SUBSIM Radio Room Forums - Extended use of full engine power

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SUBSIM Radio Room Forums (https://www.subsim.com/radioroom/index.php)

- Silent Hunter III (https://www.subsim.com/radioroom/forumdisplay.php?f=182)

- - Extended use of full engine power (https://www.subsim.com/radioroom/showthread.php?t=209946)

Leandros

12-18-13 01:54 PM

Extended use of full engine power

It would have been nice with a mod that restricts the use of "full engine power" relative to time. Either by a warning or the creation of a "technical problem". This "technical problem" should be possible to fix (by the engineers) given a little time. Repeats should result in a permanent technical problem, if possible in an erratic manner. Going full blast on all engines for hours is rather unrealistic.

That said, my feeling is that technical problems usually are fixed too quickly. The general time scale for repairs should also be variable. Just my opinion.

Fred

Sailor Steve

12-18-13 02:06 PM

For all my complaints about SH2, it actually had mechanical breakdowns and extended repair times. So did good old Aces Of The Deep.

Karl Heinrich

12-18-13 02:06 PM

That's a great idea Leandros.

We always limit the time spent running the engines at over high RPMs even though the game doesn't penalise it currently.

LGN1	12-18-13 02:28 PM

Look at Item 19 of H.Sie's great work (and the manual of it):

http://www.subsim.com/radioroom/showthread.php?t=174225

:03:

Regards, LGN1

Leandros

12-18-13 04:18 PM

Quote:

Originally Posted by LGN1 (Post 2153158)

Look at Item 19 of H.Sie's great work (and the manual of it):

http://www.subsim.com/radioroom/showthread.php?t=174225

:03:

Regards, LGN1

Thank you, LGN1 - impressive list of mods. I shall look into it.

Fred

Leandros

12-18-13 08:04 PM

Oh, well - this looked a little complicated. Need to wait to try this till I have a period with some spare time....Looks necessary, though....:hmmm:....

Fred

mrbannon

12-18-13 09:56 PM

What an interesting thread. Why? Because I blew my port engine going flank after about 10 minutes. Is that normal?

HW3	12-18-13 11:10 PM

There is also the LRT mod (longer repair time) by ZMC. As far as I know the last version is 2.04, and is made for GWX 3.0.

GreyBeard

12-19-13 12:51 PM

Quote:

Originally Posted by mrbannon (Post 2153299)

What an interesting thread. Why? Because I blew my port engine going flank after about 10 minutes. Is that normal?

Did you mean normal for real or for SH3 with this mod? If the former, I guess you'd have to find someone with intimate knowledge/experience with those engines. I use the H.sie mod, I like it. I recently had one diesel damaged, although repairable, from a crash dive to avoid an aircraft. Thankfully that doesn't seem to be the norm as I've repeated that maneuver several times without consequence. I feel it is better than being able to cruise all day at flank speed with the only detriment being fuel mileage. :salute:

mikey117us

12-19-13 01:15 PM

this is the Translated U-Boat Standing order No. 29
Permanent Order No. 29.

Full speed of main Diesel engines at sea.

During any enemy operation, cruise at full speed with both Diesels every four days for half an hour, while observing cruising times in order to detect signs of engine trouble immediately and to safeguard the full use of the boats fighting capacity when opportunity arises.

C.C. U-boats Top Secret 02809/FS of 28/1/43.
So in Reality Full Speed was War Emergency Power and AK+1 (we can't do in sh3) is Flank Speed with the Electric Motors and Batteries Tied In. And Running at full speed was necessary in the parameters above. But Long Term Running was a recipe for a Broken Boat.

Leandros

12-19-13 02:32 PM

Quote:

Originally Posted by mikey117us (Post 2153511)

Diesels + electric? That ought to be a nice modding mission...:hmmm:..

As for permanent order no. 29 I should think it a particularly good idea to run the diesels up at intervals if run for longer periods at economic cruise (langsam fahrt). Diesels do have a tendency to "dirty up". One experience the same in diesel cars which have been "lady-driven".

If I run the diesels on my old minesweeper on idle for long periods it starts to emit a sort of oily "drops" from the funnel. Goes away when pressing it somewhat.

Fred

GreyBeard

12-19-13 02:52 PM

Quote:

Originally Posted by mikey117us (Post 2153511)

this is the Translated U-Boat Standing order No. 29
Permanent Order No. 29.

Full speed of main Diesel engines at sea.

.........cruise at full speed with both Diesels every four days for half an hour, ...........

But not flank speed. :timeout: I always found that confusing. :hmmm: Why is it called full speed when it is not really full speed, but flank speed is?

