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1/25 Type VIIC/41 Scratch Build.

This is the place to post your submarine build- ups.

Postby sam reichart » Fri Nov 24, 2006 12:25 pm

Mylo-
this has been fascinating to watch, and to learn from. I just wanted to let you know that your photos/narrative plus time line are really awesome. It never ceases to amaze me as to the talent and patience of some people when they put their mind to a project. Keep up the great work!

kindest regards,
Sam
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Postby Mylo » Fri Nov 24, 2006 2:52 pm

Sam,

Glad you're getting some value from this build thread. The whole intent is to share my experiences, good, bad, right, wrong, as a learning tool.

I've enjoyed documenting this build so far with all the entries and photos. It will be kind of cool to be able to show people how this "thing" was made, if I ever have it on display anywhere. I'd love to make a sub regatta some time......bring this brute with me.

As for "talent", I don't think I have any more or less than the next guy. What I DO have is enthusiasm to learn and accomplish something. I would agree with you though that there is much talent to be found here at subcommittee. Patience.......my patience is never ending when it comes to a model project that I have interest in. My patience is NON EXIXTANT when it comes to traffic, ........or dealing with a adolescent running a till at Home Depot with a piercing through an eyebrow.

Thanks again for the comment.

Mylo
Last edited by Mylo on Fri Nov 24, 2006 4:56 pm, edited 1 time in total.
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Postby Mylo » Fri Nov 24, 2006 4:55 pm

Step 12: First drywall mud coat.

Time to complete: 2 hours.

Total time to date : 55 hours.


After some final prep and sanding, I applied the first coat of drywall (sheet rock) mud to the foam plug. The purpose of the drywall mud is to fill in all the flaws and cracks. The stuff is easily sanded and once all the coats have been applied (not sure how many that is going to be just yet) and sanded, the plug will be very smooth and uniform.

Image

Image

The goal with the mud is to have the final coat juuuuuuuuuuuuust show where the former is located without sanding completely through. The mud is messy to work with. A variety of tools are used to spread it. I bought a big 5 gallon bucketl of the stuff premixed. I don't remember the cost but it was reasonable. The premix saves a LOT of screwing around mixing it yourself and in my opinion, the extra cost is worth it, as it isn't much. The mud will be left to dry, and then lightly sanded before applying another coat. I will keep applying coats until the entire plug is uniform and without flaws.

Step 13: First mud coat sanding.

Time to complete : 2 hours.

Total time to date: 57 hours.


The first mud coat was left overnight to dry. Using 80 grit, I sanded the mud coat trying to just barely expose the formers in order to maintain hull accuracy. Only very light pressure is needed. This stuff sands easily and if it weren't for the complex shape of the hull, this step would have not taken much time. For the most part, I just used the sandpaper bulk in my hand without any tools so that I could feel the many different contours and wrap the paper around them. The only section that I used a sanding block on was the keel due to it's flat surfaces. After completing the first sanding, it became aparent that another coat of mud was needed, as suspected. It's important that when the sanding is done, that none of the formers are directly visible as it would show through as a "rib" in the fibreglass that is to be applied over top. I will keep adding coats of mud and sanding until I can just barely make out the outline of the formers from underneath the mud. This will create a smooth even surface (no ribs) while maintaining the accuracy of the hull from the formers.

Step 14: Second mud coat.

Time to complete : 2 hours.

Total time to date : 59 hours.


The second coat of mud was applied to bring the hull into uniform shape with the formers. Enough mud was put on so that the entire former was covered with a very thin layer. The mud was applied with a 6" plastic putty scraper parallel to the formers. The length of the scraper ensured that at least two formers were being touched by it during the application allowing for the mud to evenly fill the spaces in between. This layer of mud will be left overnight to dry completely. After sanding this layer, there will not be any formers exposed but they will be barely visible through the thin layer. This will eliminate any "ribs" once the fibreglass is applied.

Step 15: Second mud coat sanding

Time to complete : 3 hours.

Total time to date : 62 hours.


Sanding the second mud coat took more time because this was going to be the final coat so extra time and attention had to be spent to make sure that the correct contours of the formers were being followed. Given the position of the plug on the spine board, it was not possible to sand the area on top of the saddle tanks as well as the upper deck. After the second sanding was done, there remained just a few spot areas that would need fill / sanding. An entire coat would not be required.


