Forum rules and expectations

Hello, and welcome to the forums at the Nautilus Drydocks, formerly!

We welcome anyone with a passion for submarines and a desire to learn and share knowledge about this fascinating hobby. Use of these forums indicates your intention to abide by our code of conduct:

1. No spam. All automated messages, advertisements, and links to competitor websites will be deleted immediately.

2. Please post in relevant sub-forums only. Messages posted in the wrong topic area will be removed and placed in the correct sub-forum by moderators.

3. Respect other users. No flaming or abusing fellow forum members. Users who continue to post inflammatory, abusive comments will be deleted from the forum after or without a warning.

4. No threats or harassment of other users will be tolerated. Any instance of threatening or harassing behavior is grounds for deletion from the forums.

5. No profanity or pornography is allowed. Posts containing adult material will be deleted.

6. No re-posting of copyrighted materials or other illegal content is allowed. Any posts containing illegal content or copyrighted materials will be deleted.
See more
See less

Scratch Build project SM U-23 Class World war one U-boote. Zero Bubble model design.

  • Filter
  • Time
  • Show
Clear All
new posts

  • Scratch Build project SM U-23 Class World war one U-boote. Zero Bubble model design.

    Hello all,

    I have for the last year been covering the development of the ZB cylinders. These development of these is almost at the end as production is already underway. As a result I have been thinking for a couple of months about the possibility of returning to hull development and producing a new kit. For years I have been developing mainly Soviet boats but I find that I am at a stage where I have all the Soviet boats that I want.

    I have during that time though about producing a kit of AE2. This was the second submarine ordered by the RAN (Royal Australian Navy) in 1911 and delivered in 1914 after one of the longest early submarine voyages. This submarine was a British "E" class boat, hence 'AE2'. It has become a famous Boat in Australia because it broke through the Dardanelles on the same day as the start of the Gallipoli campaign and has become apart of the ANZAC legend becoming known as the 'Silent ANZAC.' However I decided to take a look at some other designs.

    I have always liked the really early German U-boats from the pre-war period. However this liking goes up until the start of the war. After about 1915 they start getting bumps and lumps. I like the sleekness of the earlier ones.

    So I have decided on the U-23 class. This class also shared similarities to the U-31 series of Boats. The U-23 class was the last class that were developed and laid down before the start of the war. They were also I believe the second class of Boats to have marine diesels rather than the Paraffin /Petrol engines of earlier boats.

    Click image for larger version

Name:	U26 pic.jpg
Views:	1537
Size:	60.5 KB
ID:	146224

    U-26 was of the U-23 class.

    I see that the Good Doctor Schmidt has beaten me to it with U-5 on the cards. His U-1 was a masterpiece. Also Das Werk, a company in Germany has released a kit of U-9. So suddenly at the moment it's raining Pre-WW1 German U-bootes! I have some good drawings of the U-23 class however would love to get hold of some dry dock photos but have found this rather challenging.

    This boat will be a challenge for me as I just can't PVC pipe this one. It has a constantly changing beam and so will need to be quite wide. It will be designed to take on of my ZB cylinders and will have a maximum beam of well over 100 mm wide. It will be as long at the Project 667 kit that I have on offer (around 1220 mm). The master hull will be profiles / frames and stringers, most likely covered with Balsa and then Glassed over.

    Click image for larger version

Name:	IMG-5314.JPG
Views:	1228
Size:	68.0 KB
ID:	146225

    Side view showing the ZB -1/2 cylinder with the SLA Battery in front, between them will be the ballast tank. It will be a tight fit for the cylinder vertically, sideways plenty of space. I will probably shape the Ballast tank to conform snugly with the profile of the hull.

    Click image for larger version

Name:	IMG-5315.JPG
Views:	1255
Size:	74.2 KB
ID:	146226

    David H

  • #2
    Funny, I just get large plans of this class scanned and plan to moedel it in 3D....also the UC II class.


    • #3
      Looking forward to it, David!


      • #4
        Thanks Jorg,

        The Good Doctor seems to be beating me to it again. Andreas do you have any good U-23 Class pics available that you could share? Summer has been cancelled on the East coast of Australia for the past 3 weeks it been rain, rain and rain. Crazy considering exactly a year ago we were about to pack up our cars and evaluate because of a very big and scary fire to our north was approaching. Drought to rain, rain rain.

