|
Post by suburbanite on Dec 8, 2010 22:04:50 GMT -8
There has been plenty of discussion on several threads about the relative merits of various main engines, propulsion systems and auxiliaries. One reply suggested a separate thread to discuss them. Well, here it is.
If you want to discuss the relative merits of 4 cycle vs. 2 cycle diesels, Cat vs. EMD (now owned by Cat), Diesel-Electric vs. CP Props, Z drives, bow thrusters and generators, go for it.
And if you want to share info about Busch-Sulzers, Fairbanks-Morse or Washington-Estep's bring it here too.
To kick things off I'll offer this to spark discussion: WSF has many EMDs in the fleet and the last two new classes of vessels use 710s and at least one more set is in storage for the first 144 car ferry. Standardization on 710 EMDs seems a worthy goal. Is there a better alternative? If so, why?
|
|
lifc
Voyager
Posts: 471
|
Post by lifc on Dec 8, 2010 22:53:53 GMT -8
The EMD's are not near as efficient as the newer four stroke engines, especially at lower power output. They also use large amounts of lubricating oil. The cost of fuel is not likely to decrease, other options need to be looked at.
I am curious to see what the fuel consumption of the Chetzemoka is per day, it was projected to be about 1200 gallons. The large 6 cylinder Cat although slightly less overall powerful, which is not needed on this Vessel, would have been about 700 Gallons per day.
These are an old engine design, things change, life goes on.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Dec 10, 2010 12:28:05 GMT -8
While never having any experience working on EMD`s I certainly can`t add much to this, but from what I have heard and read, maintenance on one is second to none. I understand changing powerpacks (head, piston, rod and liner) in one pull sounds alot faster and easier than the method I`m used too. It seems that WSF has always done it right as well in the sense that keeping most of the fleet powered by the same engine model and family sure makes the spares department simple and with a low lead time on getting spares in an emergency. I suppose its true that the 2 strokes are not as popular these days with the enviromentally concerned though..
|
|
piglet
Chief Steward
Posts: 138
|
Post by piglet on Dec 10, 2010 23:41:54 GMT -8
Pulling power assemblies on EMD's is very straight forward and actually requires very few special tools. My experience is from working on them in the close confines of locomotives and two of us could handle the job very easily.
|
|
|
Post by suburbanite on Dec 11, 2010 0:22:37 GMT -8
Thanks everyone for posting. I hope this can become an enlightening discussion.
And a special thank you to piglet. Comments from those with real world experience are especially valuable, especially to those of us who's firsthand ferry knowledge is limited to the auto deck and up.
I did come across some interesting information while firmly planted in my arm chair. Despite what some may think about two cycle engines being out of date designs or facing emissions problems, it seams that there may be a lot of life left in the 710 EMD engines yet. And that is because of emissions regulations.
EMD has been making Tier 2 emissions compliant versions of the 710 for several years. They were able to do that with relatively simple changes to intercooling and combustion chamber design. Tier 4 is coming for large engine makers and is a real challenge for everyone. But EMD feels that they have a significant advantage with the two cycle engine. Exhaust gas recirculation is essential to meeting Tier 4. It lowers peak combustion temperature to keep NOx levels within the new tighter limits. 4 cycle engines will have to add complicated and maintenance hungry external EGR systems. EMD can do EGR inside the cylinder with exhaust valve timing, piston shape and intake port tuning. EMD expects to meet Tier 4 with a simpler, lower maintenance approach than the competition. Perhaps that is part of the reason Cat thought EMD was worth a billion dollars.
|
|
|
Post by old_wsf_fan on Jul 9, 2011 20:01:46 GMT -8
Can someone educate me on this subject a little?
I thought all the ferries were Diesel-Electric, in other words, diesel engines running electric drive motors. I have read that this was a very efficient type of propulsion, smooth and durable.
So I guess the Steels were the last of the D/E type of propulsion?
|
|
|
Post by Barnacle on Jul 9, 2011 20:13:13 GMT -8
Can someone educate me on this subject a little? I thought all the ferries were Diesel-Electric, in other words, diesel engines running electric drive motors. I have read that this was a very efficient type of propulsion, smooth and durable. So I guess the Steels were the last of the D/E type of propulsion? No; the Evergreens, Supers, Jumbos, and Jumbo-Mk IIs all have diesel-electric propulsion. The Issaquahs, Kwa-di-Tabils, Rhododendron and Hiyu are all variants on the direct drive diesel concept.
