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The ultimate saildrive- Retractable Voidth-Schneider
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
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? -- Jim Woodward www.mvFintry.com .. "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
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 |
The ultimate saildrive- Retractable Voidth-Schneider
"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
Don't sell us Southern good ol' boys or our BBQ short. The CSS Alabama
had a retractable propeller for better efficiency under sail. (Beats the heck out of a feathering prop.) It was disconnected from the shaft and hoisted under the fantail on a rail assembly. It could be lowered and pinned to the shaft rather quickly. The Alabama had several other inovations. It could change its rig at will to disguise itself and had a retractable stack so that it could look like a pure sailing vessel. The Alabama was built in England but I think James Bulloch, the Confederate representative, got credit for the ideas. At least he does around heah. :-) BTW, Gov. Dean, I don't have a Confederate flag on my Japaneese pickup but I do understand what you are trying to say. :-) BF wrote: 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) -- 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
You imply that I'm a yankee and I take offense.
Let it be known that my great grand daddy (several times back) was one of Houston's heroes at San Jacinto and I do know good BBQ. Not sure which should cause more offense. Back to the Alabama: HOW was it disconnected and reattached. The rail thing makes sense but the attachment had to be under water, doesn't it? Rather quickly is somewhat subjective, I think. Since Semmes mentions it several times, it implies that it wasn't an easy task like shoveling several hundred pounds of coal to raise steam. Granted it was new technology but that doesn't seem to be Semmes focus. I don't recall him mentioning the "why" of the removable propeller. Ray "Glenn Ashmore" wrote in message news:fvUqb.10776$62.3537@lakeread04... Don't sell us Southern good ol' boys or our BBQ short. The CSS Alabama had a retractable propeller for better efficiency under sail. (Beats the heck out of a feathering prop.) It was disconnected from the shaft and hoisted under the fantail on a rail assembly. It could be lowered and pinned to the shaft rather quickly. The Alabama had several other inovations. It could change its rig at will to disguise itself and had a retractable stack so that it could look like a pure sailing vessel. The Alabama was built in England but I think James Bulloch, the Confederate representative, got credit for the ideas. At least he does around heah. :-) BTW, Gov. Dean, I don't have a Confederate flag on my Japaneese pickup but I do understand what you are trying to say. :-) BF wrote: 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) -- 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
"Glenn Ashmore" wrote in message news:fvUqb.10776$62.3537@lakeread04... Don't sell us Southern good ol' boys or our BBQ short. The CSS Alabama had a retractable propeller for better efficiency under sail. (Beats the heck out of a feathering prop.) It was disconnected from the shaft and hoisted under the fantail on a rail assembly. It could be lowered and pinned to the shaft rather quickly. The HMS Warrior which is in Portsmouth had the same kind of system .When all sail was called they would unpin the screw from the shaft and crank it up out of the water on a special railway. I have read someplace that it was a bit of a pain to do.. Neil Currey Building a Dix design Pratique 35 |
The ultimate saildrive- Retractable Voidth-Schneider
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
My sincere apologies to a fellow Southerner. :-)
All I really know about the CSS Alabama was from a Revell kit I built back in the late '50s. Think I paid $.89 for it and saw one go for over $600 on ebay recently. That particular model had a reputation for being pretty accurate representation The prop had a sleeve that fit through the stern and over the shaft. It was probably pinned from the inside but I would guess that the real thing was a bit harder to fit. OTOH, as you say "quickly" is a relative term. At the time 10 knots was considered a high performance boat and 60º to the wind was close hauled so they probably had some time before the pursuer got within cannon range. I would imagine that Semmes as captain of the Alabama was more concerend with the tactics of naval warfare than the intricacies of technology. The Alabama was not so much a hybred as a hermorphrodyte. It was both a sailing and a steaming vessel. She was built as a commerce raider not a ship of the line. Had she been intended for toe to toe battles she would have been one or the other. Not both. Bringing the prop out of the water greatly reduced drag under sail but was an additional hassle for the skipper to deal with. BF wrote: You imply that I'm a yankee and I take offense. Let it be known