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USS Cairo 1862 by MPB521 – Scale 1:48 - American Civil War Ironclad - First Scratch Build


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I don't remember if you have mentioned looking at this build but they found many issues with the plans of the USS Cairo from the Park Service.  They have done a lot of research while doing their project - they might have the answers about the hull you have brought up.

Kurt

 

 

Civil War Ironclad USS ST. LOUIS by thorn21g - 1:24 - POF - Gateway Model Shipcrafter's Guild

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3 hours ago, yvesvidal said:

Fascinating subject that you are building. And I love the fact that you are building it at the same scale than your previous model.

This is going to be a wonderful fleet.

 

Yves

Thank you Yves. I like the scale and thought it would be neat to show a size comparison between a work boat and a war boat.

 

-Brian

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3 hours ago, kurtvd19 said:

I don't remember if you have mentioned looking at this build but they found many issues with the plans of the USS Cairo from the Park Service.  They have done a lot of research while doing their project - they might have the answers about the hull you have brought up.

Kurt

 

 

Civil War Ironclad USS ST. LOUIS by thorn21g - 1:24 - POF - Gateway Model Shipcrafter's Guild

Kurt,

 

I did mention that one, and you are correct they have found numerous errors with the Bob Hill plans. I perused through this build several times to see what they came up with on how the stern of the boat was built. Unfortunately there is not a whole lot of detail in the build log itself and the pictures are limited. I have yet to go through their documentation that they have available to see if the details are there. These may provide some useful insight.

 

- Brian

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10 minutes ago, vaddoc said:

Brian, It seems to my that when the hull sides take the turn at the stern, the slope is reduced but it does not get vertical.

I believe you are correct. The slope gradually decreases as it comes around from the sides and at the point it makes contact with the stern-post it is pretty much vertical.

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-Brian

 

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Somethink does not add up. On the side view as well as the photos of the actual boat, the planking reaches the rudders and at that junction the stern appears vertical. On the top view plans though, it is clear that the stern is never vertical. Unless the side planks reach the outside of the rudders vertical but the planking inbetween the two rudders is at a different level and sloped. The side planks seem to indeed stop at the rudders.

 

Apologies if I am over analysing this, I tend to really over engineer and over loft my hulls! 

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Your plan is wrong.  The line that you highlighted in red is the boat’s “chine” the line between the flat bottom and the angled side.

 

The plan and the photos of the actual vessel indicate that the stern post is vertical. Assuming that the bottom continues to be flat on either side of the paddle wheel well, and the sides continue to be straight lines, not curves then the chine must intersect with the bottom of the sternpost as you show with your green line.

 

This means that the slope of the side frame relative to the flat bottom will gradually increase as you move aft until it becomes vertical at the stern post.

 

You need to redraw the chine in this area.  Unfortunately I don’t believe that you have sufficient information to actually plot this so you’ll have to use your best judgement- a nice smooth convex curve.

 

Roger

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Roger/Vaddoc, 

 

Thank you for the input on this. I figured the plans were wrong, of course it had to be after I had already got part of it built out. However, since I have been pondering this issue I think I may have it figured out a solution.

 

So first thing I did was to cut out new stern-posts so they would be in the correct vertical position.

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I then installed them and used trenails to help hold them in place.

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Then I went through and removed the hull planking in order to lengthen them to the correct chine (thanks Roger for the terminology).

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Then here just a few minutes ago I reinstalled the planking to the new chine on the starboard side.

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I had to build up the bulkhead at station 10 on the plans since the bottom has been extended and is now wider than it was previously. I will taper these built up areas toward the top so the width on the deck does not change, only the hull. This new line should provide me with the (hopefully) correct contour. Tomorrow I will finish up on the port side planking then I'm going to try filling in the newly created gap with some body filler and see if this will give me the look I am hoping for. Fingers crossed this works. If not, I'll have to tear it all down and try again.

 

-Brian

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Brian,

 

Sorry if I am causing you more heartburn but is it possible that although  frames 10 and the one preceding it match the drawing they are also wrong?  If the bottom began to narrow further forward the stern lines would taper to a finer point at the stern post as your photo seems to show.

 

Roger

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1 hour ago, Roger Pellett said:

Brian,

 

Sorry if I am causing you more heartburn but is it possible that although  frames 10 and the one preceding it match the drawing they are also wrong?  If the bottom began to narrow further forward the stern lines would taper to a finer point at the stern post as your photo seems to show.

 

Roger

Roger,

 

No heartburn caused here, This is most definitely a learning experience. All the input you all provide helps me along the way to a successful build. While I am by no means an expert model shipbuilder, the more accurate I can make this build the happier I will be and I will take all the advice I can get to make it as accurate as possible.

