The remaining hose fittings are the male & female connectors and fortunately require nothing more than drilling to take the four short brass ‘turning handles’ which were soft soldered in place and then filed to length.
The suction hoses themselves proved far more difficult to make to a satisfactory standard and after several experiments with different gauges of copper, steel and stainless steel wire I found a 1.25mm galvanised ‘garden wire’ that proved malleable enough to be formed into a long coil spring that when covered with some black heat shrink tube looked OK.
I used a length of 8mm diameter aluminium tube as a former and hand wound the galvanised wire tightly around the tube to form a spring. This was a painful process, quite literally, and caused blisters on my thumb and forefingers despite wearing protective gloves 😭
The springs were then stretched out on the rod to space the coils evenly and then drawn through the heat shrink tube, and then a heat gun used to shrink down the tube onto the springs.
While the newly formed hoses were still warm and pliable I put them on a former with the correct curvature and applied a little more heat and then left them to cool and set.
The hoses were made over length so that, when finished, I could trim them to the correct lengths to fit into the rear well of the boat with the fittings attached.
See part 4 for the final assembly...coming soon.

After test fitting the hose ends to establish the correct lengths the hoses were trimmed to size and the fittings were then glued into the hose ends with some epoxy.
On the real boat the hoses are arranged to lay on the tops of the foam tanks and they are supported on the stern coaming by a bronze hook.
I formed this hook from some brass sheet so that it holds the hoses firmly one above the other, this was primed and finished in gunmetal grey and fixed to the coaming with a couple of brass rivets and a spot of epoxy.
For a bit of extra security I cut some large diameter heat shrink to form some bands around the hoses to hold them together.
So now the hoses are all finished and I think they look really good, I’ll probably re-polish the brass fittings and apply a light coat of lacquer to keep them nice and shiny at a later stage 😎

The switch panel and wiring loom was made, tested and dry fitted a while ago and so it only needs securing to the bulkhead with four fixing screws, the two NiMh batteries were strapped down to the bearers with cable ties as close to the chines as possible and the XT60 connectors mated.
I have read that placing the heavy batteries as far away from the keel as possible improves the handling, all other heavy items are centered along the keel for symmetry and should help the boat to sit evenly in the water. I’m not sure if I will need to do any ballasting, hopefully the maiden voyages should give me an indication.
The prop shaft was greased and fitted, and with the prop, thrust washers and lock nuts in place, the clearance was adjusted and locked with some Loctite so the motor could then be installed.
The initial motor alignment was made with a solid coupler which was then replaced with the universal joint, I took the precaution to grind a flat on the motor shaft so that the locking grub screw has better grip on the shaft.
The grease tube was then fitted to the shaft clamp and secured to the side of the switch panel.
The ESC was fixed to the back of the bulkhead with another couple of cable ties and the input cables, again XT60 types, and the three pole XT60 motor connectors mated.
I have also fitted a Turnigy in-line volt, amp and watt meter in the circuit before the ESC so that I can log readings in case of spurious fuse blowing issues or unexpected battery life problems.
The water cooling tubes were then run from the water pickup, through the ESC and then back to the transom ‘exhaust’ outlet, all water connections are fitted with spring clips to ensure water tight connections. I have used quite a large bore silicone tubing to ensure maximum water flow and made sure that all bends are kink and compression free.
The R/C receiver is fixed to the rear cabin wall with some Velcro pads for easy removal, the two aerials were fitted in some plastic tubing at 90 degrees to each other as recommended for 2.4 gig systems and as high above the waterline as possible.
The receiver is connected to a separate 4.8 volt NiMh battery via a changeover switch that also has a charging connection and LED power indicator, and I have also fitted a battery voltage indicator, just because they are cheap and convenient although the R/C system that I have has telemetry that reports RX voltage as standard.
The battery charger I have chosen can handle the 16 cell series configuration of the drive batteries and so they can be charged in-situ when the main power switch is toggled over to the charge position.
The RX and lighting batteries are charged separately.
All of the servo and lighting switch cables are routed through the hull to the receiver through pre drilled holes in the bulkheads at high level for neatness and to retain the integrity of each compartment just in case 😲!!.
The servo and cables and the water cooling tubes are strapped to a supporting bar between the bulkheads for neatness and security.
With the TX switched on first, the RX is then powered up and the main power switch toggled to the ‘operate’ position, the ESC then gives a reassuring series of bleeps that confirm that all is well.
The ESC was set up using a Turnigy programming card specifically for that model of controller and if required I can tweak the settings once the boat has had a few sailings.
The last things to do now are to fit some strong magnets to hold the hatches and roofs down securely and then finally raise the RAF ensigns 😁

