Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length.

[DBS88]

With some spare time on my hands I have been wondering what features the ultimate model boat boiler would have? To narrow this down lets think about a boat size of 4 to 6 feet, 15 to 20kgs, with two  twin cylinder double acting engines, 12 mm stroke and bore running at 45 psi. So here goes to start the conversation, if money were no object what would you have on your ultimate boiler?


Fast steaming
Large steam capacity
Steam Dryer
Feed water heater
Gas pressure control
Steam pressure control
Water level control
Very well insulated

[KNO3]

At that size boat, it shouldn't be too difficult to find a suitable boiler. Do you know if it should be a horizontal or vertical type?
You could look at Pendle Steam and Clevedon Steam in the UK or Regner in Germany.

[derekwarner]

I agree with KNO3's suggestions, however manufacturers from France, Australia and China also supply model marine boilers, engines and gas regulation equipment

So, with spare time on your hands, why not use the search facility here within MBM to review a multitude of posts on model marine steam


A 12 x 12 engine running at 3 Bar is not a huge engine, however the type of hull and planned engine/propeller speed ratio will have a dramatic influence on steam consumption


You may find a review of the standard off the shelf manufacturers boiler performance & design criteria to be acceptable


1. Steam up time is usually a given or standard ratio between water volume and heat input
2. You will find [in general] the boiler steam relief valve is the usual control function for steam pressure
3. Gas flame attenuation/regulation piloted by the boiler water pressure is the control source for heat input, so also controls boiler water pressure
4. The boiler water volume/pressure will usually dictate the volume sizing of your gas tank......[disposable/refillable?]
5. A steam dryer loop [as is a feed water loop] is available as an option with most standard boiler designs
6. Insulation is usually up to the owner [yourself] however you may wish to consider extra protrusion length of all of the boiler bushes to allow for your preferred thickness of insulation material
7. One manufacturer will also let you nominate Metric or Imperial boiler bush tappings to suit your preferred accessory supplier
8. Water level control is a complex subject in itself.......sensors, controllers, makeup water pumps, check valves, R/C function over-ride?.You really need to define the criteria that you require

So you will find the items & components you require from a group of manufacturers....be it from UK, Australia, France, Germany, Japan & China
In a number of cases, principal components [ boiler/gas tank/de-oiler] are made to order, so can accommodate a number of special requirements 

[a multi-national steam plant can be a cost effective and an absolutely satisfaction in the way of assembling components from a variety of manufacturers]


Your location in the World will dictate any Regulatory requirements [Certificates for pressure vessels etc]. If you had nominated a World location in your profile could help


Derek

[Jerry C]

If you’re up to making one yourself say from plans then for the boat you describe how about this 4” return flue scotch boiler. It has drier and feed water coils. A steam driven feed pump and a 2 kW burner using disposable gas tank. Materials from Blackgates Engineering. The build is on this site calledJerry does some turning and milling. My YouTube channel captainpaxo1 has a vid of soldering up the boiler.

















Jerry.

[DBS88]

Great start to the discussion, with the experiences gained from owning and operating boilers and money no object think of this as a fantasy boiler, so imagine we are building one rather than buying one, what would you most like to include in its design?

[derekwarner]

So, if the boiler is to power your scale model Black Swan Class Sloop together with your questions on propellers [twin or single] and considering the prototype vessel utilized the following [courtesy of WIKI].......

Propulsion:Geared turbines, 2 shafts:

• 3,600 hp (2.68 mW) (original)

If you leave fantasy at the back gate , you may wish to consider a boiler producing a scale output power. So having parameters based upon the scale, possibly the most critical point here will be the weight of the steam plant as the actual Class were a tender 1250 ton displacement

Derek 

[PS....the shaft power of the prototype vessel of 2.68 mW is output power so your calculations would need to consider efficiencies  etc...Jerry in his posting of a 4" model boiler mentioned a 2 kW burner which is input power]

[DBS88]

Havering reflected on this and the helpful feedback it may have been better if the question I had asked was - what would you want from and include in the ultimate steam plant? The reason for asking is that I am building a twin engined steam powered Black Swan Sloop, it will be HM S Wren U28, it’s my first model build, and I have limited steam experience so want to  create the best steam plant that I can - so if there’s something useful you have seen or wished you had on your steam plant please do let me know

[SailorGreg]

Gosh - you're taking on a twin engined steam powered warship as your first model build?  Respect!!  Unless of course there's something you aren't telling us, like you're a professional precision engineer or a clockmaker or something similar?

Have you decided on which engine yet? It sounds like you might have, given the parameters you give in your first post.  Do keep us updated on your progress.

And good luck! 

Greg

[DBS88]

 A long time ago about 40 years ago I was an engineer, but as you say an ambitious first build. The engines have been ordered, a pair of Saito T2DRs, should arrive next week. They are more than powerful enough and in fact cause a problem in supplying enough steam to them, but more of that another time as I work on the solutions. I only plan to do this once so have gone for it - it may be fool hardy and I will make mistakes but I have confidence based on the helpful replies I have received to previous questions that any issues that arise can be solved with the help and experience of this forum

[rhavrane]

Bonjour DBS88,
For your project, I would chooze an horizontal boier, I like my JMC ones, made on demand example : https://www.youtube.com/watch?v=42a9CLfYG9I but I especially the ones with a dome, example made by JPB : https://www.youtube.com/watch?v=hR0dupJQJv0 I have to be able to add a whistle, a gas regulator and a check valve for a pump and I wish a dedicated plug to fill it without unscrewing the safety valve (not possible on lot of old boilers).
2 x T2DR require some steam, even under 30 PSI and if you wish some autonomy, either you install a large boiler, more difficult to heat or you would think about a pump, either coupled on one of the engines (my preference), or electric.