Liquid fueling (current tech)

[malcolmd]

On Befur, (27ft steam yacht) we use a diesel fired Yarrow Boiler. We have been developing this over some years, and now think we know how to build these sytems to work... so I wrote a "complete" review of the subject in our Blog - you might be interested https://sy-befur.co.uk/2024/10/11/a-com ... er-firing/

Cheers, let me know what you think....

Malcolm

[barts]

Interesting... thanks for posting a link to your blog entry! A very nice write-up.

Here in the US, the most common fuel oil burner is a steam atomizing jet. These are adaptable to smaller boats where the electrical requirements of a household-style burner are prohibitive, and works well in salt water and open boats. It does require more attention and is of course less safe overall - there's no "electric eye" to shutdown the fuel source in case the fire goes out - the fireman is a critical position. Single-handing boats with such oil burners in busy conditions can keep one hopping.

The actual design of the burner is simple enough, and there are lots of examples from the larger model steam locomotives to use as a starting point. I use a small electric fuel pump to provide fuel at a few PSI to the burner. The issues with these burners are in my experience:

* Fresh water consumption. I've seen that it raises overall water consumption to be about the same volume as fuel consumption, so one needs the same water reserves as fuel if operating in salt water. For boats boiling what they float in, the increase in water consumption should not cause problems if the boiler feed pump is adequately oversized.

* Starting.... when starting from cold there's no steam of course, and unlike full size practice, a donkey boiler for boot strapping is not workable. I've seen several approaches to this - startup on a wood fire, a small battery operated (or manual!) air compressor, a tank of C02, or a small propane bottle. I've used the latter for many years in our boat Otter. The C02 is clearly safer, but more awkward to refill; the wood fire requires a bit more work & space in the boiler, since an ash pan & air supply are needed.

* Starting and maintaining ignition... I've found that a small self-igniting propane torch is the handiest for starting such fires. Some care is needed to avoid generating a combustible mixture in the boiler prior to introducing the torch to avoid a loud "woof". I start the flow of propane or steam if we're already hot and then introduce the torch flame in the right position, and only then start the flow of fuel. If the fire goes out due to extremely gusty winds and a throttled down fire, a few moments w/ the fuel off will purged the boiler of unburned oil mist. Those who start on wood often have a hefty chuck of wood as a target for their fuel burner; this provides instant re-ignition in most cases. A hot refractory surface will also help maintain the fire. In very windy conditions, the draft changes can and do require some adjustments to air supply.

All in all, the nicest fuel I've used is wood, which is what we burn in our larger boat, Rainbow. It's practical here because we've lots of trees in the Pacific Northwest, and they often seem to fall over, keeping us supplied with wood w/ a bit of exercise. However, it does take up a fair amount of space in the boat.... with a wood fire, one can even bake muffins in the boiler at the end of the day when the fire has gone out .

- Bart

[malcolmd]

thanks Barts, interesting stuff