Having spent so much time adding fittings and detail to the removable cabin roofs and hatches the last thing I want is for them to be dislodged and see them sink without trace 😱!
Having used some amazingly strong neodymium magnets to hold the foam tanks securely in the rear well I was confident that they would be more than powerful enough to hold the various roofs and hatches in place so I scoured eBay for some suitable sizes and shapes.
I settled on two sizes, 25x6x3mm and 12x6x3mm and ordered 10 of each, more than I need but so useful to have in the bits box.
A word of caution with these magnets, always slide them apart and avoid letting them crash together as the impact can easily break them into pieces, as I discovered. Thankfully I have some spares !
For the engine roof magnets I made a couple of small plywood brackets into which the larger magnets are fixed with epoxy and these were in turn epoxied onto the inside faces of the engine room walls.
The mating magnets were let into the underside of the roof frame and firmly glued in place after double checking the mating polarity and orientation.
An identical method was used for the forward cabin roof but using the smaller magnets.
For the removable panel in the centre section over the motor I used a single pair of small magnets on the rear edge only as the front of this panel is held under the cabin door in a rebated part of the floor that forms the threshold of the door.
I had to fit a small brass handle in the rear of this panel so that I could pull the panel up and away as there is no other means of doing so without, I made a ‘hook tool’ from some brass wire for this purpose.
The floor panel in the rear cockpit is secured on it’s rear edge by a pair of the larger magnets, the forward edge being held down by the towing hook bracing stays.
The removable hatch in the rear cockpit floor was also fitted with two pairs of the smaller magnets let into the underside of the hatch and the hatch framing of the floor. One of the brass handles that I that had previously set into the hatch was bent up slightly so that I could use my brass ‘hook tool’ to release it from the magnets hold.
So now all the roofs and hatches are firmly secured by the concealed magnets and are easily removable without any fiddly catches or fixings and now there’s now very little chance of them coming adrift and disappearing!
The final finishing detail are the two RAF ensigns, one on the mast and one on the stern flagstaff.
The ensigns were made by Mike Allsop Scale Flags & Ensigns who was very helpful and advised me on the most suitable sizes for the 1:12 scale of my boat.
His flags are extremely well made, excellent value for money and look very realistic when flying and fluttering !!

Mike can be contacted at: scaleflags@outlook.com or by telephone on 01476 573331

They are hand made from a fine and flexible silk cloth that behaves like a real flag even in a slight breeze and are easy to fix with diluted PVA glue. The smaller flag was fitted to the lanyard on the mast as described in the supplied instruction sheet.
The ensign on the stern flagstaff was very carefully formed and glued so that the flag was not fixed in one place and could rotate around the shaft of the flagstaff as this piece screws into a brass fitting on the rear deck and this will ensure that it will always find it’s own position.
A small brass ring was formed and glued to the flagstaff below the ensign so it would always stay at the top and not slip down.

So, all hatches battened down, flags raised and ready for action.

That’s just about everything finished now barring any trimming and ballasting required and is ready for it’s maiden voyage.

I hope that all of you that have been following my blog have had as much enjoyment reading about my build as I have had in the building and finishing process 😁

And a big thank you to all that have contributed so much with encouraging comments, suggestions and advice 👏 😍

In preparation for the first public showing of my boat I have made a new display stand that looks a bit prettier than the first one I made.
It’s designed to be more in proportion to the boat and to give a better view of the hull and I have included some model-boats.com stickers that are available in the site shop and also some Vintage Model Works logos kindly supplied by Mike Cummings at VMW 👍

As a finishing touch I have ordered an engraved brass plate giving some details of the original craft.
I also found a wheeled flight case on eBay that the boat fits into perfectly without any adjustment to the existing foamed interior but I will have to re-make the mast to allow it to fold down for safety, not bad for £50 😁

The new stand fits into the base of the flight case but the boat also sits on some foam blocks for added support.

It’s been a while since the boat had it’s maiden voyage on the lake at St. Albans and I’m pleased to report that it looks really good in the water and goes like stink if you open up the throttle.

Sadly I still don’t have any decent video of the boat yet as I can’t film and drive the thing at the same time, but I do have some static wide shots from my GoPro.

When I do the video I’ll ask a cameraman mate to do the honours, maybe I’ll put the GoPro on the bow and then the stern to get some low action shots…the storyboard is already building in my head!!

These early runs were great as they showed up some minor problems that needed attending to.
I found that it needed ballasting slightly as it was not sitting on the waterline evenly from side to side so I flattened out some old lead water pipe and cut it into small sections so that I could add ballast incrementally.
I did this in the ‘domestic test tank’ and once I was happy the lead pieces were fixed in place inside the hull with some super strong double sided tape.

The ESC needed a little programming adjustment because I had forgotten to set the low battery level point to ‘off’ as I am using NiMh batteries and not LiPo’s , that was the cause of the short initial run time on the first outing…..DOH !!

The batteries are now held in place by Velcro straps on some bearers that I added, otherwise a battery change involved cutting cable ties and replacing them at the lakeside…not very practical.
The volt/amp/watt meter is also now on a proper bracket so that the display is more readable.
I have also changed the charging connection from the nasty Tamiya connector to a nice little panel mount XT 60 connector that HobbyKing sell, it comes with a handy blanking plug that I have drilled for a retaining cord.