Step 16: Modifying the stand.

Time to complete : 3 hours.

Total time to date : 65 hours.


It was now time to position the plug upright to work on the upper portion. After staring at my upright stand for a while, I decided that with some modifications to it, I could make it so that I could secure the sub in the stand and be able to set it on any side while in the same stand. This would be a big benefit. Modifying the stand was one of those jobs that I thought would take 1/2 hour and it ended up taking 3. Lots of fiddling and measuring, drilling and redrilling, it was a lot more work than I expected but I would not hesitate to do it again as the end result is a sub that is nice and secure in one stand that can be put on any side. Dealing with a sub of this size/scale presents problems that I'm sure the guys doing the smaller subs don't have to consider. A big sub is.....big. It's bulky and awkward more than actually being heavy (mine at this stage is about 40lbs including the weight of the stand.). Most importantly, it's fragile as the sanded mud surface of the hull marks up VERY easily.....while being big, bulky, awkward, and kind of heavy, not a good combo. As a result, I feel it important to have it stable in a stand so that it can be moved around and worked on properly. This is why I spent as much time as I did on the stand. I really think you have to when dealing with a sub of this size. You can't simply just put it in a nice cradle, particularly with an odd shaped U-Boat. It would be moving all over the place on you and it would likely end up getting damaged. Word to the wise, if you're building a big boat, expect to spend some time dealing with this stuff. Once finished, the stand worked great as I was able to move the hull around however I needed to without risk of wrecking something on it.

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More to follow.

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Postby Paul von Braun » Fri Nov 24, 2006 9:20 pm

Mylo - What are you planning to fit in the way of extra functions? Periscopes, eels? I expect you will have room for these in a 1/25th scale boat.
Oh, and before you go and cut the hull for access - consider the OTW route - the removable deck. Jeff knows what I mean, I have modified his design and used some stainless screws from work (they are supposed to go in bone you know!). I will take some photos and post them soon - I am still at it, just slowly slowly at the moment.


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Postby Mylo » Fri Nov 24, 2006 10:43 pm

Paul,

Extendable / retractable attack periscope and functioning bow torpedo tubes are planned for this baby. I've given both "some" thought, but I'm still a ways out before really having to do some engineering. I know they'll fit. I'd like to stuff as many electronic / mechanical goodies in it as I can. Has anyone ever installed a functioning hydrophone ? ....very cool to have a headset on and listen to the whine of 1/72 scale destroyer prop. Just a thought.

I really like the idea of a removable deck. I'd like to see some pics. My WTC is going to be 6" in diameter though, which is wider than the upper deck. I've been kicking around the idea of splitting it at the water line with the upper and lower paint scheme helping to hide the seam ....don't really know at this point.

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Postby Boss subfixer » Fri Nov 24, 2006 11:05 pm

Mylo,
Your skills are only over shadowed by your modesty. I for one as much as I love the WWII class of boats would never have attempted one as my first scratch build. Count me as one who is learning and admiring the quality of your work. I would like to scratch build a type XXI @ 1/48th scale, your thread has me thinking it's possible for me.
Thanks for the inspiration.
Don
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Put your heart into it, well done is better than well said... Ben Franklin
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Postby JWLaRue » Fri Nov 24, 2006 11:39 pm

Mylo,

Here's what Paul is referring to....it's how I built my OTW Type VII. Since I really hate the look of a hull cut at the waterline, especially the area of the saddle tanks, I decided to make the photo-etched deck removeable. This is not usual method of building, but I like it since it creates a much cleaner looking model....both in and out of the water. It did take a little extra effort to figure out how to do this...but I have found it to be quite worthwhile.

Image

I used G-10 (Garolite) to maintain the correct width of the top of the hull and to also provide a mounting for the 88mm deck gun and conning tower. All of the G-10 pieces are removeable so as to allow the dive module to be removed for servicing. Each of the PE deck sections are held into place by using available items like the bollards, fairleads, etc.

.....I'll be glad to answer any questions that might come up!

