|
Diesel electric
I am building a 60 foot aluminum sailyacht and considering using diesel
electric propulsion with 2 identical diesel enigins of 70 - 100 hp. The builder is not very experienced in ths field so I am doing some fieldwork myself . Anyone with experience in diesel eletric solutions in this size for sailing yachts? Cheers. Marc |
Diesel electric
I've gone around the diesel electric question on a few research vessels
where it is a good solution. It is going to be quite expensive. It makes most sense when the loads while the boat is not moving are a significant percentage of propulsion loads. This doesn't fit the ususal cruiser profile (except maybe for Skip and Lydia:) You had better have a builder who really understands it. There are going to be some complex boxes and equipment in between the generators and the props. Keeping them cool and dry will be a challange. The wiring will be unlike anything most builders have seen. It's going to take up a lot more space than a conventional propulsion plant. There will be some effeciency losses so you will need to carry more fuel on a boat that already is devoting extra space and weight to this enthusiasm. When you have problems with it and pull into Pango Nowhere, it's going to be amusing watching the locals trying to figure out how to fix it. I love diesel electric but it would not have crossed my mind to try it in a 60 foot sailboat. If having a DE sailboat is a goal in itself because you like to tinker and want to be a pioneer, cool. If you just want to sail and cruise, I would forget it. You can use that space, weight, money, and research effort much more usefully. -- Roger Long |
Diesel electric
On Wed, 1 Aug 2007 08:36:11 -0400, "Roger Long"
wrote: I've gone around the diesel electric question on a few research vessels where it is a good solution. It is going to be quite expensive. It makes most sense when the loads while the boat is not moving are a significant percentage of propulsion loads. This doesn't fit the ususal cruiser profile (except maybe for Skip and Lydia:) You had better have a builder who really understands it. There are going to be some complex boxes and equipment in between the generators and the props. Keeping them cool and dry will be a challange. The wiring will be unlike anything most builders have seen. It's going to take up a lot more space than a conventional propulsion plant. There will be some effeciency losses so you will need to carry more fuel on a boat that already is devoting extra space and weight to this enthusiasm. When you have problems with it and pull into Pango Nowhere, it's going to be amusing watching the locals trying to figure out how to fix it. I love diesel electric but it would not have crossed my mind to try it in a 60 foot sailboat. If having a DE sailboat is a goal in itself because you like to tinker and want to be a pioneer, cool. If you just want to sail and cruise, I would forget it. You can use that space, weight, money, and research effort much more usefully. There was an article in "PassageMaker" a while back about the conversion of a trawler yacht from diesel to diesel-electric. It, frankly, looked like a corporate promotion article -- perfectly lighted photos and from the prospectives , obviously professional camera equipment, but anyway. The crux of the article was that the owner removed two main engines and replaced them with a single, larger prime mover driving either an alternator or generator (I don't remember which way he got his electricity). Each of the original propellers/shafts, etc, were replaced by DC motors directly coupled to the shafts. The whole caboodle was SCR controlled and the genrator/alternator and both DC drive motors were water cooled. The electric controls looked similar to the SCR controls in an off shore drilling rig. From looking at the pictures there appeared to be little of the installation that was "off the shelf" and my guess was that the whole installation must have been far in excess of what the original twin engine installation was. Bruce in Bangkok (brucepaigeATgmailDOTcom) |
Diesel electric
Roger & Bruce; thanks for your reaction. Pioneering is nice.. but not at any
price ;-) Not my main reason for looking into this... My main objectives are : - having a backup engine with which she should at least run 4 kn without having the need for double propellors (too much drag it's a fast sailing yacht nog an moto sailor ;-) - not needing a seperate generator by using one of the main engines as a generator - less noise / vibration? Hope to get in contact with someone who has a 60 or 70 foot sailing yacht running with diesel eletric propulsion. If there is any :-) Grtz Marc sy Beluga wrote in message ... On Wed, 1 Aug 2007 08:36:11 -0400, "Roger Long" wrote: I've gone around the diesel electric question on a few research vessels where it is a good solution. It is going to be quite expensive. It makes most sense when the loads while the boat is not moving are a significant percentage of propulsion loads. This doesn't fit the ususal cruiser profile (except maybe for Skip and Lydia:) You had better have a builder who really understands it. There are going to be some complex boxes and equipment in between the generators and the props. Keeping them cool and dry will be a challange. The wiring will be unlike anything most builders have seen. It's going to take up a lot more space than a conventional propulsion plant. There will be some effeciency losses so you will need to carry more fuel on a boat that already is devoting extra space and weight to this enthusiasm. When you have problems with it and