Just a quick update today.
I have spent my available time during the past week measuring and drawing all of the parts I need to fit into the WTC tube. The main tube is 500mm long and I have drawn the ballast tube with endcaps inside. I can now arrange all of the required items into the available space so that I can determine the battery sizes. I think I might be able to reduce the length of the ballast tube by 40mm. This I have determined using the tube that Martin555 used with success. I can get even more water in my design if needed.
Tests will resume soon on the ballast system using Martin`s servo with mounted micro switch idea. I will fit two solenoid valves and possibly non return valves as well. The only real problem I would like to solve is regarding safety. I will look for a miniature pressure switch. They are around but choosing a suitable one is a little tricky.

---

I had a busy weekend planned. It was time to split the hull. It is fair to say that I had been looking forwards to having a go at this. I had made the special tools last week ready for the split.
The first job was to try to fix down the hull to a board perfectly level and rigid enough to ensure that it did not move during the cutting phase. The first thing was to find a suitable flat board, 12mm marine ply, and stick a 1” strip of sandpaper right down the middle to help to reduce the risk of the hull sliding. This done, I placed the hull roughly central on the board and marked out the positions for the anchor points for the elastic bands and screwed them in. I used standard hooks for this. The bands, two at each end, were fitted. It was surprising just how rigid this was but the hull could still slide. To stop this, I had bought some angle brackets. They were to be screwed onto the board, one each side at the centre of the hull. These proved top be very weak and I could still move the hull. A search of the garage followed to find something suitable and I came across two Krick motor mounts which were left over from the Dusseldorf motors. I screwed these to the board and the hull was rigid.
I fitted the Dremel to the special tool with four cable ties. These held it very well. I then set the height on the marker pen and tested it at each end of the weld line chosen as the split point. It was around 3mm out at one end so I placed two large washers at one end under the hull and this gave me level. I then checked to see if the hull was level across the width and twisted it until the pen made a mark at the same height on both sides using the weld line on the model as a point of reference. I them marked a cut line along both sides of the hull.
Next up was to set the height of the slitting saw using the previously drawn line. This done, I then very carefully cut the side walls taking care to only taking shallow cuts as the Polystyrene melts very easily if heated. I did this in stages leaving the hull connected at each end, behind the bands and about ½” in the centre to ensure stability when cutting the other side. I completed the cuts on both sides and then remove the hull from the board. The remaining sections still joined were then carefully cut with a 12” hacksaw blade. Success!! I had two pieces.
I then roughly cleaned up the cut joints and placed the two halves together. It was good.
Finally, for today, I made and fitted a support brace at the stern end of the deck piece as cutting into two had left this area weak.
Next time I will improve the cut surfaces, put locking devices on the deck half and location tabs to aid alignment.
Thanks for reading.
Peter.

---

I quickly made the hull splitting tools today but whilst doing them, I tried to ask myself why the marking tool. If you align the two ends when setting the hull on the board, why have a line to follow when the whole idea of the splitting tool holder is to ensure a straight cut. I made one and will use it anyway.
I think I will split the hull at my factory during next week. There is much more room there and no wife to stop me doing the usual swearing.😁

The last thing to do before completing the hull was to cut all of the vent slots on the underside. I used various sized drills and chain drilled the larger slots and filed them to shape. There is still a lot of shaping by file to do but I am going to leave this for later when I am sure they will be easier to get at.
I finally took the plunge and fixed the bow and stern assemblies to the main hull section. I used ordinary solvent cement which does create a strong bond, but will reinforce the joints with Stabilit once they become visible again. The next stage was to glue on the three main deck parts. It was a bit of a struggle to line them up exactly but In did the best I could. When gluing, care had to be taken to avoid contact at the front and rear segments so that a clean separation can be achieved when splitting the hull.
Next job was to do the vertical cuts at the separation lines. I used my Dremel with a saw blade as usual. These cuts will form the end points for the main cuts.
The next job for me is, as mentioned above, to split the hull. This is quite a tricky operation and requires a couple of special devices to be made. I am lucky enough to have all the machines required to make these at my disposal. I have started by cutting up the necessary pieces of wood. I will explain all on the next update when I have completed the separation.
Thanks for reading.
Peter.

---

The last few weeks have been taken up by trying to complete the fore and aft sections so that I can complete the first part of the build and have a completed hull. At the end of the last update, I mentioned that I had broken the dive planes in half. I checked the rigidity of the remaining stub and decided it had enough strength to stay. I prepared a 15mm length of 5mm brass tube which nicely fitted over the remaining lugs. I glued a piece of 4mm diameter aluminium rod inside so that I could drill a small hole in the middle to hold the control arm. I then glued the whole assembly together and had a nice strong dive plane again. I then filed out the bearing surfaces in the main sections to accommodate the larger shafts.
I finished of the whole assembly with control arms and proceeded to fit the prop shafts and the rear bearing assemblies. This took a fair bit of fiddling and reshaping of the angled hole through the hull but finally, after a few hours, I was happy with the results. I held the assemblies in place with elastic bands and then, when happy, used Stabilit Express glue to fix and fill. I make sure that I am fairly generous with the glue so that when I tidy it up, there are no holes left behind. I glued around the prop shaft assemblies on the inside as well and got a little bit of glue on the dive plane control arm. Whilst wiping this off, Disaster number 2. The control rod came out of its hole in the dive plane. This hole is 2mm diameter but 8” down inside of the aft section. Time for ebay. I found a pair of 11” long nosed pliers for £4.50. I bought immediately.
Today I decided to finish of the prop shafts by removing the excess glue. To do this I used small full round files, 240 grit wet and dry for roughing and 600 grit for finishing. This took a couple of hours but I am pleased with the results.
Now for the repair. I used the extra long nosed pliers and tried to find the hole whilst looking up the torpedo tube. Very difficult. I then noticed that if I shined a bright LED light into the section and looked at the side, the light showed right through the side wall of the model and the control arm pin could be seen as a shadow. With this, I managed to push the rod back into place. Phew!! I will have to think of a way I can get a little fluid super glue onto the rod without gluing the dive plane rigid.
My attention has now moved to the bow section. I have decided not to add retractable bow planes as this requires a lot of work for very little gain. I have, however, decided to fix the lift mechanisms in such a way that I can add retractable units at a later date. I hope for the next update I can complete this section and complete the hull section ready for splitting.
The WTC is still under construction but I am getting help from Doug (Mr Fleet Admiral SIR) for the electronics to get it to do what I want it to do. The next ballast unit test might also feature in the next update.
Thanks for reading.
Peter.😀

---

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.😊

---

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

▶️

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.

---

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.

---