How was the blower driven on this type of engine, and how were they cooled? If I remember correctly we had a Sultzer driving a compressor (way back in the distant past)that was air cooled, but we never saw it in the shop much as it seemed to "Just Run".Of course that engine was nowhere near the size of a marine engine.

The blowers on Mahout and her sister ship were Turbo blowers ( Brown Boveri )and they were water cooled by the main engine jacket cooling system . There were vents in the uppermost parts of the blower leading to the jacket water header tank ; they were very small bore pipes and one had to make sure they did not block up as that would have caused an air lock and overheating of the blowers . The BB blowers were excellent with very few problems .
The rotary exhaust valves were also water cooled from the jacket cooling system and their shaft glands were fed with lube oil from the main engine lubricating system .
hope than answers your question .

Regards Derek

On the RND type as you can see on the picture there is an electrical fan that starts at low rpm.
To get up the scav.air pressure on the Götaverken f.ex. they kept the internal scav.punp even with turbochargers.
With better combustion at low speed. In port it was many time easy to see what ship had a Sulzer or MAN main engines,
They usually had a lot more black smoke at start. Today they also have exhaust valve in top cover.

I have thoroughly enjoyed the discussions on this threat gentlemen. Thank you.
ps. Sailed with a Sulzer RD 76 on MV Mahout
Stuart

Stuart ;
Dont we both wish we could relive those happy days . Cheers Derek
PS hope retirement is not boring you .

Derek, thanks for your additional comments about the 3th Eng that you had on board, very recognisable story.
I think we've all met collegues like him on board.
My father was the only engineer on a small 400 tons DW coaster in the 1950's. In the year that I got my engineers certificate, which allowed me to sail on the largest vessels, I had the opportunity to sign on on a newly built coaster, for which only one engineer was required.
My father gave me the advise: "don't do it, on larger ships you will learn from the experience of your collegues on board by watching and listening." I decided to follow his advise and joined Nedlloyd, and I found out that he was right!
And so I heard the story about wrongly installed oil scraper rings on trunk piston engines several times sitting at the bar after work. Useful info. There is a story about a Nedlloyd C/E who allowed his engineers to write overtime whilst at the bar as long as they discussed work!!!! Is that something or not?

The Winterthur built 8RD76 I sailed with had a "breathing" problem causing the engine to run in a thermal overload condition.
A lot was tried to solve it: turbo's modified, aircoolers cleaned ashore ultrasonically and by using chemicals several times but nothing really helped.
The aircoolers were off-course fitted with an indicator to measure the diff.pressure over the cooler. After cleaning the coolers, the pressure drop was about an inch less, not very much.
Finally, the company decided to renew all the coolers and cut one open to see how it looked in the centre at the air side. Blocked for about 50% despite all the cleaning! (attempts)
Problem solved.
A representative of Drew Ameroid advised us to inject the aircooler cleaner (ACC-9 as I remember correctly?) aft of the blower.
As you all will remember, the discharge line of the blower passed through the top plate of the scavenge air receiver and than with a 90 degr. bend (with guide vanes in the corner of the pipe) over about one mtr. through the receiver where it entered the aircooler.
The idea was to inject ACC-9 in the horizontal part of the blower discharge line for which we had to cut holes in the receiver topplate (preferably exactly above the centre line of the pipe) and in the discharge line of the blower. Interesting job.
We had off-course a discussion how to inject the chemicals into the line, against the scavenge air flow, or with the air flow. It became "against the air flow"
I hope you all can agree with our solution, and if not: the vessel (LPG carrier) is scrapped.

Rederiert: I have sailed with an 8RND90 with the auxiliary blower in the centre of the receiver, as on Your picture, and I do not remember any difficulties with a smoking exhaust during manoeuvring. The Reed valves (a word that I will never forget thanks to Doxfordman) in the receiver were maintained on a regular basis, so that they did "Trrrrrrrrrrrrrrr instead of Trrrrr..rrrrr...rr!
The auxiliary blower kicked-in automatically below a certain scavenge air pressure (and stopped when the scav. air press. was sufficient)
The disadvantage of the auto start of the E-driven blower was that during longer stand-stll periods, whilst manoeuvring, the engine cooled down too much.
A 7RND-M which I sailed with had the auxiliary blower at the aft end of the engine, that was less favourable as the foremost cylinders got less air. That engine exhaust was sometimes black!
The Gotaverken engine with its constant pressure turbochargers in combination with conventional scavenge air pumps seems to tackle all these problems. Nice!
Best regards, Jan

Talking about chemicals. On a Sanko ship we had a British Chief.Eng. The Electro.Eng. was German.
There was some problem I don’t remember what, but the chief said "Use some chemicals".
When we was alone the German say to me " You see second this British people like to put chemicals in everything".