|
|
FNS
Voyager
The Empire Builder train of yesteryear in HO scale
Posts: 4,948
|
Post by FNS on Jul 9, 2011 22:04:03 GMT -8
To elaborate, here are the ferries and their propulsion:
WASHINGTON STATE FERRIES
TACOMA, WENATCHEE, PUYALLUP Diesel-Electric with Fixed Bladed Propellers
SPOKANE, WALLA WALLA Diesel-Electric with Fixed Bladed Propellers
HYAK, KALEETAN, YAKIMA, ELWHA Diesel-Electric with Fixed Bladed Propellers
ISSAQUAH, KITTITAS, KITSAP, CATHLAMET, CHELAN, SEALTH Direct-Drive Diesel with Controllable Pitch Propellers
EVERGREEN STATE, KLAHOWYA, TILLIKUM Diesel-Electric with Fixed Bladed Propellers
CHETZEMOKA, ISLAND HOME (KDT Prototype operating for SSA, Massachusetts) Direct-Drive Diesel with Fixed Bladed Propellers
SALISH, KENNEWICK Direct-Drive Diesel with Controllable Pitch Propellers
RHODODENDRON (Retiring soon) Direct-Drive Diesel with Controllable Pitch Propellers
HIYU Direct-Drive Diesel with Fixed Bladed Propellers
FORMER WASHINGTON STATE FERRY STILL OPERATING
GOVERNOR (Formerly WSF's KULSHAN, now operating for the SSA, Massachusetts) Diesel-Electric with Fixed Bladed Propellers CHANGED OVER IN SPRING 2011 TO: Direct-Drive Diesel with Fixed Bladed Propellers
|
|
|
Post by old_wsf_fan on Jul 9, 2011 22:21:30 GMT -8
Thank you to Barnacle and Ferrynut. My next question then is there any advantage to direct drive vs. diesel/electric? It seems to me that direct drive propulsion would be less costly to install in a given application, but would use more fuel as engine RPM for a direct drive has to be higher vs a diesel/electric engine running at a lower RPM to turn electric motors/generators? Does direct drive exert more wear on components than diesel/electric? Thanks again
|
|
|
Post by suburbanite on Jul 22, 2011 21:41:23 GMT -8
wsf fan
None of the current WSF fleet are actually direct drive diesels anymore. In a true direct drive the diesel engine and the prop shaft turn at the same RPM. To reverse the prop the engine has to be stopped and the rotation reversed just like with a reciprocating steam engine (think Virginia V). These engines were limited in RPM by the propeller speed and tended to be large and heavy for their horsepower. Direct drive diesel propulsion systems were popular in tug and ferry sized applications up to about 60 years ago. Today you will only find direct drive low speed marine diesels on very large ocean going vessels.
The diesel powered boats working for WSF today have reduction gears (or reduction/reverse gears) that allow medium speed (800-1000 RPM) or high speed (1500+ RPM) diesel engines to be used. As you suspected this is less expensive than a D-E drive of equal power. It is also lighter and that means either less hull to float it and push through the water or that more cargo can be carried. That means either a further reduction in construction and operating cost or a potential increase in operating revenue. The ratio of the reduction gear can be chosen to optimize the engine RPM for efficient cruising. The most efficient RPM may not be the lowest. Data on the specific fuel consumption of engines (gallons of fuel/horsepower hour) at various RPM is available from manufacturers and can be matched with reduction gear ratio, propellers, hull drag and anticipated operating practices to come up with the most economical design.
One of the problems with the Chetzemoka is that it has engines and gears that were sized to have enough low RPM "grunt" to start the fixed pitch prop on the bow when coming into a dock. That required large engines that are much bigger than were needed for cruising. That is why the Chetzy and her sisters have twice the horsepower of the similar sized Steel-Electrics, more than even the much larger Issaquahs.
The later two toy boats have CP props but used the same sized engine to avoid additional engineering costs, use engines that were already on hand and avoid delivery delays. That is great if you are riding at Keystone this summer but will add long term financial burdens to the ferry system. The whole KdT saga reminds me of the saying "fast, cheep or good....pick two." The state got about one and a half. They are getting the boats quickly and they are well built but not well designed for the WSF system. That shouldn't be a surprise since they are based on a design for another system with different operating conditions. And they are anything but cheap. WSF should have paid about half the price they did or received twice the boat for what they paid.
"Twice the boat" would be a fair description of the vessels WSF really wanted and badly needs, the 144s. They were designed to use a pair of 3000 horsepower EMD 710 V-12s. Six of the eight engines purchased by WSF to put in the 144s have been installed in the Chetzy and her sisters. With competitive bidding the 144s could likely be built for right around the price of the KdTs, about $70,000,000 each. We will see what the WFS actually pays after having what is essentially a monopoly supplier legislatively mandated.
The 144 propulsion system was designed based on the Issaquah class. After the troublesome controls delivered with the Issaquahs were replaced they have proven to be very reliable and efficient boats. Unlike the latter two Kdts they have a layshaft that allows the main engine at either end of the boat to send power to both props. That adds to operational flexibility, efficiency and safety.
Diesel-Electric propulsion offers the greatest reliability and flexibility. The Supers, Jumbos and Jumbo Mk IIs all have four EMD main engines. With that level of redundancy they can be operated safely at all but the fasted speeds with one main engine/generator off line. The Jumbo Mk IIs are unique among the WSFs D-Es in having alternating current generators and propultion motors. AC drive is more expensive than DC but offers even greater reliability and reduced maintenance compared to direct current generators and motors.
