I thought I had posted these already

This project came out of boredom in the first lockdown last year. I was going through some old paperwork and found the May 1980 Model Boats magazine which include a full-size plan of 70’ MGB by Graham Parkinson along with detailed construction notes. A first I was simply curious and read the article thinking that it was fairly easy and simple build. Then tidying up my workshop I started thinking that maybe I had enough left-over balsa and other bits to build this MGB. (boy was I wrong) I duly ordered the required balsa wood from SELEC not knowing that there was worldwide shortage caused by the pandemic and China buying up all the balsa it can for its wind turbine blades.
The drawings for the keel and bulkheads are re drawn with AutoCAD, printed out full size, cut out and stuck to the balsa with spray glue then cut out with the band saw. I found the most daunting to be cutting the keel to take the prop shaft as this has to be at the correct angle as well as being in the right place. Plus it dissects the keel which makes it much weaker. To overcome this, I designed and 3D printed a bush that not only held the two halves of the keel together it also holds the pro shaft at the correct angle. All this was epoxied in place and it fits snugly at the bottom of hull between bulkheads
The rest of the hull was constructed as the article described until it came to finishing. I used the described method of pouring in fiber glass resin to waterproof the inside. The article says that he used tissue paper and sanding sealer to finish the outside of the hull, a method I had never used so I thought I would try it. The finish was very acceptable and quite easy to achieve but it became apparent that it would not be hard wearing enough and dented easily.
I have used epoxy before for the hull but found it to messy, difficult to apply and didn’t get uniformity across the entire hull, so was put off using this method again. However I have recently come across a product used by 3D printers to finish their work straight off the printer without the need for sanding. XTC-3D is a two-part epoxy coating that mixes easily, is put on with a foam brush and dries to a self levelled uniform thickness.
Working time is around 30mins with a drying time of 4 hours. It can be applied to most surface’s, it is transparent had has very smooth high gloss finish that takes paints well. It is quite expensive but compares with most epoxy systems available apart from the coverage which is much superior, a small amount (50ml mixed 2:1) covered the hull with 2 coats with no wastage.
I made a further deviation from the original design, it called for the deck and cabin to covered with 1mm ply. Instead I used 1mm plasticard purely to give a better paint finish. (with less work) I had decided early on that I wanted to give my model more detail but not a true scale model based on any particular vessel, just a general representation of the MGB class from WW II.
The use of a 3D printer has been a god send in this build producing many bespoke parts not readily available particularly with the gun turrets. 1:24 scale are available to buy complete but in 1:32 scale. The author of the article had used Airfix 1:35 8th army figures for his Vickers .5 heavy machineguns and scratch built a 20mm Oerlikon gun.
The Oerlikon gun wasn’t really a problem as I found one in the correct scale from Battlecrafts. The machine guns came from Gas Patch Models Greece. These are resin cast and come in a pack of 4 beautifully made with superb detail (far too much for my needs) I also intend to use Italeri 1:35 Vosper figures for crew. The mast is a little too high but as this contains the receiver arial I think I can live with it.
From the start my intention was to go fast electric since my 2 other boats are tugs (one a paddle tug) so single prop 2 blade 30mm, direct drive from a Turnigy XK2845 3650Kv In runner motor with water cooled mount, 50 amp water cooled ESC with 4 amp BEC powered by a hardcase 6000 mAh 2S2P 2cell 7.4v 35C Lipo battery The radio is a Futuba 2 channel-FHSS-2.4Ghz.
There is also a water pump for the cooling system that has its own speed controller which is uni-directional. An unintentional by product of this system is that the water pump never shuts down completely, so with the throttle stick in neutral it pulses giving little squirts of water out of the outlet as real boats do when they are ticking over On bench testing the total current draw is 7 amps so based on these figures at 35% efficiency run time should be 18 min at full throttle. If I can get 15mins + at full throttle I’LL be happy but I don’t think I will need full throttle with a no load prop RPM 0f 27010.
It is still a work in progress although it is coming along fast, I hope that it all works ok. I will keep you posted.

