New project

[Ralph --- SSBN 598]

Is the front hatch mounted permanently?
It should be turned around like the rear hatch.

Sorry for causing so much trouble.

Not sure how accurate this drawing is but it shows the hatch orientation.

[drschmidt]

No, the hatch is just sitting there holding by gravity. I still can turn it around quite easily. btw.: I have the same drawings. They are not bad but also very inaccurate in some respects.

[Ralph --- SSBN 598]

I agree.
Most drawing are not accurate.
My current project has only a very small drawing that has no measurements at all or real information on it.
I am having to scale photos as I find them.
Another problem is it seems every time the three boats of the class went in to port something was modified.
I don't think I have two photos of one boat that are equipped the same.

[drschmidt]

Same with the nautilus. Even the paint scheme changed constantly. Which boat are you building?

[Ralph --- SSBN 598]

B-boat 1903. B-1, B-2 & B-3

Build thread is over on Sub Pirates.
The conning tower is complete.
Built from sheet plastic and brass rod for masts.
Working on hull plug now.

[drschmidt]

I love the old boats. My first build was the U-1 from 1906, Germany's first military sub ever: http://s1262.photobucket.com/user/Ma...ine%20SM%20U-1

[drschmidt]

Hven't been lazy, but as a model looks just the same after being painted with clear coat, I skipped the photos here. Now the RC equipment. And because of the detailed planning and the good tools, that works out quite nicely. Drive train, servos and pressure switch are installed:







Der Druckschalter sitzt in einer Plexiglas-Klammer und passt saugend an seinen Platz:



The drive trains are installed. Everything is quite "heavy duty". The Rabösch couplings can move along the shaft direction so that there are no unwanted forces due to differential thermal expansion of different components.



The servo linkages are sealed with rubber bellows. The additional stuffing box is there for the case that the antenna has to be route outside the pressure hull:



The linkages at the planes are an extremely tight fit. No space to waste. Only doable with self-made aids and tools, e.g. an extended hex-wrench:



And as soon as the lid is closed, no sign left of the finger acrobatics involved:

[drschmidt]

O.K., I have a week full of soldering and cabling behind me. Everything is installed! A little overview:



In the front the 4S 4100er LiFePO main battery and a 1600er LiFePo receiver battery:



In the back the servos, pressure sensor, motors and piston tank control with Hall sensor:



All cables are tightly secured so that they cannot be shreddered by the outrunners:







The brushless peed controllers fit next or into the piston tank control:



In the front the Corona receiver and the cable harness. Eberything with ferrite cored for interference suppression:



By now everything sis also programmed and calibrated. Seems like it's almost ready for the first wet tests....

[drschmidt]

The first test showed, that with the original position of the balast tank, there was no way of getting the boat trimmed right. So I had to rebuild the inner structure. Did it and now the boat is trimmed well. Nevertheless the waterline is about 1,5 cm too high. That issue can only be solved with a wtc and a new boat. Well, that's why I have made molds.....

Cheers Andreas

[Ralph --- SSBN 598]

"The water line is about 1,5 cm too high"
======================
Meaning ?

1. boat sits too low in the water = reduce weigh by removing material in boat above the waterline...usually under deck or in sail.
Scraping small areas of hull insides or drilling dimples in areas that are vertical so air is not trapped.

2. boat sits to high in the water = adding weight in bottom of boat usually on center line as near to the keel as possible and centered as needed to keep boat level in submerged trim.

[salmon]

I suppose if it is still to heavy, maybe cutting more holes in the trays and bulkheads might lighten the sub a bit, maybe even a smaller battery? Have you worked out how much you need to lighten the sub by? Of course I am assuming that is what you meant that the waterline is 1.5 cm to high. Like Ralph there are a couple of ways to interpret the meaning. Taking some equipment out and testing the water level until it sits right (maybe not level) will at least give you an idea of how much needs to be removed (weight of the removed equipment).

[Stephen Vick]

Beautiful work! This is nearly exactly how I plan the equipment tray on my U 2513....

[drschmidt]

Weight is not the issue. There's too much volume above the waterline which causes too much lift. So I have to set the boat deeper, deeper than the design waterline. Well, it works now, but building a second boat with a wtc will finally solve the whole issue.

[JWLaRue]

There's too much volume above the waterline which causes too much lift. So I have to set the boat deeper, deeper than the design waterline.

Can you clarify what you mean by that? Are you finding that the part of the boat that is above the waterline is buoyant and thus causing (too much) lift?

-Jeff

[Stephen Vick]

I think I can see what his problem is... Simply put the boat sits too high in the water (it is confusing because most of the time the opposite is true) Perhaps if he added some weight, then adjusted his piston tank to compensate? Or as he said, simply rebuild using a WTC... Wet hull boats are so much easier to trim... Either way, the work is beautiful!