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[dreadnought72]

If you have milliput left, it might be worth squeezing a pile into the bow and stern's pointy bits, just to reinforce the hull up in case of collision. The ends will take some force if the inevitable happens.


Meanwhile - looking good. I think the prop increase is justified. But (am I wrong?) I rather thought battleships of the era were all four-props, twin-rudders?


Andy

[Bob K]

That is wise advice Andy, I will reinforce both bow and stern.  The GRP thickness is not that much more than a hull half the length.  I am intending to cast the vulnerable secondary armament gun barrels in grey rubber as these too will be vulnerable to the concrete edges  of our lake.  I like the way Ron K has the very tall masts of Agincourt folding to make them less fragile for transport and handling.  At this size and weight all detail becomes delicate.

The propellers are quoted as 9 foot 6 inches, which scales to 30.2 mm at 1/96.  I have fitted 40 mm.  All the info I have shows a single rudder, although two might have been more effective. 

On costs, I will require quite a few large SLA batteries; electronics; seven GRP turrets and what will undoubtedly be a very extensive fittings kit.  On overall costs I am basing my estimate on the Dean's flagship models, plus a factor.
I knew and accepted that before I started.

At Black Park we have a new member with several 6 foot paddle steamers, including Queen of Glasgow and Waverley.  I will be taking notes on how he handles big ships.  Our big lake can get quite crowded sometimes.

[ballastanksian]

I reckon we need more Kaiserliche Marine ships to keep you Jack Tars in your place!

[Bob K]

You are right.  We do need Jutland adversaries !

A few subtle adjustments to the motors fit, adding very thin shims of Neoprene between each motor and its half cylinder aluminium shoe, adjusting each so that the motor runs quietly in good alignment.  Very quiet running.
Although each motor is only 1.9 A, the four together max's at 7.6 A.  A lot of 12V battery Ah capacity required.

Looking for things to get on with before buying the propulsion electronics . . .
Probably a good time to cut out the secondary armament apertures, and build dummy decks behind to mount the guns in. 

[Bob K]

Steering Flat

Moving forwards, the steering flat has been installed.  Supporting a 9kg / cm metal geared servo. 
I just thought a meaty servo would help with the size of the rudder, and turning the boat.
It almost looks lost in there doesn't it?



Propulsion Electronics

Well, bit the bullet.  A large consignment from Component Shop is on the way, mostly Action Electronics.  A P92 distribution board, two P93 controllers, a P94 twin controller with mixer, fuse boards, plus a load of 14 AWG silicon wire in various colours, and twenty spade connectors for batteries and motors. 

Calculations vs weighed items

At Wicksteed Park the displacement was established, by lead weights, at 29kg.  All the planning was to achieve 19kg “dry” weight for launching, supplemented by another 10kg of pumped water ballast when afloat.  With a 2.2M hull you might start thinking how are you going to add enough ballast to hold it down.  Since then I have been keeping a careful tally on the weights of components as the ship develops.  However . . .

I have a bit of a problem.  Controlling the weight, even on such a huge 7 foot ship, is proving to be harder than I thought.

To start with the stainless steel telescopic tubes, essential to fitting the hull halves together, total 4kg.  Add to that 3kg of Buhler motors, shafts and props.  I will also need a sizable array of chunky SLA batteries, for the propulsion and gunfire system in four turrets.  Of course the ply bulkheads and decks had to be robust enough to do the job on a vessel of this size.

As I keep adding stuff, and putting hull halves on the scales, it is all going OTT.  So much so that first I needed to abandon the pumped water ballast and reconcile myself to having to lift the whole ship as-is.  Even then, weight reduction is rapidly becoming a priority.  So. 2 x 10Ah at 12V for the motors, plus 4 x 5Ah 12V for the guns.  13 kg in total.  That only gives me 2kg left for superstructure and wiring.  Yippes !

Turrets

I am greatly indebted to both C-3PO for his ongoing development work on the Arduino turret bearing control system, and to Geoff for his kind assistance in helping me replicate his amazing gun fire effects.  Right now, though I have plenty to be getting on with. 

[raflaunches]

Looking good Bob


Is the servo slightly off-set to starboard? It’s hard to judge but I’d recommend having two arms going to the tiller because (in the past from bitter experience) it’s possible to get prop wash to ‘flip’ the rudder around and jam. Having two arms prevents this happening and there is a second back up just in case the first falls off.