pull into Pango Nowhere, it's going to be amusing watching the locals trying to figure out how to fix it. I love diesel electric but it would not have crossed my mind to try it in a 60 foot sailboat. If having a DE sailboat is a goal in itself because you like to tinker and want to be a pioneer, cool. If you just want to sail and cruise, I would forget it. You can use that space, weight, money, and research effort much more usefully. There was an article in "PassageMaker" a while back about the conversion of a trawler yacht from diesel to diesel-electric. It, frankly, looked like a corporate promotion article -- perfectly lighted photos and from the prospectives , obviously professional camera equipment, but anyway. The crux of the article was that the owner removed two main engines and replaced them with a single, larger prime mover driving either an alternator or generator (I don't remember which way he got his electricity). Each of the original propellers/shafts, etc, were replaced by DC motors directly coupled to the shafts. The whole caboodle was SCR controlled and the genrator/alternator and both DC drive motors were water cooled. The electric controls looked similar to the SCR controls in an off shore drilling rig. From looking at the pictures there appeared to be little of the installation that was "off the shelf" and my guess was that the whole installation must have been far in excess of what the original twin engine installation was. Bruce in Bangkok (brucepaigeATgmailDOTcom) |
Diesel electric
"Marc" wrote My main objectives are : - having a backup engine with which she should at least run 4 kn without having the need for double propellors (too much drag it's a fast sailing yacht nog an moto sailor ;-) You already have the back up. They are called sails. If a diesel used in auxilliar sailboat service doesn't run, it is as apt to be a fuel problem as anything else. Your second engine will then be down as well. - not needing a seperate generator by using one of the main engines as a generator - less noise / vibration? A big generator is going to be noiser than a small one. One large enough to drive the boat is going to be big. Air supply and exhaust are major and hard to control noise sources. Bigger generators just make it even more difficult. Generator's are not happy running at light loads. Unless your hotel load approaches 50% of your propulsion load running just the one generator for ship's service will probably result in it's running too lightly. If you do put in enough hotel load, AC, Jacuzzi, etc., to load up the generator, where are you going to carry all the fuel? Hope to get in contact with someone who has a 60 or 70 foot sailing yacht running with diesel eletric propulsion. If there is any :-) I'll be amazed if you find one for the above reasons. If you do, please let us know. Grtz Marc sy Beluga wrote in message ... On Wed, 1 Aug 2007 08:36:11 -0400, "Roger Long" wrote: I've gone around the diesel electric question on a few research vessels where it is a good solution. It is going to be quite expensive. It makes most sense when the loads while the boat is not moving are a significant percentage of propulsion loads. This doesn't fit the ususal cruiser profile (except maybe for Skip and Lydia:) You had better have a builder who really understands it. There are going to be some complex boxes and equipment in between the generators and the props. Keeping them cool and dry will be a challange. The wiring will be unlike anything most builders have seen. It's going to take up a lot more space than a conventional propulsion plant. There will be some effeciency losses so you will need to carry more fuel on a boat that already is devoting extra space and weight to this enthusiasm. When you have problems with it and pull into Pango Nowhere, it's going to be amusing watching the locals trying to figure out how to fix it. I love diesel electric but it would not have crossed my mind to try it in a 60 foot sailboat. If having a DE sailboat is a goal in itself because you like to tinker and want to be a pioneer, cool. If you just want to sail and cruise, I would forget it. You can use that space, weight, money, and research effort much more usefully. There was an article in "PassageMaker" a while back about the conversion of a trawler yacht from diesel to diesel-electric. It, frankly, looked like a corporate promotion article -- perfectly lighted photos and from the prospectives , obviously professional camera equipment, but anyway. The crux of the article was that the owner removed two main engines and replaced them with a single, larger prime mover driving either an alternator or generator (I don't remember which way he got his electricity). Each of the original propellers/shafts, etc, were replaced by DC motors directly coupled to the shafts. The whole caboodle was SCR controlled and the genrator/alternator and both DC drive motors were water cooled. The electric controls looked similar to the SCR controls in an off shore drilling rig. From looking at the pictures there appeared to be little of the installation that was "off the shelf" and my guess was that the whole installation must have been far in excess of what the original twin engine installation was. Bruce in Bangkok (brucepaigeATgmailDOTcom) |
Diesel electric
So... you might be right. No reason for me to look into this option any
