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[ooyah/2]

Thanks for that info George, really interesting. When I started modelling and used bread and butter for the ic Smeed Empress of Britain liner I had to settle for Parana pine which had knots and tended to split. I did make the hull but it was too heavy really and unstable so the model never got finished.

Colin

Hi Colin,I don't want to high jack Dave's Thread but old Churches are a source of Yellow pine , well seasoned and knot free.

George.

[DBS88]

To answer a couple of earlier questions about the displacement for this boat here is my rough calculations
HMS Daring 185 feet long, 19 feet wide, speed 28 knots
Model length 92 ½ inches - waterline
Model Scale = 185 feet divided by 92 ½ inches = 1:24
Approx displacement = Length x breadth x displacement x coefficient for a destroyer
92 ½ x 9 ½ x 4 x 0.505 = 1775 cubic inches = 29087cc = 29 kg displacement.
For 3 inches displacement  = 1331 cubic inches = 21811cc = 21.8kg
Scale displacement = 3 inches, model will sit deeper in water upto 4 inches so displacement should  be 22 -29 kg

Whilst this boat is long, I can carry it on my own without too much trouble, it’s not massively heavy, so these back of a fag packet figures seem about right.

[DBS88]

With the boiler on the bench waiting for me to have the time to fire it again and experiment with the gas jets, I thought I would share with you the boiler room in the boat.
Its also time for me to start to clean and understand more about the engines, their lubrication and the boiler filling arrangement. So heres some photos of the engine room. The twin sun engines are linked by a gearing arrangement in the green metal box, on top the square is an oiler drip feeding oil to the gears. Looking at the fourth photo, a close up of the gearing arrangement, looking at the flywheels, notice the grub screws that secure the flywheels to the crankshafts, they are at 90 degrees to each other. I learned from refurbishing an earlier version of the Sun engine, the MTB 1B, that the position of the screw (Left Hand Engine) means that one piston is top dead centre. This leads me to believe the pistons in the right hand engine are at 90 degrees to the left hand engine. In effect the engines appear to be tied together by the gearing, if one engine is turned they both turn and at the same rate, so what appears to have been created is a four cylinder single acting engine with 3/4 for and 3/4 inch stroke.
The lubrication for the engines is complex, see photo 5. The cranks, conrods and anything below the pistons is via a splash system contained in the crank case with a type and grade of oil yet to be confirmed, but probably light engine oil. The top of the engine, the valves and cylinders is lubricated by firstly the normal displacement lubricator, this appears to be for the initial phase when the engines are cooler. Then secondly by a mechanical lubricator, about which I know nothing and have no experience with. My thoughts are that this has been provided because the boiler has a steam dryer and is capable of delivering high pressure steam that has been dried and at a higher temperature preventing the displacement lubricator from working due to very little condensate. The mechanical lubricator is driven from the engine and ensures delivery of oil into the steam line to lubricate the top end of the engine, again note the drip feed oilers to provide lubrication to the pumps. 
In addition to driving the lubricator the engine also drives a water pump which takes water from an inboard tank, the water circuit is fitted with a bypass valve so will need to experiment with that to make sure the boiler water level is maintained - again I have no experience of setting up a mechanical bypass valve.
A lot of thought has gone into this layout, so it will be nice to finally get it into steam. I also noticed the steam delivery pipe size that goes into the side of the engines and that the exhaust piping is at an increased diameter as it leaves from the top of the engines to minimise back pressure allowing the engines to spin freely.

[Geoff]

What fabulous workmanship. I suspect that the original builder was an engineer of some description or a very skilled amateur and really build the boat to take the steam plant as that was his real forte. I wonder who the builder was?


Either way a very interesting thread so please keep the info and pictures coming.


Cheers


Geoff

[ooyah/2]

Hi Dave,
Taking the lubrication off the engines.
The bottom of the engine use auto engine oil as a splash lubricant, not too much as it will also push out thro' the holes and coat everything with oil. I have often wondered why Stuart never made oil fillers, 1- with a cap on it and the other with a small breather hole.
I don't see any need for the on- line lubricator as you have a mechanical lubricator  ( the black box ) which can adjust the oil delivery by lengthening or shortening the ratchet lever and it should be filled with steam oil, inside the black box is a little oscillating pump that should be submerged with oil, the mechanical lubricator is operated via the gears on the end of the starboard engine. This type of lubricator is mainly used in Loco's.