        This has given me time to start working out the profiles for my next project the U-23 class U-boat. I have divided the drawings that I have into 20 sections that I will make into profiles that work their way from the stern to the bow. This requires a bit of compass work and educated guesses as I only have the one series of drawings to work off and not many clear photos showing details. Anybody?

        I started drawing the profiles on paper, checking for symmetry by flipping them over and referring constantly to the previously plotted profiles. Some interesting curves on these boats. They are trickier then my Soviet Project boats.

        Click image for larger version

Name:	IMG-5325.JPG
Views:	1213
Size:	77.1 KB
ID:	146355
        I just wish that the original plans that I have had more profiles more evenly paced along the length of the hull. I've had to carefully plot the location of the Cylinder, ballast tank and the battery to make sure they will fit and access to each is easy.

        Click image for larger version

Name:	IMG-5324.JPG
Views:	1146
Size:	74.9 KB
ID:	146356

        Click image for larger version

Name:	U-boats Kiel 1914.jpg
Views:	1132
Size:	68.6 KB
ID:	146357

        David H


        • #5
          Hello all,

          I have spent the last week or so plotting and designing the twenty different and subtly evolving templates that work their way from the stern to the bow. All the time being conscious of the need to make sure that the middle section will be big enough to accommodate a ZB-1/2 cylinder that I intend on putting in the middle. It will also need to be able to take the 12v SLA battery up front and of course the ballast tank in the middle. I have already started thinking about the Ballast tank. I have with all my ZB boats just used a PVC pipe pressure sealed as the tank but can't stop thinking how cool it would look if I could get a brass one made that kind of looked really turn of last century. Stylish...

          Anyway, I have started cutting out the paper profiles and folding them over to check for symmetry and then plotting how the relate to the previous one and the next one to be made.
          All the while making sure that the constant width of the main raised deck stayed just that for most of the length of the boat, also making sure that the two lower outer decks blended nicely into the front of the bow and the templates 18,19 and twenty rake upwards. Also checking with the profiles of the battery cross section that It will easily be accessible in the forward hull. This has taken me most of the Day. Once the twenty profiles have been cut and checked I have then transferred them to a thin 5 mm thick sheet of particle board and then started tracing out the profiles. Once this is done I can then start cutting them with a coping saw and then checking them against the paper profiles.

          Click image for larger version

Name:	IMG-5330.JPG
Views:	1186
Size:	62.8 KB
ID:	146456

          Most of these pieces simply needed some fine sanding around the edges to bring them back down to the pen outline.

          Click image for larger version

Name:	IMG-5331.JPG
Views:	1141
Size:	68.5 KB
ID:	146457

          I will have to spend a fair bit of time making sure that the frames line up as they should.

          David H


          • #6
            A lot of work! Did you use a bandsaw? How about the keel? Airbrush for Mike finally arrived!


            • #7
              Hi Jorg,

              Ive had to use a coping saw as I don’t have a bandsaw, so it took hours of work. I don’t mind. What has taken ipeven longer is all the checking. The keel will be added after the hull has been sheeted. After all the baulkheads have been cut I then laid down the keel. This is a 5mm by 5 mm strip of hardwood that will run the length of the boat. I will be cutting out the square profile in the bottom of the baulkheads for the backbone to slot into.

              Click image for larger version

Name:	7C3A38CD-A1E2-47AB-AD66-C8B22F674804.jpeg
Views:	1173
Size:	85.6 KB
ID:	146519

              The stern section of the keel bends upward to give clearance for the twin screws and the rudder. I simply cut a series of notches into the keel to creat a curve and then glued it with some superglue.
              Click image for larger version

Name:	FE230712-8284-4FC2-B964-67800FBAF455.jpeg
Views:	1152
Size:	88.3 KB
ID:	146520

              The front of the bow curves up ward and is near vertical. I actually prefer this bow over the rounded bow of later U-Boats.
              Click image for larger version

Name:	AE82026E-E1DF-4E9C-87FC-5A07924250A3.jpeg
Views:	1153
Size:	85.0 KB
ID:	146521
              Here I have vertically placed the baulkheads in position and checking fit and alignment.i have used a hard flat piece of bench top to guarantee flatness.

