV, did some testing to see if that was the solution, pictures



Rear-end sealed and into the testingpot, left it there for a hour



View from above, no water inside, both the shaftseal and O rings kept the water outside.



Frontpart into another testingpot, pretty much the same procedure.



Had to add some weight to keep it at the desired depth, left it there for at least 1 hour, same outcome as the frontpart, no water inside.



Sealed the bottom of the torpedo release servo with some RTV, just to prefent water damage, it is really a pain in the ass to get this servo in or out.

All this steps revealed i made mistakes by not testing this really good, i got punished for this, first crawl, then walk and run, i can hear you David!!!

This weekend i want to put the Seehund together, hopefully for the last time, testing will be done when the RTV is cured, i'll report back with the outcome

Manfred.

[MFR1964]

The Seehund is build together, did some testing in the kitchen sink and made a vid





While the Seehund was drying i slapped some paint on the stand



Made the holders which hold the torpedo's in place, heavier with some strips of flat lead, this is done to ensure they will unlock when needed.



Added some foam at the keel to counteract the lead strips.



The Seehund in his stand, ready to be tested if she is watertight.





Did some tests and left her inside the sink for at least 1 hour, weight stayed the same, so she can called be watertight, wateline a bit too high, it seems that the foam at the keel can be removed, have to do some more testing to find this out.



I couldn't resist to place the torpedo's, due to the bouency of the torpedo's she will stand a bit higher in the water, will conduct some more testing inside the bath to see if they will be released.

https://youtu.be/zxNI7ZxMlvQ?si=PCjLUn3y8kZbb9r2

Also made a vid to show how all things work, including the release of the torpedo's

Manfred.

[MFR1964]

First i trimmed some torpedo's, and made the maidenrun in the bathtub,



They are all trimmed like this, giving me the garantee that they will not dive into the mud when fired, it will cost you some speed but they never get lost.

https://youtu.be/DbdIhGCca5g?si=4WW4aNfMGY5NJU6q

Remember i said she will be a surface runner?, i've changed my mind, want to make her a dynamic diver.



Made a drawing what i want to build, a vent that you can close when the boat is used to the watertemparture, thus giving you the oppertunity to run her dynamicly underwater, a job for the lathe and some alterations on the boat itself.



First batch of batteries has arrived, waiting for the second batch, now i run all my torps on a 1s lipo, i had a blown battery with two, made the hunt for small NiHm cells. want to rebuild all torps with those cells, don't like the idea of having lipo batteries in enclosed torpedo's in storage.
Lipo batteries on their own are safe enough to store them outside your boat, but the problem i ran into was, i keep the torpedo's most of the time in storage simply because you don't use them that much, they are enclosed tubes, managing those lipo's means, taking your torpedo's apart each time you want to service them.
With NiHm cells i don't have that problem, simply charge and run.

Manfred.

[MFR1964]

The inlet for the Seehund is done, batteries replaced inside the torps both for the type VII, type XXII and Ko Hyoteki are also done.



The turned inlet with the cap glued down on the Seehund, made a hole inside the deck to make this possible.



Made a provision on the schnorkelhead to make removing easier, not sure if it will stay, i can allways remove it when not needed.



The inlet tube is closed off by the cap, there is a little O ring present on the inlet tube which makes a watertight seal.



This was a bummer, after drilling the hole through the hull the Seehund didn't start anymore, opened her up, and yes offcourse i hit a wire, repared the wire and sealed her again.
In the background you can see the Marder which i allready started with, had to switch back to the Seehund for repairs



Testing if she is watertight inside a cat litter box, big enough to do some testing.



Also did some work to get her straight in the water, added some lead and foam to get this right.



Without the torps, in this configuration i want to see if she will be a dynamic diver, after that i will have a go with both torps attached.

https://youtu.be/x3yepRfnMW0?si=UejB2nTGp9FK9Lv-

Final testing to see if both torps will launch.



All batteries replaced on the type VII torps, did the same job with the torps of the type XXIII



New batteries on the Ko-Hyoteki torps, they will run slower due to the lower voltage of the replaced batteries



Made a stand for the torps to keep them safe at storage, some scrap pieces of lexan and some threaded rods, still have to add the rubber which will protect the torps when painted.



This week we had some nice days to spray some paint.



For now they are inside the Cave to dry and harden, in the end they will be weathered.


Manfred.

[SSBN659]

I always enjoy looking at your work. Just amazing!

Will Rogers
SSBBN659

[redboat219]

Manfred,
How does venting the dry hull make your boat dive dynamically?

[Schmitty1944]

This is absolutely astonishing. Truly incredible at this small scale. I am curious you mentioned it is similar to the Bibers early in this thread. Have you made a working 1/35 RC Biber as well? also based on a Verlinden kit? Is there somewhere I can see information about that? I have a fascination with midget submarines and especially the Biber. I have a couple of attempts to make one in 1/35 scale lurking at the back of my work bench.

Very impressed by your skill and enthusiasm with these small scale projects.

Jason.

[MFR1964]

Thanks Will, believe me, building on bigger boats is easier.


Romel, venting the hull is done because you have temparture difference when putting the boat in the water, it will schrink a bit, creating underpressure inside the hull, this can result in pulling in water through the O rings, normal procedure would be, driving her for about 10 Minutes before i seal her with the sealcap.
Same way is done with the Bibers.

Jason,



This is one of the Bibers, made by my mentor, i rebuilded them both, the servo's where dead, the hull itself is based on the Verlinden scale 1:35 model,
he made a mold from the resin model and rebuilded the rc hull from reinforged epoxy.
They are both dynamic divers, the torpedo's are used to hold the batteries, the Seehund was big enough to place a servo inside to control the launchmechanism hence the torpedo launching

Manfred.

[Schmitty1944]

That is very nicely built. Quite a lot of detail added even beyond the Verlinden kit. I don't want to hi-jack your seehund thread but this is very closely related.

I had exactly the same idea your mentor had although he did it much before me. I used the Verlinden kit as a starting point and made fiberglass hull. At the time I didn't realize there is a Italeria biber kit in the same scale that would probably be a much better starting point. My first attempt (the one in the foreground) made it all the way to pool testing which revealed many problems. Too heavy, not enough buoyancy. Tiny servos too weak to move controls adequately. Geared drive motor too slow to actually propel the craft. I put it on the back burner and built another one using a small toy as you had done with your Marder and I had done with the tiny FS-1 flying sub.

That one actually works very well and has a working ballast system. It does not have moving control surfaces, instead it is propelled and steered by the propellers on the torpedo s.

Seeing your work here on Seehund (and others) has got me taking another look at that Biber I set aside. I would love to know more about how yours work?

Many thanks.
Jason

[MFR1964]

Jason,

I'll dig out the archives and see what i've got, the best solution will be to make a seperate thread which will be devoted to the Bibers, be patient

Manfred.