The online lubricator works with the oil filled chamber. and as the steam comes thro' the line steam filters into the chamber and condensates and as oil floats on water it is pushed up thro' the small hole and into the steam line and then to the engines and in my opinion is not required in this set up.
The small box drip feeding the gears use auto oilfor the gears and the water pump.
[/size]
[/size]The box with the drip feed over the gears to the stern tubes use auto oil
[/size]
[/size]Timing of the engines.
[/size]Time them with the drawing that I gave for the older Sun engine and do them individuallyI don't know if the grub screws have anything to do with the timing other than indicating T.D.C. with No 1 cylinder  ( cylinder at the flywheel end )

[/size]Water bypass valve is easily adjusted once you get to know the boiler requirements, so don't worry about that, it will pass needless water back into the onboard tank.  Once you get the boat into the water or ( the big P/Pool as long as the kids are out ) you can time the length of the boilers needs as a guide before you let it go on the lake as the requirements will change under load.

[/size]Pipe sizes.
[/size]All steam engines should have exhaust pipes 50% larger in dia than the steam supply line for maximum efficiency but on smaller engines it's not very noticeable.
[/size]The steam drier is the same it should be 50% larger to let the steam expand and store an supply greater heat to the engine.
[/size]Always remember at the end of a sail check the exhaust trap to see if it needs emptied, again by experience you will get to know how much exhaust oil is collected.

[/size]It's a well thought  layout it's a pity that the builder never seamed to have a run with it as you say the boiler looks as tho' its never been fired in anger, the engines certainly look as tho' they have never been worked as the paint still looks brand new,
[/size]Like the new burner  Pendle has done you proud.
[/size]
George[/font]

[DBS88]

Geoff, thank you for your kind comments, just wondering if there is anything in the book British Destroyers 1892 - 1953 by Edgar March about HMS Daring or HMS Decoy, or possibly Boxer that would be useful? if so I will try and find a copy.


George your help and support with this and previous projects is greatly appreciated, your advice on the burner, engines and lubrication has been invaluable.

Having got the boiler well on the road to being sorted, the next most important thing I have learned from this forum is getting the props right. So I have been looking at the props, they are 3.5 inches in dia and wondering if they are the so called "steam props" - props with a ratio of greater than 1:1. How do you tell if the pitch is steeper, as for a steam prop at 1:1.5? How can I find out what the pitch is?

[ooyah/2]

Geoff, thank you for your kind comments, just wondering if there is anything in the book British Destroyers 1892 - 1953 by Edgar March about HMS Daring or HMS Decoy, or possibly Boxer that would be useful? if so I will try and find a copy.


George your help and support with this and previous projects is greatly appreciated, your advice on the burner, engines and lubrication has been invaluable.

Having got the boiler well on the road to being sorted, the next most important thing I have learned from this forum is getting the props right. So I have been looking at the props, they are 3.5 inches in dia and wondering if they are the so called "steam props" - props with a ratio of greater than 1:1. How do you tell if the pitch is steeper, as for a steam prop at 1:1.5? How can I find out what the pitch is?

Dave ,
I don't have much knowledge of props but I do make my own and I silver solder the blades at 45deg on the hub and then do at bit of twisting to see how they work , never having had a twin prop set up I can't say much other than when these engines are at full revs and the boiler can keep up the pressure these props in my opinion are just about right.
Your props look professionally made with a coarse pitch and I would leave them as such until you get on the water, but somebody better qualified than me will no doubt give some
sound advice.


George.

[Colin Bishop]

Yes, the props appear to be coarse pitch which should be suitable for relatively low RPM compared with electric motors. Given the attention to detail for the engines and the boiler it would be a reasonable assumption that the fitted props should be matched to the power plant output. Maybe it has never been run but you don't know the reason for that so I would think that the best bet is to test the installation as it stands as clearly a lot of competent thought has gone into it.

