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[Canterbury Coxswain]

Tiny,
Still really enjoying watching this superb build of such a wonderfully shaped lifeboat. I hope you are enjoying it as much as we are!
Kim
Canterbury Coxswain

[Tiny69]

I enjoy building all of my models, they just take me a long time to complete as I sometime have break away from them to think things through and plan ahead.

[Tiny69]

With the outer skin complete the next stage of the build is to line the inside of the hull with glass fibre matt and resin.  I do this to strengthen the limewood skin to stop it flexing before I start to sand the hull to its final shape.  I bought a resin kit from Halfords which contained 0.5sq metres of glass matt, 500ml of resin, hardener, mixing sticks, measuring cup and some disposable gloves.  I cut the glass matt into strips and laid them between each of the ribs.  I then poured out some resin into the measuring cup and added the hardener and mixed then thoroughly together.  Working from the stern the mixed resin was then applied to the glass matt starting at the keel and work up the side of the hull.  Using the mixing stick the resin was worked into the matt to ensure it was in contact with the outer skin of the hull and any air bubbles removed.  The resin takes about ten minutes to start to go like jelly when it becomes unworkable, which was plenty of time to work it into the matt. Once happy with the density of the applied resin I moved onto the next compartment repeating the whole process until all the compartments were completed. 
 

[Tiny69]

With all the internal compartments filled with resin I could now start to sand down the outside of the hull to the required shape.  I like to us a 120 grit wet and dry paper to take off the majority of the rough grain in the wood.  Whilst sanding I could feel the peaks and hollows that would require removing and filling.  To fill any hollow areas I use a quick sand resin filler paste that is applied and once set sanded back to shape.  The process of sanding and filling is repeated until I am happy with the final finish and shape of the hull.  Then I sand with a 220 grit paper to give a smoother finish.

[Tiny69]

I have a question, does anyone out there know what size props this vessel had?

[BFSMP]

I have a question, does anyone out there know what size props this vessel had?

Just spoke to my friend who built one of the 3 Loch ness  boats and, he was in contact with the then owner of the boat he built, RNLB Grace Paterson Ritchie.
Iain Crosbie, whom he had known for some time, about this matter. gave him the reply as the build went on.


Iain got back to him with the size which he even didn't realise although had had her out of the water at Fairlie numerous times, and the size was 3' 6" diameter,which equated to 90mm at 1;12 scale, and Neil had two cast for him at Prop Shop. So yours would be 45mm at 1;24 scale.


Just got the following pictures off the internet.


Jim.

[Tiny69]

Thanks for the prompt reply BFSMP.  From the information and pictures I have obtained I guessed at about 40mm - 45mm at 1:24, so you have confimred that 45mm is the correct size.

3ft 6ins = 42 ins x 25.4 = 1066.8mm

1066.8 / 24 = 44.45

Therefore 45mm Diameter

[BFSMP]

Thanks for the prompt reply BFSMP.  From the information and pictures I have obtained I guessed at about 40mm - 45mm at 1:24, so you have confimred that 45mm is the correct size.

3ft 6ins = 42 ins x 25.4 = 1066.8mm

1066.8 / 24 = 44.45

Therefore 45mm Diameter

 

[Tiny69]

To finish the bow and stern sections I roughly cut to shape a number of 10mm thick balsa blocks and glued them in place either side of the keel. Then using a detail sander the rough shaped balsa was sanded back to flow into the lines of the rest of the hull.

[Tiny69]

I decided to have a break from all the filling and sanding on the hull and to start making the prop shafts and tubes. Firstly I bought two 400mm long M4 thread prop shafts to use the stainless steel shafts.  I also purchased two 300mm long 6mm OD brass tubes and a length of 6mm OD brass bar to make my own tubes to the correct length.  The first stage was to make the four bearings for either end of the two tubes using the 6mm OD brass bar and turning it down 5mm in length to 5mm OD so each one would slot in to the end of the 6mm OD tube.  Then I centre drilled the end and drilled a 3.8mm OD hole down the centre.  The 3.8mm OD hole was then reamed with a 4mm OD reamer to ensure the hole was perfectly round and a good fit for the 4mm OD shaft.

