condensing without a pump

[Ethelred]

I have read on here that it is possible to run a keel condenser without a pump, relying on exhaust pressure to return the condensate to the hotwell. How well does this work in practise? It seems like a reasonable approach if running a single, say a 3 x 4, where vacuum isn't as important as on a compound, but where one needs to run closed loop.

[Lopez Mike]

That's the way my boat is set up. 3 x 4 single. There is about a foot of rise from the low end of the keel condenser to the top of the hot well. I have experimented with disconnecting the output of the condenser where it comes through the hull and letting it run into the bilge and there was no change in the engine r.p.m.

If I was running a compound I would probably add a condensate pump and run some vacuum but both theoretically and practically a single expansion engine hardly benefits enough to justify the extra fuss.

[Ethelred]

Thanks for that. That's just what I was hoping. I think we're both paid up members of the keep it simple brigade
Further to which I'm fascinated by the discussion re Mr Kitchen's rudder. Looks like you could junk all the reversing gear too and just run a single with a water pump. Mmmmm....

[Lopez Mike]

I think that it would be simpler to keep reversing gear on your single.

A reason that Bart is designing around that reversing rudder is that his engine is not designed for reversing. Even those three cylinder uniflows that Disney tried had some embarrassing failures to reverse at critical moments.

One thing to consider is a feed water pump that doesn't care about the direction of rotation. The Hypro is the commonest example. They are cheap and stone reliable if you do a little filtering of the input.

There is a reason that so many launches are direct reverse using Stevenson valve gear. Almost the only change I would do to my boat would be to have a twin in order to have less fussing to start and reverse. Between kicking the flywheel and rocking the reverse level I don't hit things or alarm anyone but a twin would be easier for a naive operator. I have kids as young as eight running my boat. Everything else including managing the fire with an eye to the future they do fine but kicking the flywheel is hard for them.

[DetroiTug]

Yes, I second the twin, like operating an electric motor for forward and reverse.

-Ron

[Ethelred]

These are the only people in the world mass-producing steam engines, Tinytech Plants in India. They're cheap, redesigned and much better made than they used to be. However as they're primarily made for electricity generating and other industrial uses they don't bother with reversing gear. One of those, a hypro water pump, a donkey boiler and a kitchen rudder and away you go.

This is about project 7 after finishing the boiler casing, refurbishing the current boat's woodwork, a bit of work on the motorbike and then there's that Mustang I've been yearning for...one day...

[Lopez Mike]

This Youtube video shows reversing gear: https://www.youtube.com/watch?v=54s4vg3IgYg

I love steam but the idea of zillions of little boilers all over India dumping CO2 gives me pause. Isn't this one of the reasons Britain lost their forests?

[Ethelred]

That's their older design. The newer ones are enclosed, use a piston valve and have no reversing gear and the enclosed design makes it difficult to incorporate one, hence the interest in the kitchen rudder. They're principally sold into Africa and forested parts of Asia where the wood as a fuel is readily available.
We lost our forests partly due to using wood to stay warm but mostly building sailing ships like the Victory.

[cyberbadger]

They're cheap, redesigned and much better made than they used to be.

Good to hear.
Oh boy there was a video with tinypower engines running and the steel balls flying out of the bearing races on the eccentrics. while the narrator was taking about the engines.

I'm all for that kind of stuff if they make a decent engine, maybe they listened to their customers... Good on them.

-CB

[DetroiTug]

"video with tinypower engines"

You mean "Tinytech" I've not heard not too many good things about those engines from India.

Tinypower on the other hand, their casting sets are first rate as are the engines that they produce and sell. I've seen them up close and they do a good job on them. Well finished and quiet running.

-Ron