 

 

With that being said, this is the solution that I came up with. I am hoping it is somewhere in the ballpark of what the actual boat looked like.

 

So I finished up the planking on the port side, trimmed the planks and applied a generous amount of body filler to the newly created void. I sanded the filler to the contour of the hull planks and the deck line and I think the result came out looking pretty good. The chine is now in line with the green line I had outlined on the plans and the terminus at the stern-post is vertical.

 

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Please for give the multiple photo angles, I am by no means a photographer and it is hard to get the right angle that shows the curve and the taper at the same time. I think I will apply one more thin coat of filler to catch the small pockets that I can now clearly see in the pictures, but otherwise I think I should be good to go.

 

Thoughts and comments on this are more than welcome.

 

-Brian

 

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Brian,

 

I went back and reviewed the series of posts for Cairo’s sister, USS ST Louis that Kurt referenced above.  On the first page there is a photo of the plan view of USS Cairo that they got from the NPS.  It is different from the one that you are using as it shows the chine running back to the stern post as we discussed.

 

On the fifth page there is a photo taken during the CAIRO salvage that shows the stern with rudder attached being lifted from the water.   It clearly shows what we have been discussing.

 

Roger

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Roger,  

 

That is totally odd that the drawings would be that much different. I went back and reviewed my copy of the HSR and they are definitely different from those they are using on the St. Louis build. 

 

I also noticed that that I am pretty much on track with the contours of the stern judging by the below pictures. 

 

This is from the HSR and show the model of the mock up for the permanent display. It clearly shows the vertical terminus of the hull planks against the stern-post.

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The second picture is also from the HSR showing the hull lines. 

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The hull lines of the sheer definitely get tighter as they come around the sides to the stern-post. 

 

I am going to go back and review where I downloaded the plans from to make sure I have the correct copy.  I know it wasn’t from the NPS website. I’m thinking it was from the Vicksburg NMP website but I’m not for certain. I’ll pull down an additional copy from the NPS and do a stare and compare to see if there are any other differences. 

 

-Brian

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  • 2 weeks later...

Hello again everyone,

 

It's been slow going on the build this week. The side hull planking is taking more time than I was expecting. The bow section was pretty easy since the curves are a lot longer with less twists in a short span but the compound curves on the aft end of the hull proved to be pretty complex in getting the bends just right. Initially my plan was to single plank the hull sides, but with the way the turns are on the aft end I needed to soak the planks to get them to cooperate, and once they were in place they shrunk up when they dried. This left several noticeable gaps that I don't think would look right just filling them in (even with the hull painted). All this coupled with the fact that I struggled to get the planks to line up just right at the bow for one reason or another, led to my decision to go with the double planking. The side planks are 1/16" x 3/16" strips so I am going with .020 x 3/16" basswood veneer strips to lay over them. this shouldn't throw my scaling off too terribly much. Plus, the thinner strips will be a lot easier to bend and line up. In the scratch build world, I'm not sure if this is cheating or not going with the second layer of planking, but I want this build to look as real as possible, so cheat I must.😈

 

Here are some of the pictures of my progress this week.

 

Laying out the first couple of runs of planking.

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My measurements didn't come out quite right and I ended up with one thin plank (about half the width of the others) in the middle. I am going to have to go back and redo my calculations, because I should have had exactly 14 - 3/16" planks along the sides.

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Completed side planking. Notice the gaps at the aft end where my planks shrank back when they dried.

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Aft planking after rough sanding. This part turned out pretty good. My guess is that since this area had a solid mounting surface underneath, the planks couldn't shrink up enough for a gap. Since the ones around the side were just glued to the bulkheads they had room to separate.

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And the bow planks misaligned.

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I am a little disappointed in this part so far, but I will get it fixed. The veneer is on order and should be in some time this week. In the meantime I will start work on the decking.

 

 

Hopefully once the veneer planks arrive and I get them installed, I will have better pictures to show. We shall see.

 

Anyhow, Thank you for looking.

 

-Brian

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Mark,

 

I actually did glue them down wet on the port side. This was my first mistake. One that I didn't make on the starboard side.

 

I had glued down the curved portion where it mounts to the solid filler blocks and in my haste to get them done (second mistake), went ahead and glued the rest down to the bulkheads before letting the planks dry. On the starboard side I let them dry first then glued them to the bulkheads. No gaps on that side. Another lesson learned. I need to heed your signature and slow it down a bit.

 

-Brian

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1 hour ago, Roger Pellett said:

If this were my model, I would not add another layer of planking.  You have a nice fair hull accurate to the plans that you used. Putty up the planking gaps and move on.  Adding another layer creates its own problems as the hull will no longer match the drawing dimensions.