With the bearings made I then made the oil tube mount using some hexagonal brass I had in my scrap box.  I used this because it would be easier to drill the hole for the vertical oil tube on a flat face.  The hexagonal brass was placed in the lathe and the end faced off, centre drilled and a 6mm OD hole drilled down the centre.  I cut a piece just over 10mm long off the end of the brass and placed that in the lathe to face off the rough cut end.  I repeated everything to make a second.  I now had what looked like two brass nuts with no threads.  I placed each one in turn in to a drill vice and vertically drilled a 6mm OD hole in to one of the flat faces.  Now I cut two lengths of 6mm OD brass tube and pushed each one in to the hole in the hexagonal brass section.

This assembly was then slipped over the 6mm OD brass tube and positioned 10mm from the end and one of the brass bearing slotted in the end of the tube.  The whole assembly was then soldered together with the help of a gas torch to provide enough heat.  The two tubes where placed in the hull in the position where they would are located and the length of each marked so they could be cut to the right length at the point where they exit the hull.  Each tube was cut and the other bearing was soldered in place ensuring it was square so the shaft would turn smoothly. 

With the tubes complete I turned my attention to the two A Frame shaft support bosses. Using a piece of 9mm OD brass bar I turned down a length of 50mm to a diameter of 8mm to give me enough to make two.  The end was faced off, centre drilled and a 3.8mm hole drilled down the centre approximately 25mm into the bar.  Next I calculated the angle needed to cut the chamfer and set the head sock to an angle of 14 degrees.  Once the chamfer was turned I cut off the boss at a length of 22mm and put that into the chuck to ream it out to 4mm and face off the other end to a length of 20mm.  I repeated the whole process to make the second boss.

I purchased two 45mm diameter brass props to fit the M4 threaded shafts.

[Canterbury Coxswain]

Tiny,
The progress is inspirational to all of us 'scratch' and 'semi-scratch' builders, giving food for thought along the way to both new marine modellers and experienced alike. I know the feeling of why you want to 'go off piste' occasionally and do something else - my excuse for having so many lifeboats on the go at the same time! Might be joining you on this approach of my Shannon this week.
I look forward to your next episode.
Kim [C.C.]

[Tiny69]

C.C. I am glad that you think my work is inspirational to fellow modellers.

I need some information to complete the A Frames and was hping someone out there has a drawing showing a stern view with the two A Frames supporting the Prop shafts so I can work out the angles of the support legs in relation to the shaft boss.  Attached is a simple sketch of what I am looking for.

Tiny

[Tiny69]

The rudder tube was the next item I decided to make in a similar manner to the prop tubes.  I turned two bearings from a section of 6mm OD brass bar but with a 3.2mm OD hole down the centre.  With those complete I cut a length of 6mm OD tube to 66mm in length and soldered the bearings into either end.  Any excess solder was removed and the tube was slotted into the hole I had already prepared in the keel.

[Tiny69]

To set the exact position of the two prop shafts I needed to make a simple plywood jib.  I cut a piece of plywood to 100mm long x 70mm high and marked the centre line of the keel down the middle and drilled two 4mm diameter holes 35mm either side.  Then using the table saw I cut a slot down the centre line so that the jig could be slotted in place on frame 9 at the correct height.  Now I could position the tubes in the hull and slot the shafts in place and test fit the two props to check the clearances around the keel and hull.

[T33cno]

Just found this thread    Fantastic 

[Tug-Kenny RIP]

A nice way to lay the props Sir.   Well done.   

ken

[Tiny69]

To make the rudder I first printed out a drawing of the main blade, cut it out and placed it on to a 1.5mm thick sheet of brass.  I scribed around the paper cut out and then drilled holes with a 2mm drill around the outline to make it easier to cut out.  The rough shape was then filed to shape with a rough file and the edges finished with a fine file.  To mount the main 3.2mm OD shaft a slot was milled from the bottom edge 25mm long.  This was repeated on the top edge.  To solder the top and bottom shafts in place I made a simple jig from a piece of plywood with a 0.85mm slot milled into it to hold the shafts at the correct height for the rudder blade to sit at the centreline of the shafts.  The bottom shaft was soldered into place.

