The ultimate saildrive- Retractable Voidth-Schneider
On Fri, 07 Nov 2003 11:14:41 -0500, Glenn Ashmore
wrote: http://www.spw-gmbh.de/en/hb/ Looks great, but I know I can't afford it. One in each end, retractable of course, would be ideal. The Staten Island ferry that crashed with loss of life last week has Voith-Schneider drives. It can dock in the most severe cross currents with no fuss at all. The earlier boats bounce their way in on the constantly-replaced pilings. The drives had nothing to do with the crash, I am sure. Rodney Myrvaagnes NYC Let's Put the XXX back in Xmas |
The ultimate saildrive- Retractable Voidth-Schneider
Why not settle for a high performance sailboat that has it all. Now If I
had $2,000,000.00 I'd buy it in a heart beat. http://www.distancia.de/ Jack "Glenn Ashmore" wrote in message news:JDPqb.10756$62.1728@lakeread04... I don't think it is quite ready for prime time yet but here is an interesting idea. A small retractable Voith-Schneider drive like those used on modern tugs. Retracts flat into the hull and when extended will deliver thrust in any direction. http://www.spw-gmbh.de/en/hb/ -- Glenn Ashmore I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com |
The ultimate saildrive- Retractable Voidth-Schneider
Why not settle for a high performance sailboat that has it all. Now If I
had $2,000,000.00 I'd buy it in a heart beat. http://www.distancia.de/ Jack "Glenn Ashmore" wrote in message news:JDPqb.10756$62.1728@lakeread04... I don't think it is quite ready for prime time yet but here is an interesting idea. A small retractable Voith-Schneider drive like those used on modern tugs. Retracts flat into the hull and when extended will deliver thrust in any direction. http://www.spw-gmbh.de/en/hb/ -- Glenn Ashmore I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com |
The ultimate saildrive- Retractable Voidth-Schneider
10500 hours of brain-work, and they haven`t figured that they could have all
that, with less complication at a fraction of the price-----------with a multihull! ;-))) Bob Jack Rye wrote: Why not settle for a high performance sailboat that has it all. Now If I had $2,000,000.00 I'd buy it in a heart beat. http://www.distancia.de/ Jack "Glenn Ashmore" wrote in message news:JDPqb.10756$62.1728@lakeread04... I don't think it is quite ready for prime time yet but here is an |
The ultimate saildrive- Retractable Voidth-Schneider
Thanks Jim,
That explanation makes a bit of sense, need to see the pictures to understand better though. I've ordered the Corlett book from my library, looking forward to reading it. Ray "Jim Woodward" jameslwoodward at attbi dot com wrote in message ... I don't know Alabama at all, but perhaps I can shed some light: Great Britain (first iron screw steamship, launched in Bristol, 1843, now back in Bristol, see http://www.ss-great-britain.com/) was refitted in 1857 for the Australian trade, which required that she sail well. To accomplish this she had a lifting screw. Perhaps Glenn should consider this for Rutu instead of a MaxProp. Take a propeller with a stub shaft, fore and aft. Put bearings on both ends and a square on the forward end. Hang the bearings on a frame that can be lifted straight up in channels. In order to raise the propeller for sailing, you: 1) remove a short section of shaft inside the vessel. 2) slide the tailshaft forward 3) raise the frame with tackle. To operate under power, it's the reverse, except that when sliding the tailshaft aft, you have to engage the square on the stub shaft in a hollow on the end of the tailshaft. That's how it's described in the text of The Story of Brunel's SS Great Britain, Ewan Corlett, Conway Maritime, 1990. However, a drawing by Basil Greenhill in the same book shows a dog clutch rather than the square. The Great Britain museum is a wonderful view into the first large ocean going screw vessel -- it's a great story, as she was rescued from the Falkland Islands where she rusted from 1886 until 1970. -- Jim Woodward www.mvFintry.com . "BF" wrote in message ... "Glenn Ashmore" wrote in message news:ghSqb.10765$62.10532@lakeread04... Jim Woodward wrote: Interesting. It's amazing to watch a vessel equipped with a VS drive -- they really can go in any direction with full thrust. I'd worry about efficiency -- the end plate is a larger problem in a small one than in a large one, a VS is not as efficient as a propeller, and you'd probably have to go diesel electric or diesel hydraulic in order to retract it, and both are lossy. Do you know what it costs? That's why I