[Bob K]

Thank you Nick.   The servo is exactly on the centre line, 100mm each side to the hull edge, must be the angle of the photo.

Having two arms sounds a good idea.  I was not sure if they might interfere with each other.
I will probably reinforce the rudder tube.  It is quite stiff with the brass inside, but fairly long to make sure it is well above the waterline. 

[ballastanksian]

Hm, I feel she might be a deep runner and you may need to bring her along to sail on days when you know you can ask people to help lift her in and out. It's one of the cons of the larger model, impressive though they are. Still, you are making good progress Bob.

Could you grind some of the milliput away to give you some grams of spare weight. A board margin if you will?

[Bob K]

You are probably right Ian.  There are usually at least a dozen or so around on our regular sailing sessions, as it might come to that.

I am taking notes from Nick's build of HMS Invincible, he is using fairly light thicknesses of styrene to build his superstructure.  I will follow his lead.  I have a good idea on the weights of the working turrets, and that should not add much significantly.

In the mean time I am constructing open retaining boxes for the Action P93's and P94, with a thin strip of Velcro to secure.  Makes them easier to access when the decks are secured in place. More later . . .

[Akira]

Bob,
 With weight considerations in mind and so important, I make the following suggestion. It is based on the power needs of a 1/16 PT boat drive by Astroflite motors. It is an expensive suggestion, but... Rather than SLA batteries, have a look at Lithium Iron Oxide replacement batteries. Available inn the same shape and dimension as 12v 7.5 ah SLA's but at 1/2 the weight. Added advantage is the Lithium are not constrained by low current discharge rates. I enclose a link to one site that carries them here, but I am sure that you can obtain them there on your side of the pond.

https://www.wholesalebatteriesdirect.com/lithium-batteries/66438-12-volt-10-ah-lifepo4-lfp12v10-lithium-iron-phosphate-battery.html

Jonathan

[dreadnought72]

Bob, here's a handy rule-of-thumb. Standard plastikard sheet sizes are 9x13 inches.


12 sheets of 1mm = 1kg

Andy

[Bob K]

Andy:  Luckily there is not that much superstructure involved, weight-wise.  I will be using balsa for bases, to keep things square, then building up from there.  Much as I like Qualcraft ships boats I will probably heat-form them from thin ABS sheet and detail.  There are a lot of them and cast resin weight mounts up.

Akira:  I have been looking into these batteries.  That particular one is not available in the UK.  Not sure what the pros and cons of Lithium Iron Oxide are, apart from being around half the weight.  Anyone else used them?
They are even more expensive here, googling similar packs.

[Akira]

Bob,
 This is from Wiki and explains the pros and cons pretty well. Hopefully they are available to you in some form. Yes they are quite expensive, but the trade is safety, discharge rate and weight.
https://en.wikipedia.org/wiki/Lithium_iron_phosphate_battery

Jonathan

[Bob K]

Power control electronics

A bit of planning required on how to mount and wire the controls for the four motors, bearing in mind that three barbettes are also in this space..

An Action P92 power distribution board, centrally positioned.  Two mounting lugs to position it, plus Velcro / adhesive servo pad.  Two Action P93 high power multi controllers for the inboard pair of Buhler’s, mounted in fixed ABS boxes on hull sides with Velcro straps.  The P94 dual 20A ESC’s with mixer mounted in another ABS box between the outer motors.  With the deck fitted in place I need to be able to easily access internal wiring, hence the readily removable units.  Undo the Velcro and pop them out.

Wire routing so that ESC outputs are reasonably close to their respective motors, and that power and control wiring can be loomed well apart from each other.  Minimum wires to connect power from this compartment to the batteries mid-ships.  Max diameter DC wiring wherever possible, 14 AWG.  Rx to be mounted towards the rear of this compartment, close under deck. 



Hopefully the wiring will come out as neatly as I intend.

Batteries

I have been having a good search online for UK sources of Lithium Iron Oxide equivalent batteries, without success.  Either very small ones or car battery size.

[ballastanksian]

I thought the distribution board was quite big until I saw it dwarfed not only by the hull, but also by the motors! The space between the outer motors is about as much room as I have for all the electronics in my Destroyer!

You will ony have a problem if you forgot something while planning, otherwise it should all go to your plans.

[Bob K]

Actually, the P92 distribution board is wider than my Dean's HMS Amazon destroyer ! 

