HMS MIMI 1915 by Ras Ambrioso - FINISHED - Scale 1:24 - Fast Motor Launch

[Ras Ambrioso]

Introduction  

This will be my third model build log posted in this forum and my second scratch build. During the previous builds, I have become attracted to fabricate, to scale, the details of the model at hand. And doing this has directed my attention to look at the evolution of the engineering of these ships and their contribution to history. This research has been just as rewarding to me as the actual fabrication and assembling of the parts that make these ships so unique.

In selecting a model to build, I have favored the period just before the end of the 19^th century and after World War I. To me, these have been the times when major changes were made in both in ship building, warfare and in the methods of propulsion.

Based on my current experience with Amapá, I decided that my models would be on scale that allowed me the best chance to obtain realistic scale details. I have selected a scale of 1/24. This scale produces a model less that 30” long that helps with my display areas.

 

 

The model

My next model is a “Fast Motor Launch” named Mimi. Built in 1915 by J. Thornycroft & Co. Ltd. Twickenham, England.  During my research I managed to obtain a plan showing the general arrangement.

 

 

 

Failing to obtain more information regarding the hull lines I ordered a copy of the plans for the British Admiralty pinnacle HMS Renown. These plans were drawn at a scale of 1:16 which I reduced to my chosen scale of 1:24. However, the Renown's length is 50ft and Mimi is only 40ft. Also, the pinnace is a single motor while Mimi has two engines.

Following with my research, I found a kit from Deans Marine in the UK for this same boat in my chosen scale 1/24. Thus, I decided to order the kit and use the molded plastic hull and scratch build the superstructure, cabin, engines, and guns. I also will use some of the fittings in the kit when appropriate. 

I am doing this because I still have a lot to learn in the art of planking and I need to go through the NRG half hull model tutorial kit. But, I really wanted to build a larger scale brass and steel Hotchkiss quick firing gun at a larger scale that Amapá’s. The model also has a WW I Maxim machine gun. These by themselves will satisfy my desires to model these guns.

 

Background history

In the first year of World War One the German forces in the colony of East Africa quickly managed to achieve supremacy over the waters of Lake Tanganyika. At the start of the war there were only five vessels on the lake capable of being armed. The Germans owned two, Belgium and Great Britain the other three. The German steamer Hedwig von Wissmann was armed with four 37mm Hotchkiss Revolver Cannons. They also had a smaller armed launch named Kingani. With this armament she damaged the Belgian steamer, and sunk the two British steamers. 

In addition, the Germans had received reinforcements with the Graf von Goetzen, a 1200-ton steamer that had been built in 1913 in Germany, and then had been disassembled, packed into 5000 crates and shipped to Dar-es-Salam. She had then been carried overland through the bush to the lake and had been rebuilt. Her armament consisted of a 105mm gun taken from the sunken Cruiser SMS Konigsberg and a spare Hotchkiss Revolving Cannon taken from Hedwig von Wissmann. The Goetzen also carried an 88mm gun as well. This made her the best armed and largest ship on the lake. With this dominance of the lake the Germans were able to launch raids into allied controlled territories.

 

The British Admiralty suggested that two motor launches be dispatched to the lake to beat the German vessels. Thornycroft was, at the time, building similar boats originally ordered as seaplane tenders for the Greek Air Force. However, the needs of the Admiralty came first and two 40ft launches, each armed with a 3-pounder gun and a machine gun, were ordered. 

The launches could reach a speed of 19 knots and were powered by a pair of 100 hp petrol engines. The large gun on the foredeck had one slight flaw, the massive recoil meant that they could only be fired more or less directly ahead. If fired to the side the ship's frame wouldn't be able to take the strain and disastrous results would follow.

These two boats were named HMS Mimi and HMS Toutou. The following picture show these boats during their trials

 

 

 

The normal practice at the time was to build the patrol boats, trial them, dismantle them and reassemble them at their destination, but as the Germans had unchallenged naval superiority on the lake, this could not be done without attracting attention from the German patrol boats.

The way around this was figured out by the squadron commander, Lt-Cdr Geoffrey Spicer-Smith. Rather than breaking them down and reassembling them under fire, why not ship them whole and transport them overland?

The launches underwent trials on 8 June 1915 and, by the middle of the month, were packed abord the SS Llanstephen Castle from London to Cape Town. At the beginning of July, they arrived in South Africa. Once they arrived, they would have to be carried over 3,000 mi inland, including the traversing of a 5,900 ft mountain range. This was accomplished using local train lines and, through the bush, by teams of oxen and steam tractors. 

Photos show the transportation mode. 

 

 

And to give you a view at the magnitude of this project, following is a map of the intended route.

