As I said before I wanted to separate the smoke from the water so I have made an outlet that will be bolted into the transom that separates the two outlets, whilst appearing to exit through the same hole. First I machined the main body having an outside diameter of 10mm and internally an 8mm diameter bore which carries the smoke out.
Into this 8mm dia there is a 5mm hole drilled at 90 degrees sideways and connects to a second body which is silver soldered to the main body, this has a 6mm entry pipe.
The water is carried out through a 6mm tube which is soft soldered into the main body. Finally an outer ring was machined; it was drilled/tapped 10BA which will allow it to be fastened into the transom. I have yet to try this for real but I see no reason for apprehension!

---

I have to thank Rob for his trail blazing manufacture of his nets as it made the process of making mine much easier.
I have made mine slightly different because early on in the build I decided to made the cabin roofs as flat and not cluttered as possible to make the painting and rubbing down much easier. So my rails that hold the nets to the roof are made to the same dimensions but are fastened to a sub board which can be attached via pre drilled pins at the very end of the build.
I cut a board to accommodate a 6 x 9 net having a spacing of 23mm squares. I tied the longitudinal ropes (WARP)to the pins and then loaded the home made “needle” which was made from a piece of 3 mm brass rod with a 2.2 hole drilled in one end to glue the rope into and the other end was machined to a point. Having loaded the needle I tied the end to a pin and started to tread the cross treads (WEFT) going through the warp tread until I had crossed all 6 warp threads and tied off on a pin at this point a dab of super glue sets the joint. This continues on 9 weft treads.
The net has now to be fastened to the cabin roof rail and the pole at the bottom of the net. This “pole” is a 3 mm dowel with holes drilled at intervals along its length. The ends are looped through the holes and back through a piece of black shrink sleeve making a secure joint. At the top a similar process of looping around the rail and securing with a piece of black shrink sleeve.finished the 1st scramble net.
“REPEAT” Sorry I forgot to show the board used to tie the warp and weft

I have laid out all the various components on a building board, not necessarily in the correct orientation/position. The only thing I do know is that water needs to come out of the 4 pipes pointing into the tin.
I have a caravan pump serving as a water scoop (to simulate the water pickup as the boat moves forward) any water going through the system into the tin is piped back into the container under the bench where the pump is.
First thoughts are similar to others in that when the fire monitors are operated the water is drawn back through the exhaust pipes and sucks air. To try and solve this I have put some small solenoid valves in the circuit. But first test show that they restrict the flow too much so a larger valve? Or I think the easiest solution would be to put another entry opening in the hull somewhere near the pump just below the water line on the side mid-ship so the pump can be connected directly and be primed when the boat is at a standstill (anybody see problems with this?) I think the only issue I can see is that when the boats in motion it may force water through the pump – then the monitor result – drip, drip. I think a properly designed inlet, that when in motion the tendency is to draw the air out of the system and not force water in until the boat is at a standstill when the water should just flow in. I have designed another outlet (not shown) for the exit of the cooling water and hopefully the smoke which has the water coming out of the centre 6mm pipe and the smoke exits through the surrounding space between the 6mm pipe and the 8mm surrounding hole.
(Ignore the black pump, top right, it was a first attempt at a water supply, it’s a car washer pump, but not powerful enough)

---

I’m not going to give details of painting blow by blow as it’s as bad as watching the paint dry and I’m sure most people are aware of the amount of time the preparations for painting take. So here are a number of pictures of the painting process, sorry miss the red oxide and the deck pictures. The whole boat is now complete with colour and only needs lacquering which will be done after the transfers are applied.

---

I thought I might try the simplest way to produce smoke and just reverse the “vapours” way of using a standard E cig unit. I was given a couple of units which were no longer needed and decide to modify the unit. I machined an aluminium ring which fitted around the air intake at the bottom; the ring has a groove machined internally to allow the air to circulate around the dual intake. A 4mm drilled hole which is drilled into the groove has a 4mm brass tube inserted. The brass tube connects a small pump via a silicon tube which blows air into the device. The battery pack will have to be modified to fit in the boat but this was just to prove the system. It produces more than enough smoke for my crash tender which will just have a scale amount of exhaust smoke, hopefully. I intend piping the smoke through the rear using a custom made water/smoke exit unit which keeps the two components separate, watch this space

