I have decided to leave the ballast system for now. I am confident that my pressurised system will work very well but I have to source a much stronger solenoid valve. Ideas on this would be welcome but weight must be a consideration along with the tube connection size.
I have turned my attention to the main build. My aim for this session was to complete the aft section and cut all of the weight reducing sections. The first job was to place all of the decking parts and forward and aft sections into place using tape and mark all around with a marker pen. The parts were removed and another line drawn about 6mm (1/4”) inside. This is so that any removed material will not be visible once the deck is fixed back into position. Lines were then drawn about 12mm (1/2”) each side of the hull half connection points and the large areas cross hatched to avoid mistakes.
Time for the Dremel. I fitted the Dremel with a 25mm (1”) diameter 0.8mm (1/32”) rotary saw blade and very carefully cut all of the sections out. To join all of the cuts together, I used a 300mm (12”) hacksaw blade. Great care had to be taken with this process not only to avoid a visible cut, but also not to remove a finger. Regular counts were taken on fingers just in case.
To complete this task. I carefully removed all of the plastic burrs with a needle file. These are quite severe with Styrene but relatively easy to remove. I was happy with the results of this cutting.
The next item I addressed was the aft section. I had to try to assemble the two halves whilst installing the rudder, aft planes and their operating rods and connectors at the same time. I had previously made the connector rods and had carried out successful trials whilst holding the parts together with elastic bands. The time had arrived to glue the halves together with all of the parts in place. I assembled all of the parts again with bands and started to glue a part at a time. Disaster. I broke the aft planes in half. I was trying to be clever and keep this part in its original supplied condition and ignored previous builds that had strengthened this part. Not a good idea. I now have to try to repair this part and put in place even though both halves are now glued together. This is a job for the next update.
Just a reminder, if anybody knows of a solenoid valve that fits the requirements, help would be greatly appreciated.
Thanks for reading. Peter.😊

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Well, I have finally taken delivery of all of the parts for testing my ballast idea. I used Martin`s idea for operating the reversing action of the pump which will eventually be operated by a small servo. This uses two micro switches wired such that the pump will operate in opposite directions dependent on which switch was activated. I have included a picture of his wiring arrangement. If you press one switch, the cylinder is filled. Press the other, and it pumps the water out. I have a solenoid valve to shut the water supply pipe down as soon as the pump is switched off. The problem I have though is how to wire up this valve so that each microswitch operation opens it. If I wire the solenoid up using the common on both switches it is in short circuit. I need the positive of the valve always to be positive. With this switch arrangement, the common terminal alternates between positive and negative. How do I wire it Doug!! The water leaks out through the pump without it.
Putting this problem aside though, the system worked perfectly. The pump managed to fill the tube about 60% before labouring. I think this will be more than enough to submerge the Submarine. What do you think Martin?
Hopefully one of you electronics guys can give me a simple solution to my solenoid valve problem. Next job is to make the assembly much smaller.
I have done a small video of the test which I hope to upload.

Gato Ballast Tank Trial

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The prop shafts and propellers arrived which now gives me a lot of things I can do to forward the build. I decided that the best way forwards was to complete the rear section, which includes the stern planes and the rudder and their operating system. The hardest part here was to mark out the cuts ion the hull halves accurately. I then used a Dremel to remove the excess material and loosely fit the shafts. As the tubes are not long enough to reach the rear bearings and skegs, I have had to turn, drill and fit some phosphor bronze bushes to act as rear shaft bearings. I hope that vibration when turning does not pull the parts off of the main hull. After this, I fitted the stern plane and rudder to check for function. There was a little resistance so I removed more material from both halves until free movement was achieved. I then turned my attention to the actuating mechanisms which would be connected to the servo rods. I had an old servo arm so I drilled part way through to a flat bottom, turned a wheel collet down and press fitted it in. The picture shows the completed arm. I will remove the excess arms when fitting them. This controls the rudder. For the stern plane, I heated up a rod of 2mm steel and flattened it to about 3mm wide. I then drilled a hole in the end to fit an aeroplane elevator/flaps connector as pictured. The next thing I will do is to assemble all of the parts and glue the two halves together. This is a job for next week. I want to do a ballast tank test this weekend.