said it was not ready for prime time. It would be fun to dock though. Especially with a retractable bow thruster. A pas de bouree up to the end of the pier and with a quick piorette and a short petit jete you are into your slip. (Tutus and leotards optional) The web site said to contact about prices and if it were objectionable they would let you know when the production gets above 10 in a batch. -- Glenn Ashmore I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com Changing the subject totally: Raphael Semmes, in his account of the CSS Alabama, mentions on several occasions of fitting the propeller (maybe he used the word screw, not sure) before making steam. Anyone have a clue what he meant. Did they actually remove the screw and shaft when sailing. If so, how, without stopping and sending divers down, which they obviously didn't do. Or did they simply disengage the screw from the drive shaft so it free wheeled, and then needed to reattach, perhaps lacking a clutching means? Or did the shaft pivot on a u-joint near the packing gland and could be pivoted so the screw was above the water line? Anyone know or have other ideas? Anyone else care? Ray (btw, I will definitely try Duke's in Ridgeway this Spring when in Charleston, hope a good thing isn't being spoiled here. Can you say Wreck) |
The ultimate saildrive- Retractable Voidth-Schneider
I'm glad you're not buying the book for just this -- the explanation is not
much more than what I said and the drawing says something different. The book is interesting in many different ways, but it's often frustrating, because of careless editing.... I saw a full size repro of the thing at Bristol, so I have an advantage. They've restored the actual ship to her original, fixed, propeller. -- Jim Woodward www.mvFintry.com .. "BF" wrote in message ... Thanks Jim, That explanation makes a bit of sense, need to see the pictures to understand better though. I've ordered the Corlett book from my library, looking forward to reading it. Ray "Jim Woodward" jameslwoodward at attbi dot com wrote in message ... I don't know Alabama at all, but perhaps I can shed some light: Great Britain (first iron screw steamship, launched in Bristol, 1843, now back in Bristol, see http://www.ss-great-britain.com/) was refitted in 1857 for the Australian trade, which required that she sail well. To accomplish this she had a lifting screw. Perhaps Glenn should consider this for Rutu instead of a MaxProp. Take a propeller with a stub shaft, fore and aft. Put bearings on both ends and a square on the forward end. Hang the bearings on a frame that can be lifted straight up in channels. In order to raise the propeller for sailing, you: 1) remove a short section of shaft inside the vessel. 2) slide the tailshaft forward 3) raise the frame with tackle. To operate under power, it's the reverse, except that when sliding the tailshaft aft, you have to engage the square on the stub shaft in a hollow on the end of the tailshaft. That's how it's described in the text of The Story of Brunel's SS Great Britain, Ewan Corlett, Conway Maritime, 1990. However, a drawing by Basil Greenhill in the same book shows a dog clutch rather than the square. The Great Britain museum is a wonderful view into the first large ocean going screw vessel -- it's a great story, as she was rescued from the Falkland Islands where she rusted from 1886 until 1970. -- Jim Woodward www.mvFintry.com . "BF" wrote in message ... "Glenn Ashmore" wrote in message news:ghSqb.10765$62.10532@lakeread04... Jim Woodward wrote: Interesting. It's amazing to watch a vessel equipped with a VS drive -- they really can go in any direction with full thrust. I'd worry about efficiency -- the end plate is a larger problem in a small one than in a large one, a VS is not as efficient as a propeller, and you'd probably have to go diesel electric or diesel hydraulic in order to retract it, and both are lossy. Do you know what it costs? That's why I said it was not ready for prime time. It would be fun to dock though. Especially with a retractable bow thruster. A pas de bouree up to the end of the pier and with a quick piorette and a short petit jete you are into your slip. (Tutus and leotards optional) The web site said to contact about prices and if it were objectionable they would let you know when the production gets above 10 in a batch. -- Glenn Ashmore I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com Changing the subject totally: Raphael Semmes, in his account of the CSS Alabama, mentions on several occasions of