 

 

 

Arrived at Lake Tanganyika in late October. On the 22nd of December HMS Mimi and Toutou were launched. For the next six month these launches managed to decimate the German naval forces in the lake. They captured the small armed launch named Kingani and commissioned it into the British navy under the name HMS Fifi. The Hedwig von Wissmann was sunk and eventually, forced the Germans to scuttle the recently arrived Graf von Goetzen after removal of her cannons to be used in the shore defenses.

I also found the following book that covers this fantastic adventure: “Mimi and Toutou’s Big Adventure" By Giles Foden.  Just finished reading the book and, I can assure you that, any historian will enjoy its read. It is an amazing story combining the Joseph Conrad’s book: ”Heart of Darkness” with the Humphrey Bogart’s movie: “The African Queen”

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I am now waiting to receive the kit from Deans marine in the UK to get started. Will keep you informed. By the way, I have not forgotten my other baby: the Amapá, that will be finished shortly .

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[allanyed]

Ras,

Thank you for sharing your research on this project.  I find it fascinating and look forward to your build.

Allan

[yvesvidal]

I love your choice of unusual boats. 

 

Yves

[KeithAug]

Fascinating little subject to model.

[Ras Ambrioso]

Thanks guys. You are the reason I picked up the hobby again. 

[Ras Ambrioso]

I am still working on Amapá but wanted to keep this log alive. It is amazing the time it takes to scratch build all the tiny details of a gunboat.

The Mimi kit from Deans Marine finally arrived and the plastic hull is beautiful. Some of the metal fittings are castings and thus a little rough. My intention is to scratch build the hull from the frames up. Can hardly wit to get started in this new project. 

The kit is intended for R/C controls and there is a YouTube presentation of a finish model on action (https://www.youtube.com/watch?v=acRCBaoglus).

 

Thanks for following.

 

[Andrew Egan]

Peter Shankland wrote a book about this expedition called Phantom Flotilla, he painted Spicer-Simpson as a rather eccentric character (with some justification I believe). Worth a read. I didn’t know Deans did a Mimi. I will watch this with interest.

[KeithAug]

On 4/20/2022 at 1:45 PM, Ras Ambrioso said:

Some of the metal fittings are castings and thus a little rough.

Ras - yes they do look pretty crude. Are you planing to try and use them or make your own? The latter might be easier.

[Roger Pellett]

Ras,  The ones that you show look that they would not be difficult to make from brass.  Nicerand closer to scale.

[FrancisMcN]

Hi Ras,  You might find the thread I started on the builder's model of Mimi in Toronto of interest and my interpretation in 1/32nd scale:

 

Also I have a set of the hull lines you can have a look at if you haven't gone too far with your alternative source to change again.  Are you in a position to look in on the model at AGO Toronto?  I would have loved the chance to check whether I had missed anything important in the cockpit or the central compartment.

 

 

[Ras Ambrioso]

Francis, Thanks for the tip. Unfortunately I live in Florida quite far from Ontario. But your model looks awesome and I have wondered the same thing about the figures. I would love to know where you got them. My scale is 1/24 which is a little larger

I have very little information on the cockpit details. My plans only shows to big hand levers at each side of the helm. It also appears to have no partition into the engine room. 

I have not done any work on this model yet, other than purchasing the hull. I am still completing my other project: Amapá, a Brazilian custom cruiser scratch built in 1/64 scale. 

[FrancisMcN]

Sorry for the delay in replying Ras - my laptop developed the black screen of death so I am waiting it to be repaired and then see if I have lost the data I had on Mimi ...........

 

On the figures, they  are the result of going through all the 1/35th military figure sets I have and finding the closest match to each position - I think the 3 pdr gun crew started life manning a WW2 2 pdr anti tank gun for example.  I usually took a resin casting of each then butchered and added as needed to achieve the final result in what I guessed would be the uniform for RN ratings in the middle of WW1 Africa!  Spicer-Simpson had his own ideas on the correct rig and he is based on a highlander bagpiper.  I suspect there ought to be a couple more crew for ammunition resupply.  I left off all the canvas screens and shade on the basis that they would have been taken down when clearing for action.

 

The attached gives the best I have on the cockpit - it looks like there is a gap in the forward bulkhead allowing access to the engines.Francis

[Ras Ambrioso]

I expect to complete Amapá by the end of August  and get started on this project. My experiences with Amapá have given a lot more confidence in my builds and this model has the advantage of starting as a kit. I expect to have a lot of fun with it and to share it with y'all.

[Ras Ambrioso]

Well guys, Amapá is finished and now is resting on display at the lobby my building. So, it is time to start building Mimi. The first thing was to clean the hull to remove the mold waxes. Then I started fabricating the hull cradle.

This is Mimi in her building board:

And this is the cradle drying the glue.