further. Spend my money on a good main engine and a nice small generator and saving a lot for extended cruising time ;-) "Roger Long" wrote in message ... "Marc" wrote My main objectives are : - having a backup engine with which she should at least run 4 kn without having the need for double propellors (too much drag it's a fast sailing yacht nog an moto sailor ;-) You already have the back up. They are called sails. If a diesel used in auxilliar sailboat service doesn't run, it is as apt to be a fuel problem as anything else. Your second engine will then be down as well. - not needing a seperate generator by using one of the main engines as a generator - less noise / vibration? A big generator is going to be noiser than a small one. One large enough to drive the boat is going to be big. Air supply and exhaust are major and hard to control noise sources. Bigger generators just make it even more difficult. Generator's are not happy running at light loads. Unless your hotel load approaches 50% of your propulsion load running just the one generator for ship's service will probably result in it's running too lightly. If you do put in enough hotel load, AC, Jacuzzi, etc., to load up the generator, where are you going to carry all the fuel? Hope to get in contact with someone who has a 60 or 70 foot sailing yacht running with diesel eletric propulsion. If there is any :-) I'll be amazed if you find one for the above reasons. If you do, please let us know. Grtz Marc sy Beluga wrote in message ... On Wed, 1 Aug 2007 08:36:11 -0400, "Roger Long" wrote: I've gone around the diesel electric question on a few research vessels where it is a good solution. It is going to be quite expensive. It makes most sense when the loads while the boat is not moving are a significant percentage of propulsion loads. This doesn't fit the ususal cruiser profile (except maybe for Skip and Lydia:) You had better have a builder who really understands it. There are going to be some complex boxes and equipment in between the generators and the props. Keeping them cool and dry will be a challange. The wiring will be unlike anything most builders have seen. It's going to take up a lot more space than a conventional propulsion plant. There will be some effeciency losses so you will need to carry more fuel on a boat that already is devoting extra space and weight to this enthusiasm. When you have problems with it and pull into Pango Nowhere, it's going to be amusing watching the locals trying to figure out how to fix it. I love diesel electric but it would not have crossed my mind to try it in a 60 foot sailboat. If having a DE sailboat is a goal in itself because you like to tinker and want to be a pioneer, cool. If you just want to sail and cruise, I would forget it. You can use that space, weight, money, and research effort much more usefully. There was an article in "PassageMaker" a while back about the conversion of a trawler yacht from diesel to diesel-electric. It, frankly, looked like a corporate promotion article -- perfectly lighted photos and from the prospectives , obviously professional camera equipment, but anyway. The crux of the article was that the owner removed two main engines and replaced them with a single, larger prime mover driving either an alternator or generator (I don't remember which way he got his electricity). Each of the original propellers/shafts, etc, were replaced by DC motors directly coupled to the shafts. The whole caboodle was SCR controlled and the genrator/alternator and both DC drive motors were water cooled. The electric controls looked similar to the SCR controls in an off shore drilling rig. From looking at the pictures there appeared to be little of the installation that was "off the shelf" and my guess was that the whole installation must have been far in excess of what the original twin engine installation was. Bruce in Bangkok (brucepaigeATgmailDOTcom) |
Diesel electric
On Aug 1, 2:15 am, "Marc" wrote:
.... Anyone with experience in diesel eletric solutions in this size for sailing yachts? ... You might want to read the two part series in PBB (http://www.proboat- digital.com/proboat/20070607/) on hybrid propulsion. They cover engine sizing and a good deal more. It sounds like you've already decided that you want to go with electric and I don't want to dissuade you However, if you are just after fuel economy and are looking at a true diesel electric system rather than an electric boat with backup generation a variable pitch propeller will do a better job than an electric transmission for a good deal less money. -- Tom. |
Diesel electric
|
Diesel electric
On Aug 1, 5:15 am, "Marc" wrote:
I am building a 60 foot aluminum sailyacht and considering using diesel electric propulsion with 2 identical diesel enigins of 70 - 100 hp. The builder is not very experienced in ths field so I am doing some fieldwork myself . Anyone with experience in diesel eletric solutions in this size for sailing yachts? Cheers. Marc The latest CRUISING WORLD magazine has a nice intro to diesel electric. July 2007 It is a modern thing I guess. A real cool idea is to always have a small generator running. And so true cool charter living is possible. A 500 gallon tank maybe. My next real boat is to have tanks worthy of fuel resale. I wanted diesel ballast. Pumped from side to side for heavy weather sailing. A 1000 gallon tank! I just inherested a Peason 26:) So I have time to plan. If you design around the tanks a good pattern is a center tank 250 gallon and three side tanks each side. Anyways that is my dream ship idea. REAL COOL chartering. All cool all the time. As money goes the cost to move the extra fuel is minimal. Sail efficiency is like steel rail after the boat goes heavy. If you have a heavy ship. Wow that is fun making a new small ship. Except here is my advice. A single engine to make the cross Atlantic voyage. A second smaller wing engine with a sail drive. 250 hp for a main. and then a sixty for the wing. Straight shaft all weather. A good diesel runs almost underwater. If your electric plans are all weather without open connection then maybe they compare to direct shafts. All the time diesel power allows full electric. SO a third diesel a 10Kw Onan suffices. And lastly. For resale value consideration, what is the correct auxillary? A new aluminum 60 footer? I would make it a charter footprint for benefit of resale. |