fitting the propeller (maybe he used the word screw, not sure) before making steam. Anyone have a clue what he meant. Did they actually remove the screw and shaft when sailing. If so, how, without stopping and sending divers down, which they obviously didn't do. Or did they simply disengage the screw from the drive shaft so it free wheeled, and then needed to reattach, perhaps lacking a clutching means? Or did the shaft pivot on a u-joint near the packing gland and could be pivoted so the screw was above the water line? Anyone know or have other ideas? Anyone else care? Ray (btw, I will definitely try Duke's in Ridgeway this Spring when in Charleston, hope a good thing isn't being spoiled here. Can you say Wreck) |
The ultimate saildrive- Retractable Voidth-Schneider
"Glenn Ashmore" wrote in message news:JDPqb.10756$62.1728@lakeread04... I don't think it is quite ready for prime time yet but here is an interesting idea. A small retractable Voith-Schneider drive like those used on modern tugs. Retracts flat into the hull and when extended will deliver thrust in any direction. http://www.spw-gmbh.de/en/hb/ Wow. I'm not a great fan of VS drives ('cause they have lower efficiency than ducted props) and they are hideously expensive. I'm surprised he has got around the VS patents! The new Volvo 70 rule allows for retractable propulsion systems - using a Volvo engine and shaft drive. Not sure how designers will make this work but it will be interesting to see if can trickle down to more mainstream designs. Now I want to sit down with a sketch pad and start thinking about this!! -- Evan Gatehouse you'll have to rewrite my email address to get to me ceilydh AT 3web dot net (fools the spammers) |
The ultimate saildrive- Retractable Voidth-Schneider
The basic VS invention was in 1928, so the base patent is long gone. While
VS may have built a patent forest around the base tree to prolong the life of its patent monopoly, this is probably far enough away from 5,000hp tugs that it's outside the forest. It does raise interesting possibilities. We are using hydraulics to drive a bow thruster and a get home chain drive to the screw, both 60hp. This might do it with one unit, and, if you put it in the middle of the boat, give you the dockside maneuverability that you get only with bow and stern thrusters. -- Jim Woodward www.mvFintry.com ... "Evan Gatehouse" wrote in message ... "Glenn Ashmore" wrote in message news:JDPqb.10756$62.1728@lakeread04... I don't think it is quite ready for prime time yet but here is an interesting idea. A small retractable Voith-Schneider drive like those used on modern tugs. Retracts flat into the hull and when extended will deliver thrust in any direction. http://www.spw-gmbh.de/en/hb/ Wow. I'm not a great fan of VS drives ('cause they have lower efficiency than ducted props) and they are hideously expensive. I'm surprised he has got around the VS patents! The new Volvo 70 rule allows for retractable propulsion systems - using a Volvo engine and shaft drive. Not sure how designers will make this work but it will be interesting to see if can trickle down to more mainstream designs. Now I want to sit down with a sketch pad and start thinking about this!! -- Evan Gatehouse you'll have to rewrite my email address to get to me ceilydh AT 3web dot net (fools the spammers) |
The ultimate saildrive- Retractable Voidth-Schneider
Jim Woodward's comment on hydraulic bow thrusters resurrected a thought
I had a long time ago and never followed up on. If you are going to pump a fluid, why not pump seawater to nozzles in the hull for thrust. Regards, Ron |
The ultimate saildrive- Retractable Voidth-Schneider
The basic reason is plumbing. Thrusters have to push a large volume of
water at fairly high speed and low pressure. That cause a lot of friction in pipes and consequent energy loss. Hydraulic systems push a relatively small amount of fluid at moderate speed and very high pressure. You can push it through smaller pipes over longer distances with less loss of energy. Much more efficient to push the water through a very short length of pipe and send the energy from the engine to the thruster with hydraulics. Ron Thornton wrote: Jim Woodward's comment on hydraulic bow thrusters resurrected a thought I had a long time ago and never followed up on. If you are going to pump a fluid, why not pump seawater to nozzles in the hull for thrust. Regards, Ron -- Glenn Ashmore I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com |
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