-Jeff
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Postby Mylo » Sat Nov 25, 2006 12:13 am

Jeff,

Yes, ....I like that idea very much. I have a lot of reserved thought about where to split the hull. I don't want anything unsightly. I really like what you have done with yours. Again, my 6" WTC wont fit if I just take out that section. I might have to entertain the thought of a 4" WTC, I could get that in I just don't know if it will have the bouyancy that I'll need to get this hulk of an outer hull out to waterline. In doing some thinking, I had planned on the 6" as I will need some volume for the ballast as well as room for the toys. That boat of yours is 1 /32, what size is your WTC in order to fit through that deck space ?

Don, .....here's how I see it. If you like U-Boats and you want a U-Boat, build a U-Boat. That was my thought process. Maybe a little blunt but.....that's how I operate. I would not have been happy and my "heart" wouldn't have been into building a nuke boat, as cool as they are in their own right. It's only when my "heart" gets locked onto something that I give it a good effort....and that goes for life in general. I'll eventually add a nuke (with launching ICBM's :) to my collection, but what I REALLY wanted right now is a U-Boat. As for it's added complexity, .....sooner or later these skills have to be learned and the only way I see is to build that type. I simply didn't want to waste time building something that I didn't want, I would have done a crap job, I know it. I warned myself from the start that it was going to take a lot of time as I'm developing many of these skills myself. The deadline is to have something in the water for next summer. If that doesn't happen.....the world will still turn. Deadlines help me stay motivated, which is why I set them but I refuse to rush. When I rush....I screw up, get frustrated, and nothing is fun.

I hope this thread helps to encourage you to step outside your building comfort zone. I've enjoyed trying to figure out the challenges so far, it's one of the things that keeps me interested in the build. I've got a looooooong way to go though and a lot of figuring to do.

Mylo
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Postby Mylo » Sat Nov 25, 2006 1:57 am

Step 17: Removing the spine board.

Time to complete : 1 hour.

Total time to date : 66 hours.


I decided in the planning stage of this boat that I was not going to remove the spine board but instead, I would just cut off the excess and sand down what was still in the foam flush to the deck, leaving whatever was in the foam. There was no pretty way to do this.

Image

I dug out my hand saw and started cutting, leaving the areas intact that were securing the hull with the zip ties to the stand. These areas would be sufficient for me to be able to place the hull upside down as it had been originally to work on the underside. I would be leaving these portions of the spine board intact until after the lower portion of the hull was painted. Once the lower hull was done, I would then remove the remaining small pieces of spine board and finish the upper deck. After the excess was cut out with the hand saw, I belt sanded the remaining part of the spine board until it was flush with the top of the formers.

Image

In all, everything went well with this technique. It saved a lot of screwing around trying to get the spine board out of the foam, which I don't think could even be done without wrecking something. That board was planted in there good. Some glue from the process of putting the formers and foam on likely seeped onto the spine board, gluing the whole thing together. Drywall mud had also made it's way in and around the spine board. I think it would have been impossible to remove it. Leaving it in place also adds strength to the plug. Unless I'm overlooking the obvious, I see no need to remove it.

Step 18 : Working upper saddle tank / deck area.

Time to complete : 8 hours.

Total time to date : 74 hours.



The upper saddle tank and deck area needed a lot of attention and "fine tuning" once the excess spine board was cut out. A thick coat (1/4") of mud was applied to the entire deck surface to bring everything up flush with the formers. Many of the foam pieces were recessed away about 1/8" from the top of the formers around the mid deck / conning tower area. In all, the foam was very inconsistant with the tops of the formers (Not sure exactly why) with differences up to 1/4" The mud was let to thoroughly dry and then sanded with a sanding block to flatten. The mud was then sanded down to the formers bringing the entire deck up flush. The fore deck proved to be the biggest challenge of the entire hull. Getting the side contour and proper "footprint" was an excercise in tedious measuring and sanding followed by more mud, by more sanding, etc., etc. 1/4" is about as thick as the mud can be applied. The rear area of the deck needed similar attention. The fine finishing of the deck area proved to be very labour intensive with an assortment of sand paper grits and sanding tools used. It didn't help that the job was messy as well, a job that I was happy to see come to an end.

Step 19 : Final mud spot filling.

Time to complete : 1 hour.

Total time to date : 75 hours.


After finishing the "major" work with the mud and sanding, I finished with spot filling some minor areas and flaws. After drying, these spots were lightly sanded.


More to follow.