Diesel electric
On Wed, 1 Aug 2007 16:44:41 +0200, "Marc" wrote:
Roger & Bruce; thanks for your reaction. Pioneering is nice.. but not at any price ;-) Not my main reason for looking into this... My main objectives are : - having a backup engine with which she should at least run 4 kn without having the need for double propellors (too much drag it's a fast sailing yacht nog an moto sailor ;-) - not needing a seperate generator by using one of the main engines as a generator - less noise / vibration? Consider putting a folding or feathering prop on the "wing" engine to minimize drag. Mount two large alternators on each engine (200+amps), and use them to drive a large battery bank and redundant inverters. That will be much cheaper to build and service than a diesel electric system, and will give you full backup for everything. Many long range cruising trawlers are being built that way. |
Diesel electric
On Aug 1, 4:44 am, "Marc" wrote:
.... My main objectives are : - having a backup engine with which she should at least run 4 kn without having the need for double propellors (too much drag it's a fast sailing yacht nog an moto sailor ;-) .... Well, I don't want to get into the my boat is faster than... ALL sailboats are slow. Still, I do have a cruising boat with top speeds right around twenty knots under sail and it has two engines and two props. It also has two rudders, two dagger boards and two hulls... An interesting side effect of having two propulsion engines is that the props are sized to WOT with both engines running and are thus "over propped" when only one motor is running. I think this is good since it means that I can run one engine slowly and still have it loaded up when motoring through a calm. I don't have a pyrometer on the engines and they are too small for commercially available flow meters so I can't really claim to know if the theory really works, but I run on the assumption that it does... Anyway, it might be fun to explore the differences in installed cost of twins vs a single and bow thruster. I think it would be easier to get home on one twin than on one bow thruster :). Another possibility would be to put in a continuous duty drop down style bow thruster on an "Z" drive. Your genset could then run that as a "get me into the dock now that I've sailed home" engine. -- Tom. |
Diesel electric
The 60' LWL motor yacht of our design launched last summer has a
conventional 200 HP 6-cyl diesel (it's a purely displacement boat and doesn't need 200 HP except in emergencies ). If I were starting on it today I'd certainly take a hard look at the Siemens ELFA boxes with the idea of installing 2 smaller engines and using only one of them most of the time. That way the engine(s) would operate at higher load and be happier. Dunno why you'd want to do that in a sailboat, though. Cheers, Micael Porter "Marc" wrote: I am building a 60 foot aluminum sailyacht and considering using diesel electric propulsion with 2 identical diesel enigins of 70 - 100 hp. The builder is not very experienced in ths field so I am doing some fieldwork myself . Anyone with experience in diesel eletric solutions in this size for sailing yachts? Cheers. Marc -- Posted via a free Usenet account from http://www.teranews.com |
Diesel electric
On Wed, 01 Aug 2007 21:00:52 -0400, Wayne.B
wrote: On Wed, 1 Aug 2007 16:44:41 +0200, "Marc" wrote: Roger & Bruce; thanks for your reaction. Pioneering is nice.. but not at any price ;-) Not my main reason for looking into this... My main objectives are : - having a backup engine with which she should at least run 4 kn without having the need for double propellors (too much drag it's a fast sailing yacht nog an moto sailor ;-) - not needing a seperate generator by using one of the main engines as a generator - less noise / vibration? Consider putting a folding or feathering prop on the "wing" engine to minimize drag. Mount two large alternators on each engine (200+amps), and use them to drive a large battery bank and redundant inverters. That will be much cheaper to build and service than a diesel electric system, and will give you full backup for everything. Many long range cruising trawlers are being built that way. You are talking about a 60 ft. sail boat. right? Generally sail boats have auxiliary engines for those times that the wind doesn't blow. There are also motor-sailers with somewhat bigger engines but they really don;t go much faster. I'm assuming that you will have a modern fin keel, broad beam, shallow hull depth, type of boat with minimum skin friction. I did a really quick calculation, assuming 20,000 lbs. displacement and came up with 45 shaft H.P., Shaft RPM of 1100 and a speed of about hull speed. Now, that is probably a bit underpowered as you will be going "up hill" sometimes but say you add another 25 - 30% and you still aren't talking about a very big engine. You've already decided on a sail boat so you have one source of power and a secondary, the auxiliary diesel. Now do a little research. Go down to the commercial docks and see how many commercial boats, guys that spend their whole lives on the water, have more then one source of moving the boat. The world's fishing fleet is probably 99% single diesel engine powered and if you've ever been on the Grand Banks in the winter time that alone should convince you that a second engine is not really vital to life and happiness. Lastly, if you are like most owners of 60 ft. bespoken yachts you are not in the first blush of youthfulness so either you have a crew or a really strong wife or you are going to need powered winches. So you have to figure on a gen-set that runs much of the time, if only to operate the autopilot. So there you go. A sixty ft. mast and enough dacron to build a circus tent, a 75-100 H.P. auxiliary engine and a generator set. And round the world you go =:-) Bruce in Bangkok (brucepaigeATgmailDOTcom) |