A lot of wiring connectivity in a compact board, and it includes a BEC circuit.  There is a tad over 100mm between the outer motors, where the P94 resides.  Distance between outer shafts is more than the beam of my Dean's HMS Skirmisher. 

As usual I will spend a large amount of time checking and rechecking all the wiring connections first.
I intend commissioning one motor at a time, starting with the inners, making sure I get the prop directions right, and by taking DC direct to each outer motor in turn.  Obviously I need to power up the outer controllers together as a set as they are from the dual controller.

[Bob K]

Wiring

My new Planet T7 is up and running with receiver bound.  I first got the port inner motor and it’s P93 controller running, then the starboard inner motor and P93.  Both very sweet with good throttle response.  Temporarily disconnecting them I next worked on wiring up the P94 dual 20A ESC’s with mixer to the two outer motors. I like to be ultra careful with electrics, working on one circuit section at a time, checking and rechecking.

All OK (phew).  The three Action boxes work the throttle and steering as I want, all that remained was to adjust the pot in the dual controller so I got just the amount of mixing I wanted.  ie:  Anything more than 25 degrees of port rudder and the port outer progressively slows.  With outer shafts 160mm apart that should help manoeuvring nicely.

If I say so myself the wiring has come out fairly neat, with power and control well separated.  See photo below.
The Action P92 distribution board used really helps keep things tidy.



Whilst in that compartment I added the second rudder linkage as Nick suggested.
I am nearly at the stage for final fitting of the deck, just need to drill-through for the Neodymium hatch magnets. 

Bow Half

With the after hull just needing batteries, turret mechanisms with controls, and detailing, I need to start thinking about the fore end of the hull.  No propulsion issues, that’s all in the aft half, this end of the hull is almost solely dedicated to turrets and fire control. I will only be firing four of the seven turrets, three in the front half, but all will train towards the bearing I set.

Another milestone completed.  That is by far the most complex propulsion system I have ever wired up.   

[ballastanksian]

"That is by far the most complex propulsion system I have ever wired up.     "

And yet that is a nice simple looking loom Bob. The number of components etc suggested potential wiring chaos!

Onwards and upwards 

[Bob K]

Not a lot to report, but now the propulsion system is running nicely, and I am making progress on the decks, I can start to feel more confident of eventually completing a successful ship for me to sail.  With the decks (unfixed) in place and the hatches fastened down with pairs of magnets she already looks impressive.



Hatches:  7mm holes in deck panels, circular magnets same thickness as hatch pressed in and epoxied.  5mm lugs under the deck, also with same magnets.  Nice feel as the three big hatches firmly self-seat themselves. 

Time to start planning the superstructure.  I am going to do the bases in 10mm balsa, with 5mm balsa for intermediate decks.  That way I can use 0.5mm styrene and 1mm ply for the vertical surfaces providing that I reinforce the internal corners.  All helps keep the overall weight down.

I am ordering the seven fibreglass turrets from Dean’s as we are nearing the point where I can plan fitting out the barbettes.  These will be quite complex, having both Geoff’s amazing gunfire system, together with C-3PO’s Arduino controlled T.A.R.G.E.T automatic bearing control.  Combining these two systems will, hopefully, give an effect on the water that I cannot wait to see. 

The main control board knows where North is.  A knob on the transmitter sets the bearing angle relative to North. The guns then train continuously on that bearing, providing each individual turret will bear, maintaining that bearing even as the ship changes course.  Add to that very effective gunfire smoke with ultra bright LED flash.  More on that later! 

Before all that, the superstructure, detailing in the casements and torpedo net booms. ( I am trying not think of the vast amount of deck planking.)  and converting the platform on my trolley to a much longer double-decker version. 

No rush.  One step at a time.   

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Thank you ballastanksian for your kind words.  For some time I kept wondering if I had bitten of more than I could build 
The combined bearing and gunfire system (if I can get mine going) will be due to the extensive and appreciated development work of both Geoff & C-3PO.   

[ballastanksian]

Well, you've planned the build like a military campaign so far Bob, so I expect the rest will follow on at a measured and considered pace.

In many ways your build will be a demonstration that developed technologies can not only work, but be built by another person and be understood, that several technologies can be combined and work.

Fellow members will see their extensive testing and developent of turret control technologies on a real ship (certainly the most main turrets anyone will see working!) in sync with Geoff's smoke and light system.

