HrMs O-13 by FreekS - 1:50 - RADIO - 1931-1940 - Last Dutch Sub “on eternal patrol”

[Veszett Roka]

You can connect the hatch to the captain's shaft with two bumpers (or even a single), thus the captain can open a hatch en-route to the flybridge and close it after he is down already. I believe it is just matter of space inside the tower or in the hull.

 

Brilliant work!

[FreekS]

Working on the “captain below” feature. O-13 has 4 hatches. I’ve made those from wood before, but to have low friction hinges I decided to print these. All hatches should open when the boat surfaces, and close before submerging. The hatch to the forward torpedo room has just enough space below it for half a crewman to stock his torso out of the hatch. 

by the way; the 1:50 winch holds the mechanism below and is the first part made with my first ever, very old Unimat-3 Lathe!
I’ve mounted him on a printed double-arm balance, so he comes vertically up. On the other side of the balance are  a 4ml blue foam-float weighted with 2 gram lead. So a “driving force” of 2 gram to either raise the float when the deck floods or to lower it when the deck drains on surfacing.

The hatch is driven by the 2ml float weighted with 1 gram of brass on the right of the pic. It all seems to work dry….

 

although there is more space underneath the bridge, the officer emerging from the hatch there has to rise full length, to be visible over the bridge rim. The double-arm balance did not fit there, so the officer is pushed up by a simple counterweight and is guided by a brass wire. It’s a little more iffy - likely needing optimisation. The nut will be replaced by a compass stand made on my lathe.

[Veszett Roka]

The double hinged arm is a very elegant solution. About the captain, i guess the friction between the push rods and the captain's wooden base cause that iffynes. If i'm right, a dome cap could solve it like this:

 

But anyways, i'm admired.

[FreekS]

That looks like a great idea!

[FreekS]

I tried the dome cap - but it did not solve the issue. So I looked for modifications to the double hinged balance - while maximising the vertical hight the (tall) Dutch captain can rise out of the hatch. I came up with a double hinged balance, with side by side pivot points. That seems to do it. 

I also tried to replace the blue foam floats for 3D printed hollow shapes which can be fitted more precise in the sail.

On the top of the picture is the printed float. The three arms keep the float and the captains platform level. The two half-cylinder shapes left and right are connected and are the float to open and close the hatch

 

still not sure if this will work in water with minimal differences in gravity force and archimedes’ buoyancy. Only a practical test will tell…

 

but first I did a basic balance test, to see how much lead the boat needs. 
the WTC endcaps were glued, and replied until airtight (I blow in a tube as a waterproof test). Then the boat was “launched” in the bath. 

it needs about 800g plus 620g that simulates a full dive tank to “hover”. And when then removing the 620g the boat was reasonably on waterline. Needs trimming though

 

very happy with this!! 
I have some more work to do to test the props and pump for the dive tank. And I need to review the front dive plane mechanism, the plane looks like it was hit by a depth charge.

Edited November 21 by FreekS

[Jim Lad]

Fascinating to see your tests with the boat.

 

John

[KeithAug]

You need a bigger bath! The mechanics continue to facinate.

[FreekS]

As usual, the first wetting of the boat has revealed some work. First, I glued 500 grams of lead in the bottom of the ship, below the WTC. Also the techrack has too much friction, so I straightened out the M3 wires and adjusted the nuts. Sanded all contact points with the PVC tubes. It now runs better. Also, I wanted a magnetic switch so the whole boat can be switched on and off without opening the bajonet, using a magnet. The normal units use relais, and I did not have the space for them. Instead I made a small circuit with one MOSFET, one resistor and a reed–switch.

I’ve tested it switching up to 2.2A, and when the reed is open there is no measurable current use. Seems to work!

The reedswitch is located inside the water tight compartment, underneath a hatch. I put a magnet inside a wooden crew member, and when I place this in the hatch, the boat is switched off. On removal before sailing, the boat is switched on. It just fits between the existing main switch inside the WTC and the Arduino controller.

I think the techrack is now complete, and next step is to test the boat in the bath, further balancing, filling and emptying the temp to dive and raise the boat and unfolding of the planes.

[Jim Lad]

Amazing!