All the vessels designed for WFS since the Evergreen State have been fundamentally well designed for operations on Puget Sound and have given good service for many years. Some may have had teething problems or troubled overhauls but the designs have been fundamentally sound. The KdTs may prove to be an exception to this. They are well built but just aren't well designed for WSFs operating conditions. WSF made a good economic decision by favoring AC Diesel-Electric propulsion for the largest vessels and Diesel-Mechanical with CP props for the 144s. Having a Jumbo out of service is expensive and they should have the most reliable and redundant propulsion systems. And the Diesel-Mechanical-CP prop system has proven itself in the Issaquahs and should be equally efficient and reliable in the 144s. I just hope the 144s start arriving in sufficient numbers that the system can have a spare vessel larger and newer than the Hiyu soon.
|
|
|
Post by electrotech on Jul 23, 2011 15:47:26 GMT -8
Dare I tweak the topic.....
How is WSF seemingly more successful with diesel-electric propulsion compared to BCF's Super C's?
(I'm not well-read on the specifics of the WSF ships)
|
|
Nick
Voyager
Chief Engineer - Queen of Richmond
Posts: 2,078
|
Post by Nick on Jul 31, 2011 11:57:52 GMT -8
Dare I tweak the topic..... How is WSF seemingly more successful with diesel-electric propulsion compared to BCF's Super C's? (I'm not well-read on the specifics of the WSF ships) I don't see how WSF is more successful than BCF with regard to diesel electric propulsion. The Super-Cs had very minimal teething issues, and none of them had anything to do with the propulsion systems. The Super-Cs are a very good example of why diesel-electric is so great: They can run at service speed (21kts) with one engine offline, and can make 18kts with 2 offline. What I'm curious about is why WSF only uses diesel electric in their large vessels. I would have thought that increased reliability and flexibility would be an asset all their ships could benefit from.
|
|
|
Post by Kahloke on Sept 1, 2012 7:44:57 GMT -8
|
|
|
Post by compdude787 on Jan 8, 2013 8:27:48 GMT -8
Do you think the KdT's all need to be re-engined ASAP? Their engines definitely have too much horsepower for their size. 6,000 hp is insane for a boat that small.
I think they do need more efficient engines so they stop wasting so much fuel.
|
|
|
Post by Kahloke on Nov 22, 2013 15:44:36 GMT -8
22-Nov-2013:
From David Moseley's weekly update:
|
|
|
Post by Kahloke on Jan 17, 2014 14:59:20 GMT -8
|
|
|
Post by suburbanite on Oct 10, 2014 20:57:44 GMT -8
Is the Hyak hybrid repower dead?
|
|
|
Post by PeninsulaExplorer on Oct 11, 2014 13:35:25 GMT -8
Is the Hyak hybrid repower dead? No, the contract was awarded in June of 2014 and will start in October of 2015 to the May of 2016.
|
|
|
Post by suburbanite on Oct 11, 2014 17:47:08 GMT -8
Now that is a crying shame. Putting that kind of money into a into a 49 year old hull makes no sense. Maybe WSF wants an old boat that they can quietly retire if the repower turns out poorly. I was hoping the Hayk could go out with some dignity, and her telegraphs.
|
|
|
Post by Barnacle on Oct 12, 2014 5:11:18 GMT -8
Now that is a crying shame. Putting that kind of money into a into a 49 year old hull makes no sense. Maybe WSF wants an old boat that they can quietly retire if the repower turns out poorly. I was hoping the Hyak could go out with some dignity, and her telegraphs. I'm interested in the project, and it looks good on paper; I hope it comes out well. But I'm with you--it will be a sad day when those lovely old telegraphs disappear from the boat. They're the last of their kind in the system and it will be the end of an era.
|
|
|
Post by R30A on Oct 17, 2014 17:36:05 GMT -8
|
|
|
Post by Barnacle on Oct 21, 2014 9:45:14 GMT -8
Also assuming anyone bids on either contract.
|
|
|
Post by Kahloke on Nov 18, 2014 18:02:59 GMT -8
|
|
|
Post by Barnacle on Nov 19, 2014 7:20:22 GMT -8
So why is fuel now a third of its budget? Has the cost gone up for fuel that much? Or have they cut money for maintenance? The problem with percentages is that they still have to add up to 100 at the end of the day. I didn't see where the actual cost in real dollars was put forth. When did the cost recovery shift from 20 years to "a decade with 20 more years of savings after that"? And can I get a peek at their crystal ball which magically tells them fuel prices for the next thirty years? I have some questions about the next few years' Super Bowl, World Series, and Stanley Cup champions... I'm not against LNG as a fuel, but I think any LNG vessels WSF wants to operate should be started from the keel up, not a retrofit. Do it from the beginning and do it right.
|
|
|
Post by Kahloke on Nov 19, 2014 7:29:53 GMT -8
I'm not against LNG as a fuel, but I think any LNG vessels WSF wants to operate should be started from the keel up, not a retrofit. Do it from the beginning and do it right. I kind of agree with you there. My biggest concern about retrofitting the Issaquah's with LNG tanks is how those top-side tanks will affect vessel stability. What do those tanks weigh?
|
|