 

Roger

Roger,

 

This is what I would like to to, but since my planking at the bow didn't quite line up it would still be noticeable even after the hull was painted. Something that would bother me every time I looked at it (just the way my little OCD pea brain works).

 

My thoughts on what you are saying about no longer matching the drawing dimensions would be this: 

 

The original hull planks were about 3" thick using the scaling from the plans which equates to about 1/16" (the thickness of the planks that I used) scaled down to 1:48 . The veneer planks that I have ordered are .020" or just a smidgen over a 1/2 mm thick which would be roughly 1" scaled up. I figured that during the sanding to fair the hull, I'm almost sure that I took at least that much off of the original planking for the veneer to make no more than a 1/2" difference at most in the overall width of the boat. At least this is what my crazy math calculates to. Then again my math has been known to be wrong.

 

-Brian

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Hello everyone,

 

I know we may have beat this horse to death, but the subject has been on my mind and I wanted to throw this out there to any future City Class Iron Clad builders. As Roger stated before, the plans that I have are wrong. With that being said, here is what I discovered after reviewing my source material. The Bob Hill plans are the ones that are wrong. His plans plans have the chine turning into the outboard keels and terminating a couple of feet forward of the stern post. This is the way that I built my model the first time around. I used these plans since they were a lot clearer than the HSR plans. I didn't think to do a side by side comparison of them, taking for granted that I thought the Bob Hill plans were correct.

 

Bob Hill Plans.

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The drawings in the HSR are correct where they have the chine turning into the outboard keels and terminating at the stern post.

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There are several other noticeable differences that I have discovered as well between the two plans and now I am going back and making several adjustments to my build because of them. I'll point them out in later posts. But, since this was on my mind I figured I'd post it now. I have still not gone back and looked at the step-by-step documentation the USS St. Louis build to see if they pointed this issue out, so if anyone else has looked and found that they have mentioned it, then please forgive my duplication of info.

 

-Brian

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Hello again Everyone,

 

I'm back with another update. It's been a little slow going, I've been making some adjustments to another error I ran across. This error was partly my fault for not looking at both sets of plans and misinterpreting the ones that I was going by. From here on out, I am going to build this primarily from the HSR plans and just use the Bob Hill plans for clarity purposes and placement of some deck features.

 

So when I originally built the hull I was using the Bob Hill plans. Where I screwed up was thinking that the paddle wheel opening was further forward that it actually was. When I built it I misread the forward paddle wheel opening (shown in red on the diagram below) as the axle for the paddle wheel and the curved hull area (shown in green below) as the forward wall of the waterway. So to correct this I moved the forward waterway wall back from frame 50 to frame 40. I then rebuilt the curved hull area from just aft of frame 45 to frame 40.

 

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Hull after the adjustment.

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After all that, I finally started work on the deck planking. This was a long drawn out process due to the fact that I had a change of heart and decided that I am going to go ahead and do a little of the inside detailing. I still haven't ironed out all of the plans yet, but I am to try and make it to where one side or the other swings open (or removes) to show the cannons, engine, boiler and crew quarters. I figured that since I was going to go through the effort of building this boat that I might as well go for it all.

 

Starting of the deck planking. For these I used 1/16"x 1/8" basswood strips to fit the correct scale of the plans. Center strip was 1/16"x1/4" basswood.

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The red area is the boiler hold. I am going to have to remove the bulkheads from this area to install the boiler and some of the coal in the fire room. This will be done after I get the support beams on the aft pontoons behind the paddle wheel. These beams will help hold the hull in place since I don't want to take any chances on possibly weakening it by removing the bulkheads.

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More of the planking in place.

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My granddaughters came for a visit while I was working on the boat and they insisted that I let them help. It's hard to argue with a three and four year old. Not to mention my heart melts when they give me the "puppy dog eyes". So I caved and gave them both a piece of wood to sand and since they "helped" I felt obliged to put their names on the boat as well. 

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Finished deck planking.

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Next step is to mark out all of the hatchways and get them cut out. Then I'll put the aft pontoon beams in and remove the unneeded bulkheads.

 

Thank you for looking and all the likes and kind comments.

 

-Brian

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  • 2 weeks later...

Vaddoc,

 

Thank you. The girls were tickled that they got to help, and the smiles on their faces was priceless. 

 

I chose basswood wood because I am familiar with it from many of the kits that I’ve built in the past. It’s rather inexpensive, it’s an easy wood to work with and cleans up nicely. Since most of this model is going to be painted I didn’t want to go with the more expensive alternatives. 

 

-Brian

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