Colin

[ballastanksian]

Hi Dave,


From experience running 5incch gauge locos, the mechanical pump is filled with steam oil containing lanolin and the mechanism is to actually force a small measured amount in for each cycle as the oil is thicker (certainly at room temperature) than other oils), though being near the engine, it will probably soften some.  By the way, is the phot deceiving us as it looks like the gears are not meshing.

As Colin and George said, make sure your engines and steam plant works and then get testing those props to see if they are actually right for the type of vessel and powerplant you have. These early destroyers often had a series of small props on each shaft. I havn't read my book on early destroyers for a couple of years and so might not be right about multiple props on reciprocating plant.

[tghsmith]

this era was of great experimentation, the quest for speed was a hard fight,, creating boilers that could maintain steam, engines that could survive the high RPMs,, the turbina tested multi props on the shafts,, many torpedo boats and destroyers had staggered props and engines,(so one prop wouldn't "steal" water from the other, and keep the hull narrow as possible) this was also the start of test tanks for hull shapes,, The USS Vesuvius on of the fastest in her time had the prop shafts angled outward, but her narrow stern could not fit a large enough steering engine and she couldn't turn at speed..

[Geoff]

I think the props on the model are about right as steam tends to be relatively low revolutions so large coarse props are perfect for this. Real destroyers had to have smaller props as they would otherwise cavitate at the tips due to the rotational speed. One of the issues with early turbines were they turned too fast so they had to have smaller diameter props and go to four props to get the power in the water.


Personally I would bet if you get both those engines warmed up and going it will go like a rocket!! Long thin hulls take very little effort to move. I suspect the two engines are used to make it self starting.


We should also consider the age the model was built and suspect radio  control was probably not possible so it may have been a free runner albeit radio has been added later.


I await the next installment with considerable interest!


Cheers


Geoff

[DBS88]

Thankyou for sharing your views and advice about the props being the steeper pitch props, its reassuring since it makes such a difference to the engine revs required and to the amount of steam that the boiler needs to produce for those revs to be achieved. I am not looking to change the props, I just wanted to see if they were the steeper pitch props, and I agree totally with getting the boat running before seeing if anything needs changing.

If anyone knows anything about who built this boat I would love to hear from them, I would love to chat to the builder, to buy them a pint and learn from them, after all they have done a fantastic job and it would be a nice for them to know that the boat will be going under steam soon and hopefully running free on a lake not to long after that.

From what I have now read, it appears that in 1894, following HMS Darings first sea trials a study was undertaken and that is the first time cavitation had been identified as a problem.

To illustrate the effect of the propellors pitch on the revs required to achieve the desired speed on the water heres another back of a fag packet calculation, the difference in rpm is dramatic

Scale speed = square root of scale x true speed
1 Knot = 0.514 m/s therefore 28 knots = 14.4 m/s
Square root of 1/24 x 14.4m/s = 2.939 m/s = 6.6 mph

Prop RPM to achieve scale speed.
Prop dia 3 ½ inches 9cm, pitch 1:1 therefore 1 revolution moves forward 9 x 1 = 9cm
Props only 75% efficient therefore moves 6.75 cm per rev.
Scale speed = 2.939 metres per second
Revolutions to move 2.939 m = 293.9cm/6.75cm = 43.5 per second
Revolutions Per Minute = 43.5 x 60 = 2610

If Prop is 1:1.5 then 1 revolution moves forward 9cm x 1.5 = 13.5cm
Prop 75% efficient so moves 10.125 cm per revolution
Scale speed = 2.939 metres per second
Revolutions to move 2.939 m = 293.9cm/10.125cm = 29 per second
RPM = 29 x 60 = 1740

[steamboatmodel]

I have been following this for a while, it is a fantastic model. One think I have noticed is none of the piping is lagged, this should be done especially the steam feed pipes, as you want to keep the heat in and not lose the benefit of drying the steam.
Gerald.   

[raflaunches]

Hi Dave


PM system doesn’t allow pictures to be attached so I’ve put them on your thread. The Edgar J March is a very interesting and informative book but costs a small fortune to get a good copy. It has five pages in the subject more dedicated to the working of the hull and engines. The Norman Friedman book differs by having plans drawn by AD Baker III of Daring (and Havock of which is very similar to Daring/Decoy) and some very good clear photos one of which spreads over two pages.
As promised here is my tiny Velox (still not started properly!)- just has the prop shafts and tubes stuck in place, note how tiny the props are!

