OILER

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SPEED
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STORIES

Capt. Patrick Moloney checked of his notebook and found some stuff of interest on oiler speed. The 143's had 18 foot props with 18' pitch (one full turn with no friction loss should push the ship ahead 18 feet).

  This information came from Terry Kuehn 's question - What is the fastest Hassayampa has ever gone?

In practice and normal operating conditions I used 72 rpm for 12 knots (unrep speed).  That would be with 75-80% load, and the bottom and sides not too fouled.  At the end of a long IO (Indian Ocean) deployment with a full load and a foul bottom and the waterline looking like a kelp garden it took 76 turns to make 12 kts.
The MISPILLION took 80 rpm to make 12 kts.  Must have had smaller wheels.

On HASS I could vary speed from dead slow (25 or so turns) up to 105 without letting the Chief Engineer know. From 105 to 115 I'd warn the Chief, but could get the turns on demand.  Above 115 turns was more of a production.  We had to take the forced draft blowers up to 4th speed which was a big electrical load.  Every once in a while we would push her up to 125 turns, which got us to the 20 knot range.  We would be watching the doppler speed log on the bridge and when it edged over 20 there would be high five's and a happy notification to the engineroom.

One time we had a high priority job involving a frigate on a special mission.  We ran with her at 20 knots for a day and night, then in the morning I dropped to 19.1 knots and refueled her with one rig and one pump.  Fastest we ever did it.  Sea conditions were good and the ships were handling like they were on rails.  I don't think we used more than 5 degrees of rudder and stayed within 0.5 degrees of romeo corpen (unrep course).
HASS was always the fastest of the sisters because we pushed her harder.  When I had PONCH it was monsoon season in the IO and we couldn't push too hard.  On the princess KAWISHIWI they pampered the plant.  I used to give the engineers a hard time when I'd ask for a fast bell and they would have to check with the Chief.  They didn't like to hear about what we could do on the HASS.

When unrepping you couldn't ask for a 1 rpm speed change.  The engineers would laugh at you.  If I needed one, I'd ask for up three turns, then later when the plant settled out, drop 2 turns.  More often than not, I'd ask for a two turn increase on one shaft and just adjust by steering to offset it.

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Capt. Pat -  Oct. 17, 2010,




Boy does this bring back memories!
Lary Harris 75-78


As I remember from the USS Kawishiwi days (pre-MSC) the engineering plant was a real nightmare, and there were two BIG things that limited our top speed and our reliability.


The generators (SSTG's) were 500 KW each, and all three needed to be on line in order to get to 4th speed on the forced draft blowers (and run all of the hotel services as well).  The problem was (in addition to the fact that there was almost no reserve capacity) that the generators did not play well together.  When all three were running in parallel they had a bad tendency to "hunt", with the generators surging and swapping load amongst the three.
This would become progressively worse with time until the KW meters and Power Factor meters would be making wild swings and the governors would visibly be opening and closing the steam throttles to the generators.  Finally, inevitably, one generator would trip out (the reverse current relay on the main generator breaker of one machine would "open").  Then there were two generators running at about 115% of rated load and the duty electrician on the switchboard had about 20 seconds to "strip" the board of non-vital loads or the remaining two generators would also trip on overload and we would go D. I. W. .  This happened so frequently that we engineers developed a sort of PTSD.  I remember sitting in a nice restaurant in Honolulu with a very attractive date (cute little Army nurse) when the management dimmed the lights.  Before I could stop myself I had jumped to my feet and sprinted to the door (heading to the engine room, of course).  This really put a damper on the evening, not to mention startling the other guests. 

The Navy spent a lot of money trying to figure out what the problem was - but they kept looking at the governors as the culprit.  This was sort of logical as the problem was manifest by an inability to evenly share the KW load (i.e. all three generators pulling an equal horsepower load).  The governors were repeatedly disassembled, inspected and rebuilt.  Modifications such as needle bearings were included in the linkage between the governors and the steam throttle valves to reduce hysterisys and lost motion.  We spent weeks at the PHNSY running the generators on "salt box" artificial loads to measure their response to various loads.  All to no avail.  They were still lousy right up to their final day in USN service.

