Steam engine / boiler maintenance

[Jstemwedel]

I am planning to build a 23 ft. x 7.5 ft., 2.8 ft. draft launch (Gartside design no. 125). This vessel will be used on Lake Superior for trips to, and around, the Apostle Islands. The design calls for a steam engine of 8-10 hp. I am wondering how well this will work for the intended environment. I would like to make trips of up to 50 miles in one day. How much wood/coal would this require? I am also wondering if the steam plant would have sufficient reliability for Lake Superior, which is a fresh water sea, notorious for its storms and ice-cold water. Should I be considering a different power option, as sad as that would be?

[gondolier88]

Hi,

It has a very large displacement for it's length, as such this is no fast launch. 8hp will give you around 6-7Mph. I would recommend you look for a larger (10-12hp) engine, I can't see what the recommended prop' is on the drawing, but with a three blade prop with plenty of pitch (>=1.2 x dia.) and as large a diameter as you can swing you should be ok.

The boat has enough beam for decent coal bunkers so I really wouldn't worry overly much on fuel stowage- if you can store 6x(25kg) bags of coal you will be able to steam all day with plenty left in reserve for times when you need plenty of steam.

I would give boiler choice careful thought however- first of all you have a lot of water to play with, do you plan on day trips to and from base, or camping trips to remote spots? When you say 'stormy', do you mean electric storms, squalls, gales or hurricanes? Do you plan to run at hull speed all day, or tootle around at 3-4Mph?

You will not want a tall, heavy VFT if you have anything like a running swell you want your centre of gravity to be as low as possible- a high centre of gravity will just exaggerate any rolling motion as you make the righting moment more. Have you considered a locomotive type boiler- this is unusual on your side of the pond, but it would fill your requirements perfectly- low COG, steady steaming- but can be forced to produce steam quickly if needed. They are economical to run as they are a horizontal boiler, they leave usable space both above and below the barrel- a flat 'table' above, and room for storage or feed tank below (again keeping COG low in the boat). Other than a watertube boiler, they also are relatively lightweight for the power they produce.

A nice launch design if you choose to build it- 'though I don't envy you planking that stern...!

Greg

[Jstemwedel]

Thanks for your comments.

The design calls for a 20" x 30" propeller and recommends 8-10 hp. From your remarks it seems 10 hp should be the minimum.

Most of our trips will be from one base, but will occasionally camp overnight on an island. The one-way distance to most places we would want to go in the Apostle Islands would be 20 - 25 miles.

We would only plan to be out in fair weather, but Lake Superior weather is somewhat unpredictable, and a calm summer day can go to 4 -6 ft. seas in an hour or two. That is one reason I chose a design with plenty of beam, even though its a sacrifice in speed. In the fall and winter (when we would NOT be out), waves often reach 20 ft (with extremes of 30+ feet).

I have no objection to horizontal boilers, but am a bit concerned about the safety of a fire tube boiler (a severe steam tractor explosion in Ohio a few years ago comes to mind....)

While we're at it, I would be interested in comments on the engine type I should consider. To my way of thinking, simplicity would be preferred over other virtues, but I don't know whether single cylinder units are possible in the HP range I need. Probably will need to go with a 2 cylinder compound?

[DetroiTug]

Regarding required horsepower, just to give a rough idea. The tug 22 feet long steel hull, 8 foot beam, weighs around 4500 pounds, is ran at average 60 psi and 300 rpm, and it makes hull speed of 5-6 knots and more no problem.

Using the PLAN formula:

Pressure: 60 psi X Length of stroke in feet: .33 X Area of 3" piston 7.06" X Number of revolutions per minute 300 = 41936.4 /33,000 = 1.27 X 2 cylinders = 2.54 hp.

-Ron

[Jstemwedel]

Thanks Ron. Great looking boat -- I looked it up on Youtube!

What fuel do you burn, and what is your typical fuel consumption?

[mtnman]

Just my 2 cents, If you're not an experienced seaman I'd shy away from Superior. At least I wouldn't travel more that a couple hundred feet from shore. That lake is a killer.

