Single vs Twin: It's Baaaaack!

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RT Firefly said:
Greetings,
This thread was nonsense from the first post. I'm on my second bag of popcorn.
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I am outa beer.
But be back as soon as I re stock !

Hope not to miss anything while I am out.

:dance:
 
RickB said:
Here's proof you can have it both ways so stop pissssing on each other ...
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RE the pic on post 432 (my I-pad only does certain things. It corrects most of my spelling though.

Now if GB (and the rest) made their twins like this and put the same amount of power in both singles and twins we could compare them and learn which is more efficient. They no doubt thought it was too much trouble .. Money.

Heavy reverse throttle on the stbd eng, half throttle ahead w full right rudder and this guy would come very close to revolving in it's own length.
 
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RT Firefly said:
Greetings,
Mr. Murray M. Hmmm....Just how close to Saltspring ARE you?
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Well up the coast, I assure you, and I never partake in that reefer madness. There are these cute little mushrooms however, that give a particular scintillating sparkle to ones day...
 
RickB says "The other way around, a single diesel for cruise and two gas turbines for sprint. A delightfully complex and expensive combining gearbox drives two screws through over-running clutches for a CODAG drive."

Rick, while I respect your posts, your information here is wrong. I toured the HMCS Calgary, a Halifax class FFH (still have the peaked hat) and personally observed the pair of diesels and the single gas turbine in the ER. If I understood correctly what I was looking at (nobody there was from the engineering crew to explain) they all drove a single screw through a combining transmission. Some may have had a refit since I was aboard that one, but I doubt any have been repowered to your suggested configuration. In any event, so long as the fuel barge is nearby, sprint is what they do.
 
koliver said:
RickB says "The other way around, a single diesel for cruise and two gas turbines for sprint. A delightfully complex and expensive combining gearbox drives two screws through over-running clutches for a CODAG drive."

Rick, while I respect your posts, your information here is wrong. I toured the HMCS Calgary, a Halifax class FFH (still have the peaked hat) and personally observed the pair of diesels and the single gas turbine in the ER. If I understood correctly what I was looking at (nobody there was from the engineering crew to explain) they all drove a single screw through a combining transmission. Some may have had a refit since I was aboard that one, but I doubt any have been repowered to your suggested configuration. In any event, so long as the fuel barge is nearby, sprint is what they do.
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per wikipedia...
2 × General Electric LM2500 gas turbines, generating 47,500 shp
1 × SEMT Pielstick Diesel engine, generating 8,800 shp
1 × Royal de Schelde cross-connect gearbox
2 × Escher Wyss controllable pitch propellers
 
manyboats said:
RE the pic on post 432 (my I-pad only does certain things. It corrects most of my spelling though.

Now if GB (and the rest) made their twins like this and put the same amount of power in both singles and twins we could compare them and learn which is more efficient. They no doubt thought it was too much trouble .. Money.

Heavy reverse throttle on the stbd eng, half throttle ahead w full right rudder and this guy would come very close to revolving in it's own length.
Click to expand...

Eric

Our twin screw Tolly can easily be turned on its own length in either direction. Also, with rudders set at correct angle as well as applicable forward or reverse on proper engines and throttles adjusted correctly per engine she travels directly sideways in either direction away from a side tie or for any other reasons. Those items are another plus for twins. BTW: While in “idle rpm” I seldom touch the pilot wheel (leaving rudders straight) except when setting the rudders for any sideways movement or when going straight through a long canal. All other “idle speed” boat maneuvers are accomplished simply via shift positions, and when in gear throttle adjustments as may be required. :thumb:
 

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Now to take the whole twin engine thing to another level of what caan be done.
I was Chief Engineer on a Product tanker many years ago that had main propulsion of 2 x V20 Pielstick engines ( French built but still classed as Hitlers revenge)driving a single shaft with a variable pitch prop this was thru a gearbox to reduce the RPM to an acceptable level.
Also out of this gear box each engine could drive a 900 kw generator.
All connections were by air bag clutches so that various combinations could be made.
Very versatile but still a crappy set up.

This on a small scale may appeal to some of those that like multiple engines.

Cheers
Benn
 
Just to move this closer to the magic 500 posts and armageddon, when I hired into Boeing four of the five Pegasus-class PHMs were lined up side by side in the Renton high-bay building in the space that later became the 757 assembly line and today is another 737 line. Impressive vessels out of the water but they and the smaller Jetfoils that were built in the same building were not anything to write home about.

What we (Boeing) did with the jetfoil program was, in essence, design a machine with sophistication and technology approaching the jetliners of the day and then put it in a salt water environment.

When I lived in Hawaii we did the TV commercials for SeaFlight, the interisland high-speed ferry system that operated three Boeing Jetfoils. They were totally unsuited for a salt water, open ocean environment. For the relatively few years that SeaFlight was in operation, at least one of their boats was up on blocks every day at their maintenance yard having the latest short circuit or component failure sorted out.

The only place the Boeing Jetfoil proved successful was the run between Hong Kong and Macau where amazingly, they still operate today,
 
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RT Firefly said:
Greetings,
Mr. Peter B. Medicinal use only!

au_60.jpg
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Where do you come up with all these things from RTF..?
That post448 made me laugh so much me eyes watered so I couldna see mon...
 
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Greetings,
Mr. Peter B. Where is not important. My only concern is for your "buggered" fingers my brother...
 
RT Firefly said:
My only concern is for your "buggered" fingers my brother...
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Good point. I can accept (intellectually as opposed to physically...not that there's anything wrong with it) fingers doing the buggering, but how does one have their fingers buggered?
 
RT Firefly said:
Greetings,
Mr. Peter B. Where is not important. My only concern is for your "buggered" fingers my brother...
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Wasn't that the working title of one of the sequences they left out of the movie "Deliverance?"
 
RT Firefly said:
Greetings,
Attention Mr.'s Murray and Marin...

Definition of buggered (British & World English)

Please refer to post #448 again and keep it clean please. I don't think Mr. Peter was referring to the same type of INN-U-ENDO (sp?) you are.
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Isn`t Innuendo an Italian suppository?
Definitely not touching any "buggered fingers", physically or metaphorically.
(Just helping get to the magic 500)
 
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