Sisson Triple

[barts]

Hallo Ron,
the design was 9 knots, with a reqired power of 24-25 HP.
Speeding and racing was never the intention.
I was very surprised at the 10 knots.

The engine shows a definite tendency to prefer left hand rotation
(much easier starting), and Sisson built around this time (1906) some
engines for the Windermere Saloon Launches where left-hand is the norm -
as far as I know, I could be wrong.

The steam consumption does also not fit with my calculations,
that was the reason to go for 9 knots.

Scotty

Note that the difference in power required from 9 to 10 knots is 1.37
(10^3/9^3); linking up to slow down even a little should help reduce
steam consumption significantly. Does the engine link up well? How's
the vacuum?

I wonder if this engine was modified/designed for more power than
normal to compete more effectively on Lake Windermere.

- Bart

[Scotty]

Hallo Bart,
linking up is not very satisfactory, the vacuum is very bad (appr. 50 %)
and the exhaust steam temperature much too high (appr. 95 °C) which in
my opinion is a further sign that something is definitevly wrong (overloaded).

If the engine was ever built for Windermere is NOT proven, it was stated by
the former owner, but I have my doubts.
There is nothing to be found about this engine on the website of the Museum.

I'm of the opinion:
- the engine was optimised for left hand running?
- some "expert" has tampered with the valve settings?

You can imagine how easy it is to tell the owner, that he has bought the wrong propeller.

Scotty

[DetroiTug]

If the exhaust temperature is very high, steam consumption by calculation is too high, the valves may simply be worn out and not sealing.

A good indicator, will it start in any orientation without a simpling valve? If yes, the valves need work.

-Ron

[gondolier88]

Was this engine formerly in the launch 'Gustav Primm'? If so, then yes it was built for a Windermere Launch

The engines in the Windermere launches are right hand rotation.

Marshall valve gear does not take kindly to being linked up at all, reducing the throw of already small valve movements only inhibits the performance.

I would be keen to see what the state of the valves is- any wear in the rings would indicate blow-by is occuring, it is very easy to muck the piston valve settings up on these engines as they are such short throw- these engines run perfectly well in both directions so I'm more than sceptical of your hunch of left handed running.

I can't tell on the photo, but if the engine is identical to Swallows engine in the Steamboat Museum I'm sure I could get permission to measure the valves up on hers for a comparison- although with everything going on there I'm not sure when I would get chance!

Greg

[Scotty]

Hallo Greg,
yes, the engine was in the "Gustav Prym".
There the steam consumption was no problem - oil fired boiler.
The only Windermere launch which fits would be the Shamrock?

The engine is similar in cyl. dimensions to the engine of "Swallow", but has a longer stroke at 8".

Interesting about the valve rings, according to the former owner there are no valve rings.
So we will have to take the valves out and check, this could explain a lot.

I would be very interested on any information on the valves, rings and dimensions.
There will be time enough as the engine would be taken out in autumn at the earliest.
Some other tests have to be done and slow steaming is more fun than racing.

Thank you for the information
Scotty

To answer Ron's question:

A good indicator, will it start in any orientation without a simpling valve? If yes, the valves need work.

It starts very easily, but sometimes you have to go quickly to the other direction with the reversing lever.
The simpling valve was and is never used.

[gondolier88]

Hi Scotty,

Indeed, the engine you have was built for Shamrock!

You could be right- many Sissons were plain bobbin piston valves and weren't ringed. However, this means that any misalignment over the years will be causing problems now. I'm still sure the valves lie at the heart of the problem, more than likely wear issues of one sort or another.

I'll ask and see what we can do about getting some comparitive measurements from Swallow's engine.

Another place to look is very carefully at the valve gear- there are many rocking bearings in the Sissons/Marshall setup, where small amounts of wear will make large differences in valve movements.

Very happy to see the engine is repowering a boat and not static in a museum somewhere- very good news indeed!

Greg

[Scotty]

Hallo Greg,

I'll ask and see what we can do about getting some comparitive measurements from Swallow's engine.

Thank you very much. Of course we will bear any costs arising.

I would also be interested in the overhaul procedures of the Windermere engineers vor valves and valve gear.

best regards
Scotty

[Scotty]

Coming back to the direction of rotation:

here http://www.shamrocktrust.org.uk/about.html you can find following:

The Propeller
The propeller is three-bladed, 27" (840mm) diameter x 40" (1m) pitch, left hand, and is driven via a 2" (50mm) diameter solid steel shaft. The original propeller on Swallow was borrowed to use as a pattern for casting in PB3 bronze at Vickers in Barrow.

Left or right, that's the question.

Scotty

[gondolier88]

Scotty,

Apologies- I remembered I had a picture of swallows prop- won't load up from my phone though! However, it is left-handed as you thought, not right handed as I could have sworn it was!

I asked at the museum yesterday about measuring up Swallows engine- provisionally it shouldn't be a problem, however it is now packed away with all the other engines in storage awaiting the new museum's construction so won't be available for comparison for quite a while unfortunately!

I believe that one of the universities over here has most of the archive for Sisson's drawings library which may also be a lead- I'll see what I can do to find out for you.

If you have an email adress I can send you the picture of Swallow's prop if you are interested?

Greg

[Scotty]

Thanks,
I have sent you a PN.

Scotty