smoker unit for model boat

▶️

---

Having trialled the various options for rotating the monitors I have decided to use the gears option. I am going to mount the servo in the roof. The cabin roofs have bridge pieces which are just about correct to mount some aluminium bars on which will carry the servo
I have reinforced the inside of the roof where the base of the monitors fit as the roof is only made from 1/32” ply, I use an aluminium disc - 25mm dia x 1mm thick . The monitor bases are fastened using three 8BA csk screws and nuts.
(I must say at this point that people may wonder why I use BA nuts, bolts and screws and not metric, it’s because I have a good range of all BA taps and dies)
The aluminium bars are slotted to take the servo and allow for adjustment and again fastened using 8BA hex hd screws and the bars are attached to the roof again using 8BA screws and into the wood! (I have successfully used machine threads into wood of all sizes, this requires the wood area to be treated, I use a RONSEAL product that is for treating rotten wood, it’s a very viscous liquid and soaks into the wood and after an hour or so it goes rock hard the tapped holes can then be clean up with a tap) I can adjust the fit of the gears to give a nice smooth rotation; all that needs to be done now is to design the water system.

---

Having created the “rotating” monitors I have to deal with the rotation mechanism and since the design requires the central tube to rotate I have a few different options to consider, they include:-
1 solid rod drive
2 Belt driven
3 cord driven
4 modified servo
5 gear driven
Having looked at the rotation of a standard servo which appears to be about 170 degrees, if I want to have something in the order of 300/360 degrees there will have to be some sort of increase in end movement.
Option 1- rod driven although very controllable it’s limited to about 170 degrees otherwise it gets locked at either end of the cycle.

Option 2 - Belt driven needed a couple of pulleys machined up this meant the large pulley was 50 mm dia and the small one was 10mm dia. The drive belt was an “O” ring. This option works very well and could be a possibility.

Option 3 - Cord driven this system is simply a cord running from the servo arms round a 10mm pulley twice (to give some grip) but between the servo arm and cord is a spring to give some tension in the cord, again could be a possibility

Option 4 – a servo modification (addition of resisters) servo this has already been shown by Graham and although an easy option for an electronics engineer a bit more difficult for me, but achievable. However for my configuration it’s not suitable as I can’t drive onto the end face of the rotating tube.

Option 5 – Gear driven would need a pair of gears at a ratio of 10 teeth to 50 teeth and some modification to a gear to fit on the servo. This was the last option to be tried and looks as if it may be the best option. The rotation of 360 may be OK but from a practical point of view I don’t need water spraying over the cockpit or front deck. So I decided to change the gear ratio to 30:10 this gives a rotation of about 280 degrees which I think gives a good spread of spray (see top view of deck).
All the prototypes were built on scraps of ply and with an old servo. Having proved my system; I will now build it into the cabin roof in such a way that the gear ratios can be changed if required.

---

Some thought has to be given how to hold all these remaining parts, firstly I need to make sure that I can replicate an upward incline since there won’t be any up and down movement, only rotation.
Here comes another jig, a simple block of ½ inch hardwood with the angle cut at 200 and the corner removed to allow all the soldering to take place.
Carefully marking out a centre line I used small brass pins to hold the pre silver soldered pipes in position on the flat sides. I now used some clamps to hold the brass pipes in place, check all the alignments then flux is applied.
Very gently apply the heat with a soldering iron until the solder flows, it’s important to tack both ends of each pipe first on each side as at this stage the set-up is delicate to say the least and can be dislodged very easily. Then follow round to complete the joints making sure you don’t overheat the whole assembly and melting the parts already soldered.
Next I need to test for leakage, if all OK I can carry on to fettle the joints, I don’t use files or abrasive paper to do this I only use a scalpel to remove any excess solder it’s so easy and better results are achieved.
This also applies to cleaning up the white metal fittings; the main posts need to have a better base with some sort of fastening arrangement made, so an aluminium piece is machined up with three holes for fastening to the roof, this was then epoxied to the main post.
The next job is to make the handles, for this I used some 3mm plate which I cut some slices off with a slitting saw. In its raw state it is hard and needs annealing before bending.
The pieces were all cut to length and then drilled in a jig to ensure all the pieces were exactly the same, I can now leave a drill in both the end holes which keeps the pieces together while they are placed in the machine vice with a piece of round bar at the back to give a nice radius.
The handles need a cross bar with “knobs on” so a little bit of machining and then the assembly can be done.
The handles are soft soldered in place at the correct distance; I now need to drill and tap 10 BA the main body pipes to hold the handles in place. When these are assembled they will be put together with some epoxy on the screws and between the faces.
Whilst using the epoxy I can glue the white metal exit pipe in place, this now completes the assembly.
Next a coat of etch primer followed by a coat of grey primer then finally bright red, these will be left to fully dry before I attempt looking at the rotary system