Diesel electric
|
Diesel electric
On Aug 1, 7:15 am, "Marc" wrote:
I am building a 60 foot aluminum sailyacht and considering using diesel electric propulsion with 2 identical diesel enigins of 70 - 100 hp. The builder is not very experienced in ths field so I am doing some fieldwork myself . Anyone with experience in diesel eletric solutions in this size for sailing yachts? Cheers. Marc http://www.avanteyachts.com/joomla/i...at_port792.jpg Joe |
Diesel electric
On Aug 1, 5:15 am, "Marc" wrote:
I am building a 60 foot aluminum sailyacht and considering using diesel electric propulsion Marc Got to agree with Roger Long. On the other hand ya could go down to your local rail yard and find the guy who works on locmotives. Think.............. EMD Electric Motor Division Bob |
Diesel electric
On Aug 1, 7:36 am, "Roger Long" wrote:
I've gone around the diesel electric question on a few research vessels where it is a good solution. It is going to be quite expensive. It makes most sense when the loads while the boat is not moving are a significant percentage of propulsion loads. This doesn't fit the ususal cruiser profile (except maybe for Skip and Lydia:) You had better have a builder who really understands it. There are going to be some complex boxes and equipment in between the generators and the props. Keeping them cool and dry will be a challange. The wiring will be unlike anything most builders have seen. It's going to take up a lot more space than a conventional propulsion plant. There will be some effeciency losses so you will need to carry more fuel on a boat that already is devoting extra space and weight to this enthusiasm. When you have problems with it and pull into Pango Nowhere, it's going to be amusing watching the locals trying to figure out how to fix it. I love diesel electric but it would not have crossed my mind to try it in a 60 foot sailboat. If having a DE sailboat is a goal in itself because you like to tinker and want to be a pioneer, cool. If you just want to sail and cruise, I would forget it. You can use that space, weight, money, and research effort much more usefully. -- Roger Long Fair call Roger . Only time I've seen it pulled off are for very big anchor handling vessels and Mississippi river pushboats. With that type of work with very very heavy loads it saves a ton of money on reduction gears, and engine maintaince. The constant RPM is a charm, and with all three gensets (EMD's) going they had the torque to snap off anything. He could save space and go small scale with some of the new Azipod propulsors. I seem to recall someone's making a yacht size Azipod, it would make racing around the bouys a blast. Joe |
Diesel electric
On Thu, 02 Aug 2007 10:40:27 -0400, Wayne.B
wrote: On Thu, 02 Aug 2007 18:16:04 +0700, wrote: So there you go. A sixty ft. mast and enough dacron to build a circus tent, a 75-100 H.P. auxiliary engine and a generator set. My point was that if you put a couple of *big* alternators on each engine you don't really need a generator, and what would have been the generator engine can now drive an off center shaft with a folding prop. That way you can have it all more or less. If you want super reliability, it is also necessary to have seperate fuel tanks for each engine with appropriate transfer and filtration plumbing, along with seperate batteries, etc. Not to start a war, but I still don;t understand why you want sails and two motors... Your engine sizing estimates do not take windage into account which can be considerable on a 60 footer trying to motor into a 30 or 40 kt headwind. And yes, sometimes it is necessary. I also take some issue with your comparison to single engined commercial boats. Those boats almost always have spacious engine rooms with room to work, lots of essential tools and spares, and someone aboard who knows how to get the job done. That is not the case with most 60 foot sailboats that I've seen. Well, I did admit that it was a quick and dirty calculation. But, if you have 30 - 40 Kts of wind you've got super sailing weather for a 60 ft. boat. You are right about engine rooms but I'm not so sure about people who know how to get the work done. Example: The average Thai fishing boat, say 50 - 60 ft. that makes voyages to Indonesia or Bangladesh to poach fish usually had a Thai Captain, maybe a Thai 1st Mate, and the rest of the crew are Burmese who are hired for probably less then $100 a month. I'm not so sure about their expertise. But, you have hit the nail on the head -- there are vast quantities of people driving around in boats that don't know a thing about the hardware. The neighbor boat to me had some people working on it, I asked the Owner what was doing and he told me he was having the engine oil and filters changed. A nice guy but didn't know where the oil filter was. Bruce in Bangkok (brucepaigeATgmailDOTcom) |