I have also finally got around to upgrading the firmware on my Turnigy i6 radio to the 10 channel version so that I can assign the lighting to the switches properly and have the rotation of the searchlight on one of the two rotary knobs.

I can use the old 6 channel RX in the new boat….blog coming soon.

Since completing this model have started work on a new boat and I promised those following my Crash Tender build blog that I would post an update here.

The new model is a ‘Thames River Police Launch’ constructed from a kit by Vintage Model Works.

The new blog is here:
https://model-boats.com/builds/view/47891

I'll try to update the blog regularly as I have plenty of 'photos detailing the construction since June 2018.

I hope that you will enjoy following this new build and I welcome all comments and suggestions...... and if you like the updates please hit the 'like' button 👍

Robbob.

I’ve not posted anything on this blog for quite a while as I have since moved house from London to Buckinghamshire into a ‘new build’ house with an internal garage which I have finished converting into my new workshop. With all of the business of settling into a new house out of the way I decided that it was about time to get back to some model engineering.
First job, some much needed refurbishment of my Vintage Model Works 46” RAF Crash Rescue Tender.
I’ll be posting updates on that in a short series and I hope you will be interested in how it went……

On the last outing of my crash tender the run time from a fully charged set of NiMh batteries was very short and I had to bring the boat in after only a few laps of the lake. I changed the batteries over to my second pair and tried for another run but the performance of the boat was similarly disappointing.

Those NiMh batteries are now about 8 years old and despite regular maintenance charges are clearly not capable of delivering the power required for the boat to perform as it has previously.

It’s clear that the batteries are in need of replacement and it is also a good opportunity to move to a better battery chemistry. The obvious choice is LiPo and so I began by finding a battery of the right voltage, capacity and most importantly, size.
The old NiMh batteries were 9.6 volts each and wired in series to give a 19.2 v supply and they were placed either side of the prop shaft to give the correct balance, however I was confident that a single LiPo would easily do the job of the two old batteries but to maintain the balance of the boat I would either need to make up a dummy battery of equivalent size and weight to maintain the equilibrium or put in two new batteries.

I decided that the simplest, although more costly, way to proceed was to have a second battery in the hull that I could change over to when required.

My research turned up a suitable battery pack made by Overlander, a 5C LiPo at 18.5 V and 5000mAh capacity, and not only was it almost a similar size it was also a very close equivalent weight to the old NiMh pack. However I would need to make some alterations to the battery compartment to accommodate the difference in height of the LiPo packs.

As one single new battery was more than adequate to run the boat it meant that I could retain the existing wiring harness without modification as I did not want to have to incorporate any kind of changeover switch to facilitate a battery change, I would simply do it as a plug swap.

I purchased the new batteries from my local model shop. Yes, I do have one nearby I’m pleased to say!
Al’s Hobbies in Volverton, Milton Keynes is quite close to my new home and it’s a delight to go there to feast on the aroma of a traditional model shop.

Older readers will know to what I am referring to!

With the batteries back in the workshop I was able to make some true comparisons between the old and the new packs to confirm their suitability.

In the pictures you can see the battery compartment with the NiMh battery supports and Velcro retaining straps that will need modification.

Also the comparative size and weight of the old and new batteries and some wiring and cooling ‘plumbing’ that will have to be removed to make way for the new battery set.

OK...time to get some tools out 😁

As the battery/receiver compartment was already quite crowded I decided to do away with the separate receiver battery, switch and voltage meter. The receiver would now be powered by the BEC in the speed controller. The power meter was also removed as it was seldom used to log any power parameters and it just overcomplicated the wiring loom.

The first job was to modify the battery cradles and Velcro securing straps and to remove the receiver and its associated power switch and battery voltage indicator, and also the cable loom and cooling pipe support bar that would make it difficult to put the new batteries in the hull.

After removing all of the plumbing and wiring the support bar was cut away from the bulkhead with a fine tooth saw and the other end removed from the rudder servo compartment too. Both holes were cleaned up and painted with silver Hammerite to seal the plywood and then a 20mm rubber grommet fitted into each of the old holes hole to seal the compartments. I then had to use my right-angle drill attachment to get a step drill into the hull to make new holes for the wiring and plumbing. These were also painted to seal the ply.

With the support bar out of the way I could then put back all of the servo wiring to the receiver. As I had drilled the new holes through the bulkheads quite high up I was able to tuck the servo wiring up and out of the way of the new batteries, some needed extending as I had to reposition the receiver, and I also used some new silicone tubing for the cooling pipes as they were both slightly too short after re-routing them.

After some other mods to the battery support bars and some new Velcro retaining straps both of the batteries fitted nicely into the compartment with relative ease.
Easy removal of the batteries is important as I will not be charging these new packs in-situ, although I have retained the in-board charging facility.

Next up…a bit of re-wiring and motor cooling.