---

The white metal items supplied are OK but really don‘t lend themselves to being working items. Graham93 has already completed a version which looks just like the drawing and photos available, and are the best I’ve seen. The bar has been set so here goes, whenever an item like this is been contemplated it’s always good to spend some time in planning a sequence of operations and assessing the problem area’s at the start of the work and if possible dealing with these parts first. Failure of the difficult process doesn’t mean you have wasted work on other parts that are now scrap.
I think the most difficult and problematic piece is the pipework that sits at the top and curves round in two halves, this in reality is a casting, however replicating it can be done using brass pipe. Brass pipe can be purchased in annealed form; however my stock wasn’t so the first job was to anneal the tube.
Heating to a dull red heat and allowed to cool, this treatment will soften the metal completely. In some books it is suggested that the brass should be quenched in water (which is what I do) after heating but this is to speed up the commercial process, and quenching has no effect on the annealing process. So tube annealed we need some method of retaining its tubular form during bending, in plumbing I use a spring but when you compare wall thickness/dia a spring would have to be mighty strong and so small.
An easy alternative is to crimp one end of the tube and put some soldering flux down the tube, follow this by heating with a low temperature blow torch to melt solder and fill the tube, then allow to cool.
You now have a soft tube which when bent will hold its shape. That’s the next challenge, the shape, and being able to replicate it twice, so an easy jig is required.
Having marked out a scrap piece of hardwood I cut the “U” shape using the band saw and filled a groove along the top edge, this was then placed under my drill press with the appropriate dia bar (this must be calculated accurately as it helps to create the final form) on top of the tube, then just pull gently down (it takes very little force) this jig leave a small amount to finish bend to a complete a circle, the excess length is trimmed off and then I used a piece of hard wood with a small radius on the end to tap the final curve.
Next the circle needs to be cut into two pieces I used a small slitting saw in the milling machine. Now it’s time to remove the solder, simply heat up holding in plyers and then shake vigorously to expel the solder. (Make sure you do this on your own and wear safety glasses.)
The white metal “main pillar fitting” and the monitors final “exit pipe” will be used in the unit and all that is required is to mount them in the lathe and drill a 4mm hole through each and clean up the casting. Next I cut 4 pieces of 4mm brass pipe; these will form the main water passage. Two more machine turned items are the “pivot post top” that feeds water through the 2 brass pipes into the “junction block” which then feeds into the exit pipe, sounds all very simple?
Having made all the components, it’s time to think about fastening them all together. First items to be joined are the “upstand pipe” to the “pivot post top” X 2 also the “feed to exit pipe” and the “junction block” X 2, these four joints are all to be silver soldered.
I mounted them in a piece of wood and placed a tight spring brass ring around the upright pipe to stop then sliding down when heated. Having the joints spotlessly clean is paramount, the flux is added, I insert very small pieces of silver solder into the holes at the top cross holes (less is more) a gentle heat, and watch as the flux goes “glassy”, this is closely followed by the solder melting, watching at the lowest point of the joint for the tell-tale shinny liquid metal.
No fettling is required so the 4 parts are dipped for 45 minutes in masonry brick cleaner (dilute hydrochloric acid) the parts are now clean and ready for the next soldering activity. See part 2

---

Trying to juggle refit of the new workshop with keeping the build going so did a first primmer coat on the whole boat, looks good and As Im away on holiday next 2 weeks it wil give it time to harden off so any minor defects can be seen to before final pimer coat , and then some colour.
Sorry about poor quality pictures, I am working on a very old computer and don't have any picture editing facilities. (my computer totally failed and Im awaiting a new delivery so maybe off line for a while)

---