Diesel electric
|
Diesel electric
In article om,
Joe wrote: On Aug 1, 7:36 am, "Roger Long" wrote: I've gone around the diesel electric question on a few research vessels where it is a good solution. /snip/ I love diesel electric but it would not have crossed my mind to try it in a 60 foot sailboat. If having a DE sailboat is a goal in itself because you like to tinker and want to be a pioneer, cool. If you just want to sail and cruise, I would forget it. You can use that space, weight, money, and research effort much more usefully. Fair call Roger . Only time I've seen it pulled off are for very big anchor handling vessels and Mississippi river pushboats. With that DE propulsion seems to be getting moderately popular in new big catarmarans: the new Lagoon 420 uses a DE drive system, as do boats from Africat and Broadblue (the last-named uses the Ossa powerLite drive, based around the bady diesel from the Smart Car). In a monohull you're more limited in the ability to keep the generator at upper deck level, but in a 60' boat it ought to be do-able. A quick google on "diesel electric catamaran" turned up some poterntially helpful links. The Ossa system is described at: http://www.ossapowerlite.com/ -- Andy Breen, not speaking on behalf of the University of Wales "The internet, that wonderful tool for bringing us into contact with things that make us wish we could scrub our brains out with dental floss.." (Charlie Stross) |
Diesel electric
On Thu, 02 Aug 2007 23:49:12 -0400, Wayne.B
wrote: On Fri, 03 Aug 2007 08:45:38 +0700, wrote: Not to start a war, but I still don;t understand why you want sails and two motors... Well, they weren't my specs but I can understand the motivation. Let's start with the premise that a boat needs aux propulsion for various good reasons - entering harbors; short handed sailing with one or two people; lack of wind; wind in wrong direction; schedules to meet; broken furling gear; etc. These things all occur in real life as opposed to the "ideal". Let's additionally assume that a modern 60 foot boat also needs a generator to provide power for air conditioning, refrigeration, freezers, emergency battery charging, entertainment equipment, microwave oven, etc. So that's one way of getting to two engines that most folks on a well appointed 60 footer would not argue with. I guess that my point was that since we are talking about a 60 ft. displacement boat two engines aren't going to push it much faster then hull speed anyway so why two. Now that you've got two engines, how do you provide backup functionality if one breaks down? Hence my suggestion for heavy duty alternators on each allowing them to do double duty as power generators and back each other up in that role. In addition, I would also equip the second engine with an off center shaft and folding/feathering prop which allows it to serve as back up to the primary aux engine. Modern boats with modern conveniences have a lot of complexity, and the more redundancy the better in my experience. My own cruising boat these days is a trawler with all the back up systems I can manage - twin engines, twin generators, multiple battery banks, and multiple charging sources. The idea being to eliminate as many single points of failure as possible, be able to cruise in the boondocks with confidence, and to keep the boat going until we can reach a suitable repair facility. So far the strategy has paid off. In three years of ownership and 10,000 miles of cruising we have experienced two unscheduled shutdowns of main engines and numerous generator issues, none of which were show stoppers because of the backup systems on the boat. I can't fault your thinking. We were coming bringing a boat back from Singapore to Phuket last September, coming out of Langkawi Harbor and were on the Fly Bridge. My wife commented, rather calmly I thought, "The boat is full of smoke." I looked down the hatch and IT WAS! Haven't moved so fast in years and trying to remember where the closest fire extinguisher is.... Got the engine hatch open and no flames but a lot of smoke. Shut down both engines and jumped down in the engine room (compartment). No fire that I can see but the bilges are pretty full. It turned out that the S.B. exhaust elbow broke letting exhaust and raw water into the boat. I got everything closed and pumped out and we motored sedately back to our original anchorage on one engine. Redundancy IS good. Bruce in Bangkok (brucepaigeATgmailDOTcom) |
Diesel electric
"Michael Porter" wrote in message ... The 60' LWL motor yacht of our design launched last summer has a conventional 200 HP 6-cyl diesel (it's a purely displacement boat and doesn't need 200 HP except in emergencies ). THANKS! We still have to calculate but expect to end up with 150 to 170 hp. The yachts displacement should be around 22 to 24 tons metric. If I were starting on it today I'd certainly take a hard look at the Siemens ELFA boxes with GREAT will do for sure!! the idea of installing 2 smaller engines and using only one of them most of the time. That way the engine(s) would operate at higher load and be happier. Right! Planning on looking into a solution with 2 diesel engines and 2 propellors too. Curieous about the drag (speed loss) due to a second propellor. And of course it is a saling boat and it is only an auxilary engine BUT after spending some time in the Med I have the experience that if you have any type of schedule (even allowing ample spare time) you just need to motor from time to time. Cheers Marc |
Diesel electric
Looks like a great article. THX!