[gondolier88]

Thanks for your comments.

The design calls for a 20" x 30" propeller and recommends 8-10 hp. From your remarks it seems 10 hp should be the minimum.

Most of our trips will be from one base, but will occasionally camp overnight on an island. The one-way distance to most places we would want to go in the Apostle Islands would be 20 - 25 miles.

We would only plan to be out in fair weather, but Lake Superior weather is somewhat unpredictable, and a calm summer day can go to 4 -6 ft. seas in an hour or two. That is one reason I chose a design with plenty of beam, even though its a sacrifice in speed. In the fall and winter (when we would NOT be out), waves often reach 20 ft (with extremes of 30+ feet).

I have no objection to horizontal boilers, but am a bit concerned about the safety of a fire tube boiler (a severe steam tractor explosion in Ohio a few years ago comes to mind....)

While we're at it, I would be interested in comments on the engine type I should consider. To my way of thinking, simplicity would be preferred over other virtues, but I don't know whether single cylinder units are possible in the HP range I need. Probably will need to go with a 2 cylinder compound?

A larger engine would give you the reserve to make sure you can get out of those situations when you need the power- they happen with higher regularity and with surprising speed than most imagine on inland lakes- I work on a puddle in comparison to Superior, but come across potentially boat/life threatening situations as a daily occurrence- 9 times out of 10 avoided through action on our behalf and swift use of steam power- we cruise at 8Mph with 8nhp, but require 20nhp to reach 12Mph- a fairly representative example of what reserve power is all about. Not only that, but a larger engine and boiler working at 40% output is far more efficient than a plant running at 90% output.

If you are worried about a horizontal fire-tube boiler exploding then you are already a far more responsible steam engine operator than the person who had the boiler explosion you mention. There are literally thousands of horizontal firetube boilers worldwide that are looked after by responsible people that are perfectly fine. You are right in thinking that if something went wrong with a water tube boiler it usually has less repercussions, but things tend to go wrong with water tube boilers more because of people's attitude towards their 'inherent safety'- whereas an owner of a fire tube boiler must keep in in tip top condition.

I would recommend you do as much research on plant set-up as you can.

You don't need a compound for what you are doing- you are only on good quality, clean freshwater, a high pressure twin will provide enough power, with simplicity in bucket loads, massive weight and space saving and quiet to boot.

Have look here; http://www.steamboatengines.co.uk/index.htm

Greg

[fredrosse]

Steam power is very reliable, while more work than a gasoline or dissel to keep running, as long as you have fire and water the steam plant will go. Not so with an engine that relies on electrics, or worse yet, electronics, and tiny small components like injectors, etc.

While the statement above is entirely true, there are many dissel engines that are very reliable, the ones that need no electricity to start and no electricity to run. Gasoline engines all require electrics, electricity and water do not mix well.

[fredrosse]

A locomotive type boiler (or, better yet, a gunboat type boiler) is every bit as safe as any other type, provided it is properly designed, properly maintained, and properly operated.

There are some types of boilers that can endure mis-treatment better than others, for example some coil/flash boilers have almost no risk of explosions, but these types have bad features also, and generally require more sophisticated controls. But a water level type boiler, be it firetube or watertube, is not a risk provided it is properly designed, properly maintained, and properly operated.

[Jstemwedel]

In response to earlier post ("Just my 2 cents, If you're not an experienced seaman I'd shy away from Superior. At least I wouldn't travel more that a couple hundred feet from shore. That lake is a killer."), I am a licensed Master of steam or motor vessels, any gross tons. That being said, I'm not so arrogant as to think that means very much if my boat can't handle the conditions. Best to avoid those conditions in the first place. Lake Superior has wrecked many ships and boats, but is also very popular for recreational boaters in the summer, particularly around the Apostle Islands. I have a VERY healthy respect for the big lake.

Could someone give an idea of how much maintenance is required for a small steam plant? I am familiar with large boilers and turbines, but I don't have any idea how to scale that level of maintenance down for a launch-size plant.