USS Detroit (Omaha Class)

This should make an interesting contrast to the other build of the same ship.
I am making my second attempt to build this ship. The first failed when the prop shafts ended too far into to interior of the ship, leaving too little room for equipment. After a little measuring I decided that the room was there and I would try again, with a slightly different approach. Failure is a real possibility.

Here is my 'keel'. I have taken the lines from the plan and cut the form. This gives me a flat bottom with about 1/16 of an inch missing from the bottom, which I will fill in later. First the 'keel' is screwed onto a flat board. This gives me a nice secure base to work from. Next, the ribs and end pieces are inserted into the slots (The slots for the bow and stern pieces are not yet cut in this photo).

Here the ribs and end pieces are installed. The bow is so narrow that it contains no useful space. I have decided to bring the bow piece back to station #4, to provide stiffness. This also acts as armour for the bow section, so I won't have to fit it. This also means that I cannot use the forward turret, since it is between stations #4 and #3. No worry -- since I can use one of the casemate guns insstead. (Note: I will need to drill holes in station #2 to allow water (and BB's) to pass into the rest of the ship.

Here is a shot showing that I do learn from my mistakes. I have pre-drilled the holes for the prop shafts. (The camera lens has warped the perspective). The little horns on the sections were supposed to fit to the edge of the deck (The deck is narrower than the hull), but it didn't work and they were cut off.

Here the top rail is dry-fitted. Once the top rail is on, I will cut the cross pieces of the ribs. I am handling the curving deck by doing straight lines angled to approximate the curve. This will allow me to have flat hatches, I still have the top deck (1/8 inch plywood) which will fit over the top rail and smooth out the curves. Also -- once the top rail is on I can remove the hull from the board.

 

I have a question for you ,the plans set I have show her bulged on the bottom so that she is a little bigger then on the top. In the first hull I built it turned out to be a self righting hull, this supposedly copys what was said about the orginals according to what I can find out.
Buddy

 

Yes, the hull is kind of round -- with the sides sticking out quite a bit further than the deck (Tumblehome). It probably doesn't look like that on this because a lot of the curve on the cross-section is hidden by the wood on the bottom. The bottom piece will be sanded to conform to the curve once the hull is rmoved from the board.
It's round on the bottom too.

 

Of the three plan sets I have, two had bulged rib sections. I did stumble across a picture on the internet showing one of the ships being launched. From what I can see from that picture, it looks like it had a bulged shaped hull. Nothing I've read so far says anything about the Omahas getting bulges during refits.

Something that is interesting is the flat deck outline between stations 3 and 5. Curiously enough, the version I'm building has those same flat areas. Heh.

These two builds are going to be neat with the contrasting building styles and techniques. Nice going!

 

Mike
I will get a hold of the guy down south and see if he can bring the Detroit up with him so we can see how they compare. I now wish my other computer had not gone bad , I didnt manage to save the pics from it.
Buddy

 

I have attached the caprail. On the last attempt I tried to cut notches in the cap-rail and fit them into tabs on the section forms. However, because of the curve of the deck the placement for the notches got progressively out of place (The overhead view being shorter than the actual length of deck). This led to some cutting and trimming and an overall bad feeling.

This time I simply glued the caprail directly on top of the sections. I let the glue dry and then drilled holes through the cap-rail and into the cross piece. Then I tapped in an epoxy covered peg of bamboo (cut from a barbecue skewer). Once the eqoxy is really set I'll trim and sand the pieces flat. Since another 1/8 inch deck is going over this, no one will ever see the mark of the peg

I also started gluing in the water channeling / side pieces (to make the side solid up to 1 inch below water line) . This is 3/16 balsa. I will cap it with 1/8 ply and then epoxy over it.
So far so good. It's not perfect I am pleased with it. I will hold off on completing the water channeling for now. The next priority will be to install the prop shafts because that's were the last build foundered.

 

I have most of the final 1/8 inch of top deck on now - just the quarterdeck to do.

I realized I can't install the shafts until I shape the hull, or the shafts will interfer. So I have contued installing the water channelling. I hope to remove it from the board tomorrow and start shaping the null. More pictures when that's done.

 

I have some shots showing my progress so far. I have the deck on and the hull sanded more or less into shape. Some more sanding required, but it's almost there. The top layer of water channeling (between the ribs) is in except for the very back where I will install thge prop shafts first.

And the end-on shot. Here, only one cross piece has been cut away. They will come out later. You can see how the bottom layer of the cap-rail forms the lib for the hatch.

A look at the bottom. I still have a layer of 1/16 balsa to put on the very center. This will take care of the flat spot. You can see the holes made by the screws that held the keel to the board.


Three shots showing the prop shaft install. First the 'kit' I used.

Here it is in the boat. The pieces keep the shafts parallel. The other piece is at the stern. I lined everything up, then tacked the shafts in place with hot glue -- then used CA on the tabs ...

and then slide them up against the bulkhead. Then I expoxied them.

Next I will finish putting the waterchannling and bottom pieces on the hull and sand it all up.
Then hatches, or the rudder. Depends on how I feel.

 

Looking real good, hope ours turn out as nice.

 

I have made a set of hatches out of 1/8 PVC foam. Not too bad but not a real tight fit. I'll have to do something about that. They do make it look more like a boat and less like a half-raised barn.

I have ordered a set of gears for the rudder. I am going to try something a little off-beat. I am going to use 2 bevel gears from an R/C car differential. One gear on the rudder, and the other, set at 90 deg, on a mounting. The servo will be connected to the gears via a drive shaft.

This is the simplist setup I can think of. I tried drive gears, they couldn't bring the swing arm far enough forward. Even four gears set in a row wouldn't be far enough. This way I hope to do with just 2 gears. I looked at belts, but nothing really fit.
Pictures to follow.

 

Very clever. There really isn't much room back there to play with.

 

A couple of pictures showing the mockup of my steering gear. Pretty rough so far -- and it's a bit high, but should fit. The trick will now be to get the rotation from the servo to the gears. I am thinking of standing the servo on its end and attaching a drive shaft directly from the servo to the gear. More pictures when it's in the boat.

 

Can you flip the shaft gear over, so the servo gear comes in from the bottom side of it?

 

That might work, but I think there is enough room anyway.

Update -- not much progress. Not a lot of garage time this week. I did start the superstructure because I can do them in the house, but the result (forward SS up to wheel house)) was ugly and weighed a ton. I managed a little garage time today and redid what I have in balsa and foam. Still ugly, but much lighter.
I put on the bottom 1/16 inch so I can shape the round bottom, but haven't shaped it yet. I hope to that this week and also to put the epoxy and FG on the bottom.
Rule #1 -- do at least one thing every day, no matter how small, and you will eventually finish.

 

An update: I have spent the last few days applying a layer of epoxy and FG over the outside of the hull. It's stll a little rough, needing a little trimming and sanding, but the job is finished.
Here is a picture of the ship with its hatches and what I have of the forward superstructure.
Here is a shot of the inside. The cross pieces have all been cut away and there is full access to the inside. The props shafts haven't been trimmed yet, so they protrode well into the interior.
Here is a shot of the stern showing the props.

Still a ways to go - but progress is being made. I still need to fill in the gaps (by the ribs) of the water channelling, but I might install the motors and pump first, just to see what I dealing with inside. I am also going to have to start to consider my armament options.

 

Looking good so far. keep up the good work.

 

Nice work there Rob!

 

Since its a single rudder ship, won't it turn better with the props closer in? Also a question for you, what size props did you go with, will help me decide on mine. Thanks