              David H


              • #8
                Outstanding Dave. What scale is it?


                • #9
                  Hi Scott,

                  Thank you and once again an unusual scale, 1/54.



                  • #10
                    Hello everyone,

                    I am at the tail end of the summer holidays and have managed to get a good amount of work done on U-23. As seen in the previous photos I had cut out all 20 bulkheads and managed to get them into position along the keel and a top spine for want of a better term. I had to make sure that the Keel was straight and the top spine also with no sagging possibly caused by the bulkheads leaning one way or the other. Gussets were glued in place along the keel to support the vertical position of the Bulkheads and also make sure there was none of the sideways deviation. After being content with the straightness of the keel and then bulkheads I then glued in the top spine.

                    You may also notice on the previous pictures that there are notches cut where the sides curve down. This is for the side stringers that will form the widest part of the hull. The beam, effectively. Once the bulkheads ,keel and top spine were glued in, I then cut the balsa strip at about 5mm x 5mm square and then placed that in the side notches. I had to make minor adjustments to the notices to make sure that the stringer was straight on both sides.

                    Click image for larger version  Name:	IMG-5366.JPG Views:	0 Size:	87.1 KB ID:	146744

                    The bow features a near vertical bow line. This was joined simply for starters with a piece of balsa connecting the keel with the top spine and getting some reinforcing later. The side stringers that follow the line of the bean did not extend all the way. I have had to add further sections bow and stern. Pins hold them in place until glued. This take me back to the days when I built RC Sailplanes.

                    Click image for larger version  Name:	IMG-5368.JPG Views:	0 Size:	89.4 KB ID:	146745

                    Click image for larger version  Name:	IMG-5373.JPG Views:	0 Size:	86.6 KB ID:	146746

                    Further gussets have been placed to hold and secure the beam stringer to the bulkheads. All the time whilst doing this checking that the bulkheads remained straight and true. I had also started checking that the bulkheads deviated by the same amount each side of the top spine. The beam stringer effectively terminated forward at Bulkhead 19 as the side saddled disappears into the hull forward of this the hull drops vertically to the keel.

                    Click image for larger version  Name:	IMG-5375.JPG Views:	0 Size:	84.7 KB ID:	146747

                    Click image for larger version  Name:	IMG-5294.JPG Views:	0 Size:	88.7 KB ID:	146749

                    I have only so far found only one pic of U-23. The one above which i suspect was taken after launch as the caption below says Krupp Germaniawerft Kiel. (thanks Jorg!) I will be using pics of U-23/26 because that was the class although U-22 was similar.

                    Click image for larger version  Name:	SM_Unterseeboot_22_(front).jpeg Views:	0 Size:	50.1 KB ID:	146748

                    The basic shape is starting the take form. I intend on putting further stringers around the sides as I will be sheeting the hull initially with 2-3mm thick Balsa sheet. The stringers will help stop sagging or should I call it oil canning?

                    Please, if anyone has obscure pics of this boat, especially dry dock ones that would be greatly appreciated...

                    David H


                    • #11
                      Hello all,

                      Less work this week as I have been back at work for the start of a new teaching year. However I did manage to get a few more structural aspects of the hull cut out and glued into place. I have spent several hours measuring the bulkheads either side of the center axis and making sure that they are the same. I have been looking at the curve of the hull from every bulkhead and making sure that the transition from one to the other is smooth and not too abrupt. I have been eyeballing down the length of the boat and looking to see if any bulkheads stand out. These were sanded down and if needed to gain material I cut strips of Balsa and curved them around the outer shape of the Bulkhead to conform. once glued down they would be sanded to make sure that the transition would be uniform.

                      Click image for larger version

Name:	IMG_5384.JPG
Views:	1034
Size:	76.6 KB
ID:	146992

                      I then took my sanding board and sanded down the tops of the bulkheads and the top spine to make sure they were level. I had to be very careful that as I push the top along my long sanding board I don't catch and pull the bulkhead right out out and trash the whole thing. In this pic above you can see the Balsa inserts along the curves to bring the bulkhead into alignment and transition with the rest of the hull.