Leandros

12-19-13 04:58 PM

Quote:

Originally Posted by GreyBeard (Post 2153552)

But not flank speed. :timeout: I always found that confusing. :hmmm: Why is it called full speed when it is not really full speed, but flank speed is?

Ok, I am with you on this one - "full speed" is, I believe, something you can live with for a reasonable time while flank speed is really a sort of emergency effort. It was the same with aircraft piston engines at the time. 5 minutes was often set as a maximum but some engines could take it better than others. In a deplasement boat it really means very little regarding what you get out of it. When you have reached the ideal hull speed it takes so very much to increase it. In a aircraft it did, as in a climb with already reduced speed. In aircraft engines it was often coupled with water-methanol injection from a separate fuel tank. The Griffon engines in the Typhoon and Tempest were known to be more sensitive to overboost than, say, the Rolls-Royce or Allison V-12 engines. Simply because the Griffon was more powerful.

Fred

Maltadog

12-20-13 05:07 AM

<pedantic_mode>
The RR Griffon engine was build in late spitfire versions (Mk XIV mostly).

The engines which powered the Hawker Typhoon and Tempest were variants of the Napier Sabre.
</pedantic_mode>

:know:

GJO	12-20-13 05:14 AM

Quote:

Originally Posted by Leandros (Post 2153546)

Diesels + electric? That ought to be a nice modding mission...:hmmm:..

As for permanent order no. 29 I should think it a particularly good idea to run the diesels up at intervals if run for longer periods at economic cruise (langsam fahrt). Diesels do have a tendency to "dirty up". One experience the same in diesel cars which have been "lady-driven".

If I run the diesels on my old minesweeper on idle for long periods it starts to emit a sort of oily "drops" from the funnel. Goes away when pressing it somewhat.

Fred

Thank you Fred - you have provided an answer to a real life situation that we have had for some time. The old Kelvin diesel on our boat does just that after extended inland waterway runs at >250 rpm (I often get covered in small droplets of black oil from the diesel exhaust!) and it needs a real blast at 500+ rpm every now and then to clear it.
I believe that similar orders about the management of diesel engines were issued to German tank crews.

Leandros

12-20-13 06:14 AM

Quote:

Originally Posted by Maltadog (Post 2153689)

Whatever...:salute:....

Literature on the P-40 with Allisons in combat also frequently describes using an overboost function. It is usually stated to be used for max. 5 minutes.

Fred

Leandros

12-20-13 06:16 AM

Quote:

Originally Posted by GJO (Post 2153691)

Another issue in this context might be the visibility at sea of the exhaust fumes.

Fred

GJO	12-20-13 06:59 AM

Quote:

Originally Posted by Leandros (Post 2153713)

Another issue in this context might be the visibility of the exhaust fumes.

Fred

Indeed, according to my father (who was in the Royal Artillery HQ section during the Normandy landings) that was how they spotted the German tanks - it soon became known that (in his words) "The 'Jerry' would punctually start all their tank engines at the same time every morning and run them fast initially sending up clouds of dirty smoke and this gave the gunners the range and target" - the range was calculated with a stopwatch by comparing the time elapsed between sighting the initial exhaust smoke and then hearing the noise. Possibly a case where the renowned German punctuality was not such a positive asset . . .

GreyBeard

12-20-13 09:34 AM

Quote:

Originally Posted by Leandros (Post 2153588)

Ok, I am with you on this one - "full speed" is..............Griffon was more powerful.

Fred

Thank you for the explanation, now I get it. Back in the early `80's a few Formula 1 race teams began using engines that became know as qualifying grenades. Their hp was increased so much that they lasted 2/3 laps before "grenading" themselves. They were essentially the "flank speed" of Formula 1 engines. They were outlawed because not all teams could afford them.

:salute:

the dark knight

12-20-13 10:50 PM

Just a heads up guys, German tanks in WWII ran on high octane gasoline. The only country using Diesel's in tanks was Russia. The reason most people think German tanks were Diesel is because, unlike the Sherman, they did not burst into flames when a shell pierced the armor. The Germans, unlike the U.S.A., had the fuel tanks isolated in their own compartments, so spilt fuel, or a ruptured fuel tank was less likely to catch fire on hot exhaust pipes.

I have read that Germania built engines in the Type VII would spin a bearing, or throw a rod if run at high speeds for very long. On the other hand, having a M.A.N. engine was a blessing. I have heard they were better built, and made more power at the same RPM as the Germania Werft engines. So perhaps it boils down to a few things; engine manufacturer, how the engines have been taken care of (maintenance), and number of hours on the engines them selves.

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