that my great grand daddy (several times back) was one of Houston's heroes at San Jacinto and I do know good BBQ. Not sure which should cause more offense. Back to the Alabama: HOW was it disconnected and reattached. The rail thing makes sense but the attachment had to be under water, doesn't it? Rather quickly is somewhat subjective, I think. Since Semmes mentions it several times, it implies that it wasn't an easy task like shoveling several hundred pounds of coal to raise steam. Granted it was new technology but that doesn't seem to be Semmes focus. I don't recall him mentioning the "why" of the removable propeller. Ray "Glenn Ashmore" wrote in message news:fvUqb.10776$62.3537@lakeread04... Don't sell us Southern good ol' boys or our BBQ short. The CSS Alabama had a retractable propeller for better efficiency under sail. (Beats the heck out of a feathering prop.) It was disconnected from the shaft and hoisted under the fantail on a rail assembly. It could be lowered and pinned to the shaft rather quickly. The Alabama had several other inovations. It could change its rig at will to disguise itself and had a retractable stack so that it could look like a pure sailing vessel. The Alabama was built in England but I think James Bulloch, the Confederate representative, got credit for the ideas. At least he does around heah. :-) BTW, Gov. Dean, I don't have a Confederate flag on my Japaneese pickup but I do understand what you are trying to say. :-) BF wrote: 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) -- 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 -- 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
Glenn Ashmore wrote:
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/ Boy, that thing takes up a BUNCH of height (27+")! (I think I have room enough under the cockpit, though.) And if it can only drive a 32' boat to 5 knots without overheating (if I interpret correctly, English is not their first language), there's something seriously wrong right now. We do 5 knots using only .2 gph, which calculates to somewhat under 7 HP. And 380v AC onboard isn't my favorite thing. In the power industry, anything over 220 required pretty special precautions. Still, when they get things smoothed out, it could be a very interesting system. -- Jere Lull Xan-a-Deux ('73 Tanzer 28 #4 out of Tolchester, MD) Xan's Pages: http://members.dca.net/jerelull/X-Main.html Our BVI FAQs (290+ pics) http://homepage.mac.com/jerelull/BVI/ |
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 |
The ultimate saildrive- Retractable Voidth-Schneider
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The ultimate saildrive- Retractable Voidth-Schneider
On Sun, 9 Nov 2003 00:35:06 -0800, "Evan Gatehouse"
wrote: "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!! I have long thought that a vertical saildrive could be made in a retractable form. A non-folding prop could be keyed so it could be gotten vertical from inside, and the whole thing lifted through a tubular well. A diisk on the bottom could retract into th ewell far enough to allow a faired surface to fit the particular hull to be added with microballoons and epoxy. It could be made in azimuthing form, but that would add a lot to the price. It couldn't be ducted without makig the well much larger, but for a sailboat efficency isn't as important as getting out of the way. I believe it would come down to which is cheaper, if they both take up as much room inside. We don't really know if he has gotten around the VS patents, do we? They may just not have noticed him, or don't feel threatened. Rodney Myrvaagnes NYC Let's Put the XXX back in Xmas |
The ultimate saildrive- Retractable Voidth-Schneider
I asked the same question, as we expect to have a fairly high capacity fire
pump aboard. Turns out that aside from Glenn's and Brian's explanation (which are correct, you want low speed, very high volume for a thruster and a fire pump does the reverse) that a "standard" hydraulic bow thruster is off the shelf and relatively cheap (to the extent that anything in our world is cheap), particularly since we have the prime mover and want hydraulics aboard anyway for windlass, docking capstans, crane, and get home chain drive (that's a bonus which was cheap). Also, one of the advantages of the bow thruster is that it eliminates all the single point of failure issues in the steering system -- the bow thruster is proportional electric controlled, and can be run, if necessary from the autopilot, continuously, at sea. That eliminates the tiller head, tiller arm, two heavy blocks and tackle, and the two hearties to heave on them if the steering failed. And, of course, even that doesn't save you if the rudder itself breaks or jams. It is possible to buy venturi jet thrusters that might work from the fire pump, but they won't solve the steering issue, and they are generally for larger vessels. -- Jim Woodward www.mvFintry.com .. "Ron Thornton" wrote in message ... 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 |
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