Marc wrote in message oups.com... On Aug 1, 2:15 am, "Marc" wrote: ... Anyone with experience in diesel eletric solutions in this size for sailing yachts? ... You might want to read the two part series in PBB (http://www.proboat- digital.com/proboat/20070607/) on hybrid propulsion. They cover engine sizing and a good deal more. It sounds like you've already decided that you want to go with electric and I don't want to dissuade you However, if you are just after fuel economy and are looking at a true diesel electric system rather than an electric boat with backup generation a variable pitch propeller will do a better job than an electric transmission for a good deal less money. -- Tom. |
Diesel electric
wrote in message ... I'm assuming that you will have a modern fin keel, broad beam, shallow hull depth, type of boat with minimum skin friction. I did a really quick calculation, assuming 20,000 lbs. displacement and came up with 45 shaft H.P., Shaft RPM of 1100 and a speed of about hull speed. Sorry... I'm not into these calculations. Displacement is 22 to 24 ton metric Lastly, if you are like most owners of 60 ft. bespoken yachts you are not in the first blush of youthfulness so either you have a crew or a Sorry I still am at 39 ;-) No crew for me... expect for my wife and / or a friend (or two) So there you go. A sixty ft. mast and enough dacron to build a circus Expect to be using a 24 to 26 meter mast.. so a little more. BUT still conviced I will be motoring from time to time anf not only for harbouw manoevres. Cheers Marc |
Diesel electric
On Aug 3, 5:48 am, "Marc" wrote:
Looks like a great article. THX! You are welcome. I notice the the link I posted is broken in my browser so if anyone else is interested they might want to go to http://www.proboat-digital.com and look for the june/july issue. Professional Boat Builder is an usually good rag. There were a couple of points that I thought were interesting about the article: 1) despite the fact that Calder is somewhat famous and well connected he obviously had trouble shaking real numbers out of the d/e folks and in the end resorted to a good deal of hand waving and extrapolation. We mortals may have trouble getting enough disinterested information on small d/e setups to do any valid engineering. 2) thermodynamics version 3.0 for the new digital age (tm) as brought to you by Solomon Technologies is still pretty much the same old stuff we learned back in the steam age. You still have to balance the equations and there ain't no such thing as a free lunch. 3) the inefficiencies in small boat propulsion systems are primarily the result of propeller inefficiency at slow rpms which result in lightly loaded engines which are inefficient producing a vicious circle. The logical place to break the circle is at the propeller. Attempts to break the circle at the transmission are very likely become exercises in moving the problem around rather than fixing it. -- Tom. |
Diesel electric
Printing the article seems impossible. Understandable.. any idea how I can
get a digital or print copy of the article? wrote in message oups.com... On Aug 3, 5:48 am, "Marc" wrote: Looks like a great article. THX! You are welcome. I notice the the link I posted is broken in my browser so if anyone else is interested they might want to go to http://www.proboat-digital.com and look for the june/july issue. Professional Boat Builder is an usually good rag. There were a couple of points that I thought were interesting about the article: 1) despite the fact that Calder is somewhat famous and well connected he obviously had trouble shaking real numbers out of the d/e folks and in the end resorted to a good deal of hand waving and extrapolation. We mortals may have trouble getting enough disinterested information on small d/e setups to do any valid engineering. 2) thermodynamics version 3.0 for the new digital age (tm) as brought to you by Solomon Technologies is still pretty much the same old stuff we learned back in the steam age. You still have to balance the equations and there ain't no such thing as a free lunch. 3) the inefficiencies in small boat propulsion systems are primarily the result of propeller inefficiency at slow rpms which result in lightly loaded engines which are inefficient producing a vicious circle. The logical place to break the circle is at the propeller. Attempts to break the circle at the transmission are very likely become exercises in moving the problem around rather than fixing it. -- Tom. |
Diesel electric
On Aug 3, 12:02 pm, "Marc" wrote:
Printing the article seems impossible. Understandable.. any idea how I can get a digital or print copy of the article? ... I'll bet PBB would sell you one ? subject=Professional BoatBuilder). You could save each page image (right click save image as) to someplace (eg. your desktop) and then print them individually. You might also be able to save the web page for off line viewing with a grabber (eg. spiderZilla)... Good luck, -- Tom. |
Diesel electric
On Aug 3, 9:43 pm, Evan Gatehouse