I haven't as yet but I will post some

During the first lockdown I came across drawing by Graham Parkinson published in the May 1980 edition of Model Boats. Its a fairly simple build and very basic with no real detail but ideal for a quick build. (or so I thought) it is semi scale (1:32) 26.25 ins. long with a beam of 8 ins. originally powered by a RS540 type motor with a plain 35 two bladed prop. It now has a brushless motor (2900kv) and two blade 30mm prop powered from a lipo 2S 6000 mAh. 35C hard case battery via a 50Amp ESC with a 4amp BEC. For a change I wanted speed so the ESC and motor are water cooled. the water is circulated via pump that has its own speed controller running of the BEC supply. This only runs in forward and with the throttle set at zero it just a sort of "put put's" while the boat is stationary. Out of the water the current draw at f throttle is 7amps so run time should be around 30 mins at full throttle. The boat described in the article is very basic but dose list a couple of reference books. I found a number of pictures online so decided to make the model more detailed. (mistake no.2)My wallet is now quite light. The main challenge was the twin .5 caliber Vickers heavy machine gun turrets. If I had built this to 1:24 scale the there are plenty of "off the shelve parts" that can be obtained, but not in 1:32 scale. The rear Orelikon gun however is available in 1:32 scale. The Vickers guns are available from Gas Patch in Greece again expensive but very good resin cast in a four pack.
I had just bought a 3D printer so it was put use printing parts in PLA that could not be bought. In the end I have become quite proficient with Fusion 360 3D design software Cura 4.2 and Meshmixer
At the time of writing this I have just painted the hull and it is waiting for its final top coat. I deviated from the construction method in magazine and gave it 2 coats of XTC-3D epoxy, expensive but its the best I have used for this job (50ml's in total for both coats) and it gives a really good finish.
I am not after a true scale model but a good representation. I will be using a basic 2 channel radio with no frills

A bit of confusion over what i wrote last night (note to self dont mix the internet with rum) I did not use a piezo unit, I used ultrasonic units, the kind that are fitted to fire places to produce the smoke and flame effect. The water depth seems to be the critical factor in the amount of mist produced. I am not looking for masses of dark smoke just enough to simulate diesel exhaust. This was just a prototype that works quite well but I am going to revisit it and try to improve the output and look for an ultrasonic unit that will work at 12v

I have made a smoke generator using a piezo transducer and a P68s variable speed brush less fan controller from action electroncs. The transducers tend to be 24v dc and are relatively cheap (£2-£3 each). I am using S3 lipos so I only have 11.4 available but a very cheap variable output unit gives me 24v. The fan is connected in-between the receiver channel for the throttle and the speed controller. The fan speed increases with the throttle and follows the throttle speed regardless of direction. The net effect is quite pleasing for diesel exhaust simulation, with a steady stream when the stick is centralised and the fan just idling. On fwd/rev throttle movement you get an increasing amount of exhaust dependent on speed. I have this installed in my Forceful paddler with twin funnels. The effect is quite realistic but can be difficult to see. I am looking for a another transducer that will produce more vapour. in its present configuration it will run for around 3 hours before topping up is required.

Your probably right about the motors i just thought why not try them, might be an expensive mistake for no real advantage apart from speed and maybe a little quieter. Thanks for the advice about bracing I'd not thought of that it may be a little flimsy.

I'm considering Model Slipay Tamar Class as my next project. I have never used styrene before (other than Airfix in my youth). Every article I have read on this model have used a twin Speed 600 ECO set up. I am toying with the idea of brushless but have no idea where to start in terms of equivalent motors etc. any idea anyone?😁