                      Click image for larger version

Name:	IMG_5377.JPG
Views:	1045
Size:	90.1 KB
ID:	146993

                      As you can see in this pic the beam stringer on the port side did'nt extend sideways enough, I had to create an extra strip of Balsa to create a smoother more consistent curve around the stern of the boat.

                      Click image for larger version

Name:	IMG_5376.JPG
Views:	1040
Size:	88.9 KB
ID:	146994

                      Overall I am pretty happy with the alignment and consistency of the frame. I took a sheet of 2mm Balsa and cut out a profile that would match the central raised deck on this sub. Early U-boats featured three decks the inner raised deck and two side decks over the saddle tanks lowered about 300 mm lower than the center. So i spent a fair bit of time making sure that the profile was symmetrical and that the centre line aligned with the centre line of the top spine. then that the deviation sideways equally matched the sides of the Bulkhead profiles of this raised middle deck section.

                      Click image for larger version

Name:	IMG_5382.JPG
Views:	1075
Size:	80.0 KB
ID:	146995

                      Click image for larger version

Name:	IMG_5383.JPG
Views:	1058
Size:	81.4 KB
ID:	146996

                      More next week. As mentioned, please, anyone with good photos of this class please get back to me, as yet I haven't been able to find much more.



                      • #12
                        It's most refreshing to see a traditional model-builder at work. Most instructive, sir.

                        Resident Luddite


                        • #13
                          Hello all,

                          Thanks David,

                          So after creating the top middle deck section with a strip of balsa and then checking the width of the top section of the Bulkheads I then turned towards giving the hull a little more definition by creating further channels in each of the bulkheads to take another stringer along the side of the hull on both sides. This would increase the rigidity further and allow further points of contact with the sheeting when it came time to lay down on the side of the hull when closing up. So i marked a line along the length of the hull about half way up the height of the bulkheads and made sure that they were all level. I then took with my Dremel cut off disc and started cutting the grooves needed to place the stringers, also made of balsa down in place and flush with the outer edges of the bulkheads.

                          Click image for larger version

Name:	IMG_5393.JPG
Views:	1008
Size:	61.5 KB
ID:	147196

                          You can clearly see some of the balsa strips designed to widen the bulkheads and make sure that they are flush through the curve with the stringers. These stringers will give extra points of gluing and adhesion to the balsa sheet that will be laid down to cover the hull. They also help to give a more full perception of the overall hull shape.

                          Click image for larger version

Name:	IMG_5389.JPG
Views:	998
Size:	88.8 KB
ID:	147197

                          All this Balsa is taking me back to the days when I would make Sailplanes out of Balsa and Plywood spars. I would then cover the wings with a very fine silk and dope as they were vintage scale models. I still have my Reiher, 'Sperber Junior' and 'Minimoa' in the rafters. Beautiful Gull wing gliders designed in the golden age of soaring... the beautiful thing about Balsa is that it is so easy to work work. You can glue pieces that are a bit rough and not precise and just sand to size. This is the case with the bow. It is a bit rough but after lots of sanding will look the part.

                          Click image for larger version

Name:	IMG_5391.JPG
Views:	1022
Size:	78.5 KB
ID:	147198

                          At this point i have also taken the keel of the boat and rubbed it sideways back and forth along my flat sanding board. It didn't need much. It was pretty close to straight.

                          Click image for larger version

Name:	IMG_5401.JPG
Views:	992
Size:	85.1 KB
ID:	147199

                          I then repeated the process by measuring half way between the earlier stringer and then keel I marked out another line. Then taking the Dremel, I then cut another set of notches for another stringer to be set in place. Once all the stringers were in place and dried I then went over the framework and gave a smooth and slow sanding. You have to go slowly so that the paper doesn't catch and pull the bulkheads out of place.

                          Click image for larger version

Name:	IMG_5400.JPG
Views:	1007
Size:	82.9 KB
ID:	147200

                          Once again, If anyone has pics, please don't hesitate to get hold of me,

                          Dave h


                          • #14

                            Regards Gantu


                            • #15
                              Here's are some real newbie questions for you.

                              Wassup with the radio masts? Did they have to be folded down when they dove? Did the periscope extend up above the masts? How does that work?

                              Captain Curious
                              Born in Detroit - where the weak are killed and eaten.