At this point I realised that I had made an error with the top shaft by soldering the boss on the top to mount the servo horn on.  I would not be able to slide the rudder shaft into the rubber tube as the diameter of the boss is 5mm and the rudder tube is only 3.2mm OD.  After a bit of head scratching I figured if I removed the boss from the end of the shaft I could at least solder the rudder blade to the shaft.  The top shaft was soldered in place and all the excess solder filed away.  On top of the rudder blade is a square box which I made from two pieces of 1.5mm brass sheet soldered together.  To solve the problem with the servo horn boss I cut a slot down the length of it.  This would allow the boss to clamp onto the shaft when the servo horn screw was tightened up.

[Canterbury Coxswain]

Nice one Tiny!
Some good explanations, photos and captions. This should be of help to many - whatever they are building or hoping to. What I always say is 'there's more than one way to skin a cat'. What I also like is that fact that you 'confess' your mistakes. I try to do the same on my Shannon 'thread'. I hope it gives heart to others to have a go and learn by our 'deviations' and solutions.
I've had a very busy last four weeks, so hope to get back into the workshop myself this afternoon.
Keep the build  posts coming. Are you a member of the LBES? It would be good to have your 'in build' Clyde on the stand at Warwick in November. I can send you a membership form if required.
Kim
[Canterbury Coxswain]

[Tiny69]

Kim,

I am not a member of the LBES and at the moment am unable to commit to any future events until next seasons footie fixtures are announced and I know which weekends I will be attending Everton's home games.

So on with the build and at this point I was ready to permanently install the two prop shafts and tubes.  To support the ends of the tubes inside the hull I made two brackets from some plywood and using two part epoxy glued them in placed.  The two shafts were now locked in place with the help of the plywood jig holding the shafts in place on the outside of the hull.  I next applied some car body filler to fill the two slots were the shafts pass through the hull.  On the outside of the hull I also applied a small amount of filler paste were the shafts exit the hull and sanded it to shape.

[Tiny69]

With both prop shafts permanently in place I could now make the two A Frames that support the ends of the shafts. I only had some photos of the boat out of the water to work from. Using the CAD software I drew up the two frames to work out the angles of the support legs and then printed the drawing. This drawing was then transferred on to a piece of scrap plywood which was to be the base of the jig. I had already made the two centre bosses so only needed to make two support legs for each of the frames. I drilled two 8mm OD holes into the plywood and inserted the two bosses to the right height. The legs are made from 6mm x 1mm brass strip cut to about 40mm in length. With the bosses set at the desired angle in the jig using accurately cut pieces of plywood and the ends of the support legs were filed to the matching angle to neatly fit. The brass strips were secured in place against the bosses using some more off cut of plywood ready to solder the joints. All the parts were disassembled, cleaned, reassembled in the jig and then soldered together.
 

[Tiny69]

The next stage was to work out the exact positions of the two A Frames and drill holes in the hull for the legs to pass through.  I eventually drilled two over size slots on each side of the keel and used the prop shaft jig to hold the shafts in place so the frames were held in position whilst the two part epoxy glue set.  Once secure I was able to fill the holes with filler paste and sand smooth.  On the inside of the hull I also applied some filler paste around the tops of the protruding legs.

To support the bottom of the rudder the skeg was made from 6 x 3mm square brass tubing with a 2mm diameter brass pin soldered in place to slide into the bottom tube of the rudder.  The skeg has two more brass pins that are slotted into two holes drilled into the plywood keel.

[Tiny69]

Along the length of the hull I decided to fit a 6mm deep brass keel to match up with the rudder skeg.  From the skeg working forward two strips of 3mm square section were glued on top of each other and pinned into the plywood keel.  To make the section around the curved bow a simple jig was made and slots cut into the brass at 5mm intervals.  This made it easier to bend the strip to shape in the jig and then solder between each of the slots to hold its shape.  This was then fitted to the keel and filler paste applied and sanded to shape it into the rest of the hull.

[Tiny69]

Continuing on with the hull the next step was to clearly define the edge of the top plate which had become somewhat lost with all the sanding. To achieve this lengths of 1mm OD brass rod were glued in place to define the edges.  Then a thin skim of filler paste was applied up to the brass rod on both sides and allowed to set.  The filler was then sanded back to a smooth finish using the brass rod has a guide to produce the edge.

[T33cno]

Ingenious 
I'll bet your looking forwards a coat of primer 

[Tiny69]

Not far off now.