I tend to use LiPo's but they can be temperamental and need the correct charger. They are smaller and lighter than NiMH and give you a much greater output. NiMH are similar in size to LiPo but are heavier and will not have the same sort of power available. Lead acid are the easiest to use in terms of charging but are much heavier and larger then the other 2 types but tend to be cheaper. Lead acid are a good option if you need the ballast or are not limited on physical size. Cost is also a consideration a good quality charger can be an hefty investment but will serve you well and if you buy the correct type will charge/discharge any battery type that you have. I have heard horror stories about LiPo's bursting into flames, which my son did with his RC car. this was down to him not understanding this type of battery. I have not had good results in terms of endurance with NiMh but Lipo's if correctly selected will last much longer, a word of warning here though, they will stop working suddenly with no indication like running slow etc so if using LiPo's you will, need an alarm on each battery. Lead acid is much easier to in terms of Voltage either 6 or 12v with real problems when connecting them in series or parallel for use or charging, a little harder with the other two types but not impossible. This has probably confused you even more but I am sure you will come the correct battery. I have to confess I have an interest in this build as I intend it to be my next project👍

Your probably right but it just annoys me that I didn't do anything about the noise at the time of contruction

I have recently constructed a rotating radar mast for my 1:48 scale paddle tug "Forceful" I have used a geared 6 volt 60 RPM motor which gives a realistic scale rotational speed. it is a little noisy but only when close up. it is driven by a direct shaft running up the centre of the mast not prototypical but gives a pleasing effect. I may rebuild this at a latter date to eliminate the noise

It may be a transmitter/receiver problem or it may be in your drive setup that rears its ugly head once your on the water and your motor is under load. I had a similar problem with a twin motor setup which was fine out of the water but after 10 mins in the water I would lose drive to one or both props or one would slow down and just go round in circles (very embarrassing). I had no problem with radio setup so it had to be in the drive chain. I ended up changing both motors for ones with more armature poles, higher torque output and a different gear ratio. it also highlighted a problem with my first choice of battery which quite frankly were pants and used to produce similar symptoms as you describe. I now use Lipo power packs, they do have disadvantages but you can not knock the power to weight ratio. The main problem I was having appeared to be down to the 3 pole motors that were fine until they were under load, this caused the motors to overheat which in turn increases the current drain on the battery's, the net result is the motor starts to arch across the commutator and effectively becomes a dead short which in turn shuts down your ESC's or drains your battery's very quickly. As you probably know if this was to happen with Lipo's there would be no need for a smoke generator! Of course this only applies to brushed motors if you are using a brush-less motor then it will probably not help you.

This boat is still under constrution (Ive still to finish "Shell Pioneer") so a lot of the above is only guess work however a bench test at full throttle, with sound generator, amplifier and smoke generator operational it drawing less than 3A. The majority of this was the smoke generator with the drives only drawing 0.25A (under no load) so if these figures do not increase too much once in the water i should get a much longer running time from my 2 lipo packs (Motor: 2xMFA970D161LN) (ESC: action elelectronis dual 10A ESC/mixer) (5/10)

I am so pleased to see this blog as I am also in the midst of building my own "forcefull". Your build is much further advanced than mine so hopefully I may be able to pick your brain in future about the many problems that I am bound to encounter. Your drive system looks much like mine apart from I am using 2 x 540's low noise motors with built in 16:1 gearbox and the final drive being belt drive reduction giving me a maximum no load rpm of 230 on the paddle rims. I am using an action Electronics dual mixer & ESC's in tank steer mode for speed control. I don't know how it will handle exactly in this mode but I do have the option of a conventional mixer mode with a rudder servo. At the moment my paddles are not feathering, this is just for getting in the water quicker and will be replaced in time when I can access to a lathe to make the ecentrics

Dose anyone know where I can get or have for sale a hull for this boat I would be grateful for any help in my new build.

This is my first working RC build but here goes. A bit vauqe about the fiqures because we are still on the slipway. it is scratch built from the Phil Thomas drawing "Shell Pioneer" Twin prop with Kort nozzle steering, bow thruster, working fire monitors and lights. Throtle & steering control via Action Electronics P40E mixer. 2x 2S25C4000mA lipoly's. 6 Ch radio (4 used). draws around 4.5A hope to get 30min run time minimum. Third ESC for bow thruster. (Motor: 2x MFA940051LN) (ESC: 3xViper 15A) (5/10)