 

More to follow soon.

 

 

[Ras Ambrioso]

The cradle is finished and I started  the fabrication of the propellers support brackets. These were furnished in the kit, but they are kind of rough so I am going to reproduce them in brass. But then I realized I had to set the shafts first to see the layout and get the right angle on the supporting shafts. Following is the dry fit of the shafts using the white metal fittings

Started the fabrication of the supports after measuring the actual angle of the shafts and these are the parts.

Then, I set up my Unimat lathe  to reduce the part of the exposed shaft and tragedy ensued. After I finished the first shaft my 3 jaw chuck locked up and I couldn't get the piece out of the chuck.

I decided to proceed with the build by fabricating the hull frames that will fill the empty hull. For these I used the only plan that I have available (see my post #1).

Then I found that the Dean's hull actually does not totally match the original plans of this vessel so I have been making templates until I got the right layout.

I also reinforced the thin hull where the propeller supports and the rudder will be installed.

Then, one of my neighbors helped me with the unlocking my 3 jaw chuck and I will be back in business tomorrow. 👍

 

 

 

 

[wefalck]

Another project that I missed until today ... although I would be mentally/historically on the other side of the fence

 

[Ras Ambrioso]

Wefalck, I miss your comments and your amazing knowledge of the history of these ships. I am working on Amapá internal structure and found differences between the molded hull that I bought and the plans of the actual boat. Right now I am fabricating the two petrol engines. Unfortunately, I have found very little information on the actual engines installed in the boat. In my searches on google the closet thing I found is the following

So I am now working to replicate it (somewhere within my tolerance). Most of the Thornycroft information I found is for diesel engines and essentially later engines. If you have any better data let me know. I am trying to figure out the actual controls from the helm. 

Edited September 4, 2022 by Ras Ambrioso

[wefalck]

Ras, sorry can't help you there with any substance. 

 

Looking through my list of literature, I found a couple of references that might be helpful:

 

Anonym (1914): Nautical Terms - Motor Boats - Marine Gasoline Engines - Management of Marine Gasoline Engines - Motor-Boat Navigation - Motor-Boat Rules and Signals.-  p., Scranton (International Textbook Company). - available as eBook, but I don't have the link anymore.

 

OVERTON, G.L. [Ed.] (1926): Catalogue of the Collection in the Science Museum. Water Transport. VI. Marine Engines & VII. Marine Boilers.- ? p., London (H.M. Stationary Office). - I don't have a copy of this catalgoue, but you could have a look at the on-line resources the Science Museum in London now offers: https://collection.sciencemuseumgroup.org.uk/search/objects/categories/marine-engines?page[number]=1

 

I have also a few books on early German boat-motors, but this is likely not to be very helpful here. The (practical) pioneers for IC motors in boats were first the Danes and then the Dutch and Germans, I believe.

[Ras Ambrioso]

Wefalk, thanks for the effort and the information. I went to the Overton museum site and I found a tiny picture (thumbnail) of the type of engine arrangement similar of what I need. Since I am not building this model for a museum or for historical accuracy I am going to go with a "representation" of what I think the engines would have looked like.The thumbnail I found follows

.

Very similar with the arrangement I have seen. Thanks again.

[Ras Ambrioso]

Being working on a simile of the petrol engines. The following photo shows the various parts built.

The crankcase, transmission and starting crank support.

Cylinders, and cylinder head housings.

The engine being assembled.

The starter cranks.

 

And finally the engine dry fitted to the boat.

I also installed the fore and aft sub-decks with the marked accessories

I am now researching the engine attachments such as carburetor, magneto, plugs, intake and exhaust manifolds. Most of these will not be visible once the cabin roof is in place but, I thought that the engine would not be complete without them. I am having a lot of fun researching and figuring out what to use to represent these items.

 

Thanks to all you for the likes and comments.

[KeithAug]

On 9/9/2022 at 10:12 PM, Ras Ambrioso said:

Most of these will not be visible once the cabin roof is in place but, I thought that the engine would not be complete without them

Ras - In a few years time camera bearing nanobots will be crawling all over her, stick with the hidden detail it will soon be visible.

Edited September 16, 2022 by KeithAug

[Ras Ambrioso]

Continuing with the engines, I tackled the intake manifold using solder material that was the same diameter that I needed. I did some experiments with the soldering with some failures.

Too much solder

I refined my technique and using the same jig came out with two acceptable manifolds.

The carburetors are coming up next and I had the great idea of casting them using the same low temperature solder. As a test, I made a mold drilling a piece of hardwood and proceeded to melt the solder into the holes. So far so good.