wrote: .... On a cat a SIMPLE D/E system would almost seem to work rationally (like Glacier Bay "do away with the batteries philosophy"), but I LIKE the redundancy of twin engines instead of a more complex genset/motor/controller system .... One of the joys of yachting for me is that it is supremely and unapologetically irrational :). I certainly don't want to discourage folks from finding beauty in systems and practices even when they are hard to rationalize. Like you, I like the redundancy of twins. I can attest that it has been comforting to know that when one engine eats the bearings on its salt water pump and spits them all over the engine room or drops its propeller into the depths that my boat still has propulsion. The Ossa (Glacier Bay) system looks interesting and could drive twin props with multiple gensets so it might be pretty durable. I have read their tech paper (http://www.ossapowerlite.com/tech_library/ fuel_efficiency/fuel_efficiency.htm). If you take them at their word the system might well use less fuel in typical service than an old mechanically governed over sized diesel system with a fixed prop that was significantly undersized for its average service would... I can imagine a scenario where it would be an easy system to rationalize (a large yacht with big hotel needs and big fuel bills). On the other hand, I was a little taken aback by the argument that claimed a long commercial history of d/e propulsion because of its inherent efficiency and also claimed that efficiencies of their system were the result of very recent advances in technology and their proprietary systems. I suppose you just have to take them at their word for the second bit as their tech paper has no sources or verifiable numbers on efficiencies. My understanding of the history of marine diesel electric is different from theirs. I know that for the past hundred years or so d/e systems have been used by navies and commercially for a number of very good reasons. Those reasons include the ability to run under water (submarines), to operate quietly (ASW) , to provide quick changes in power over a wide range (tugs), to provide for multiple, remote or vectorable thrusters (platforms), to provide for big hotel needs (cruise ships) and so on. However, I don't think it is historically correct to put fuel efficiency, per se, in that list. This is certainly one of those cases where I would love to be proven wrong. The siren call of a relatively cheap technological fix for the woes of small boat propulsion and power generation is strong. But, caveat emptor. -- Tom. |
Diesel electric
Some interesting reading on Diesel Electric:
Fischer Panda: http://www.solarnavigator.net/fische...l_electric.htm Nordhavn: http://www.nordhavn.com/constr_con/diesel_electric.php4 FAST: http://www.feys.org/System/our_system.htm Cruising World: http://www.cruisingworld.com/article...ID=396&catID=0 "Marc" wrote in message ... I am building a 60 foot aluminum sailyacht and considering using diesel electric propulsion with 2 identical diesel enigins of 70 - 100 hp. The builder is not very experienced in ths field so I am doing some fieldwork myself . Anyone with experience in diesel eletric solutions in this size for sailing yachts? Cheers. Marc |
Diesel electric
On Sat, 04 Aug 2007 07:43:54 GMT, Evan Gatehouse
wrote: I LIKE the redundancy of twin engines instead of a more complex genset/motor/controller system Absolutely, redundant is good, simple is good, unnecessary complexity is not. Trains and large ships have good engineering reasons for D/E, small cruising boats do not. As an FYI, 60 ft *is* small. |
Diesel electric
On Sat, 04 Aug 2007 17:40:05 -0700, "
wrote: The siren call of a relatively cheap technological fix for the woes of small boat propulsion and power generation is strong. But, caveat emptor. On a small boat it makes a lot more sense to use technology by installing a couple of large alternators, a good sized battery bank, and a large sine wave inverter. That's what we've done on our boat and it has greatly reduced generator run time and improved fuel economy. |
Diesel electric
On Fri, 3 Aug 2007 17:39:13 +0200, "Marc" wrote:
I have the experience that if you have any type of schedule (even allowing ample spare time) you just need to motor from time to time. Absolutely right. You can reduce prop drag to almost zero by using a folding or feathering prop. http://www.gori-propeller.dk/ http://www.martec-props.com/ http://www.spw-gmbh.de/eng/index.html http://www.flexofold.dk/ http://www.autoprop.com/ |
Diesel electric
THANKS!
"Harbin Osteen" wrote in message ... Some interesting reading on Diesel Electric: Fischer Panda: http://www.solarnavigator.net/fische...l_electric.htm Nordhavn: http://www.nordhavn.com/constr_con/diesel_electric.php4 FAST: http://www.feys.org/System/our_system.htm Cruising World: http://www.cruisingworld.com/article...ID=396&catID=0 "Marc" wrote in message ... I am building a 60 foot aluminum sailyacht and considering using diesel electric propulsion with 2 identical diesel enigins of 70 - 100 hp. The builder is not very experienced in ths field so I am doing some fieldwork myself . Anyone with experience in diesel eletric solutions in this size for sailing yachts? Cheers. Marc |
| All times are GMT +1. The time now is 10:26 PM. |
Powered by vBulletin® Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Copyright ©2004 - 2014 BoatBanter.com