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Postby U812 » Sat Nov 25, 2006 3:54 am

Mylo,

all I can say at this point is that I'm very impressed. Clean work. Big boat in record time too. Super job. Now you have inpsired me!

Steve
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Postby Paul von Braun » Sat Nov 25, 2006 5:40 am

Mylo - I know it's a bit far away yet, but for my boat I had considered a seperate watertight compartment in the conning tower to house the scopes and the torpedo fire control gubbins - it would also help with the metacentric height and therefore stability when submerged.
Perhaps we can swap ideas, etc when the time comes. Would be interesting to see if we could each manage to make it all in 2 different scales, 1/25th for you and 1/32nd for me!
With regard to the deck, I think you might consider making a lip at the top of your female mould ala OTW for the deck to sit on - again Jeff will know what I mean. Dont worry too much about the diameter of the wtc being bigger than the hull at the deck - I have to flex my hull for removal and it doesnt suffer as a result. If you make your wtc as well as you have done everything else thus far it shouldnt need to come out too often anyway. Are you going to add the hull's surface detail at this juncture? It will all be transferred to the female mould if you do, and save time doing it to the finished hull if you do.
Oh, and I thought I should mention that I am going on holiday to Munich next Friday. That means a trip to The Bavaria Film studios. And we all know what that means....!!!!!!!!!!!!!!!! :D :D :D


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Postby Mylo » Sat Nov 25, 2006 9:05 am

Steve,

.....you mean to tell me that 75 hours to do what I have done so far is a "record" ??.... Don't forget, I started this thing on October 20th and have just been posting my log regularly, that's all. Once I get caught up to where I currently am, the additions to the thread won't cover so much progress. I've been spending an average of 3 hours a day..........every day on this thing for 5 weeks. If I have inspired YOU, then....I must be doing something right. That certainly is a compliment, thanks.

Paul,

I was thinking the same thing in regards to the separate WTC for the scope but in order for my scope to fully extend (more correctly, fully retract), I'm going to need it to enter into the main WTC, much like the real thing does. The extendable/retractable scope mechanism will function in a similar manner to a piston tank, in that it will advance up and down a main threaded shaft dependant on the direction of the rotation of that shaft. I've come up with some ideas in which the scope WTC is more of an addition to the main WTC rather than a complete separate unit. Agreed, the addition of some bouyancy up top in the tower will add to the subs submerged stability. I'm going to have plenty of added lead weight in the keel. Again, I haven't put a ton of engineering thought into it at this point but certainly, I'd love to bash heads on this idea to get something figured out. I figure I'm about......oh.....300 hours away before I tackle the scope issue.

I can not add hull surface detail at this point as the plug is only painted foam, which while it makes for a good shell, will not hold the scribed detail. I will be adding the hull details once it is glassed. I have to come to a decision pretty quick as to HOW MUCH detail I'm going to put in. A sub this scale allows for some pretty good rivet counting......but........if I'm EVER going to get it in the water, I'll have to draw the line somewhere. I'll be crossing over that bridge soon.

I was wondering if I was going to be able to flex the hull to get the 6" WTC in and out. If that is what you do, that's excellent to know. If that's the case, I'll definately be planning to split my hull at the deck line like what Jeff has done. I think that's a great idea, it looks real good.

Unfortunately, I can't spend much time in my ship yard today, but I'll be posting more "Steps" later on.

Mylo
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Postby JWLaRue » Sat Nov 25, 2006 2:06 pm

Hi Mylo,

The dive module in my Type VII is 110mm (a bit shy of 4-1/3") in diameter. All of the G-10 transverse pieces are removeable to allow me to pull the dive module out through the area of the deck gun....and as Paul as noted, the hull does need to flex slightly to when pulling it out.

Since your boat is 1/25th scale, it looks like you could go as high as 140mm (about 5-1/2") in diameter and would end up with no more flexing than I see in my hull.

-Jeff
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Postby Mylo » Sat Nov 25, 2006 3:34 pm

Jeff,

Thanks for the calculations. I'll eventually see when I get an actual hull to work with. Sounds like I'll be close though for a 6".

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Postby Mylo » Sat Nov 25, 2006 3:57 pm

Step 20 : Shaping the "Atlantic Bow".

Time to complete : 1 hour.

Total time to date : 76 hours.