[raflaunches]

Some more pictures

[DBS88]

When we started this discussion it was unclear what ship this was a model of; now with the info from Nick together with the other contributions we can now be more certain than ever that this model is indeed HMS Daring or her sister ship HMS Decoy. Putting a name to the model and finding out the history of the real boats is really bringing this project to life for me, its given it a personality, so thank you.

Gerald, those props on your Velox are things of beauty, good luck with your build, I will follow with interest. Re the lagging, Gerald, you are right that is on the list of things to do, first is to get it all running, then I will go through and make improvements and finish off things like the pipe lagging. Have seen pipes insulated with silicon tubing (Mark T) that look very effective so may give that a go, happy to listen to suggestions on the best ways to lag the pipes to keep the heat in and stop the fingers from being burnt!

[Geoff]

The standard method for lagging model steam pipes is thin string wrapped spirally round the pipe (takes ages but looks good) and then sometimes painted to prevent it absorbing moisture and any oil which would reduce the effectiveness. Its a fun process particularly when fitting it retrospectively!


Cheers


Geoff

[Geoff]

Just caught on the plans that it does indeed have two torpedo tubes together pointing in different directions! I stand corrected as I thought this was a later concept so another identifying factor making it Daring or Decoy!


Cheers


Geoff

[KNO3]

Hi, regarding lagging steam pipes: I have found that winding piles with thick cotton twine is very effective for insulation. You can paint the twine over so it doesn't get stained by oil. I have painted them with white correction fluid (liquid paper), which gives a very matte appearance, like plaster. But normal paint is fine too.

[steamboatmodel]

The others have beaten me in replying. I have always used the string method for insolating model pipes, It's not that different from doing the full-size ones, which I have done in the past. you wrap the pipe with something that will trap air. fiberglass for the full size cotton string for the models, then you add something to protect the insolation. With full size we used a tape that you wound in the opposite direction to which you wound the insolation, you then paint the tape. With the models you just paint with ether white out or paint. I have not tried the silicon tubing, but will try it in a future model.
Gerald. 
PS The last full size piping I did was over fifty years back for steam heating, housed in a six foot round underground tunnel four miles long. We first had to strip and clean the pipes of the original asbestos, which was done in full hazmat suits with breathing gear.  Once we had the pipes and tunnels clean and asbestos free we check and repaired any leakers, then recovered all the pipes. This was done during a very cold January during which the steam could not be shut off and temperatures in the tunnel sometimes reached 90 degrees F. 

[DBS88]

Great tips on doing the pipe insulation, very helpful. There is a lot of piping to do so it will take a while. At the moment, due to Santa arriving soon, the basement has to be cleared so that Santas helper (me) can make some presents for the Grand kids, so with that HMS Daring is now safely up on a shelf, waiting til I can get her down again to do any meaning fun work. So I have taken the opportunity to start cleaning and repairing bits. Since Geoff has confirmed the twin torpedo tubes were a feature of HMS Daring/Decoy, here are some photos of them cleaned up together with a section from the as fitted plans for Decoy that I have just got hold of.

[Geoff]

Very interesting and nice. On my model of Velox at 1/48 scale I used some stainless steel old fountain pens as the torpedo's - right colour and size! Note that on the plans you can see the tops of the cylinders for the engines. Sometimes these were sufficiently tall to reach above the deck so an oblong covering was used to give clearance - the first TBD's were very small!


Cheers


Geoff

[DBS88]

I have continued cleaning up a few bits, Have made a start from the front, so heres the front three guns. When I got them they were dirty and going rusty, however, I decided against trying to make them look like new, so have taken them apart and given them a sympathetic restoration. Hopefully they still look old, but good.

[rhavrane]

Bonjour Dave,
Incredible work on these guns ! Your project is just amazing ans is worth the energy you put in this restoration 
They could have been operational...

[KNO3]

Those working mechanisms on the guns are very nice.