When the 143's were turned over to MSC this issue was studied again, as the problem was quite well known and this would never work with the reduced level of manning planned by MSC.  Fortunately the engineers at MSC quickly recognized that the problem was with with the exciters and voltage regulators on the generators, not the governors.  The original exciter / regulators were archaic General Electric "Rototrol" proprietary units which were of a WW II era design.  These were replaced with more modern brush-less exciters and solid state regulators - problem solved and the generators played well together forever after.  Generator capacity was still marginal, but now only a mechanical failure would stop the generators and they were pretty trouble free.

The second problem with operating at high speeds was that the originally installed boiler feed pumps were also marginal. These were Pacific pumps of a traditional multi-stage design and they just did not have sufficient capacity to  supply the boilers.  This was compounded by the boilers themselves which had quite small steam drums for boilers of their steam generating capacity.  These boilers needed feed pumps with lots of capacity in order to quickly supply additional feed water to the boilers when answering bells (as changes in steam pressure while maneuvering causes "shrink" and "swell" - spurious changes in the apparent water level in the boiler sight glasses).  The inadequate capacity of the feed pumps meant that we spent a lot of time with water out of sight either high water or low water in the sight glasses.  This caused the MPA to drink a lot as I remember.  At full speed both feed pumps were running at full capacity and if one pump failed (which happened frequently with these pieces of  crap) the EOW had about 15 seconds to start closing the throttles before we had a severe low water casualty.  Everyone really needed to be on their toes 24/7 when we were doing anything over 12 knots.

Again, MSC came to the rescue by replacing the Pacific feed pumps with a pair of Coffin pumps.  These things were real gems - one moving part with a steam turbine driving a single stage impeller.  One pump had more than enough capacity to run the ship to 21 knots, so there was always a standby pump.  These were amazingly reliable as well, and I never remember having a problem of any kind with the Coffin pumps. 

The electrical controllers for the forced draft blowers were problematic. There was a complicated multi-speed controller for each forced draft blower motor.  These controllers were about the size of a large double-door refrigerator and the inside was a maze of relays, time delay controls  and iron-washer resistor banks.  In the USN days, when we were maneuvering and speed changes were expected,  the EMC on the Kawishiwi would position himself between the two controllers, with the doors tied open.   When a relay stuck or a time delay failed to do it's proper thing, he would poke around with a sawed off broom handle until order was restored. The arcing and sparking was quite dramatic.

I don't think that MSC did any real drastic modification to these controllers, but they did change out the control switches at the burner front to a different switch that took a much more deliberate action on the part of the operator to shift from one speed to the next, preventing an accidental 2-4 or 1-3 speed change without going through the proper sequence.  I do remember that the forced draft blower motors were a bit unusual in that they were "bar wound" - that is the motor windings were made from pre-formed copper bars as opposed to copper wire which is the normal instance.

Even in the USN days the Kawishiwi could put on a pretty good turn of speed when she was cooperating.  During the days when Foster S. "Tooter" Teague, Capt. USN, (of Vietnam Era "Top Gun Fighter School" fame) was our skipper and we would go out for local weekday ops from Subic Bay, Tooter wanted to get back to the pier in time for a fun filled Friday night at the Cubi Point O' Club.  This was during the austere and fuel conscious early 1970's when the fleet was put on a strict 12 knot transit speed for reasons of fuel economy.  At about 1330 on Friday afternoons Tooter would ring up "All ahead Flank" and we would leave the rest of the task group wallowing along at 12 knots while we high-tailed it back to Subic at 20 - 21 knots.  Even though Tooter was not the Senior member of the task group, he had enough of a reputation that SOPA turned a blind eye to this.  Everyone knew that you did not want to be the one to get between Tooter and his Cutty Sark. 

That's how I remember it !

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Best wishes, Lary Harris  -  Oct. 17, 2010.

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