Another catastrophe. I could not remove the lead from the mold. If I make the mold out of metal, what can be used as a mold release?  I am now thinking making a simile of a SU carburetor using brass tubing and lathe turned brass rods. Any suggestions?  Your comments will be appreciated

I then turned to the other end of the engine and fabricated the spark plugs.

The one on the far left shows the brass jacket that will be painted white to represent the porcelain and the nails will be clipped to fit the holes previously made in the cylinder head. I will them make a manifold where to introduce the cables and direct them to the far end of the engine where the magneto will be located.

 

Thank you for your likes and comments.

 

[Ras Ambrioso]

Well, when you are scratch building it means you have to scratch your head several times to decide how to build something. For this project I only had one sheet with the general layout and three cross sections of this boat. Deans Marine offered a kit at the scale I had selected for the model with a molded hull in styrene (?) and the materials to make a R/C model in plastic. I decided to use the hull and scratch build all the details. One my interests was to build the engines and, after a failed research, I used the information on the cross sections, several inquiries on google, and my engineering background to come with an acceptable looking simile. So far so good.

No where I could find what to do for the carburators since I had assumed that a "petrol" engine requires one. I figured that a 100 HP the engine would need a carburetor with at least a 3 Inch throat. I remembered, back in my youth, my dad had an MG-TC with a beautiful set of SU carburators. So I decided to do SUs for these Thornycroft engines. And this was the result

I developed an intake manifold (see post #22) and also fabricated an exhaust manifold. This is how the port engine looked after I finished. 

Boy, was I pleased! I went on and built the second engine making sure that the new engine was an starboard engine.

Then, another catastrophe.

 

There is barely any space between the engines to fit my contraptions. The drawings indicated that both engines were identical but the engineer in me saw that there would be no way to service these engines within the space between the engine blocks and the hull so I figured that a RH-LH arrangement would work. Also, as I noted before, the molded hull is about 1/4 inch narrower (6 inches in the actual boat) than the drawing sections shown thus limiting access even more. Scaling the actual space available between the engine mounts came out to only 12 inches available access for service. The fact that the roof of the engine room has two huge hatches led me to believe that the intention of the builder was to remove the engines for any service and that would have been very difficult by the shores of lake Tanganyika.

My solution now is to redesign the intake manifold and relocate the carburators to the front and lower side of the engine.

I am so much fun. LOL

 

[wefalck]

It seems that your head scratching had similar effect as Samantha's twiched nose (remember 'Bewitched' ?): the engines are definitely coming along nicely 👍

Edited September 23, 2022 by wefalck

[Charter33]

On 9/15/2022 at 11:26 PM, Ras Ambrioso said:

Another catastrophe. I could not remove the lead from the mold. If I make the mold out of metal, what can be used as a mold release?

Impressive work there Ras. Another material that you could use for a mould when casting is cuttlefish bone. Inexpensive and available from pet shops jewellers often use it for a 'one off' item. You can get a smoother finish to the casting if you shape the cavity by pressing into it rather than carving. I'm sure that there will be tutorials on-line out there to help you.

Good luck!

Graham

[Ras Ambrioso]

Wefalk, thanks again. Bewitched was one of my favorites back then. Look my next post for the results of the "nose twitching".

 

Graham, thanks for your advise. I never heard of cuttle fish (calamari) bones being used on anything. Learn something every day.

[Ras Ambrioso]

After my catastrophe with the carburators I changed the design to a front mounted carburetor feeding a straight down manifold. It worked.

 

The engines still need a little dressing up but for all purposes I considere them finished. They will be put aside until I finish the engine room and cockpit. The next item are the gear shift levers that will stand at either side of the helm. These were provided in the kit but following my desire to scratch build I tried to develop a simile.

 

Next I am going to tackle the helm itself. For this one I feel I will use the steering wheel provided in the kit. With the engines completed I worry about the remaining controls: throttle, choke, and the instruments: RPM, compass. Based on the models I have seen there were very few accessories to run these engines. We will see what comes to my old brain.

 

 

 

[KeithAug]

40 minutes ago, Ras Ambrioso said:

Bewitched was one of my favorites back then

Was that because of the great story line or was it more related to Samantha's hull lines?😆

[mtaylor]

3 hours ago, Ras Ambrioso said:

Graham, thanks for your advise. I never heard of cuttle fish (calamari) bones being used on anything. Learn something every day.

Once upon a time, cuttlefish bones were available in pet shops for pet birds to shape their beaks with.   My grandfather made Bavarian style cuckoo clocks and used those bones for his carved decorations.    I assume that they may still be available.  Back then, there were different sizes for different size birds.   So a pet shop or anyplace that sells pet supplies might be a good source or starting place to look for them. 

[wefalck]

Jewellery-making supply shops normally carry them (or at least list them in their catalogues).