The very tip of the bow on this type VIIc/41 has what is called an "Atlantic Bow" which has a certain shape to it, making it more efficient in high seas. Basically, the tip is flared out at the top. I sanded the MDF bow tip until it had this "Atlantic Bow" appearance. It's one of the things that distinguishes the VIIc/41 from the VIIc, so it was important to model correctly and have distinctly different.

Image


Step 21 : Rear Dive Planes and Armature masters.

Time to complete : 3 hours.

Total time to date : 79 hours.


The rear dive planes and armatures were made in the exact same manner as the rudders. That being, trace a template from the plans, cut out the template, use the template on a piece of MDF. Cut and sand the piece of MDF until it has the proper profile. After sanding, insert the casting pins. Sounds simple, doesn't it. The "Time to complete" does NOT include all my failed attempts at making these parts and starting over. By the end of this project, I'm sure to be a "Master Cutter/Sander guy".

Image


Step 22: "Stern Fix".

Time to complete : 4 hours.

Total time to date : 83 hours.


I took a measurement of the entire hull and discovered that I was 5/8" TOO SHORT !! What the.........?? !! After examing the entire thing along with the plans for.....a long time, measuring this, remeasuring that, .....I was able to determine where the problem was. It was in the stern, in the area where I had inserted the extra ribs. I KNEW I should have taken more care when I was putting that area together. In short, ....the hull aft of rib -9 was 5/8" too short. Choking back tears, I dug out my hack saw and cut the stern off at rib # -9. I had to cut throught the reinforcement rod that I had put in this area. I then removed the MDF stern tip from the cut off portion, sanding the facing clean to remount it. I then cut more foam to shape and inserted ANOTHER piece in there that was 5/8" (after sanding it down from 1"). I measured the "new" stern piece until I was SURE it was the right length/size. The piece was then remounted to the exposed # -9 rib using gorilla glue. Once the glue was dried the foam was rasped to shape then sanded. Once sanded, a coat of mud was applied. Once dried, the mud was sanded. Voila, new stern. Remeasure hull.....bang on. Spending as much time as I did at the stern, I also noticed that the area where the stern planes are mounted to was angling towards the hull slightly. A measurment concluded that this skinny portion of the stern was in fact sloping up towards the hull by a couple degrees. This section was cut out and a new MDF piece put in that had the right angle, which makes it run parallel to the keel as it is supposed to.

Step 23: Front Dive Planes and Armature masters.

Time to complete : 3 hours.

Total time to date : 86 hours.


The front dive planes and armatures were made in the exact same manner as the rear ones.

Image


Step 24 : Anchor Well

Time to complete : 1 hour.

Total time to date : 87 hours.


Using a template traced from the plans and my "angle measuring tool", I mounted the template to the foam hull in the correct position like everything else, through careful measurements. Luckily, the anchor well fell exactly in between formers # 103 and #107, which would make things that much easier when it came time to carve the well out. The anchor well was then traced onto the hull using the template as a guide. Using my rotary tool, I carved out the anchor well with a little sanding drum as the bit. I had some plans from the Fritz Kohl plan set that showed how deep and what contour the anchor well is. After the rotary tool, I sanded it. After the sanding, mud was applied and allowed to dry at which time, it was sanded smooth.

Image

Image

Image



Step 25 : Stern Torpedo opening.

Time to complete : 1 hour.

Total time to date : 88 hours.


Since the stern tube will not be functioning, only the opening up to the outer torpedo door needs to be modelled. Using the plans as a guide for determining how much of each rib is "notched out" to allow for the torpedo opening, I used the rotary tool with a small sanding drum to sand out the foam as well as the area of the MDF stern tip. According to the plans, the outer door is flush with rib # -9 and so the foam was sanded out to this rib as it was one of the ribs used as a former. Once the area was sanded out using the rotary tool, I hand sanded it with a finer grit followed by a layer of mud. Once the mud was dry, the area was again sanded.

Image


Step 26 : Stern skid / prop strut masters.

Time to complete : 3 hours.

Total time to date : 91 hours.


These two stern pieces were made like every other. Plans, Trace to MDF, Cut, Sand. (usually followed by throw the first piece out and start over. Again, "Time to complete" does NOT count "re-do's"). The prop strut took extra care due to it's thin profile and generally being more fragile to handle.

Image


More to follow.

Mylo.
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