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Just a small update today.
I have just completed the test ballast unit. The end caps are held in with fabricated bolts so I do not expect problems here. I do, however, expect problems with pipes blowing off due to the pressure I am going to create in the tube when water is pumped in. I will order some clips to try to solve this potential problem. I expect them to arrive during next week. Tests will begin next weekend. Just enough time to purchase water proofs and an umbrella.😊

I have started work on the Water Tight Compartment this weekend. I have started by turning the end caps for the internal ballast tank and then made two end caps for the 70mm diameter by 2mm wall section main WTC tube. The internal ballast tube is 60mm diameter with a 4mm wall section in case I want to pressurise it. I have yet to determine the exact ballast system I will use. I am trying to cover all bases so that I can make this final decision later.
I have now assembled the ballast unit and all looks good. I have made a test tube about 80mm long to test the main WTC tube and caps. I had a little trouble keeping the o rings in place as the thinner wall tube has distorted slightly and is oval. I filed a chamfer at each end of the tube to help the rings squeeze nicely. This improved the situation and all was looking good,
Earlier today I tied the test WTS to a brick with both end caps in place to check for leaks. I then lowered it to the bottom of a water butt and filled it with water. The unit was left there for 90 minutes. On removal I was pleased to see that there were no leaks. The depth was around 50cm.
I have now decided to ballast the submarine in one of two ways. The first is to have a reversible water pump and a motorised valve. The pump would both fill and empty the tank with the valve opening and closing the entry pipe. The air inside the chamber would be pressurised so my concern would be the capability of the pump to have enough power to overcome the back pressure created by the air compression. The second possibility would be to have the pump fill a bladder inside of the ballast tube. This would mean that the inner tube need not be water or air tight so the air would not be compressed in the same way so the pump would not need to be so powerful.
The pictures show the production of the end caps and the assembled unit. The test tank is also shown. The ballast tube with the end caps fitted inside the WTC tube is also pictured.
The prop shafts have been delayed by 8 weeks in Hong Kong even though they said they had sent them to me on 12th June. Royal Mail informed me that they were finally sent on 23rd August. I can continue with the main model build on their arrival. This is important so that I can establish exactly how much room I have for the WTC.

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This weekend I decided to do more work on the Gato Submarine. Now I am starting to realise how big this job to build the model is, let alone the WTC which I am thinking about and starting to plan in tandem.
I have been working on the stern module today trying to get the rudder and aft planes in a working state. I have followed the video made by a kind soul on the internet which I am finding very helpful. To make them fit properly has resulted in a lot of filing and reshaping particularly on the rudder. All of the edges were interfering all over. After a considerable amount of adjusting, they now fit and work perfectly. A hole was carefully drilled right through the height of the rudder to allow for a shaft to be inserted for operation. Small holes were also drilled through some waste material to produce two running bearings for the rudder shaft.
There has had to be a considerable amount of material removal inside the stern module halves to allow for the planes and rudder to work. This was done using a burr in the Dremel and files. Great care was taken not to remove too much and go right through the part.
I am having a little problem with warpage of one of the stern halves. You can see the gap between the parts in one of the photographs. It might be that they will glue together without incident if I fix them well with bands during curing. Does anybody have a cunning plan to straighten this part before gluing?
I have purchased the propeller shafts and tubes so further work on this module will continue when they arrive, probably towards the end of July.
I have now purchased my chosen motors. They are MFA 360. I have also ordered the raw materials to make the motor mount and servo trays. I wonder if I have to put the usual three suppressors on the motors if running a 40Mhz transmitter.
Next time I am going to work on the bow planes. I will have them working and retracting. I bought the gears for the retracting mechanism today but have found them to be too big on diameter to fit two side by side in the bow module. The gears are perfect in every other way so I think I will reduce them to quadrants which should fit nicely. More cad design work for me I think.

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Just a small update today as I have been spending most of my available time on the Dusseldorf.
Over the past week I have glued the two main fuselage halves together and then tidied up the joints.
There is a lot of interest in Submarines in the USA and one particular modeler has created some very helpful video blogs of his build. I have been watching these which has taken up several hours. I am now getting an idea as to how difficult this is going to be.
Within the videos, you can see a very useful stand has been constructed to aid the build. I just had to copy it using toilet overflow parts. The sub rotates nicely on the rollers.
I have to try to find some materials for the retracting bow planes next which I think will be my first real challenge. Next update might take a few weeks.😀

I am about to start the most ambitious project to date. This one will be running alongside the three others currently on the go, The Police Boat which is nearly completed, The Dusseldorf Fire Boat which is well underway and the PTB upgrade.
My intention is to change this Revell model into a static dive radio controlled Submarine. I am lucky that Martin555 has agreed to help whenever I get stuck which will be invaluable since he has already almost completed the same.
I started by purchasing the model from Amazon for less than £50. I have also purchased the water tight tube for the electronics. I will make the end caps and sealed internal plugs from some 80mm diameter nylon I had at work. It will now come in handy that I am a toolmaker and have a considerable array of machines at my disposal.
I will turn the plugs next week and find suitable o rings.
I have started to prepare the hull. There is an enormous amount of work required to adjust the standard kit. A lot of cutting and drilling.
I have prepared the split lines and glued in the alignment pegs.
I have ordered suitable shafts and propellers from the USA. They should be here in a couple of weeks.
Next job is to stick the two halves together and start the cutting.

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