In the modern age where it is harder to find a new and exciting 'first', you will definitly get the model boating fraternity looking!

[Bob K]

Casemate Openings

Next up was creating fourteen casemate embrasures, ten in the fibreglass hull and four in the plywood ‘step’ between the fore and aft deck levels. For some reason the ply apertures came out a few mm above the ones in the hull sides.  I believe I have the deck heights correct, but the step depth seems shorter than the hatch rectangles moulded into the hull. 
Oh well, looks like I should have ignored to embossed rectangles.  Now I have to re-cut them higher to match.



After carefully finishing off the rectangles, using a size gauge for consistency, I made up sets of doors for them, adding the hinge bars and hinge pins.  One question I am searching to find an answer for is about these doors.  Obviously designed to hinge close, but were the very long gun barrels fully retracted into the hull or were there semi-circular openings that closed around the barrels?    The barrels are very long, and I find it difficult to see how the whole gun mounting could have been withdrawn that far  into the hull.
Once I have figured that out I will fit the doors in their open positions, then make up parts of the inner gun deck and its detail. 

I am still contemplating whether to make the secondary armament barrels from cast silicon rubber as they will be very vulnerable to damage on the model when coming alongside and in transport.  Protrusions up to 50mm beyond the hull are asking for trouble.  The torpedo net booms will also need careful consideration as they too could be liable for quayside grinding.  I have some ideas I am working on.

[ballastanksian]

There was a thread concerning the retracting of secondary armament here a couple of years ago almost certainly to be found on the Warships R&D page. I recall Colin Bishop was a regular contributor to the debate and recall it concerned Victorian era ships. You may find more detail to answer your question there after a quick hunt.

On the matter of rubber barrels, it reminds me of a book I read at college by an author who made models of cars using prototype materials and engineering practices. He made his tyres by machining two part moulds from acrylic (Perspex) and then scribing in the tread. He would then syringe a suitable silicone rubber coloured black and could see that the rubber had filled all the orifaces.

While machining a mould would be a challange, machining a barrel and making a two part mould from acrylic resin would allow you to produce rubber barrels in a similar way. I think you would need a stiffer rubber so that the barrels didn't droop.

Casting rubber barrels with a slight upward curve to counter the worst of the droop would be possible, but some experimenting woud be required to get the 'Anti droop' right! Other possibilities might include resin barrels made in two sections with strong elastic through them so that any impact would temporarily distort the barrel before the elastic pulled it back into shape- Think collapsible walking stick concept, or a single piece barrel set on the end of a spring.

Alternatively, have all the barrels as maximum traverse ahead or rear and hope their lesser protrusion would lessen the risk of damge. Alternatively, try a combination of these ideas 

[Colin Bishop]

Yes, there was a discussion a while back. It concerned the pre dreadnoughts where the 6 inch secondary armament could be retracted into the gun deck. I'm not sure that it was possible to do the same with the dreadnought battleships though. The guns always appear to be protruding from the hull.

As Ballsatankian says, perhaps best to have all the secondary armament trained as far inboard as possible and avoid concrete pondsides!

Colin

[Bob K]

Thank you both gentlemen, some good food for thought.  I will have a trawl through those Mayhem sections,
I know the Minotaur and Cressy type secondary armament did protrude, with hatch covers that closed over the barrels.  The lower deck guns often could not be used except in relatively calm conditions.
These barrels really look long, both from pictures and the plans.  Difficult to see how they could be fully retracted.
Of course the real ship never had to contend with concrete lake edges or double decker transport trolleys !
Some excellent ideas there Ian.  A principle danger is that forward facing barrels will tend to impact end-on.
She will need to come close in so we can get the lifting straps in place.
Maybe a sprung telescopic 2 section barrel, mounted in a rubber block?  Some trials needed.

I am a little miffed about the hull cut-outs, having followed the embossed rectangles on the hull.  It was only after cutting out the ply step apertures I noticed the disparity.  Life !

[Colin Bishop]

I suspect that part of the problem is that the more modern guns had longer barrels so they could not be withdrawn into the hull.

If you think that protruding detail is likely to be a problem, and I do appreciate your concern on this, then a possible option would be to fit  underwater fenders in the form of bent piano wire which could be mounted in hull sockets and project horizontally along the midships part of the hull to protect the hull detail. They would be invisible in operation but keep the side of the hull sufficiently clear of concrete pool sides etc.

Colin